122 results about "Multi-stage flash distillation" patented technology

A desalination process is disclosed which combining two or more substantially different water treatment processes in a unique manner to desalinate saline water, especially sea water, to produce a high yield of high quality fresh water, including potable water, at an energy consumption equivalent to or less than much less efficient prior art desalination processes. In this process a nanofiltration step is synergistically combined with at least one of sea water reverse osmosis, multistage flash distillation. multieffect distillation of vapor compression distillation to provide an integrated desalination system by which sea water can be efficiently and economically converted to high quality potable water in yields which are at least 70%-80% greater than the yields available from the prior art processes. Typically a process of this invention using the nanofiltration initial step will produce, with respect to sea water feed properties, calcium, magnesium, sulfate and bicarbonate ion content reductions of 63%-94%, pH decreases of about 0.4-0.5 units and total dissolved solids content reductions of 35%-50%.

An optimal thermal seawater desalination process is disclosed, which combines two or more substantially different water pretreatment processes in a unique manner and in a special configuration, hereto unknown to prior desalination arts, to produce a high yield of high quality fresh water, including potable water. In this process a two stage NF membrane pretreatment unit (NF₂) with an energy recovery turbo charger (TC) device in between the stages or equipped with an energy recovery pressure exchanger (PX) is synergistically combined with at least one thermal desalination unit to form a dual hybrid of NF₂-Thermal (FIG. 4 ), or alternatively the two stage NF₂ unit is synergistically combined with a two stage SWRO unit (SWRO₂) with an energy recovery TC in between the stages or combined with one stage SWRO (SWRO₁) equipped with an energy recovery TC or PX system and the reject from the SWRO₂ or SWRO₁ unit is made make-up to a thermal unit to form a tri-hybrid of NF₂-SWRO_{2 reject}-Thermal (FIG. 5 ). In both the cases of di- or trihybrids the thermal unit is equivalent to a multistage flash distillation (MSFD) or multieffect distillation (MED) or vapor compression distillation (VCD) or thermal reheat (RH) evaporator. Typically a process of this invention using the two stage NF₂ initial pretreatment step will perform a semi-desalination step by reducing feed TDS by about 35 to 50%, but most important, especially to the thermal seawater desalination process, it removes the water recovery limiting, scale forming hardness ions of Ca⁺⁺ and Mg⁺⁺ by better than 80% and their covalent anions of sulfate to better than 95% and bicarbonate to about 65%. The removal of scale forming hardness ions, especially SO₄⁼, and bicarbonates allowed for the operation of thermal unit in the above hybrids at top brine temperature (TBT) much greater than its present TBT limit by the singular conventional process of 120° C. for MSFD and operation of MED or VCD or RH unit at TBT much higher than their present TBT limit of 65-70° C., with many advantages gained by this process over prior art sweater desalination processes. The process of this invention exceeds all prior thermal seawater desalination arts in efficiency, including water yield, product water recovery ratio and unit water cost as well as in energy consumption per unit product which is equivalent or less than other efficient prior art seawater thermal desalination processes. By this process, an NF product recovery ratio of 75 and 80% or better is achieved from the high salinity Gulf sea (TDS≈45,000 ppm) and about an equal product recovery ratio is also obtained from the SWRO or thermal unit when it is operated on NF product for a total water recovery ratio in excess of 52% for seawater

The invention discloses a system for desalinating seawater by waste heat from a power plant. The system comprises a condenser circulating seawater taking branch system, a seawater multi-stage fresh evaporation branch system and a boiler smoke waste heat heating seawater circulating branch system which are divided according to the flow direction of seawater to be desalinated, and also comprises a vacuum pumping branch system, and a fresh water and seawater pollution discharge branch system, wherein the vacuum pumping branch system and the fresh water and seawater pollution discharge branch system are used as auxiliary systems connected with the seawater multi-stage fresh evaporation branch system. A multi-stage fresh evaporation method is adopted by the system. Because the waste heat of a condenser and boiler smoke of a power plant is utilized, energy sources needed for desalinating the seawater in a conventional distillation method are omitted, the operating cost in desalinating the seawater in a distillation method is reduced, and simultaneously the prepared fresh water is distilled water which can be partially used as supplementing water for the boiler of the power plant, the treatment cost for softening water in the power plant is saved, energy is saved, and the environment is protected.

