A pretreatment equipment and method for kitchen and restaurant wastewater

Abstract

The present invention discloses a pretreatment device and method for kitchen waste water. The device includes a sealed tank (1), and an inlet water system (2), a waste oil discharge system (3) and a sludge discharge system (4) are arranged outside the sealed tank (1). The kitchen waste water enters the sealed tank (1) through the inlet water system (2), and after the oil and sludge in the waste water are stratified, they are discharged through the waste oil discharge system (3) and the sludge discharge system (4) respectively. The pretreatment device for kitchen waste water further includes an oil scraping system (5) and a sludge scraping system (6), which can scrape the deposited grease and sludge in the sealed tank. The device disclosed by the present invention is simple to operate, convenient to maintain, and has a high oil-water separation efficiency. The pretreatment method disclosed by the present invention has a high oil content in the recovered waste oil, a high sludge concentration, and a low oil content in the effluent.

Description

Technical Field

[0001] The present invention relates to the field of sewage treatment, specifically to the field of kitchen waste water treatment, and particularly to a pretreatment device and method for kitchen waste water with a relatively high oil content. Background Art

[0002] The kitchen sewage in the catering service industry contains a large amount of oil and lipid substances. If not effectively removed, it will adhere to the outer walls of pipelines and inspection wells, forming oil scale that is difficult to remove, resulting in poor drainage of the pipelines. Especially in winter, the grease cools and solidifies at low temperatures, easily causing serious siltation and pipeline sanitation problems.

[0003] In addition, after the grease enters the sewage treatment plant, in the subsequent secondary biochemical treatment stage, it will adhere to the surface of microorganisms, causing difficulty in breathing for the microorganisms and a decline in the ability to degrade pollutants. Seriously, it will lead to a large number of deaths of microorganisms. Therefore, for kitchen waste water with a relatively high oil content in restaurants, hotels, canteens, etc., oil substances must be removed in the pretreatment stage before being discharged into the municipal pipe network.

[0004] Currently, the commonly used methods for removing floating oil and dispersed oil mainly include gravity oil removal method and coalescence oil removal method. Among them, the commonly used processes in the gravity oil removal method include oil removal tanks, horizontal flow oil separation tanks, and inclined plate oil separation tanks. Among them, the oil removal tank has high oil removal efficiency, but requires pressure inlet water, has high operating costs, and has complex internal equipment; the horizontal flow and inclined plate oil separation tanks have simple structures, but poor oil removal effects and large floor areas. Moreover, the commonly used oil separation tanks in the prior art do not have effective oil discharge, sludge discharge, and cleaning measures. After operating for a period of time, grease accumulates and sludge deposits, resulting in serious siltation and blockage of the oil separation facilities and affecting the oil removal effect.

[0005] Therefore, there is an urgent need to provide a pretreatment device for kitchen waste water with a simple structure, high oil removal efficiency, small floor area, and capable of recovering grease. Summary of the Invention

[0006] In order to overcome the above problems, the inventors of the present invention have conducted intensive research and designed a pretreatment device for kitchen waste water. Through the tangential water inlet system, waste oil discharge system, and sludge discharge system provided, it can utilize the density difference of oil, water, and sludge to make them stratified, and then discharge them from their respective discharge systems through the siphon effect; through the oil scraping system and sludge scraping system provided, it can effectively scrape the deposited grease and sludge in the sealed tank body to prevent siltation and blockage; through the stirring, heating device, and promoting separation agent outflow device provided, it can effectively improve the oil-water separation rate and separation efficiency, thus completing the present invention.

[0007] Specifically, the object of the present invention is to provide the following aspects:

[0008] In a first aspect, a pretreatment device for kitchen waste water is provided. The device includes a sealed tank 1, and an inlet water system 2, an oil waste discharge system 3 and a sludge discharge system 4 are arranged outside the sealed tank 1.

[0009] The kitchen waste water enters the sealed tank 1 through the inlet water system 2, and after the oil sludge in the waste water is stratified, it is discharged through the oil waste discharge system 3 and the sludge discharge system 4 respectively.

[0010] In a second aspect, a pretreatment method for kitchen waste water is provided, preferably carried out by using the device described in the first aspect. The method includes the following steps:

[0011] Step I: Connect the device and introduce the kitchen waste water to be treated through the inlet water system.

[0012] Step II: Turn on the driving motor and the external heating device to stir and heat the kitchen waste water.

[0013] Step III: After the water, oil and sludge in the sealed tank are stratified, turn on the first vacuum pump to discharge the waste oil on the top layer.

[0014] Step IV: Turn on the water pump to discharge the waste water layer, and then turn on the second vacuum pump to discharge the bottom sludge.

[0015] The beneficial effects of the present invention include:

[0016] (1) The pretreatment device for kitchen waste water provided by the present invention is simple to operate, designed as a closed structure, has good sanitary conditions, a long service life and is easy to maintain.

[0017] (2) The pretreatment device for kitchen waste water provided by the present invention increases the residence time of the waste water by setting a tangential inlet pipe, and improves the efficiency of oil-water separation.

[0018] (3) The pretreatment device for kitchen waste water provided by the present invention has a conical shape at the top and bottom of the sealed tank, a large pool depth, saves floor space, and is convenient for collecting and concentrating waste oil and sludge.

[0019] (4) The pretreatment device for kitchen waste water provided by the present invention is provided with a top oil scraping system and a bottom sludge scraping system, which can prevent the inner wall of the tank from depositing grease and sludge, avoid siltation and blockage, and improve the oil removal efficiency.

