Solar water distillation module and flushing system for processing supersaturated brine wastewater

Abstract

An improved solar water distillation system which is effective for processing supersaturated brine commonly used in lithium mining comprising: a flushing system for controlling and substantially minimising cross-contamination of condensate stream(s) and salt deposits and / or treatment liquid, having a first flushing station integrated at a first location on a frame part of a solar still upstream from a treatment liquid separator, and including transfer means; wherein liquid from a liquid source is transferred to the first flushing station by the transfer means at a predetermined rate effective for dislodging and displacing solid salt deposits on the solar still.

Description

Solar water distillation module and flushing system for processing supersaturated brine wastewaterField of the Invention

[0001] The present invention relates to an improved solar water distillation system for treating wastewater from production sites such as mining and assisting repairing such sites by effectively converting waste effluent / water to provide a substantially freshwater resource and regenerative environmental water.

[0002] In particular, the present invention relates to an improved solar water distillation system which is effective for processing supersaturated brine commonly used in lithium mining.

[0003] The invention has been developed primarily for use in brine extraction mining for precious minerals and metals such as lithium, potassium, magnesium and other rare earths located within supersaturated brines. It can also be used in repair and rectification of commercial mining sites and the like to provide a source of potable water from a contaminated supply containing high concentrations of salts and will be described hereinafter with reference to this application. However, it will be appreciated that the invention is not limited to this particular field of use.Background of the Invention

[0004] Mining activities can cause huge environmental impacts, including pollution of water, disruption or destruction of wildlife habitats, deforestation, and other negative outcomes.

[0005] Brine extraction is a commonly used method to extract valuable minerals and metals from supersaturated brine using evaporation pond and / or tank and / or any liquid storage devices to reduce the water content of the brine to allow salts to crystallise. This process reduces the water tables of both the brine and surrounding freshwater aquifers and does not remedy the impact by producing clean water.

[0006] By way of example, Chile, Bolivia and Argentina have the largest combined lithium reserves in the world located in underground supersaturated brine. Lithium, a critical component of batteries that power electric vehicles, smart devices, mobilephones, laptops, renewable power plants and other technologies is helping transition away from fossil fuels. Lithium metal is extracted in a number of ways including through evaporation of brines found beneath salt flats in South America. Supersaturated brine containing water, lithium, sodium chloride, magnesium, potassium and other rare earths, is pumped into massive pond(s) and / or tank and / or any liquid storage devices where lithium is separated by an evaporation process, which can take many years. A significant drawback of this process is that it alters the water table and drains already scarce water resources, damages wetlands, and harms indigenous communities.

[0007] In countries such as Chile and neighbouring states, which boasts about 90% of the world’s lithium reserves, more effort needs to be placed on recovering potable water from this supersaturated brine. This is particularly the case in lithium mining and processing where ponds and / or tank and / or any liquid storage devices contain high concentrations of salts and other contaminants, to supplement dwindling water resources as a direct result of lithium and the like mining practices.

[0008] While a transition to lithium-ion batteries may signify a step towards sustainability, the problems associated with lithium mining and processing does not come without a cost to communities, ecology, environment, water resources. One problem faced by local indigenous communities in Chile for example, is that ponds and / or tank and / or any liquid storage devices which once contained potable water have been contaminated and now unusable and / or drained in the process of extracting the brine and in some cases the post processing of salts collected from evaporation ponds and / or tank and / or any liquid storage devices. Manufacturing one tonne of lithium carbonate, which is a precursor to compounds used in lithium-ion batteries, requires about 600,000 litres of water. The freshwater used for lithium production in Chile, Argentina and Bolivia comes from the desert subsoil and the brine pumped which is stored in surface ponds and / or tank and / or any liquid storage devices for evaporation to extract the lithium.

[0009] Other mining activities can also cause huge environmental impacts, including pollution of water, disruption or destruction of wildlife habitats, deforestation, and other negative outcomes.

[0010] Water is essential in most mining processes. When excavating coal, metal ores, or other minerals, rocks and minerals that contain sulphur may be exposedto water and oxygen. This water holds highly polluting substances such as lead, zinc, iron, mercury, and cadmium. Acid or wastewater is often stored in a Tailings Storage Facility (TSF), as it has the potential to poison downstream waters and destroy already fragile ecosystems.

[0011] Managing wastewater both on active and abandoned mine sites is now becoming more important than ever as tailings storage facilities reach their limits and pose ecological and environmental disasters waiting to happen if a heavy rain event occurs. It is estimated that there are over 32,000 tailings dams located across operational and abandoned mine sites throughout the world. Abandoned mines and 1 TSF failures can leach harmful toxins into the soil and water, polluting the environment and posing a risk to human health.

[0012] Recently, much effort has been expended on taking steps to remediate abandoned mines and make them safe.

[0013] An object of the present invention is to process supersaturated brine to provide a source of potable water using solar stills. Solar stills (or panels) are generally used to treat a source of contaminated water by producing water vapor from evaporation and collecting condensate formed on surfaces of the solar still separate from the contaminated water. A solar still generally comprises an inclined frame, an inlet end for ingress of a treatment liquid, an outlet end having a trough for collection of condensate, a support base on the inclined frame for dispersing the treatment liquid by gravity between the inlet and outlet ends, and a solar transmission enclosure about the frame, and spaced from the support base, on which condensate is formed on inner surfaces and displaced towards the condensate collection trough. Existing solar stills have not been able to process brine above 180,000 parts per million therefore unable to treat supersaturated brine.

[0014] Existing solar stills focus on trying to maximise evaporation of a treatment liquid to form a condensate, and to provide structures to prevent cross contamination of condensate with the treatment liquid. It is usual for solar stills to have a liquid treatment separator structure close to the outlet end of a solar still, which diverts excess treatment liquid out of the frame assembly separate from the collected condensate.

[0015] However, such solar stills do not function effectively if the treatment liquid contains a high concentration of salts because as the treatment liquid moves over the support base, salt crystallises with evaporation within the solar still and solid salt is deposited throughout the solar still, which (a) disrupt flows, (b) cause direct contact with the enclosure and cross contamination of condensate streams, (c) solid deposits can break away and end up with collected distilled water, and (d) cause blockages at or near the exit points for both the treatment liquid and / or the condensate water not allowing either to exit. This is clearly undesirable and defeats the purpose of obtaining a potable water source.

[0016] Such inefficiencies significantly impact the operation of a solar still and adversely affect condensate quantity and quality. To date there has been no practical way of producing potable water from supersaturated or highly concentrated brine ponds and / or tank and / or any liquid storage devices, which contain high concentrations of salts, using a solar still.

[0017] In view of the above, it is desirable to have an improved solar still module and / or a system that addresses and / or ameliorates at least one or more of the prior art deficiencies or at least provides a practical variation to avert from one of more of the prior art deficiencies.

[0018] It is to be understood that, if any prior art information is referred to herein, such reference does not constitute an admission that the information forms part of the common general knowledge in the art, in Australia or any other country.

[0019] Summary of Invention

[0020] In a first aspect of the present invention there is disclosed a flushing system for a solar still, wherein the solar still is adapted to separate an incoming liquid treatment stream from a collectable condensate, the flushing system comprising: a first flushing station adapted to be located upstream from a liquid treatment separator and spaced from a solar transmission inner surface on which condensate from the treatment liquid forms on evaporation, wherein the first flushing station is adapted for receiving a liquid source; a liquid delivery device interconnecting the first flushing station and the liquid source adapted to deliver liquid from the liquid source to the first flushing station; a controller for controlling the liquid delivery device between a flushing and non-flushing condition; wherein in a flushing condition the first flushing stationdelivers a flow of liquid to urge displacement of salt buildup on a lower end of a support base / tray towards the liquid treatment separator and to substantially minimise cross contamination with condensate and a condensate collection trough aft of the liquid treatment separator.

[0021] The present invention represents a significant advance over prior art solar still systems because it can process liquid treatment wastewater containing high concentrations of salt to obtain a potable water source by significantly minimizing the adverse effects of solid salt deposits and consequent cross-contamination. The delivery of liquid by the first flushing station dissolves and dislodges solid salt deposits in advance of a liquid treatment separator so that the liquid treatment separator captures the salt accumulated either in solid or dissolved form thereby mitigating cross contamination with collected condensate and condensate streams.