The invention discloses an organic waste recycling method and a sterilization apparatus used in the method. The method comprises the following steps: collecting; carrying out anaerobic fermentation to obtain biogas, primary biogas residue and primary biogas slurry; carrying out secondary fermentation: adding a certain amount of biological inoculant and an auxiliary material into the primary biogas slag, modifying, and carrying out secondary fermentation to obtain secondary biogas residue and secondary biogas slurry; carrying out low temperature drying on the secondary biogas residue at 45-60DEG C, and crushing to prepare a solid organic fertilizer; processing the biogas slurry to prepare a liquid fertilizer; and depositing organic wastewater, carrying out flash evaporation, purifying through carrying out silver ion sterilization, mixing the obtained purified water with the liquid fertilizer, and carrying out field irrigation spraying. The sterilization apparatus comprises a heating tube, the heating tube is a cylinder with the bottom buckled to the arc-shaped top, the inner wall of the arc-shaped top is provided with a plurality of exhaust pipes, and the bottom is provided with a plurality of separation plates to form an S-shaped channel extending along the bottom; and the sterilization apparatus also comprises a steam generation device, wherein biogas is used to heat in order to generate steam.

The invention discloses a thermal power plant desulphurization wastewater purification system including a desulphurization wastewater pretreatment system, a multi-medium filter, a forward osmosis-nanofiltration coupling concentration-desalination system, a multi-stage flash evaporation system and a horizontal crystallization box which are successively connected. The invention also discloses a thermal power plant desulphurization wastewater purification method including wastewater neutralizing treatment, heavy metal precipitation treatment, flocculation treatment, clarification treatment, sludge dewatering treatment, clear water filtration treatment, forward osmosis concentration treatment and multi-effect negative pressure flash evaporation crystallization. With chemical treated desulphurization wastewater as raw material, pretreated wastewater passes through the forward osmosis-nanofiltration coupling concentration-desalination system and then enters the multi-stage flash evaporation system, the flash evaporation efficiency is greatly improved, final products comprise a brick making raw material, industrial salt and distilled water, and the purpose of turning waste into treasure is achieved.

The combination multi-effect distillation and multi-stage flash evaporation system integrates a multi-stage flash (MSF) evaporation system with a multi-effect distillation (MED) system such that the flashing temperature range of the MSF process is shifted upward on the temperature scale, while the MED distillation process operates in the lower temperature range. The multi-stage flash evaporation system includes a plurality of flash evaporation/condensation stages, such that the multi-stage flash evaporation system receives a volume of seawater or brine from an external source and produces distilled water. The multi-effect distillation system includes a plurality of condensation/evaporation effects, such that the multi-effect distillation system receives concentrated brine from the multi-stage flash desalination system and produces distilled water.

The invention discloses a multi-effect membrane distillation-multistage flash evaporation seawater desalination system. The multi-effect membrane distillation-multistage flash evaporation seawater desalination system comprises a steam jetting pump (9), a concentrated water discharge pump (1), a material liquid circulating pump (2), a vacuum pump (3), a product water pump (4), N membrane assemblies, N freshwater flash evaporation tanks, N+1 heat exchange assemblies and N-1 concentrated water flash evaporation tanks, wherein the plurality of membrane assemblies and heat exchange assemblies are connected in series to form 'multi-effect' distillation in the term of the traditional distillation; the plurality of freshwater flash evaporation tanks and the plurality of concentrated water flash evaporation tanks are connected in series to form 'multistage' flash evaporation in the term of traditional distillation; the multi-effect membrane distillation process and the multistage flash evaporation process are coupled, secondary steam generated by membrane distillation is used for heating material liquid seawater, high-temperature concentrated seawater and product water which are discharged by membrane distillation are subjected to flash evaporation stage by stage, and the flash-off steam is used for heating material liquid seawater, so gradient utilization of energy and double concentration of the material liquid are realized, vaporized latent heat is effectively recovered, and heat efficiency, water making ratio and concentration ratio of a system are increased.