[0020] (5) The pretreatment device for kitchen waste water provided by the present invention can separate and float the emulsified oil in the waste water at high temperature by setting a heating device, and can heat the grease collected at the top to liquefy the condensed and solidified grease, which is convenient for discharge.

[0021] (6) The pretreatment device for kitchen waste water provided by the present invention can effectively improve the oil-water separation efficiency by setting a stirring device and a periodically flowing out separation promoter.

[0022] (7) The kitchen waste water pretreatment method provided by the present invention has a high oil content in the recovered waste oil, a high sludge concentration, and a low oil content in the effluent. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 The overall structural schematic diagram of the kitchen waste water pretreatment equipment showing a preferred embodiment of the present invention;

[0024] Figure 2 The connection relationship schematic diagram of the water inlet system and the sealed tank showing a preferred embodiment of the present invention;

[0025] Figure 3 The detailed structural schematic diagram of the stirring member and the central fixed shaft showing a preferred embodiment of the present invention;

[0026] Figure 4 The horizontal through groove structural schematic diagram showing a preferred embodiment of the present invention;

[0027] Figure 5 The structural schematic diagram of the exhaust hole showing a preferred embodiment of the present invention.

[0028] Explanation of the reference numerals in the drawings:

[0029] 1 - Sealed tank;

[0030] 2 - Water inlet system;

[0031] 21 - Water inlet pipe;

[0032] 3 - Waste oil discharge system;

[0033] 31 - First valve;

[0034] 32 - Waste oil discharge pipe;

[0035] 33 - Waste oil collection bucket;

[0036] 34 - First vacuum pump;

[0037] 4 - Sludge discharge system;

[0038] 41 - Second valve;

[0039] 42 - Sludge discharge pipe;

[0040] 43 - Sludge collection bucket;

[0041] 44 - Second vacuum pump;

[0042] 5 - Oil scraping system;

[0043] 51 - Oil scraping arm;

[0044] 52 - Central fixed shaft;

[0045] 521 - Inner shaft;

[0046] 522 - Outer shaft;

[0047] 5221 - Horizontal through groove;

[0048] 53 - First support member;

[0049] 531 - First connecting plate;

[0050] 532 - Second connecting plate;

[0051] 54 - Oil scraping brush;

[0052] 6 - Mud scraping system;

[0053] 61 - Mud scraping plate;

[0054] 62 - Second support member;

[0055] 621 - Vertical rod;

[0056] 622 - First horizontal rod;

[0057] 623 - Second horizontal rod;

[0058] 7 - Support plate;

[0059] 71 - Liquid storage bottle;

[0060] 72 - Fixed plate;

[0061] 73 - Heating device;

[0062] 8 - Stirring member;

[0063] 81 - First stirring plate;

[0064] 82 - Second stirring plate;

[0065] 83 - Exhaust hole;

[0066] 831 - Retaining frame. Detailed implementation mode

[0067] The present invention will be further described in detail below with reference to the drawings and embodiments. Through these descriptions, the features and advantages of the present invention will become more clearly defined. Among them, although various aspects of the embodiments are shown in the drawings, the drawings do not have to be drawn to scale unless otherwise specified.

[0068] In the first aspect of the present invention, a pretreatment device for kitchen waste water is provided, as Figure 1As shown, the device includes a sealed tank 1, and an inlet water system 2, an exhaust waste oil system 3 and a sludge discharge system 4 are arranged outside the sealed tank 1.

[0069] The kitchen waste water enters the sealed tank 1 through the inlet water system 2, and after the oil sludge in the waste water is stratified, it is discharged through the exhaust waste oil system 3 and the sludge discharge system 4 respectively.

[0070] According to a preferred embodiment of the present invention, as Figure 1 shown, the sealed tank 1 is a closed structure, including a top, a body and a bottom arranged in sequence.

[0071] Both the top and the bottom of the sealed tank are conical.

[0072] In a further preferred embodiment, the top cone angle of the sealed tank 1 is 120° - 180°;

[0073] The bottom cone angle of the sealed tank 1 is 120° - 180°.

[0074] Among them, the inventor of the present invention found that setting the sealed tank to the above structure is beneficial to the concentration of sludge and grease.

[0075] In an even more preferred embodiment, the sealed tank 1 is made of stainless steel, carbon steel, polymer material or reinforced concrete.

[0076] According to a preferred embodiment of the present invention, as Figure 2 shown, the inlet water system 2 includes an inlet pipe 21, and the inlet pipe 21 is tangent to the body of the sealed tank 1, so that the inlet water is along the direction of the pool wall.

[0077] Among them, the inlet water is along the direction of the pool wall and enters horizontally to form a swirl, which can increase the path of the sewage traveling in the pool, extend the oil-water separation time, and improve the oil-water separation effect. The oily waste water forms a swirl along the horizontal direction of the pipe wall in the tank, and uses the density difference of oil, water and sludge to form a stratification of upper-layer waste oil, middle-layer sewage and lower-layer sludge.

[0078] Among them, the size of the inlet pipe 21 satisfies that the water flow velocity is 0.01 - 1.0 m / s, preferably 0.05 - 0.8 m / s, and more preferably 0.1 - 0.5 m / s.

[0079] According to a preferred embodiment of the present invention, the exhaust waste oil system 3 includes a first valve 31, an exhaust waste oil pipe 32 and an exhaust waste oil collection bucket 33 arranged in sequence.

[0080] Among them, the first valve 31 is arranged at the top of the sealed tank 1.

[0081] In a further preferred embodiment, a transparent observation window is provided on the waste oil discharge pipe 32 to observe the waste oil discharge situation.