[0022] Preferably, in a flushing condition liquid from the liquid source is delivered to the first flushing station at a predetermined rate of delivery effective to displace solid salt deposits formed within the solar still by evaporation of the treatment liquid at or close to the eluting end to substantially minimise cross-contamination with condensate streams and collected condensate.

[0023] It is found that the first flushing station is capable of physically dislodging and moving salt deposits formed by evaporation at or close to the outlet end of a solar still. The ability of the first flushing station of the flushing system to move salt deposits is effective in substantially reducing contact between solid salt deposits and condensate stream (s) formed on surfaces of the enclosure and walls within a solar still, and helps direct salt deposits on the base support towards the liquid treatment separator which in turn allows egress of treatment liquid from the solar still separate from the condensate trough and collection.

[0024] The first flushing system thereby improves operation of a solar still to effectively obtain a source of potable water from a highly concentrated brine treatment liquid.

[0025] The first flushing station can include an infeed conduit adapted to fit within the solar still enclosure located towards a lower end portion of the solar still frame assembly for receiving a flow of liquid from an external liquid source, wherein the infeed conduit has a series of openings therein and wherein liquid is delivered tothe conduit at a predetermined rate effective by a delivery means to dislodge and move solid salt deposits on a transfer surface of the solar still. This substantially prevents accumulation of solid salt deposits at or close to a lower end of the solar still which can otherwise be in contact with condensate streams formed within a solar still or dislodged or displaced into a distilled water outlet.

[0026] The liquid delivery means can be a pump for transferring liquid from the liquid source. The liquid source can be the treatment liquid. The first flushing station can further include a controller for operating the pump. The controller can include a timer to control operational flushing.

[0027] The flushing system can further include a second flushing operation which comprises a flooding system adapted to flood the solar still at a predetermined time to dissolve salt deposits for removal. The flooding system can include a flow system for transferring liquid from a liquid source to the frame assembly via inlets in the frame assembly close to the top end thereof.

[0028] In operation of the flooding system, the solar still can be closed to allow flooding of the panel by the liquid and dissolution of salts, and reopening of the solar still for removal. The flooding system can operate on a timing mechanism that retains the flooding liquid within the solar still for a period of time to dissolve the salts. The liquid used in the flooding operation can be returned to the treatment liquid source. The flooding can be for a predetermined period of time and preferably undertaken overnight.

[0029] The flushing system can further include a third flushing station, integrated with the first flushing system and the flooding system with one or more flow controllers. The second flushing station being adapted for salt removal and cleaning of a salt separator element of a solar still assembly. A separator element can be used in a solar still assembly to receive and direct any excess treatment liquid from a support base to a second outlet in the bottom frame end of the solar still frame assembly separate from the condensate collection trough and condensate outlet.

[0030] The third flushing station can comprise at least one inlet on the frame assembly adapted to communicate with the liquid treatment separator; a source of distilled water or clean water; one or more conduits for connecting the source of distilled or clean water to the at least one inlet on the frame assembly; and a pump fordelivering distilled or clean water from the source of distilled or clean water, wherein the water is delivered to the liquid treatment separator to flush the separator to substantially remove salts from the separator via the separator outlet and subsequently through the second outlet in the bottom end of the frame.

[0031] In one aspect, the second flushing operation can include two inlets oppositely disposed on sides of the frame assembly for circulating the source of distilled or clean water through the separator to substantially remove trace salts by dissolution through the separator outlet.

[0032] In a related aspect of the present invention there is disclosed a method of processing a treatment liquid having high concentration salt or brine waste liquid for potable water, the method including: providing a solar still having: an inclined frame assembly and a frame enclosure, the frame assembly defining an inlet end for ingress of a treatment liquid and outlet end, the outlet end including: a condensate trough in communication with the frame enclosure for receiving and collecting condensate from condensate streams formed on internal surfaces of the frame enclosure, a first outlet in communication with the trough for collection of condensate from the trough, and a second outlet for egress of excess treatment liquid; a base support on the frame assembly including a base tray and material cover thereon defining a pathway for treatment liquid movement between the inlet and outlet ends of the frame assembly; a separator member located on the frame adjacent to and upstream of the condensate trough, the separator adapted to receive an end of the base support and thereby receive excess treatment liquid from the base support condensate collected in the trough, and the separator having an outlet adapted for fluid communication with the second outlet in the outlet end; providing a flushing system for controlling and substantially minimising cross-contamination of condensate stream(s) and salt deposits and / or treatment liquid comprising: a first flushing station located on the frame extending on or over the support tray upstream from the separation member and being connected to a liquid source, the first flushing station having one or more liquid spray outlets; the method further comprising transferring liquid from the liquid source to the first flushing station at a predetermined rate, wherein liquid spray is effective for dislodging and moving solid salt deposits on the support tray to the separator element.

[0033] The flushing system can further include a flooding system integrated with the first flushing station, wherein the frame assembly includes one or more inlets at atop end portion of the fame assembly, and conduits for interconnecting a liquid source to the one or more inlets; wherein outlets in the frame assembly are closed and a volume of liquid supplied to fill the solar still, wherein salt in the frame assembly is dissolve and the liquid removed from the solar still by reopening the outlets.

[0034] In a further related aspect of the present invention there is disclosed a solar still apparatus for obtaining potable water supply from treatment liquid having a high concentration or close to saturated levels of salt, comprising: an elongate planar frame assembly defining a perimeter having a top end and a bottom end and side portions, supported on an angle to allow a flow of treatment liquid from the top end towards the bottom end thereof; a disbursement header mounted to the planar frame assembly located close to the top end forming a reservoir for receiving and disbursement of treatment liquid therefrom; a support tray mounted to the planar frame assembly and having a planar upper surface and opposite facing surface, wherein the upper surface is heat conductive and adapted to reflect solar energy; a porous material sheet overlaying at least a part of the plastic sheet providing a material flow path, a top portion of the porous material sheet in fluid communication with the disbursement header and adapted to draw treatment liquid from the reservoir and distribute over an upper surface of the support tray; an upper solar energy transmission wall attached to the planar frame extending over and spaced from the upper surface of the elongate support tray; a separation member mounted at or close to the bottom end of and within the planar frame assembly extending between the side portions of the planar frame assembly, the separation member having an opening to receive an end of the support tray, and having an outlet rearward of the opening extending through a treatment liquid outlet in the bottom end of the frame assembly to allow egress of excess treatment liquid; a condensate receiving trough at or adjacent to the bottom end of the frame assembly aft of the support tray, wherein condensate on an inside surface of the plastic is collected in the condensate receiving trough; a condensate outlet in the bottom end of the frame assembly separate from the liquid treatment outlet for egress of condensate, the condensate outlet being in fluid communication with condensate in the condensate receiving trough; a flushing system including a first flushing station mounted to the frame on or over the support tray and upstream from the separation member, the first flushing station being interconnected to a fluid source; wherein in use, the first flushing station dispenses fluid from the fluid source upstream to theseparation member to substantially reduce buildup of salt deposit caused by evaporation, and thereby minimize contact with condensate streams and movement of solid salt deposit to the condensate receiving trough causing contamination of the distilled water therein.

[0035] The condensate collection trough can be formed by cooperation between the bottom end of the frame assembly and a rear portion of the separation member. The condensate trough is separate from the separation member, and the condensate trough is adapted to receive condensate formed on and transferred from the plastic sheet overlying the frame assembly. In one embodiment, the outlet of the separation member extends through the condensate trough to funnel excess treatment liquid out of the bottom end of the frame assembly without contacting the condensate. Prior art solar stills cannot prevent solid salt deposits from contacting condensate streams and entering the condensate collecting trough.

[0036] However, the flushing system of the present solar still module has been found to substantially prevent or eliminate buildup of solid salt deposits as the treatment liquid moves along the porous material sheet over the support tray. In prior art solar still modules, salt deposits form close to the end of the material flow path with liquid evaporation, and solid particulates can be displaced over the base tray receiving member and mix with condensate received in the condensate receiving trough.

[0037] The first flushing station can include a perforated conduit mounted between side frame portions of the planar frame, positioned upstream of the tray receiving member on a portion of the porous material sheet, the conduit being interconnected to a fluid pump and a fluid source external of the frame assembly.

[0038] In use of the first flushing station, fluid from an external source can be pumped through an inlet pipe on a side portion of the frame assembly into the perforated conduit and onto the material sheet. The fluid source can be treatment liquid. Preferably the perforated conduit is located adjacent to the lower end of the porous material sheet so that the porous sheet is disposed to flushing by the first flushing station at a rate sufficient to disperse any solid salt deposits into the separation member.