The invention relates to a combined absorption carbon dioxide trapping and compressing treatment technology, and belongs to the field of decarburization and carbon dioxide emission reduction. A physical absorption method and a chemical absorption method are combined in the technology, and high pressure absorption-middle pressure desorption is carried out to realize high efficiency and low energy consumption decarburization. The technology comprises the following steps: carbon-containing airflow enters a physical trapping process and is desulfurized, the desulfurized airflow goes through a physical absorption tower and undergoes an affiliated process to remove most carbon dioxide, and the obtained airflow undergoes a chemical trapping process to remove residual carbon dioxide; a sulfur-containing rich solution undergoing desulphurization regeneration and a carbon-containing physical adsorbent-rich solution undergoing multistage flash evaporation generation respectively return to a physical absorption tower; a chemical adsorbent-rich solution undergoing thermal desorption regeneration returns to a chemical absorption tower; and carbon dioxide discharged from a flash evaporation tank and a desorption tower undergoes multi-stage compression to meet geological storage conditions. A heat exchanger is used in a technologic system to recover heat, and an expander is used to recover work. The combined absorption carbon dioxide trapping and compressing treatment technology has the advantages of high carbon trapping rate, low energy consumption, and suitableness for large-scale carbon trapping and compression treatment of high-pressure carbon dioxide-rich airflow.

A process and system for producing a H₂-containing product gas and purified water from an integrated catalytic steam-hydrocarbon reforming and thermal water purification process. Raw water, such as salt water, is heated by indirect heat transfer with reformate from the catalytic steam reforming process for purifying raw water in one of a multiple effect distillation process and a multi-stage flash process.

The invention discloses a multi-stage flash distillation seawater desalination system of low-temperature multi-effect steamer vapor compression distillation. The system comprises a back presser, a compressor, a low-temperature multi-effect evaporator, a multi-stage flash distillation device, a final stage flash distillation chamber, a heater, a heat source steam pipeline, a feed seawater pipeline and a fresh water outlet pipeline. In the system, the heat source steam is taken into the back presser to act so as to drive the compressor to work; all the finally acted secondary steam in the low-temperature multi-effect evaporator is regarded as the firstly acted heating steam after being compressed by the compressor; the exhaust steam of the back presser is regarded as the heat source steam of the multi-stage flash distillation device; the waste heat in the fresh water of the multi-stage flash distillation device and the low-temperature multi-effect evaporator is recycled and used in final stage flash distillation chamber; and the cooling water in the final stage flash distillation chamber is respectively regarded as the feed seawater of the low-temperature multi-effect evaporator and the multi-stage flash distillation device. By providing different steam parameters suitable for power plants, the multi-stage flash distillation seawater desalination system of low-temperature multi-effect steamer vapor compression distillation disclosed by the invention has the advantages of high energy utilization rate, high thermal efficiency, high yield of the desalted water, little dosage of the feed seawater, and the like, and is widely applied to the field of seawater desalination.

The invention discloses a multiple-effect evaporative crystallization system and method for utilizing compressed air and a heat pump to dispose wastewater containing salts in a power plant. Accordingto the method, the compressed air is introduced from an air separation device of the fuel gas power plant to assist in atomization of the wastewater containing the salts in the power plant, the air (waste gas) which is already used for assisting in atomization serves as a heat source of the heat pump to be conveyed into a heat pump evaporator through a draught fan, the waste gas is cooled, dehumidified and then recovered, and condensed water generated by using the evaporator for condensing vapor in the air is discharged at regular intervals; predisposed wastewater of the power plant flows intoa heat pump condenser for heat exchange and preheating with refrigerating fluid vapor at first; contact-type mass transferring concentration is conducted on the preheated wastewater and the waste gascooled and dehumidified by the evaporator in a concentration chamber, and the concentrated wastewater with high concentration flows into a multi-level flash evaporation device for flash evaporation.Desalted water generated during flash evaporation converges at a water collecting tank, circulating wastewater in the flash evaporation device flows into a spraying chamber for further atomized concentration with the assistance from the compressed air, the wastewater containing the salts is evaporated in the spraying chamber till complete crystallization, and generated crystallized salts are stacked at a discharging port in the bottom of the spraying chamber and removed by a scraper at regular time. The system fully utilizes waste heat and achieves energy gradient utilization and zero discharge of the wastewater in the power plant.