[0082] In an even more preferred embodiment, the waste oil discharge system 3 further includes a first vacuum pump 34, and the first vacuum pump 34 is connected to the waste oil collection barrel 33 through a pipeline.

[0083] In the present invention, after the first valve is opened, the waste oil on the top layer in the sealed tank is discharged into the waste oil barrel through the siphon effect under the action of the first vacuum pump for collection.

[0084] According to a preferred embodiment of the present invention, the sludge discharge system 4 includes a second valve 41, a sludge discharge pipe 42, and a sludge collection barrel 43 arranged in sequence.

[0085] Among them, the second valve 41 is arranged at the bottom of the sealed tank 1.

[0086] In a further preferred embodiment, a transparent observation window is provided on the sludge discharge pipe 42 to observe the sludge discharge situation.

[0087] In an even more preferred embodiment, the sludge discharge system 4 further includes a second vacuum pump 44, and the second vacuum pump 44 is connected to the sludge collection barrel 43 through a pipeline.

[0088] Among them, after the second valve is opened, the sludge on the bottom layer in the sealed tank is discharged into the sludge collection barrel through the siphon effect under the action of the second vacuum pump for collection.

[0089] According to a preferred embodiment of the present invention, the kitchen waste pretreatment equipment further includes an oil scraping system 5 and a sludge scraping system 6.

[0090] The oil scraping system 5 is arranged on the top of the sealed tank 1 to scrape the waste oil on the tank wall.

[0091] The sludge scraping system 6 is arranged at the bottom of the sealed tank 1 to scrape the sludge on the tank wall.

[0092] In a further preferred embodiment, the oil scraping system 5 includes an oil scraping arm 51 and a central fixed shaft 52, and the oil scraping arm 51 is connected to the central fixed shaft 52 through a first support 53.

[0093] According to a preferred embodiment of the present invention, there are a plurality of the oil scraping arms 51, which are evenly distributed around the top end of the central fixed shaft 52.

[0094] The plurality of oil scraping arms 51 are all inclined and present an "umbrella-shaped" structure.

[0095] In a further preferred embodiment, the oil scraping arm 51 has a cuboid structure.

[0096] In a further preferred embodiment, there are two oil scraping arms 51, which are arranged symmetrically with respect to the central fixed axis;

[0097] The included angle between the two oil scraping arms is the same as the top cone angle of the sealed tank 1.

[0098] According to a preferred embodiment of the present invention, as Figure 1 shown, an oil scraping brush 54 is provided on the side of the oil scraping arm 51 close to the inner wall of the sealed tank 1,

[0099] The oil scraping brush 54 is made of a flexible material and is arranged in contact with the inner wall of the sealed tank 1 to scrape off the grease deposited on the inner wall.

[0100] In a further preferred embodiment, the oil scraping brush 54 is made of modified loofah sponge, and the modification is to perform oil-repellent modification on the loofah sponge to improve the hydrophilic and oil-repellent properties of the loofah sponge.

[0101] Among them, loofah sponge is the vascular bundle in the loofah fruit, which has a unique three-dimensional porous physical structure and excellent mechanical strength, and can be made into various washing, filtering and cushioning products. It is also a rich renewable resource, with the characteristics of being cheap, degradable and environmentally friendly.

[0102] In the present invention, the loofah sponge is commercially available.

[0103] In a further preferred embodiment, the modification is carried out according to the following steps:

[0104] Step 1, pre-treat the loofah sponge.

[0105] According to a preferred embodiment of the present invention, the pre-treatment is to soak the loofah sponge to remove impurities in the loofah sponge,

[0106] The soaking is carried out with an acetic acid solution.

[0107] In a further preferred embodiment, the mass concentration of the acetic acid solution is 20% - 40%, preferably 28% - 35%, and more preferably 30%.

[0108] The inventor of the present invention has found that soaking the loofah sponge with the acetic acid solution of the above mass concentration can effectively remove impurities in the loofah sponge, and the addition amount of the acetic acid solution is suitable to completely soak the loofah sponge.

[0109] In a further preferred embodiment, heat is applied to make the temperature of the acetic acid solution 60 - 80°C, and the soaking time is 2.5 - 3.5 h.

[0110] Step 2: Wash the loofah pre-treated in Step 1, and then soak it in the modifier solution.

[0111] Among them, the washing is to clean the soaked loofah with deionized water to clean the acetic acid solution and prevent reaction with the components in the modifier solution.

[0112] According to a preferred embodiment of the present invention, the modifier solution is composed of raw materials including the following parts by weight:

[0113]

[0114]

[0115] Preferably, the modifier solution is composed of raw materials including the following parts by weight:

[0116]

[0117] In a further preferred embodiment, the hydrophilic particles are one or more of hydrophilic nano-silica, hydrophilic nano-titanium dioxide, and hydrophilic graphene oxide, preferably hydrophilic nano-silica.

[0118] In a still further preferred embodiment, the particle size of the hydrophilic particles is 50 - 150 nm, preferably 70 - 130 nm, such as 100 nm.

[0119] According to a preferred embodiment of the present invention, the hydrophilic particles are prepared according to the following steps: Add 5 parts of nano-particles, 0.5 - 0.8 parts of additive, and 40 - 60 parts of solvent into a reaction kettle, react at 40 - 70 °C for 3 - 8 h. After the reactants are cooled, filter the product under reduced pressure and dry it at room temperature for 15 - 24 h, and then grind and screen to obtain hydrophilic particles with hydroxyl groups on the surface.

[0120] In a further preferred embodiment, the additive is one or more of polyacrylic acid, polyacrylamide, oxalic acid, and trimethylsilanol.