[0039] Preferably the fluid rate exiting the perforated conduit and timing can be controlled so that fluid can exit the conduit at a predetermined rate at timed intervalsonto the material sheet which is effective to liquify solid salt particulates formed or retain the treatment fluid at this point in a fluid condition. In this way, the flushing system reduce blockages from solid salt deposits which could bypass the mouth and enter the condensate trough causing cross-contamination of the condensate. Salt precipitation can be reduced or at least controlled in a liquid state to continue movement over the support tray and enter the liquid treatment separator and exiting the frame assembly via the separation outlet, thereby substantially eliminating cross contamination that may otherwise occur with condensate collected in the condensate trough.

[0040] The flushing system of the solar still can include a second flushing operation which comprises a flooding system adapted to flood the solar still at a predetermined time to dissolve salt deposits for removal. The flooding system can include a flow system for transferring liquid from a liquid source to the frame assembly via inlets in the frame assembly close to the top end thereof.

[0041] In operation of the flooding system, the solar still or panel can be closed to allow flooding of the panel by the liquid and dissolution of salts and reopening of the solar still for removal. The flooding system can operate on a timing mechanism that retains the flooding liquid within the solar still for a period of time to dissolve the salts. The liquid used in the flooding operation can be returned to the treatment liquid source. The flooding can be for a predetermined period of time and preferably undertaken overnight.

[0042] The flushing system of the solar still can further include a third flushing station, integrated with the first flushing system and the flooding system by one or more flow controllers. The second flushing station being adapted for salt removal and cleaning of a treatment liquid separator element of the solar still assembly. A separator element can be used in a solar still assembly to receive and direct any excess treatment liquid from a support base to a second outlet in the solar still frame assembly separate from a condensate collection trough and condensate outlet.

[0043] The third flushing station can comprise at least one inlet on the frame assembly adapted to communicate with a separator element; a source of distilled water or clean water; one or more conduits for connecting the source of distilled or clean water to the at least one inlet on the frame assembly; and a pump for deliveringdistilled or clean water from the source of distilled or clean water, wherein the water is delivered to the separator to flush the separator to substantially remove salts from the separator via the separator outlet and subsequently through the second outlet in the outlet end of the frame. In one aspect, the second supplementary system can include two inlets for circulating the source of distilled or clean water through the separator to substantially remove trace salts by dissolution through the separator outlet.

[0044] The flushing system including the first flushing station, second flooding system and third flushing station can include a control means for the pump wherein the pump can be switched on at a predetermined time(s) at a predetermined rate. The system of the present invention provides a practical means to overcome the problem of cross-contamination of collected condensate by solid salt deposits when using heavily concentrated brine treatment material. The system of the present invention allows effective use in relation to treatment liquid having higher concentrated solids in the source water on a continual basis.

[0045] The system of the present invention can process treatment liquids in industrial and mining applications and in particular in lithium mining I processing where the concentrations of salts, magnesium, lithium chlorides and other contaminants would normally render a solar still and systems inoperable.

[0046] In one embodiment the disbursement header of the solar still can includes a longitudinal opening for receiving a portion of the porous material sheet therein. The disbursement header can be generally tubular and provides a volume for receiving a reservoir of treatment liquid from a treatment liquid supply.

[0047] Preferably the system of the invention includes a reservoir clip adapted to fasten the disbursement header to the top end of the frame assembly. The clip stabilises the orientation of the opening in the disbursement header so that treatment liquid does not easily overflow. The reservoir clip can be attached between the top end of the frame assembly and the disbursement header to enable the porous material sheet to be received and retained within the reservoir. Preferably the clip includes a plug which sits within and closes an end of the disbursement header.

[0048] Preferably the condensate outlet is located in a bottom end of the frame assembly in communication with the condensate trough, whereby the angledarrangement of the frame assembly to the horizontal and vertical promotes egress of the condensate from the condensate trough to the condensate outlet.

[0049] In an operating condition, treatment liquid such as saline or salt loaded water such as sea water or brine, is supplied to the disbursement header. Treatment liquid is dispersed by the porous material sheet over the support tray.

[0050] Treatment liquid being moved by the porous material from top to bottom, exposes the liquid to solar energy passing through the upper solar energy transmission wall and / or reflected from the support tray. The treatment liquid evaporates from the porous material sheet and condenses on at least (i) the inner surface of the upper plastic sheet, (ii) the inner surface of the lower transmission wall, and (iii) lower surface of the support tray. Condensate travels along the surface of the transmission wall and falls into a condensate trough at the lower end of the frame assembly behind the separation structure and exits the condensate trough through an outlet in the bottom end of the frame assembly.

[0051] Excess treatment liquid accumulating at the bottom end of the porous material sheet is collected by the treatment liquid separator structure and exits the frame assembly via an outlet rearward of the opening of the separation structure extending through a treatment liquid outlet point in the bottom end of the frame thereby separate from the condensate collection trough and condensate outlet point.

[0052] The flushing system of the solar still of the present invention provides a first flushing station, which delivers liquid that can be treatment liquid or water, onto a lower end portion of the porous material sheet where a treatment liquid is close to the end of the porous sheet. The first flushing station upstream of the treatment liquid separator, helps to displace solid salt buildup and solubilize heavily concentrated treatment liquid and reduce potential for precipitation of solid salt. The combined treatment liquid and flushing material is received through the opening / mouth of the liquid treatment separator and passed out through a rear outlet point cooperating with a liquid treatment outlet in the bottom frame end. The flushing fluid from the first station can be returned to the disbursement header for recycling treatment.

[0053] The improved solar water distillation module can further include a rain collection gutter mounted to the bottom end of the frame assembly so that rain contacting the external surface of the upper solar energy transmission wall can rundownwardly on the outside of the module to be collected by the gutter. The gutter can include a rainwater collection device. In one embodiment, the invention can include a plurality of solar still modules connected in series.

[0054] The improved solar water distillation module provides distinct separation of an input liquid treatment supply stream and multiple condensate (distilled water) streams formed within the module. The specific construction features of the module substantially reduce the possibility of cross-contamination of the condensate streams and treatment liquid, and increases the distillation quality and efficiency.

[0055] In a further related embodiment, there is provided a solar still system for obtaining potable water supply from a waste treatment liquid having a high concentration of salt, comprising: an elongate planar frame assembly supported on an incline having a top end and a bottom end, wherein the bottom frame end includes a first outlet point for egress of excess treatment liquid and a second outlet point for egress of collected condensate; a base support on the frame assembly defining a flow path for waste liquid treatment from the top frame end towards the bottom frame end; solar transmission film material enclosing the frame assembly and defining a condensate pathway between the top and bottom ends of the frame assembly; a liquid treatment separator mounted to the frame upstream from the bottom end and spaced from the solar transmission film, having: an opening adapted to receive a lower end portion of the base support and an outlet opposite the opening and coincidental with the first outlet point, the separator adapted to receive excess waste treatment liquid and transfer to the outlet point separate from the condensate; a condensate collection trough downstream of the liquid treatment separator and adjacent the bottom frame end, the condensate collection trough adapted to receive condensate from inner surfaces of the solar transmission film, wherein the second outlet point allows egress of condensate from the condensate trough; a flushing system including: a first flushing station mounted to the frame assembly upstream from the liquid treatment separator and extending across the frame assembly perpendicular to the waste treatment liquid flow path, wherein the flushing station is interconnected to a fluid source; a second station being a flooding system adapted to flood the solar still in a separate operation to the flushing station, at a predetermined time to dissolve salt deposits for removal, wherein the flooding system includes a flow system for transferring liquid from a flush source, wherein, in operation, the solar still can be closed to allow flooding of the solarstill and dissolution of salts, and reopening of the solar still for removal; a third flushing station for cleaning a trough element of the solar still, comprising a source of distilled water, one or more conduits for connecting the source of distilled water to a trough end of the solar still, and pump for transporting distilled water from the source distilled water and circulating through the treatment liquid separator and removing any trace salts from the treatment liquid separator; wherein in use of the flushing system: the first flushing station dispenses fluid from the fluid source upstream of the treatment liquid separator to substantially reduce buildup of salt deposit by evaporation in a first zone and thereby minimizes salt deposit from cross contamination of condensate in the condensate collection trough; the second flooding station operates by closing outlet points and introducing a fluid source through inlet points close to the top end of the frame assembly and the liquid treatment inlet point to treat a second zone by flooding the solar still and reopening the outlets to remove dissolved salts; and the third flushing station adapted to flush the treatment liquid separator to remove salts therefrom to the liquid treatment outlet point.