The invention provides a device and a technology capable of combining high-salt content oil field sewage treatment and viscous oil recovery, and belongs to the technical field of sewage treatment. The device and the technology can be utilized for sewage treatment of a petroleum exploitation industry, a petroleum refining industry and chemical production processes, especially, realize high-efficiency treatment of high-salt content oil field sewage, and effectively combine high-salt content oil field sewage treatment and viscous oil recovery. The device is characterized mainly in that the device comprises a burning evaporator used in high pressure water, a multi-stage flash evaporation pot, a spray evaporator and a steam injection boiler. Through the device and the technology, advanced treatment of high-salt content oil field sewage is realized; fresh water and salt slurry can all be obtained; zero discharge is realized really; and waste water production is avoided. In addition, high-temperature high-pressure secondary steam and gas can be combined with boiler steam so that viscous oil can be recovered according to an optimal ratio and full utilization of energy is realized. The device has a compact structure, high efficiency and good economy. The technology is stable, reliable and novel oil field sewage treatment technology.

The invention discloses a plate type multistage flash evaporation desulfurization wastewater treatment and recovery device and method. The device mainly comprises plate type heat exchangers, a plate type condenser, a boiler, flash evaporation tanks, fresh water tanks, water pumps and stainless steel pipelines. Pretreated desulfurization wastewater enters the plate type heat exchangers stage by stage, and enters the first-stage flash evaporation tank for flash evaporation after being heated to certain temperature, secondary steam enters the plate type heat exchanger of the next stage to be condensed to release latent heat to preheat the desulfurization wastewater, the concentrated desulfurization wastewater enters the flash evaporation tank of the next stage for flash evaporation, the process is sequentially implemented to the final stage, the secondary steam of the final stage enters the plate type condenser, the condensed fresh water of each stage enters a fresh water pond for recovery, a part of the concentrated desulfurization water is continuously flash-evaporated as circulating liquid, and the other part of the concentrated desulfurization water is treated in a centralized way after entering a concentrate treatment pond. According to the device and the method, the latent heat of the secondary steam can be recovered, the concentration multiple is high, the occupied area is small, the energy consumption is low, and the zero emission of the desulfurization wastewater can be realized.

This invention belongs to the domain of environment-protection technology which is used to the solid fuel of the urban rubbish pyrogenation. It utilizes the fuel from the urban rubbish to the seawater desalination following the steps: 1) carry the solid fuel to the seawater-desalination place; 2) burn; 3) producing sea steam by the burning heat and the steam condenses to the fresh water. During the desalination, it can adopt multi-scale instant steam or multi-efficiency steam. The sea water transforms to the fresh water by steaming after deleting the suspended substance. Meanwhile, it produces condemned inorganic-salt waste liquid which can get NaCl, MgCl2, MgSO4 via crystallization. It can also get NaOH, H2, Cl2 via dialyses or compounds the H2 and Cl2 to HCl which is the chemistry material. This invention can make the rubbish resource, reduction, non-harm which comes to circulation and save much oil and coal that are non-recycled fossil fuel. It has good social and environmental benefits.

The invention provides an antisludging agent for a hot method during sea water desalination. The antisludging agent for the hot method during sea water desalination contains deionized water, alcohols, imidazoles, hydrolytic polymaleic anhydride, ethylenediamine tetramethylene phosphonate, carboxyethylthiosuccinic acid and acryloyl morph copolymer in mass percent of (30-60):(2-8):(0.5-1.5):(5-35):(5-10):(2-15):(15-30). The antisludging agent for the hot method during sea water desalination can be applied to a multiple-effect distillation and multi-stage flash distillation system, has good inhibiting effect and dispersing effect on multiple dirts such as calcium carbonate and calcium sulphate, has a good copper corrosion inhibiting effect and does not influence smell and colour of a water product.

The invention discloses a Texaco gasifier black water heat recovery and treatment system. The Texaco gasifier black water heat recovery and treatment system comprises a multistage flash evaporator system and a flash evaporation heat exchange system, the multistage flash evaporator system comprises a high-pressure flash evaporation tank, a low-pressure flash evaporation tank and a vacuum flash evaporation tank, the flash evaporation heat exchange system comprises a compressor, a cooling grid and a heating heat exchanger, the gas phase outlet of the high-pressure flash evaporation tank is connected with the gas phase inlet of a hot water tower, the cooling rid is arranged in the hot water tower, the outlet of the cooling grid is connected with the inlet of the heating heat exchanger through a pipeline, and the inlet of the cooling grid is connected with the refrigerant outlet of the heating heat exchanger; the liquid phase outlet of the high-pressure flash evaporation tank is connected with the liquid inlet of the heating heat exchanger, the liquid outlet of the heating heat exchanger is connected with the inlet of the low-pressure flash evaporation tank, and the liquid phase outlet of the low-pressure flash evaporation tank is connected with the inlet of the vacuum flash evaporation tank. The flash evaporation heat exchange system absorbs heat in the hot water tower and uses the absorbed heat to heat blank water among the flash evaporation tanks, so the heat recycling efficiency is high, and the gas-liquid conversion efficiency in the hot water tower is increased.