[0121] The solvent is one or more of ethylene glycol, ethanol, n-butanol, and n-hexane.

[0122] According to a preferred embodiment of the present invention, the first surfactant is one of fatty alcohol polyoxyethylene ether 9, sodium lauryl polyoxyethylene sulfate, and sodium dodecyl sulfate.

[0123] According to a preferred embodiment of the present invention, the weight ratio of the loofah to the modifier solution is 10:(50 - 150), preferably 10:(70 - 120), and more preferably 10:100.

[0124] The inventor of the present invention has found through research that when the weight ratio of loofah sponge to the modifier solution is less than 10:50, the modification is incomplete; when the weight ratio of loofah sponge to the modifier solution is greater than 10:150, the modification is complete, and further increasing the amount of the modifier solution will cause waste of resources.

[0125] Among them, adding the loofah sponge to the modifier solution for soaking is to introduce hydrophilic and oleophobic groups onto the loofah sponge.

[0126] In a further preferred embodiment, the modifier solution is pre-heated, and the temperature after heating is 120-150 °C.

[0127] In a still further preferred embodiment, the soaking time of the loofah sponge in the modifier solution is 3-7 h, preferably 4-6 h.

[0128] Among them, the solution is appropriately heated during the soaking process to maintain the temperature.

[0129] The inventor of the present invention has found through research that if the soaking time is too long, it will not increase the modification effect and will cause waste; if the soaking time is too short, the modification is incomplete and the hydrophilic and oleophobic effects are poor.

[0130] Step 3, drying the loofah sponge treated in step 2 to obtain the modified loofah sponge.

[0131] Among them, the drying is carried out at 100-140 °C. When the drying temperature is lower than 100 °C, the drying time is longer and the efficiency is low; when the drying temperature is higher than 140 °C, it is easy to cause oxidation of the modified groups.

[0132] In the present invention, the obtained modified loofah sponge is made into an oil scraping brush that can be arranged on the oil scraping plate according to the commonly used oil brush manufacturing process in the prior art.

[0133] According to a preferred embodiment of the present invention, the first support member 53 includes a first connecting plate 531 and a second connecting plate 532. Among them, the length of the first connecting plate is less than the length of the second connecting plate.

[0134] The first connecting plate 531 is connected to the upper half of the oil scraping arm 51, and the second connecting plate 532 is connected to the bottom end of the oil scraping arm 51.

[0135] In a further preferred embodiment, the first connecting plate 531 is in a shape similar to "C", including two inclined plates and a horizontal plate connected between the two inclined plates.

[0136] The two inclined plates are respectively connected to the upper half of the two oil scraping arms, preferably vertically connected.

[0137] In a further preferred embodiment, a through hole is provided at the center of the horizontal plate for the central fixed shaft to pass through.

[0138] Preferably, the second connecting plate 532 is a horizontal plate, and a through hole is provided at its center for the central fixed shaft to pass through.

[0139] According to a preferred embodiment of the present invention, the sludge scraping system 6 includes a sludge scraping plate 61 and a second support member 62, wherein,

[0140] The sludge scraping plate 61 is fixedly connected to the bottom end of the central fixed shaft 52 through the second support member 62.

[0141] In a further preferred embodiment, there are a plurality of the sludge scraping plates 61, which are evenly distributed around the central fixed shaft 52,

[0142] The plurality of sludge scraping plates 61 are all inclined and arranged in an "inverted umbrella" structure.

[0143] Preferably, the sludge scraping plate 61 is in a cuboid structure, and its lowest point is flush with the bottom surface of the central fixed shaft.

[0144] In a further preferred embodiment, there are two sludge scraping plates 61, which are symmetrically arranged about the central fixed shaft in a mirror image,

[0145] The included angle between the two sludge scraping plates 61 is the same as the bottom cone angle of the sealed tank 1.

[0146] According to a preferred embodiment of the present invention, the second support member 62 includes a vertical rod 621 and a horizontal rod that intersect perpendicularly. The horizontal rod includes a first horizontal rod 622 and a second horizontal rod 623 that are arranged in parallel,

[0147] The first horizontal rod 622 is fixedly attached to the bottom surface of the central fixed shaft, and both ends of the second horizontal rod 623 are fixedly connected to the two sludge scraping plates respectively.

[0148] In a further preferred embodiment, a through hole is provided at the center of the first horizontal rod 622 to facilitate the passage of the central fixed shaft;

[0149] The length of the first horizontal rod 622 is less than the length of the second horizontal rod 623.

[0150] In a further preferred embodiment, the vertical rod is a hollow structure, and the central fixed shaft is coaxially arranged inside the vertical rod.

[0151] In the present invention, the oil scraping arm and the sludge scraping plate are respectively fixedly connected to the central fixed shaft through the first support member and the second support member, so that the oil scraping arm and the sludge scraping plate can move synchronously with the rotation of the central fixed shaft.

[0152] According to a preferred embodiment of the present invention, as Figure 3 shown, the central fixed shaft 52 is a double-layer structure, including an inner shaft 521 and an outer shaft 522 arranged concentrically,

[0153] A cavity is formed between the inner shaft 521 and the outer shaft 522.

[0154] In a further preferred embodiment, both the first support member 53 and the second support member 62 are fixedly connected to the outer shaft 522,

[0155] The inner shaft 521 and the outer shaft 522 can rotate relative to each other.

[0156] In a still further preferred embodiment, the top and bottom ends of the inner shaft and the outer shaft are connected by bearings.