[0056] Other aspects of the invention are also disclosed with reference to accompanying drawings and examples.

[0057] Brief Description of the Drawings

[0058] Notwithstanding any other forms which may fall within the scope of the present invention, preferred embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings in which:

[0059] Fig. 1 is a diagrammatic representation from side elevation of a solar still in accordance with a preferred embodiment of the present invention;

[0060] Fig. 2 is a photograph of internal components of the lower end of the solar still in figure 1 from one side of the solar still;

[0061] Fig. 3 is an expanded photographic view of the solar still in figure 2 from the lower end;

[0062] Fig. 4 is a diagrammatic representation of a top end portion of the solar still;

[0063] Fig. 5 is a vertical cross-section of the top end portion of a solar still;

[0064] Fig. 6 is a photograph of a reservoir clip used to secure the disbursement header shown in figure 4 to a top end of the frame assembly;

[0065] Fig. 7 is a schematic representation of an industrial processing setup of multiple arrays of solar stills in accordance with a preferred embodiment of the present invention;

[0066] Fig. 8 is a diagrammatic representation of an industrial processing setup of multiple arrays of panels in accordance with a preferred embodiment of the present invention.

[0067] Fig. 9 is a diagrammatic representation of a solar still and flushing system including a first flushing station to remove solid salt deposits in accordance with a preferred embodiment of the present invention using a first flushing station introducing fluid at inlet 133;

[0068] Fig. 10 is a diagrammatic representation of a solar still in Fig. 9, further including a second flushing station comprising a flooding system introducing liquid at a second point at a higher rate to remove solid salt deposits and dissolve excess salts in accordance with a preferred embodiment of the present invention;

[0069] Fig. 11 is a diagrammatic representation of a solar still as in Figs 9 and 10 further including a third flushing system to introduce liquid at inlet 150 at the liquid treatment separator to remove salt deposits and residue salt from the liquid treatment separator and condensate collecting trough, in accordance with a preferred embodiment of the present invention;

[0070] Fig. 12 is a diagrammatic representation of a flushing system for a solar still to remove solid salt deposits in accordance with a preferred embodiment of the present invention.

[0071] Description of Preferred Embodiments

[0072] It should be noted in the following description that like or the same reference numerals in different embodiments denote the same or similar features.

[0073] Throughout the body of the specification and embodiments supersaturated brine is understood to generally contain solids above 300,000 parts per million, compared to seawater of 35,000-540,000 parts per million.

[0074] Referring to the drawings (figures 1 to 3 and 7 to 12), there is shown a solar still 100 according to the present invention for obtaining potable water supply from a treatment liquid having a high concentration or close to supersaturated levels of salt.

[0075] In one embodiment shown in figures 1 and 9, the solar still includes a flushing system therefor comprising a first flushing station 132 located upstream from a liquid treatment separator (separator member) 117. The first flushing station includes an infeed pipe 134 which is integrated into the side of the frame assembly by inlets (inlet points) 133 close to the lower frame end 102 and extends between opposite side frame portions 103 and 104 of the planar frame assembly, perpendicular to the liquid treatment flow path, and positioned upstream of the liquid treatment separator 117 on a portion of a base support 12 spaced from a solar transmission wall 115 (fig 5) enclosing the assembly. The infeed pipe 134 includes a series of openings 135 which allow exiting fluid 136 to directly contact solid salt deposits 137 formed at the lower end of a base support 12 (fig. 5).

[0076] The first flushing station further includes a solenoid valve 152a interconnecting the frame outlets 133. In one embodiment, the fluid source is the treatment liquid 160, however the fluid source can be a source of gas, air or liquid. A feed piping system 250 (refer figure 12) is configured to deliver fluid from the fluid source 160 to the infeed pipe 134 at a predetermined rate which is effective for dislodging the solid salt deposits 137 into the liquid treatment separator 117 downstream therefrom. In a flushing condition, a relatively high flow of fluid is fed into the infeed pipe 134 which is effective to dislodge solids 137 building up in a zone in the solar still upstream of the treatment liquid separator, towards the bottom of the base tray 110. This first flushing station minimizes contact between the salt and condensate streams and substantially prevents solid salt break off migrating to the condensate collection trough 127.

[0077] There is also shown a controller 152b and 154, such as a solenoid valve, for controlling isolation and redirection flows between a flushing and non-flushing condition. In a flushing condition the predetermined rate of delivery of the liquid from the liquid source to the first flushing station is effective to displace solid salt deposits formed within the solar still by evaporation of the treatment liquid at or close to a lower end portion of the base tray to substantially minimise cross-contamination withcondensate streams and condensate collection trough. The operation of the first flushing station optionally uses treatment liquid to be input at significantly higher feed rates into the solar still to push out solids built up during the solar still treatment process of input supersaturated brine.

[0078] As shown in figures 10 to 12, the solar still of the invention further includes a second and third flushing stations. The second flushing station is a flooding system comprising an isolation valve 152a interconnecting inlet flush points 151 at opposite sides of and adjacent to the top end 101 of the frame assembly, and the treatment liquid inlet dual flush and feed point 159.

[0079] The flooding system (shown in figure 10) includes a source of flush liquid 165, which can be distilled or clean water obtained using condensate collected from operation of the solar still, and a flow system operable by the isolation valve 152a for transferring the liquid from liquid source 165 to the frame assembly via the inlet feed points 151 and dual purpose inlet 159.

[0080] Figure 12 shows a schematic solar still with integrated flushing system. The flushing system shows three liquid sources 201 , 202 and 203 interconnected to a first flushing station 204, a second flushing station being a flooding system 205, and a third flushing station 206. Each liquid source is interconnected to the frame assembly by conduit infrastructure 250 at different zones (upper, lower and intermediate) of the solar still. Figure 12 shows intended fluid flows for each separate zone.

[0081] In operation of the flooding system, the output feed points including 130 and 131 of the solar still are closed by valves 152a and 152b to allow flooding 163 of the solar still by the liquid and dissolution of salts, and reopening of the outlets for removal. The flooding system can operate on a timing mechanism such as a solenoid valve 152a that retains the flooding liquid within the solar still for a period of time to dissolve the salts. The liquid used in the flooding operation can be returned to the treatment liquid source for further processing. The flooding can be for a predetermined period of time and preferably undertaken overnight.

[0082] The third flushing station is located at a further inlet feed point 150 located towards the bottom of the solar still above the liquid treatment separator 117 to direct flow of unsaturated water 164 directly into the separator 117 to dissolve anysolids within the separator itself and in conjunction with the flooding system can be used to dissolve solids on the outer side of the separator.

[0083] As the solar still has a condensate collection trough 127 for receiving distilled water downstream of the separator 117 and two exit points 130 and 131 (for egress of excess treatment liquid and distilled water respectively), flushing of the separator needs to be controlled to ensure that the condensate collection trough 127 and / or the distilled water exit 131 is not cross contaminated with the brine being used to flush the solar still or the built up solids pushed out. This requires a series of valves to control the flows exiting the frame assembly. The valves (not shown) can also be used to block all outlet (exit) points from the solar still to enable the solar still to be filled with non-saturated water to dissolve solids on internal structures if required.

[0084] As shown in the drawings, the solar still 100 for processing a waste treatment liquid of supersaturated brine comprises an elongate planar frame assembly of general rectangular configuration supported by legs 105 and 106 on an angle to the horizontal to define a flow path of a treatment liquid from a top frame end 101 towards the bottom end 102 thereof. A solar transmission film 115 encloses the frame assembly between the top and bottom ends and condensate formed by evaporation of the treatment liquid contacting inner surfaces of the surrounding film, moves from top to bottom on the film and is received in a condensate collection trough 127 adjacent the bottom end 102. Any excess treatment liquid is received by a liquid separator 117 located upstream of the condensate collection trough 127.

[0085] The solar still of the invention further includes a flushing system for controlling salt buildup and minimizing cross-contamination of condensate flows and condensate received in the condensate collection trough. In one embodiment shown in figure 1 , the flushing system comprises: at least a flushing station adapted to be located upstream from the collectable condensate trough, wherein the flushing station is adapted to receive a fluid from a fluid source; a liquid delivery device interconnecting the flushing station and the fluid source adapted to deliver fluid from the fluid source to the flushing station; a controller for controlling the liquid delivery device between a flushing and non-flushing condition; and wherein in a flushing condition the flushing station delivers a flow of fluid to urge displacement of salt buildup formed on a lower end portion of the inclined flow path towards a liquid treatment separator intermediatethe flushing station and the collectable condensate trough, and thereby to substantially minimise cross contamination with condensate in the collectable condensate trough.