The invention discloses a Rankine cycling and seawater freshening dual-efficiency recovery system. The system adopts the technical scheme that an evaporator, a steam turbine, a condenser and a working medium pump are sequentially connected, and the steam turbine is connected with a generator shaft, so as to form a Rankine cycling heat power generation system; high-temperature waste gas exhausted by an engine is directly subjected to heat exchange with working medium at the gas side of the evaporator, and a water pump is sequentially and serially connected with the seawater pipe of a three-stage flash evaporating chamber; the seawater in a first-stage flash evaporating chamber is subjected to heat exchange by the condenser, and then is changed into high-temperature seawater to sequentially enter the three-stage flash evaporating chamber, and along with the continuous evaporation of the seawater, the seawater with relatively higher concentration is drained by the concentrate seawater passage of the three-stage flash evaporating chamber; and the interiors of the first-stage flash evaporating chamber, a second-stage flash evaporating chamber and a third-stage flash evaporating chamber are respectively provided with a steam and water separator, and outlets of the three steam and water separators are connected in parallel to form a freshwater delivery passage. When the residual heat of the exhausted gas of the engine is utilized to generate power, the freshwater supply requirements on ships are met by a multi-stage flash evaporating seawater freshening device, so the fuel economy of the ships is greatly improved.

The invention discloses a multistage high-efficiency flash evaporation sludge dewatering treatment system and a method. The utilization problem of sludge pyrolysis multistage flash evaporation secondary steam is solved in the invention. The system comprises a pretreatment unit, a boiling unit, a multistage flash evaporation unit and a dewatering and backmixing unit, the pretreatment unit comprises a mixer for mixing the sludge through a rotor pump, the boiling unit comprises a heater connected with the sludge mixer and a boiler connected with the heater, the multistage flash evaporation unit comprises a flash evaporation device and a heat energy recovery device for conveying steam in the flash evaporation device to the heater, the dewatering and backmixing unit comprises a screw dewaterer for conveying separated water to the sludge mixer through a reuse water pump, the screw dewaterer is connected with a secondary flash evaporation device. The method sequentially comprises: sludge mixing, heating treatment, continuous flash evaporation and dewatering separation. The system and the method are adopted to recover the flash evaporation secondary steam, so the heat energy utilization rate in the sludge treatment process and the reliability of a sludge treatment device are increased.

The invention relates to an energy-saving method in production of aluminium oxide and especially relates to a high-pressure dissolution-out and evaporation combined energy-saving method in production of the aluminium oxide. The method includes following steps: heating dissolved-out raw ore pulp with new steam employed in a high-pressure dissolution-out process to obtain new steam condensed water; performing a flash process to the new steam condensed water to form a flash steam under a pressure of 0.4-0.6 MPa; sending the flash steam through pipelines to a mother liquid evaporation process for partially replacing new steam; carrying out a multistage flash process to the dissolved-out raw ore pulp after the high-pressure dissolution-out process, wherein a flash steam, under a pressure of 0.4-1.0 MPa, is generated in first-stage flash from the fourth stage to the sixth stage in the multistage flash process with from the ninth stage to the eleventh stage being pre-heated; and sending the flash steam to the mother liquid evaporation process through pipelines for partially replacing the new steam. The method is characterized by employing a new high-pressure dissolution-out and evaporation combined energy-saving technology so that thermal energy in a system can be utilized better, thereby achieving a purpose of saving energy.