[0157] According to a preferred embodiment of the present invention, a support plate 7 is provided on the outer wall of the outer shaft 522 and below the first support member 53,

[0158] A liquid storage bottle 71 is provided on the support plate 7, and a first through hole is also provided on the support plate 7. The size of the through hole is the same as the size of the liquid outlet of the liquid storage bottle 71.

[0159] In a further preferred embodiment, as Figure 4 shown, a horizontal through groove 5221 is formed on the circumference of the outer shaft 522 and below the support plate 7,

[0160] The upper groove surface of the horizontal through groove 5221 is flush with the lower surface of the support plate 7.

[0161] Wherein, the horizontal through groove divides the outer shaft into an upper half and a lower half. The upper half and the lower half of the outer shaft are respectively connected with a driving mechanism, and the movement of the stirring member sludge scraping system is synchronized. The support plate is synchronized with the movement of the oil scraping system.

[0162] In a still further preferred embodiment, a fixing plate 72 is arranged in cooperation with the horizontal through groove 5221. The fixing plate 72 is fixedly connected with the inner shaft 521,

[0163] The fixing plate 72 is arranged in a fitting manner with the support plate 7.

[0164] Wherein, the horizontal through groove can rotate horizontally relative to the fixing plate.

[0165] Preferably, a second through hole is formed on the fixing plate 72. The size of the second through hole is the same as the size of the first through hole,

[0166] The position of the first through hole changes with the change of the position of the fixing plate. When the first through hole rotates to the lower part of the second through hole, the two are communicated, and the liquid in the liquid storage bottle can flow out.

[0167] In the present invention, when the outer shaft of the central fixed shaft rotates relative to the inner shaft under the action of an external force, the horizontal through groove rotates horizontally relative to the fixing plate, so that the first through hole and the second through hole are periodically communicated, and then the liquid in the liquid storage bottle flows out periodically, which can improve the automation degree of the equipment and improve the efficiency.

[0168] According to a preferred embodiment of the present invention, a separation promoting agent is contained in the liquid storage bottle 71, and the separation promoting agent is mixed by components including the following weight ratios:

[0169]

[0170] Preferably, the separation promoting agent is mixed by components including the following weight ratios:

[0171]

[0172] In a further preferred embodiment, the natural polymer microspheres are one or more of albumin microspheres, gelatin microspheres, starch microspheres and chitosan microspheres,

[0173] Preferably, they are starch microspheres.

[0174] In a still further preferred embodiment, the average particle size of the natural polymer microspheres is 40-120 μm, preferably 60-100 μm.

[0175] The inventor of the present invention found that the natural polymer microspheres in the above particle size range have a large specific surface area and strong adsorption performance, and can enable the microparticles in the oily sewage to be adsorbed on the surface of the microspheres efficiently and uniformly.

[0176] According to a preferred embodiment of the present invention, the flocculant is a composite flocculant, including polyacrylamide, poly(dimethyldiallylammonium chloride) and an inorganic flocculant,

[0177] The inorganic flocculant is selected from one or more of aluminum chloride, ferric sulfate, ferric chloride, potassium alum, polyaluminum chloride, polyferric sulfate, polyaluminum sulfate, polyferric chloride sulfate and activated silica.

[0178] In a further preferred embodiment, the inorganic flocculant is selected from one or more of aluminum chloride, ferric sulfate, ferric chloride, polyaluminum chloride, polyferric sulfate and polyaluminum sulfate.

[0179] Preferably, the inorganic flocculant is selected from one or more of aluminum chloride, ferric chloride, polyaluminum chloride and polyferric sulfate.

[0180] In the present invention, the function of the inorganic flocculant is to increase the collision of coagulated solids, and its hydrolysis products agglomerate, bridge and flocculate to form sedimentable or filterable flocs.

[0181] In a further preferred embodiment, the weight ratio of the polyacrylamide, polydimethyldiallylammonium chloride and inorganic flocculant is 10:(3-5):(4-6), preferably 10:(3-4):(4-5), and more preferably 10:4:5.

[0182] The inventor of the present invention has found that using the composite flocculant in the above ratio can effectively improve the oil-water separation rate of oily wastewater.

[0183] According to a preferred embodiment of the present invention, the surfactant is an anionic surfactant and / or a non-ionic surfactant, preferably an anionic surfactant.

[0184] More preferably, it is anionic polyacrylamide and / or sodium dodecylbenzenesulfonate.

[0185] According to a preferred embodiment of the present invention, the pH regulator is one or more of calcium phosphate, sodium citrate, potassium citrate, and citric acid.

[0186] In a further preferred embodiment, the pH regulator is sodium citrate and / or potassium citrate.

[0187] According to a preferred embodiment of the present invention, a heating device 73 is provided in the cavities of the inner shaft 521 and the outer shaft 522.

[0188] The heating device 73 is a spiral heating tube.

[0189] Among them, the spiral heating tube is connected to an external heating device, and the external heating device is arranged outside the sealed tank.

[0190] According to a preferred embodiment of the present invention, a stirring member 8 is further provided on the outer wall of the outer shaft 522. The stirring member 8 is in a "cross" shape and has a plurality of them, which are evenly distributed on the outer wall of the outer shaft 522.

[0191] Preferably, the stirring member 8 includes 2-4 layers, and each layer is evenly distributed on the outer wall of the outer shaft 522.

[0192] In a further preferred embodiment, the stirring member includes a first stirring plate 81 and a second stirring plate 82, which are perpendicular to each other.

[0193] In the present invention, the stirring member is arranged in a structure where the first stirring plate and the second stirring plate intersect perpendicularly, which can make the stirring flow field present an axial and radial intersection, so that the oily kitchen waste water can be stirred evenly and sufficiently.