[0086] Referring to figs. 9 to 12, supersaturated brine is delivered to a storage pond and / or tank and / or any liquid storage devices to enable this to be fed to the solar still. This pond and / or tank and / or any liquid storage devices can serve multiple purposes:• Provide each solar still with treatment liquid at a rate a predetermined rate per solar still (in the current invention between 4-8 litres per hour), required to optimise evaporation purposes:• Provide each solar solar still with an additional liquid, which can be treatment liquid at a predetermined rate (in the current invention approximately 121 / hr) to each solar still to ensure crystallised solids are being removed during daily operation of the solar stills:• Collecting concentrate after evaporation for either: a. further downstream processing (in the case of lithium mining an evaporation pond an / or direct lithium extraction processing); and / or b. Continually recycling the brine through the solar still solar stills as shown.• During a daily operation, a water pump will push the treatment liquid being source brine from the storage pond and / or tank and / or any liquid storage device to each solar still (in the current invention approximating 18 Iph). The pump will run off solar stills allowing for full automation of the daily processing.• All outflows from the solar stills are by gravity flow into: c. Subterranean tanks, ponds or other storage devices for condensate; or d. The storage pond and / or tank and / or any liquid storage device for recycling purposes of the treatment liquid.

[0087] An initial volume of the condensate could be manually transferred to a separate tank for reuse in the daily flushing of the condensate collection trough of each solar still in a series of solar stills and / or the entire solar still.

[0088] The solar still of the invention is effective to remove solid salt deposits formed in the liquid treatment flow path as the salt crystallizes with evaporation ofliquid. The buildup of salt deposits in the liquid treatment flow path allows solid contact with condensate streams on condensate surfaces, and such buildups can also bypass the separation member 117 directly into the condensate collection trough 127.

[0089] The solar still 100 includes a support base 12 mounted on the frame assembly extending between the top frame end 101 and the bottom frame end 102. The support base further includes a support tray 110, a plastic underlay 114 overlapping the support tray and a material cover 113 extending substantially over the plastic underlay.

[0090] A lower end portion of the support tray 110 is received within a longitudinal opening of the separation member 117. The separation member 117 extends between opposite sides of the frame assembly. The frame assembly includes a liquid treatment outlet 130 at the bottom end 102 which is in communication with an outlet 65 of the separation member 117 where excess treatment liquid from the support base is received and exits the frame assembly separate from collected condensate.

[0091] A condensate collection trough 127 for collecting condensate is located between the separation member (treatment liquid separator) 117 and the bottom end of the frame 102. The bottom end of the frame also includes a condensate outlet 131 in communication with the condensate collection trough 127 for removal and collection of condensate from the condensate collection trough 127. The separation member 117 is adapted to separate excess treatment liquid from condensate collected in the condensate trough 127 to minimise cross contamination.

[0092] The solar still includes a liquid treatment inlet 159 at the top end of the frame for ingress of treatment liquid from a liquid treatment source 160, and a disbursement header 107 supported by a top end portion of the support tray to receive treatment liquid from the treatment inlet. A top end portion of the porous material 1 13 is received through an opening 123 of the header 107 and resides in a reservoir 9. The porous sheet is made from natural fibre materials such as wool, propylene, polyester and polyester blended materials, which draws treatment liquid in the reservoir 9 and distributes the treatment liquid 37 over the area defined by the upper surface of the support tray, by capillary action.

[0093] The frame assembly is enclosed by solar energy transmission walls 115 which are spaced from the support tray and the separation member to prevent contact between condensate streams formed on the inner surfaces of the solar transmission walls and the treatment liquid.

[0094] In operation of the solar still, treatment liquid is fed into the inlet and the liquid disperses over the base tray by the porous material, and as solar energy passes through the upper solar energy transmission wall, the input liquid evaporates off the porous material and condenses on a plurality of surfaces including inner surface of the upper transmission wall, inner surface of lower transmission wall, and underneath surface of the base tray. The separation member receives any excess treatment liquid that remains on the porous material and this is directed outside the frame assembly via an outlet in a portion of the separation member in communication with frame outlet 130 at bottom frame end 102. A plurality of condensate streams flows from the condensate surfaces into the condensate collection trough 127 at the bottom end 102 of the frame downstream of the separation member. The condensate trough 127 is in fluid communication with a second frame outlet point 131 in the bottom end 102 to allow egress of collected condensate from the condensate collection trough for collection separate from the excess treatment liquid.

[0095] In the figures there is a flushing system for a solar still comprising a first flushing station 132 located upstream from liquid treatment separator 117 (separator member), which extends across the base tray 110 perpendicular to the flow path of treatment liquid and being spaced from solar transmission walls 115 on which water vapor condenses.

[0096] The flushing station 132 is interconnected to a fluid source 160 via opposite inlets 133. The flushing station includes a feed pipe 134 which is integrated into the side of the frame assembly close to the lower end 102 and runs across the solar still to allow for a higher flow of the treatment brine to be fed into the solar still to remove solids building up towards the bottom of the base tray and blocking the exists for both the non-evaporated brine and the distilled water produced

[0097] The feed pipe 134 is mounted between side frame portions of the planar frame and positioned upstream of the separation member 117 on a portion of the porous material sheet 113. The conduit 134 and inlet are interconnected to a pumpedfluid source 160 external of the frame assembly. The feed pipe 134 includes a series of perforations or openings 135 through which fluid 136 is injected or sprayed onto the salt deposits.

[0098] The flushing system is configured to deliver fluid from the fluid source 160 to the first flushing station 132 at a predetermined rate which is effective for displacement of solid salt deposits caused by the evaporation of treatment liquid and crystallization of salts. There is also shown a controller 152b such as a solenoid valve, for controlling the station between a flushing and non-flushing condition.