The invention discloses a high-temperature-resistant scale inhibition dispersing agent and a preparation method thereof. The high-temperature-resistant scale inhibition dispersing agent is prepared from the following raw materials in parts by weight: 15-25 parts of hyperbranched macromolecules, 23-47 parts of a multipolymer, 10-15 parts of modified chitosan and 20-45 parts of deionized water. Thehyperbranched macromolecules are organic phosphine hyperbranched macromolecules taking melamine as a core. The multipolymer is prepared by copolymerization of amino acid, carboxylic anhydride and sulfonate. The high-temperature-resistant scale inhibition dispersing agent capable of being used for multistage flash evaporation and sea water desalination systems is prepared from hyperbranched macromolecules, multipolymer and modified chitosan. Compared with the existing similar products, the high-temperature-resistant scale inhibition dispersing agent prepared by the invention has excellent performance and is particularly more outstanding in the aspects of sulfate and silicon scale inhibition, and efficient, energy-saving and stable operation of a multi-effect evaporation and sea water desalination system is realized.

The invention belongs to the field of sea water desalinization, and particularly relates to a sea water desalinization method by utilizing an industrial waste heat combined multi-stage flash evaporation device, and a device applied to the method. In order to solve the problems existing in the prior art, the invention provides the sea water desalinization method by taking industrial waste heat as a heat source and with adjustable elastic change of water production capacity, and the corresponding device. Particularly, the sea water desalinization method by waste heat recovery adopts the technical scheme that the method comprises the following steps that 1) flue gas of a boiler and low-pressure dead steam of a steam turbine perform heat exchange and then the low-pressure dead steam serves as power steam; 2) the power steam is supplied to a heater of the multi-stage flash evaporation device to heat raw sea water; 3) the heated sea water is sprayed into a first-stage flash evaporation chamber by a water injector; and 4) the sea water in a brine tank is sprayed into a next-stage flash evaporation chamber by the action of a water injector of the next-stage flash evaporation chamber until strong brine is discharged by a final-stage flash evaporation chamber.

This invention discloses device and method for completely flash-evaporating sodium aluminum solution during the production of aluminum oxide. The method comprises: (1) introducing the liquid to be evaporated from the raw liquid pool to a multi-stage canula preheater through a centrifuge pump; (2) heating the liquid by secondary steam in the multi-stage canula preheater and new steam in the new-steam preheater; (3) flash-evaporating in a multi-stage flash-evaporator; (4) discharging through a discharge pump to obtain evaporating mother liquid. This invention adopts two-step multi-stage preheating at different temperatures, and controls the temperature difference of multi-stage flash-evaporator cooling to between 10-13 deg.C, thus making full use of secondary steam, largely lower the investment and simplify the process.

The invention discloses a multi-stage flashing sludge continuous hydrothermal treatment device, and the multi-stage flashing sludge continuous hydrothermal treatment device comprises a raw mud buffertank, a homogenization reactor, slurrying reactors, a hydrothermal reactor and flashing reactors which are sequentially connected. The number of the slurrying reactors is at least one, and the numberof the flashing reactors is at least two, the slurrying reactors are sequentially connected in series and the flashing reactors are sequentially connected in series. The homogenization reactor and theslurrying reactors arranged from front to back are also in one-to-one correspondence connection with the flashing reactors which are arranged from the back to the front. The multi-stage flashing sludge continuous hydrothermal treatment device is simple in equipment and process, the sludge treatment efficiency is high, and the energy consumption is effectively reduced.

The invention discloses an A/O forward osmosis treatment system and a treatment process for black and odorous water. The system comprises a black and odorous water suspended matter removal device, an organic matter treatment device, a forward osmosis device, and a multistage flash evaporator connected with a water outlet in a supporting layer side of the forward osmosis device. A water inlet of the organic matter treatment device is connected with a water outlet of the suspended matter removal device; a water outlet of the organic matter treatment device is connected with a water inlet in an active layer side of the forward osmosis device; a water outlet in the active layer of the forward osmosis device is connected with a water inlet of a sedimentation basin; and a concentrated water outlet of the multistage flash evaporator is connected with a water inlet in the supporting layer side of the forward osmosis device. According to the A/O forward osmosis treatment system and the treatment process for the black and odorous water provided by the invention, a forward osmosis technology and an A/O process are combined for co-treating the black and odorous water, so that organic matters and nitrogen substances of the waste water are efficiently removed, the membrane pollution is less, a concentrated raw material solution subjected to osmosis treatment is added with a phosphate removing agent so as to be treated and then discharged into a recovery device, and the impact of the discharge of the concentrated water on the environment is avoided.