[0194] Preferably, the first stirring plate 81 is inclinedly connected to the outer shaft 522, and the included angle is 30 to 60 degrees.

[0195] In a further preferred embodiment, a plurality of exhaust holes 83 are provided on both the first stirring plate 81 and the second stirring plate 82.

[0196] The plurality of exhaust holes are evenly arranged.

[0197] In the present invention, providing exhaust holes on the stirring plate can prevent the kitchen waste water from splashing during the stirring process.

[0198] According to a preferred embodiment of the present invention, as Figure 5 shown, a retaining frame 831 is provided in the exhaust hole 83, and the retaining frame is in a cross structure.

[0199] In a further preferred embodiment, the outer edge of the retaining frame 831 is in a blade shape to break up a small amount of lumpy substances in the waste water.

[0200] In a further preferred embodiment, both the central fixed shaft 52 and the stirring member are made of heat-conducting materials.

[0201] Among them, the heating device heats the central fixed shaft, which can also heat the stirring member, and thus can heat the waste water during the stirring process.

[0202] During the heating process of the oily kitchen waste water in the present invention, a part of the emulsified oil can be separated and floated at high temperature, and at the same time, the condensed and solidified grease collected at the top of the sealed tank can be liquefied, which is convenient for discharge.

[0203] In the present invention, the waste water after oil removal in the sealed tank is discharged by a water pump, and the water pump can be a submersible pump placed above the sludge layer in the tank or a vacuum pump placed outside the tank.

[0204] According to a preferred embodiment of the present invention, the top end of the central fixed shaft 52 is located outside the sealed tank 1, and a driving motor is provided on the outer wall of the top end of the central fixed shaft 52 to drive the rotation of the outer shaft of the upper half of the central fixed shaft.

[0205] Preferably, the outer shaft of the lower half of the central fixed shaft is also connected with a driving motor to drive the movement of the outer shaft of the lower half.

[0206] In a further preferred embodiment, the kitchen waste water pretreatment equipment further includes a control system, and the control system is a PLC control system.

[0207] Among them, the control system is respectively connected to the water inlet system, the first vacuum pump, the second vacuum pump, the water pump, the external heating device and the drive motor to control the operation of each system.

[0208] In a further preferred embodiment, the kitchen waste water pretreatment equipment further includes a spray treatment system to perform backwashing on the sealed tank.

[0209] In a second aspect of the present invention, a method for pretreating kitchen waste water is provided. Preferably, the pretreatment equipment described in the first aspect is used. The method includes the following steps:

[0210] Step I, connect the equipment and introduce the kitchen waste water to be treated through the water inlet system.

[0211] Among them, the size of the water inlet pipe in the water inlet system satisfies that the water flow velocity is 0.01 - 1.0 m / s.

[0212] Step II, start the drive motor and the external heating device to stir and heat the kitchen waste water.

[0213] Among them, through the control system, control the oil scraping system, the mud scraping system, the heating device and the stirring member to start, heat and stir the waste water introduced into the tank to promote the separation of oil, water and mud.

[0214] Step III, after the water, oil and mud in the sealed tank are stratified, start the first vacuum pump to discharge the waste oil on the top layer.

[0215] Among them, through the control system, open the first valve and the first vacuum pump at the top of the sealed tank, so that the waste oil on the top layer in the tank is discharged into the waste oil collection bucket under the action of vacuum through the siphon effect. During the discharge process, the waste oil discharge situation can be grasped through the transparent observation window on the waste oil discharge pipe to control the opening or closing of the first valve and the first vacuum pump.

[0216] Step IV, start the water pump to discharge the waste water layer, and then start the second vacuum pump to discharge the bottom sludge.

[0217] Among them, the waste water after oil removal in the tank is discharged through the submersible pump above the sludge layer in the tank or the vacuum pump outside the tank; after the waste water is discharged, open the second valve and the second vacuum pump, so that the sludge at the bottom of the tank is discharged into the sludge bucket under the action of vacuum through the siphon effect; during the discharge process, the sludge discharge situation can be grasped through the transparent observation window on the sludge discharge pipe to control the opening or closing of the second valve and the second vacuum pump.

[0218] In the present invention, optionally, after excluding sludge, the water spraying treatment system is turned on to wash the inner wall of the sealed tank.

[0219] Example

[0220] Preparation of Modified Luffa Sponge in Example 1

[0221] Step 1: Take 0.5 kg of loofah sponge, completely immerse it in acetic acid solution with a mass concentration of 30%, heat the acetic acid solution to 70 °C, and soak for 3 h.

[0222] Step 2: Wash the loofah sponge soaked in Step 1 with deionized water for 3 times, and then immerse it in 5 kg of modifier solution preheated to 130 °C.

[0223] The components and contents in the modifier solution are as follows: hydrophilic nano-silica with a particle size of 100 nm: polyvinyl alcohol: methacrylic acid: sodium lauryl polyoxyethylene ether sulfate: deionized water = 5:15:70:35:90.

[0224] Among them, the hydrophilic nano-silica is obtained by reacting nano-silica, oxalic acid and ethylene glycol according to a weight ratio of 5:0.6:50 at 60 °C for 5 h, cooling and then filtering under reduced pressure, and drying at room temperature for 20 h and then grinding and sieving.

[0225] Soak the loofah sponge in the modifier solution for 5 h.

[0226] Step 3: Dry the loofah sponge obtained in Step 2 at 120 °C to obtain the modified loofah sponge.

[0227] Example 2

[0228] The method used in this example is similar to that in Example 1, except that in Step 1, it is soaked in acetic acid solution with a mass concentration of 20% for 3.5 h.