[0099] In a flushing condition the predetermined rate of delivery of the fluid from the fluid source to the first flushing station is effective to displace solid salt deposits formed within the solar still by evaporation of the treatment liquid at or close to one end of the base tray to dispose of the salt through the liquid treatment separator 117 to substantially minimise cross-contamination with condensate streams and collected condensate. Figure 9 shows the flow of liquid from the treatment liquid source 160 to feed pipe 134 via inlet point 133. Liquid 136 exiting the openings 135 dislodge the salt deposits 137 towards the separator 117 exiting outlet point 129 in the rear of the separator and coincidental outlet point on the bottom frame end 130. The liquid 160 exiting the outlet point 130 can be returned to a storage for saturated concentrate (SC) for further use or processing.[000100] The solar still system of the present invention includes a flushing system having a first flushing station adapted to flush built up solids in a first zone upstream of the treatment liquid separator, which is caused by evaporation during normal daily operation when exposed to the sun; a second flushing operation comprising a flooding station for flushing a second zone towards the top frame end; and a third flushing station adapted for flushing a third zone including the treatment liquid separator and condensate collection trough. In the third flushing station there is provided another inlet feed point on a side portion of the frame assembly located adjacent to the liquid treatment separator, wherein a flow of non-saturated water can be directed to the third zone directly into the liquid treatment separator to dissolve any solids therewithin. In one aspect of operation of the third flushing station, the condensate collection trough can be flooded with overflow liquid from the third flushing station.[000101 ] The solar still has a condensate collection trough for receiving distilled water from condensate streams, and two outlet points on the bottom frame end for egress of distilled water and excess treatment liquid (non-distilled water) entering the liquid treatment separator. The flushing system needs to be controlled to ensure that the condensate collection trough and / or the distilled water outlet point is not cross contaminated with brine being used to flush the solar still or the built-up solids pushed out or the non-saturated brine used to dissolve the solids. This requires a series of valves to control the flows exiting the solar stills which is an important step. The valves can also be used to block all exit points from the solar still to enable the solar still to be filled with non-saturated water to dissolve solids on internal structures if required.[000102] A benefit of the solar still of the invention is that the internal fabric which is used to wick the input treatment liquid from a disbursement header over the flow path is able to hold greater loads of solid salt deposits without impacting the operation of the solar still, the quality of the water and / or its longevity. The process to manage flushing and / or controlling the exits can be manual or automated.[000103] In use of the flushing system, fluid from an external source is pumped through the inlet pipe into the perforated infeed pipe and onto the material sheet at a lower end thereof. The perforations dispose the salt deposits on the material sheet to flushing to disperse any solid salt deposits into the liquid treatment separator 117.[000104] In use the flushing system dispenses fluid 135 from the fluid source at or close to the liquid treatment separator 117 to substantially reduce buildup of salt deposit by evaporation on the porous material sheet and thereby flush solid salt deposit to the separation member thereby reducing cross-contamination of the collected condensate in the condensate trough.[000105] Figures 4 and 6 shows a reservoir clip 136 which integrates the disbursement header, reservoir, porous cloth, with the top side of the solar still.[000106] The clip comprises a body 137 with shaped opposite ends 138 and 139 which are adapted to engage the top frame end and disbursement header respectively. The clip can further include a plug 140 which is shaped to fit an open end of the disbursement header. In use, the reservoir clip assists to stabilise the orientation of the opening in the disbursement header so that treatment liquid does not easily overflow. The reservoir clip is attached between the top end of the frame assemblyand the disbursement header to enable the porous material sheet 113 to be received and retained within the reservoir.[000107] This reservoir clip 136 improves the operation of the solar still by: a) Ensuring sufficient reserve source treatment water / fluid remains in the reservoir by means by stopping it flowing out either side of the reservoir and down either side of the solar still ensuring the entire fabric is saturated.[000108] The reservoir clip is mechanically held in position by means that allows a degree of floating movement so that the cylindrical Reservoir can move sufficiently move across a broad spectrum of temperature without causing excessive stress to the assembly and cloth.[000109] Referring to figure 7, there is shown a method of industrial processing of concentrated or near saturated brine comprising a plurality of solar still panels 14 of the present invention and panel array feedlines, forming an integrated array.[000110] In figure 7 there is provided: a treatment liquid holding means 1 holding raw source water; a mains supply line 3 from the treatment liquid holding means to the array of solar stills; a branch supply line 5 from the mains supply line 3 adapted to supply treatment liquid to the solar stills in a separate row of the integrated array of solar stills; a pumping means 4 operatively attachable to the branch supply line 5 to deliver the treatment liquid from the holding tank to the one or more rows of the solar still array; conduit infrastructure 6, 8 for collecting condensate from the one or more rows of integrated panel arrays; a condensate storage tank 9; a conduit for receiving excess treatment liquid; a flushing system; the method including introducing treatment liquid to the mains supply line and the at least one array; returning excess treatment liquid from the at least one array to the treatment liquid holding means; and delivering the condensate from the at least one array to a distilled water holding tank via gravity fed storage tank(s).[000111 ] The flushing system includes a perforated conduit mounted between side frame portions of the planar frame and extending between solar stills in the integrated array. The flushing system is positioned upstream of each of the liquid treatment separators of each solar still in the array on a portion of the porous material sheet, and the conduit is interconnected to a fluid pump and a fluid source, which could include the condensate tank, external of the integrated array of solar stills.[000112] In use of the flushing system, fluid from an external source is pumped through an inlet pipe into the perforated conduit and onto the material sheet. This extends throughout each row of solar stills in an integrated array. The perforated conduit is located adjacent to the lower end of the porous material sheet in each solar still assembly so that the porous sheet is disposed to flushing to disperse any solid salt deposits into the opening or mouth of the treatment liquid separator.[000113] The rate of flushing fluid exiting the perforated conduit and timing can be controlled by a pump so that fluid can exit the conduit at a predetermined rate onto the material sheet which is effective to liquify solid salt particulates formed or retain the treatment fluid at this point in a fluid condition. In this way, salt precipitation can be reduced or controlled in a liquid state to continue movement over the base support and entering the treatment liquid separator and exiting the frame assembly via a rear opening or throat cooperating with the liquid treatment outlet 130 thereby substantially eliminating cross contamination with condensate collected in the condensate trough.[000114] The pump can be switched on at a predetermined time(s) at a predetermined rate. The system of the present invention provides a practical means to overcome the problem of cross-contamination of collected condensate by solid salt deposits when using heavily concentrated brine treatment material. The system of the present invention allows effective use in relation to treatment liquid having higher concentrated solids in the source water on a continual basis.[000115] The at least one row of integrated array can comprise up to 40 solar stills. Preferably the method of industrial processing of concentrated or near saturated brine includes multiple rows of integrated arrays.[000116] The method of industrial processing of concentrated or near saturated brine further includes providing a flushing system comprising flushing infrastructure for the at least one array of solar stills including a flushing source, and a perforated conduit passing through each solar still on or over an end portion of the porous material sheet, wherein the infrastructure interconnects the flushing source to each perforated conduit in the array. The method of processing further includes a control system for operating the flushing system to deliver the flushing source at a select rate and predetermined time to assist reducing salt deposition during condensation and thereby minimise cross-contamination of the condensate liquid with salt deposit.[000117] Referring to figure 8, there is shown an alternative method 100 of processing contaminated waste in accordance with the invention using an integrated solar still or panel array 115. The method includes providing: a treatment liquid holding means 110 holding raw source water; a mains supply line 111 from the treatment liquid holding means to the array of solar stills; a branch supply line 113 from the mains supply line 111 adapted to supply treatment liquid to the solar stills in a separate row of the integrated array of solar stills; a pumping means 112 operatively attachable to the branch supply line 5 to deliver the treatment liquid from the holding tank to the one or more rows of the solar still array; conduit infrastructure 114 for collecting condensate from the one or more rows of integrated solar still arrays; and a solar still conditioning device 116. The solar still conditioning device is integrated to the mains supply feed line 111 and in use applies electrical resonant frequencies and magnetic treatments to the treatment water to disrupt the bonding ability of dissolved minerals to prevent or reduce scale buildup on solar stills in the integrated array.[000118] As shown in Figures 9 to 12 the flushing system comprising a first, second and third flushing operations, can be interconnected to each solar still in the array of solar stills.[000119] Solar Still Flooding Process:[000120] As outlined above, the evaporation process from the saturated source brine will cause crystallisation of salts within the solar still:• During daily operation some crystallised solids will exit the solar stills with the concentrated outflows, but the majority will remain inside the solar stills (most visibly on the on the internal porous material sheet). These therefore optimally require an flushing process overnight (automatically timed or manually operated) to: o Avoid disrupting the daylight solar evaporation process during the day (Note: this can be done during the daily operation if required); o Ensure the internal porous material sheet remains moist as this prevents solids hardening and becoming more difficult to remove and provides longevity to the internal element.Night flushing process will utilize:o a separate pump to deliver a higher feed rate (in the current invention of approximately 120 L / hr) of brine so as the brine can exit the solar still at the rate approximating the input flow) to each solar still via the main top centre feed point and side flushing ports (third flushing station); o The third flushing station as well as the existing main top centre feed port to ensure optimal flow across and down the solar still; and o Flow rates and pressure will be controlled by a master regulator on the main line and emitter fittings on the solar still ports.• Flushed salt crystals are washed back out to the storage pond and / or tank and / or any liquid storage device for constant recycling. (Note: this flush process uses pressure flows to push excess salt deposits out as suspended solids rather than to reabsorb them as soluble components). This flushing will not remove all crystallised solids however the remaining salts will not impact the performance of the solar still the next day.• The internal Solar still separator will utilise the second flushing station and a separate pump absorbative flush cycle with water supplied from the unsaturated flush tank using a separate pump. The unsaturated water can be returned to the same tank for re-cycling use until an excessive level of saturation is reached.[000121 ] As the above processes will occur overnight or prior to daily operation, the pumps should utilize stored power likely accumulated via Solar photovoltaic panels and battery storage during the day. The overnight flushing and the separator flush should be operated on timers and require little / no labour involvement.[000122] It is noted that the potential exists that an infrequent flush using saturated or unsaturated water may be required during the day and this can be readily done manually with the above implementation).[000123] Remedial Flush (Intermittent)[000124] There can be a need to utilise unsaturated water to give a solar still or an array of solar stills a flush to clear out an excessive Build Up of Crystallised Solids. Whilst the overnight flushing process removes most of the crystallised salts some built up solids will remain each day and therefore there will be a gradual accumulation ofthese salts within the solar still over time (primarily on the internal porous material sheet ). This build up does not impact on the volume of condensate produced from the solar still but can:• Impact on the level of salts mixing with the condensate; and / or• Lead to blockages with the outlets from the solar still.[000125] The system outlined therefore has the ability to utilized the unsaturated water to via the third flushing station:• Dissolve built up solids within on the internal porous material sheet ; and / or• Overfill the lower part of the solar still above the separator area to remove and residual salt or clear any blockage. This can be done with one solar still or an array of solar stills but it is likely to be intermittent only.[000126] Automation & Control of Solar Stilll Maintenance and Outputs.[000127] Due to the daily operation and flushing requirements, the use of isolation and redirection valves / solenoids will be required for the solar still. Per the installation shown in figures 9 to 11 there are the following input and output flows:• Input Flows: o Daily Operational inflows using treatment liquid using the top feed pipe in conjunction with the first flushing station; o Saturated overnight flushing inflow using a flushing fluid using the third flushing station; o Unsaturated flushing using the third flushing station; and o Unsaturated flushing inflow using unsaturated water utilising the second flushing station.• Output flows: o Saturated Concentrate outflows (during daily operation and overnight flushing (with saturated liquid) o condensate outflows (during daily operation); and o Unsaturated water outflows (during separator flush and remedial flushes)[000128] To maintain the integrity of both the condensate collected and the concentrate water outflows the use of isolation valves / solenoids 152a and 152b along with redirection solenoid valves 153 and 154 are required as per below:[000129] Table of Processes[000130] Benefits of the system include:[000131 ] The combined actions of the flushing system enables effective flushing of supersaturated brine from first, second and third zones of the solar still, i.e. all areas of the solar still can be effectively cleaned;[000132] The solar module can be used effectively for cleaning high salt concentrated brine pond and / or tank and / or any liquid storage devices and tailing dams;[000133] The invention allows the solar still to deal with higher concentrated solids in the source water on a continual basis;[000134] The solar still enhances capability to be used in industrial and mining applications and in particular in lithium mining / processing where the concentrations of salts, magnesium, lithium chlorides and other contaminants that would normally render a solar still and systems inoperable.[000135] Allows the introduction and flushing of the internal soalr still / cloth / reservoir utilising distilled water obtained from the solar still for the purpose of recirculation and a flushing process as an improved process feature.[000136] The flushing system provides for distinct separation from the liquid supply stream and the condensate (distilled water). The process applied within the solar distillation unit provides for the input water to be separated into two distinct output streams (distilled water) and non-distilled water. To achieve the aim of producing distilled water these separate streams must be separated within the solar distillation unit. This flushing system of the invention reduces the possibility of contamination of the distilled water produced and increases the distillation efficiency by ensuring the internal separation of the input water and the distilled water.[000137] Interpretation[000138] Embodiments:[000139] Reference throughout this specification to “one embodiment” or “an embodiment” means that a particular feature, structure or characteristic described inconnection with the embodiment is included in at least one embodiment of the present invention. Thus, appearances of the phrases “in one embodiment” or “in an embodiment” in various places throughout this specification are not necessarily all referring to the same embodiment, but may. Furthermore, the particular features, structures or characteristics may be combined in any suitable manner, as would be apparent to one of ordinary skill in the art from this disclosure, in one or more embodiments.[000140] Similarly, it should be appreciated that in the above description of example embodiments of the invention, various features of the invention are sometimes grouped together in a single embodiment, figure, or description thereof for the purpose of streamlining the disclosure and aiding in the understanding of one or more of the various inventive aspects. This method of disclosure, however, is not to be interpreted as reflecting an intention that the claimed invention requires more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive aspects lie in less than all features of a single foregoing disclosed embodiment. Thus, the claims following the Detailed Description of Specific Embodiments are hereby expressly incorporated into this Detailed Description of Specific Embodiments, with each claim standing on its own as a separate embodiment of this invention.[000141 ] Furthermore, while some embodiments described herein include some but not other features included in other embodiments, combinations of features of different embodiments are meant to be within the scope of the invention, and form different embodiments, as would be understood by those in the art. For example, in the following claims, any of the claimed embodiments can be used in any combination.[000142] Different Instances of Objects[000143] As used herein, unless otherwise specified the use of the ordinal adjectives “first”, “second”, “third”, etc., to describe a common object, merely indicate that different instances of like objects are being referred to, and are not intended to imply that the objects so described must be in a given sequence, either temporally, spatially, in ranking, or in any other manner.[000144] Specific Details[000145] In the description provided herein, numerous specific details are setforth. However, it is understood that embodiments of the invention may be practiced without these specific details. In other instances, well-known methods, structures and techniques have not been shown in detail in order not to obscure an understanding of this description.[000146] Terminology[000147] In describing the preferred embodiment of the invention illustrated in the drawings, specific terminology will be resorted to for the sake of clarity. However, the invention is not intended to be limited to the specific terms so selected, and it is to be understood that each specific term includes all technical equivalents which operate in a similar manner to accomplish a similar technical purpose. Terms such as "forward", "rearward", "radially", "peripherally", "upwardly", "downwardly", and the like are used as words of convenience to provide reference points and are not to be construed as limiting terms.[000148] Comprising and Including[000149] In the claims which follow and in the preceding description of the invention, except where the context requires otherwise due to express language or necessary implication, the word “comprise” or variations such as “comprises” or “comprising” are used in an inclusive sense, i.e. to specify the presence of the stated features but not to preclude the presence or addition of further features in various embodiments of the invention.[000150] Any one of the terms: including or which includes or that includes as used herein is also an open term that also means including at least the elements / features that follow the term, but not excluding others. Thus, including is synonymous with and means comprising.[000151 ] Scope of Invention[000152] Thus, while there has been described what are believed to be the preferred embodiments of the invention, those skilled in the art will recognize that other and further modifications may be made thereto without departing from the spirit of the invention, and it is intended to claim all such changes and modifications as fall within the scope of the invention. For example, any formulas given above are merely representative of procedures that may be used. Functionality may be added or deleted from the block diagrams and operations may be interchanged among functionalblocks. Steps may be added or deleted to methods described within the scope of the present invention.[000153]

[0052] Although the invention has been described with reference to specific examples, it will be appreciated by those skilled in the art that the invention may be embodied in many other forms.[000154] Industrial Applicability[000155] It is apparent from the above, that the arrangements described are applicable to a solar still module for use in water industry, solar industry, waste management industry and manufacturing industries.

Claims

Claims:1 . A flushing system for a solar still having an inclined flow path and a liquid treatment separator in the flow path, adapted to separate by condensation an incoming supersaturated brine treatment liquid stream to a condensate collection trough downstream from the liquid treatment separator, the flushing system comprising: a flushing station located in the flow path upstream from the liquid treatment separator, wherein the flushing station is adapted to receive a fluid from a fluid source; a fluid delivery device interconnecting the flushing station and the fluid source adapted to deliver fluid from the fluid source to the flushing station; a controller for controlling the fluid delivery device between a flushing and nonflushing condition; and wherein in a flushing condition the flushing station delivers a flow of fluid to urge displacement of salt buildup formed on a lower end portion of the inclined flow path, towards the separator and thereby to substantially minimise cross contamination with condensate streams and condensate in the condensate collection trough.

2. The flushing system of claim 1 , wherein in a flushing condition liquid from the liquid source is delivered to the flushing station at a predetermined rate of delivery effective to displace solid salt deposits formed within the solar still by evaporation of the treatment liquid at or close to the end of the flow path, to substantially minimise cross-contamination with condensate streams and collected condensate.

3. A solar still flushing system for a solar still comprising: a flushing station adapted to be located upstream from and close to an eluting end of the solar still, wherein the flushing station is adapted for communication with a liquid source, in operation, and delivery of liquid at its location; a liquid delivery member interconnecting the flushing station and the liquid source; a controller for controlling the liquid delivery member between an in use and non-use condition;wherein when the controller is in an in use condition, the liquid delivery member of the system is adapted to transfer the liquid from the liquid source to the flushing station to deliver the liquid at a predetermined rate effective to dislodge and displace solids formed by evaporation of the treatment liquid at or close to the eluting end.

4. The solar still flushing system of claim 1 or 3, wherein the flushing station of the flushing system includes a conduit with a series of openings therein for receiving a flow of liquid from the liquid source, and delivery of the liquid at the location at a predetermined rate is effective to dislodge and move solid salt deposits on a transfer surface of the solar still.

5. The solar still flushing system of claim 1 or 3, wherein the liquid delivery member is a pump for transferring liquid from the liquid source.