[0229] Example 3

[0230] The method used in this example is similar to that in Example 1, except that in Step 2, hydrophilic nano-graphene oxide is used to replace hydrophilic nano-silica.

[0231] The hydrophilic nano-graphene oxide is obtained by reacting nano-graphene oxide, polyacrylamide and ethanol according to a weight ratio of 5:0.8:60 at 70 °C for 6 h, cooling and then filtering under reduced pressure, and drying at room temperature for 24 h and then grinding and sieving.

[0232] Example 4

[0233] The method used in this example is similar to that in Example 1, except that in Step 2, the components and contents in the modifier solution are as follows: hydrophilic nano-silica with a particle size of 100 nm: polyvinyl alcohol: methacrylic acid: sodium lauryl polyoxyethylene ether sulfate: deionized water = 5:18:60:40:100.

[0234] Example 5

[0235] The method used in this example is similar to that in Example 1, except that in Step 2, the components and contents in the modifier solution are as follows: hydrophilic nano-silica with a particle size of 100 nm: polyvinyl alcohol: methacrylic acid: sodium lauryl polyoxyethylene ether sulfate: deionized water = 5:20:100:30:110.

[0236] Example 6

[0237] The method used in this example is similar to that in Example 1, except that in Step 2, based on 0.5 kg of loofah sponge, the amount of the modifier solution added is 2.5 kg, and the soaking time is 7 h.

[0238] Example 7

[0239] The method used in this example is similar to that in Example 1, except that in Step 2, based on 0.5 kg of loofah sponge, the amount of the modifier solution added is 7.5 kg, and the soaking time is 4 h.

[0240] Example 8

[0241] In this example, the sealed tank is made of stainless steel material, its top cone angle is 150°, its bottom cone angle is 150°, and the size of the water inlet pipe meets the requirement of a water flow velocity of 0.2 m / s;

[0242] There are 2 oil scraping arms, and the included angle between them is 150°. The oil scraping brushes are made of the modified loofah sponge prepared in Example 1;

[0243] There are 2 mud scraping plates, and the included angle between them is 150°;

[0244] The separation promoter contained in the liquid storage bottle is prepared by mixing components in the following weight ratios: 5 kg of starch microspheres (average particle size of 80 μm), 1.25 kg of polyacrylamide, a mixture of polydimethyldiallylammonium chloride and aluminum chloride (the mass ratio of the three is 10:4:5), 0.75 kg of sodium dodecylbenzenesulfonate, and 0.25 kg of sodium citrate;

[0245] The stirring member has 2 layers, with 4 in each layer.

[0246] Example 9

[0247] This example is similar to Example 8, except that the top cone angle of the sealed tank is 120°, the bottom cone angle is 120°, and the size of the water inlet pipe meets the water flow velocity of 0.01 m / s;

[0248] The oil scraping brush is made of the modified loofah sponge prepared in Example 2.

[0249] Example 10

[0250] This example is similar to Example 8, except that the top cone angle of the sealed tank is 140°, the bottom cone angle is 140°, and the size of the water inlet pipe meets the water flow velocity of 1.0 m / s;

[0251] The oil scraping brush is made of the modified loofah sponge prepared in Example 6.

[0252] Example 11

[0253] This example is similar to Example 8, except that the separation promoter contained in the liquid storage bottle is composed of components mixed in the following weight ratios: 5 kg of gelatin microspheres (average particle size of 120 μm), 1.00 kg of polyacrylamide, a mixture of polydimethyldiallylammonium chloride and polyferric sulfate (mass ratio of the three is 10:3:6), 0.60 kg of sodium dodecylbenzenesulfonate, and 0.20 kg of potassium citrate.

[0254] Example 12

[0255] This example is similar to Example 8, except that the separation promoter contained in the liquid storage bottle is composed of components mixed in the following weight ratios: 5 kg of starch microspheres (average particle size of 80 μm), 1.25 kg of polyacrylamide, a mixture of polydimethyldiallylammonium chloride and ferric chloride (mass ratio of the three is 10:5:6), 0.80 kg of sodium dodecylbenzenesulfonate, and 0.25 kg of sodium citrate.

[0256] Experimental Example

[0257] Experimental Example 1

[0258] The modified loofah sponges prepared in Examples 1 to 7 were respectively subjected to water contact angle tests and underwater oil droplet contact angle tests. The test methods are as follows:

[0259] Water contact angle test: Test using an optical contact angle tester (SL200KS video optical contact angle measuring instrument). Fix the loofah sponge on a glass slide and keep it horizontal. Then drop water droplets onto the surface of the loofah sponge, and measure the water-loofah sponge contact angle with a camera;

[0260] Underwater oil droplet contact angle test: It was tested using an optical contact angle tester (SL200KS video optical contact angle measuring instrument). The loofah was pre-wetted with absolute ethanol and then completely replaced in ultrapure water. After that, it was fixed on a glass slide and then placed in a cube container. Then, the model oil dichloroethane was dropped onto the surface of the loofah in water, and a camera was used to measure the contact angle of dichloroethane.

[0261] The test results are shown in Table 1 as follows:

[0262] Table 1

[0263]

[0264]

[0265] As can be seen from Table 1, the modified loofahs prepared in Examples 1-7 of the present invention have excellent hydrophilic and oleophobic properties, and the oil scraping brushes prepared with them can effectively scrape the waste oil on the inner wall of the sealed tank.