6. The solar still flushing system of claim 1 or 3, wherein the flushing station further includes a controller for operating the liquid delivery member.

7. The solar still flushing system of claim 1 or 3, further including a flooding system adapted to flood the solar still in a separate operation to the flushing station, at a predetermined time to dissolve salt deposits for removal.

8. The solar still flushing system of claim 7, wherein the flooding system includes a flow system for transferring liquid from a flush source, wherein, in operation, the solar still can be closed to allow flooding of the solar still and dissolution of salts, and reopening of the solar still for removal.

9. The solar still flushing system of claim 1 or 3, further including a third flushing station for cleaning a trough element of the solar still, comprising a source of distilled water, one or more conduits for connecting the source of distilled water to a treatment liquid separator of the solar still, and pump for transporting distilled water from the source distilled water and circulating through the treatment liquid separator and removing any trace salts from the treatment liquid separator.

10. A method of processing a treatment liquid having high concentration salt or brine waste liquid for potable water, the method including: providing a solar still having:a frame defining an inlet end for ingress of a treatment liquid and outlet end including a condensate collection trough at the outlet end for receiving and collecting condensate; a support tray defining a pathway for treatment liquid between the inlet and outlet ends of the frame; a treatment liquid separator adjacent to and upstream of the trough adapted to receive a lower end of the support tray therein and receive excess treatment liquid separate from the condensate collected in a condensate collection trough downstream; providing a flushing system for controlling and substantially minimising crosscontamination of condensate stream(s) and salt deposits and / or treatment liquid comprising a first flushing station located on the frame extending over the support tray upstream from the treatment liquid separator and being connected to a liquid source, the first flushing station having one or more liquid delivery outlets; the method further comprising transferring liquid from the liquid source to the first flushing station at a predetermined rate effective for dislodging and moving solid salt deposits on the support tray.11 . The method of claim 10, further including a flooding system adapted to flood the solar still in a flooding operation at a predetermined time to dissolve salt deposits for removal, wherein the flooding system includes: an inlet at a top end portion of the solar still for receiving a liquid, wherein outlets in the solar still are closed when liquid is transferred into the inlet to allow filling of the solar still; reopening outlets for egress of the liquid and / or recirculating the liquid to dissolve and remove salt buildup.

12. The method of claim 10 or 11 , further including a third salt removal system for cleaning the treatment liquid separator comprising opposite inlets in the solar still frame adjacent the treatment liquid separator; one or more conduits interconnecting the inlets to a source of distilled or unsaturated water, and a pump for transporting the water to the inlets for circulating through the treatment liquid separator and removing any trace salts therefrom.

13. The method of claim 12, wherein the condensate outlet and excess liquid treatment outlet are closed before commencement of cleaning to allow overflowof water into the condensate collection trough, and reopening said outlets for egress of water.

14. A solar still system for obtaining potable water supply from a waste treatment liquid having a high concentration of salt, comprising: an elongate planar frame assembly supported on an incline having a top end and a bottom end, wherein the bottom frame end includes a first outlet point for egress of excess treatment liquid and a second outlet point for egress of collected condensate; a base support on the frame assembly defining a flow path for waste liquid treatment from the top frame end towards the bottom frame end; solar transmission film material enclosing the frame assembly and defining a condensate pathway between the top and bottom ends of the frame assembly; a liquid treatment separator mounted to the frame upstream from the bottom end and spaced from the solar transmission film, having: an opening adapted to receive a lower end portion of the base support and an outlet opposite the opening and coincidental with the first outlet point, the separator adapted to receive excess waste treatment liquid and transfer to the outlet point separate from the condensate; a condensate collection trough downstream of the liquid treatment separator and adjacent the bottom frame end, the condensate collection trough adapted to receive condensate from inner surfaces of the solar transmission film, wherein the second outlet point allows egress of condensate from the condensate trough; a flushing system including a first flushing station mounted to the frame assembly upstream from the liquid treatment separator and extending across the frame assembly perpendicular to the waste treatment liquid flow path, wherein the first flushing station is interconnected to a fluid source; wherein in use the first flushing station dispenses fluid from the fluid source upstream of the treatment liquid separator to substantially reduce buildup of salt deposit by evaporation and thereby minimizes salt deposit from cross contamination of condensate in the condensate collection trough.

15. The solar still system of claim 14, wherein the flushing system further includes a flooding system adapted to flood the solar still in a separate operation to the first flushing station, at a predetermined time to dissolve salt deposits for removal.

16. The solar still system of claim 15, wherein the flooding system includes a flow system for transferring liquid from a flush source, wherein, in operation, outlet of the solar still can be closed to allow flooding of the panel and dissolution of salts, and reopening of the solar still for removal.

17. The solar still flushing system of claim 14, further including a third flushing station for cleaning a treatment liquid separator of the solar still, comprising a source of distilled water, one or more conduits for connecting the source of distilled water to the treatment liquid separator, and a pump for transporting distilled water from the source distilled water and circulating through the treatment liquid separator for removing any trace salts.

18. The solar still system of claim 14, further including a disbursement header including a reservoir mounted to the planar frame assembly located close to the treatment liquid inlet at the top frame end for receiving and disbursement of the waste treatment liquid therefrom;19. The solar still system of claim 14, further including a base support including a support tray, a plastic overlay, and a material sheet overlaying at least a part of the plastic overlay to distribute the waste treatment liquid over an upper surface of the support tray, the support tray mounted to the planar frame assembly spaced from the solar transmission film, wherein a top end portion of the material sheet is adapted to be in fluid communication with the treatment liquid in the disbursement header reservoir.

20. The solar still system of claim 17 wherein the treatment liquid separator is mounted to the frame assembly of the solar still upstream from the condensate collection trough and spaced from the solar transmission film, wherein the treatment liquid separator includes an opening forming a mouth adapted to receive a lower end portion of the base support tray to receive excess waste treatment liquid, and an outlet rear of the opening cooperating with a liquid treatment outlet on the bottom frame end for egress of waste liquid from the frame assembly.

1. A solar still system for obtaining potable water supply from a waste treatment liquid having a high concentration of salt, comprising: an elongate planar frame assembly supported on an incline having a top end and a bottom end, wherein the bottom frame end includes a first outlet point for egress of excess treatment liquid and a second outlet point for egress of collected condensate; a base support on the frame assembly defining a flow path for waste liquid treatment from the top frame end towards the bottom frame end; solar transmission film material enclosing the frame assembly and defining a condensate pathway between the top and bottom ends of the frame assembly; a liquid treatment separator mounted to the frame upstream from the bottom end and spaced from the solar transmission film, having: an opening adapted to receive a lower end portion of the base support and an outlet opposite the opening and coincidental with the first outlet point, the separator adapted to receive excess waste treatment liquid and transfer to the outlet point separate from the condensate; a condensate collection trough downstream of the liquid treatment separator and adjacent the bottom frame end, the condensate collection trough adapted to receive condensate from inner surfaces of the solar transmission film, wherein the second outlet point allows egress of condensate from the condensate trough; a flushing system including: a first flushing station mounted to the frame assembly upstream from the liquid treatment separator and extending across the frame assembly perpendicular to the waste treatment liquid flow path, wherein the flushing station is interconnected to a fluid source; a second flushing station comprising a flooding system adapted to flood the solar still in a separate operation to the flushing station, at a predetermined time to dissolve salt deposits for removal, wherein the flooding system includes a flow system for transferring liquid from a flush source, wherein, in operation, the solar still can be closed to allow flooding of the panel and dissolution of salts, and reopening of the panel for removal;a third flushing station for cleaning a trough element of the solar still, comprising a source of distilled water, one or more conduits for connecting the source of distilled water to a trough end of the solar still or panel, and pump for transporting distilled water from the source distilled water and circulating through the trough and removing any trace salts from the trough wherein in use of the flushing system: the first flushing station dispenses fluid from the fluid source upstream of the treatment liquid separator to substantially reduce buildup of salt deposit by evaporation in a first zone and thereby minimizes salt deposit from cross contamination of condensate in the condensate collection trough; the second flooding station operates by closing outlet points and introducing a fluid source through inlet points close to the top end of the frame assembly and the liquid treatment inlet point to treat a second zone by flooding the solar still and reopening the outlets to remove dissolved salts; and the third flushing station adapted to flush the treatment liquid separator to remove salts therefrom to the liquid treatment outlet point.

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