[0266] Experimental Example 2

[0267] The equipment of Examples 8-12 was respectively used to pretreat the oily kitchen wastewater. Among them, the influent wastewater had a COD content of 120000 mg / L, an NH3-N content of 1500 mg / L, a TN content of 4000 mg / L, and a TP content of 350 mg / L. After the oil, water, and sludge were layered, the waste oil, wastewater, and sludge were discharged. The rising velocity of the wastewater, the oil content rate of the collected waste oil, the sludge concentration, and the oil concentration in the wastewater were respectively detected by ① calculation method: residence time = tank volume / influent flow rate; ② distillation method; ③ drying and weighing method; ④ infrared spectrophotometry. The results are shown in Table 2.

[0268] Table 2

[0269]

[0270]

[0271] As can be seen from Table 2, for the kitchen wastewater treated by the equipment described in the examples of the present invention, the oil content rate of the recovered waste oil is as high as 70%, the sludge concentration can reach 100 g / L, and the oil content in the wastewater is lower than 100 mg / L, which can effectively pretreat the kitchen wastewater.

[0272] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "upper", "lower", "inner", "outer", "front", "rear", etc. is based on the orientation or positional relationship in the working state of the present invention. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention. In addition, the terms "first", "second", "third", and "fourth" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0273] In the description of the present invention, it should be noted that unless otherwise clearly specified and defined, the terms "installed", "connected", and "coupled" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection in general; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0274] The present invention has been described above in combination with preferred embodiments. However, these embodiments are only exemplary and only serve an illustrative role. On this basis, various substitutions and improvements can be made to the present invention, and these all fall within the protection scope of the present invention.

Claims

1. A pretreatment device for kitchen and restaurant wastewater, characterized in that, The device includes a sealed tank (1), and an inlet water system (2), a waste oil discharge system (3) and a sludge discharge system (4) are arranged outside the sealed tank (1). The kitchen waste water enters the sealed tank (1) through the inlet water system (2), and after the oil and sludge in the waste water are stratified, they are discharged through the waste oil discharge system (3) and the sludge discharge system (4) respectively. The kitchen waste water pretreatment device further includes an oil scraping system (5) and a sludge scraping system (6). The oil scraping system (5) includes an oil scraping arm (51) and a central fixed shaft (52), and the oil scraping arm (51) is connected to the central fixed shaft (52) through a first support (53). An oil scraping brush (54) is arranged on one side of the oil scraping arm (51) close to the inner wall of the sealed tank (1). The oil scraping brush (54) is made of a flexible material and is arranged in a fitting manner with the inner wall of the sealed tank (1) to scrape off the grease deposited on the inner wall. The oil scraping brush (54) is made of modified loofah sponge, and the modification is to perform oleophobic modification on the loofah sponge, and the modification is carried out according to the following steps: Step 1, pre-treat the loofah sponge to remove impurities in the loofah sponge. Step 2, wash the loofah sponge pretreated in Step 1, and then soak it in a modifier solution. Step 3, dry the loofah sponge treated in Step 2 to obtain the modified loofah sponge. Among them, the modifier solution is composed of raw materials including the following parts by weight: Hydrophilic nanoparticles 5 parts Polyvinyl alcohol 10 - 20 parts Methacrylic acid 50 - 100 parts Surfactant I 20 - 50 parts Deionized water 60 - 120 parts; The Surfactant I is one of fatty alcohol polyoxyethylene ether, sodium fatty alcohol polyoxyethylene ether sulfate and sodium dodecyl sulfate.

2. The device according to claim 1, characterized in that, The sealed tank (1) is of a closed structure, including a top, a body and a bottom arranged in sequence, and both the top and the bottom of the sealed tank are conical. The top cone angle of the sealed tank (1) is 120° - 180°, and the bottom cone angle is 120° - 180°.

3. The device according to claim 1, characterized in that, The waste oil discharge system (3) includes a first valve (31), a waste oil discharge pipe (32) and a waste oil collection barrel (33) arranged in sequence, and a transparent observation window is arranged on the waste oil discharge pipe (32) to observe the waste oil discharge situation. The sludge discharge system (4) includes a second valve (41), a sludge discharge pipe (42) and a sludge collection barrel (43) arranged in sequence, and a transparent observation window is arranged on the sludge discharge pipe (42) to observe the sludge discharge situation.

4. The device according to claim 1, characterized in that, There are multiple oil scraping arms (51), which are evenly distributed around the top end of the central fixed shaft (52). The multiple oil scraping arms (51) are all inclined and present an "umbrella-shaped" structure.

5. The device according to claim 1, characterized in that, The central fixed shaft (52) is of a double-layer structure, including an inner shaft (521) and an outer shaft (522) arranged concentrically. A cavity is formed between the inner shaft (521) and the outer shaft (522), and a heating device (73) is arranged in the cavity.

6. The device according to claim 5, characterized in that, A support plate (7) is arranged on the outer wall of the outer shaft (522) and below the first support (53). A liquid storage bottle (71) is arranged on the support plate (7), and a separation promoter is contained in the liquid storage bottle (71).

7. A pretreatment method for kitchen waste water, which is carried out by using the equipment described in any one of claims 1 to 6, characterized in that, The method comprises the following steps: Step I, connecting the device and introducing the to-be-treated kitchen waste wastewater through the water inlet system; Step II, starting the driving motor and the external heating device to stir and heat the kitchen waste wastewater; Step III, after the water, oil and sludge in the sealed tank are layered, starting the first vacuum pump to discharge the waste oil at the top layer; Step IV, starting the water pump to discharge the wastewater layer, and then starting the second vacuum pump to discharge the sludge at the bottom layer.

8. The method according to claim 7, wherein In Step I, the size of the water inlet pipe in the water inlet system satisfies that the flowing water speed is 0.01 - 1.0 m / s.

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