CN1295981A

CN1295981A - Method and apparatus for treating sewage from catering business

Info

Publication number: CN1295981A
Application number: CN 00126738
Authority: CN
Inventors: 邓明恺; 邓武军; 邓国红
Original assignee: Individual
Current assignee: Individual
Priority date: 2000-12-13
Filing date: 2000-12-13
Publication date: 2001-05-23
Anticipated expiration: 2020-12-13
Also published as: CN1163425C

Abstract

The present invention relates to a method for treating sewage of food and beverage trades and its equipment, includign three portions of pre-treatment, chemical cleaning treatment and terminal treatment, in which the pre-treatment portion includes grate, screen mesh, residue-settlement pool and oil-separating pool, after the sewage is pre-treated, and fed into the cleaning equipment where the bleaching powder and ferrous sulfate solution are added, and stirred to make chemical cleaning treatment, its terminal treatment portion includes filtering process, and can obtain reuse water or discharge water meeting the national discharge standard. Said invented method is small in occupied floor area. its equipment is simple, and high in anti-pollution effect, and its investment is low.

Description

Method and device for treating restaurant sewage

The invention relates to a method and a device for treating restaurant sewage, belonging to the sewage treatment field. Is particularly suitable for sewage treatment of hotels, restaurants, hotels and collective canteens.

The existing catering sewage is not treated generally, and a few units are treated by adopting a biochemical method in environmental engineering of environmental science of encyclopedia of Chinese encyclopedia, wherein the treatment process comprises the steps of grid, screen and desilting tank pretreatment → pressurized dissolved air aeration → secondary sedimentation sludge backflow → discharge, and the defects of large floor area of treatment site, high investment, small daily treatment capacity, sewage retention timeThe treatment facilities of the Xinxing hotel in the long, for example, Dian Haizhou area occupy 400 square meters, the total investment is 80 ten thousand yuan, the effective volume of the treatment facilities is 400 cubic meters, the daily treatment capacity is 30 cubic meters, the retention time of the sewage in the treatment system is 13 days, and the discharged water quality is BOD₅The CODcr concentration can only reach the 2-3 level standard of GB-8978-96 Integrated wastewater discharge Standard, so the large occupied area and investment cannot be popularized in cities.

The invention aims to provide a treatment method and a treatment device which have the advantages of small occupied area, investment saving, short pollutant degradation period and high decontamination efficiency.

The invention relates to a physical-chemical-physical processing method mainly based on chemical processing and a device for realizing the method, which comprises three parts of physical method pretreatment, chemical purification treatment and physical method terminal treatment. The pretreatment part is to remove larger floaters in the sewage by a physical method in turn by a grid, a screen is used for removing smaller food residue fragments, a sediment tank is used for settling the food residues which are difficult to settle in the flowing sewage, the specific gravity is less than 2 and is more than 1, an oil separation tank is used for settling the residues again and separating most of oily pollutants, the chemical purification treatment part is to use bleaching powder and ferrous sulfate as water purifying agents in a water purifier, and a series of chemical and physical actions such as decomposition, dissociation, oxidation, reduction, neutralization, flocculation, settlementand the like are generated as a result of oxidation reduction, so that the chemical purification and physical purification rates of the pollutants are improved. The device is mainly a purifier, the terminal treatment part is carried out by a physical method, the device is mainly a filter and a corresponding water pipe and a valve for filtering and discharging the sewage after chemical treatment, different filter media are selected according to the needs of users to respectively obtain non-potable recycled water and discharged water meeting the first-level standard of GB-8978-96 Integrated wastewater discharge Standard, the terminal treatment of residues is to separate residues and water by the filter, the water enters an oil separation tank, and the residues can be used as planting fertilizers.

The invention is further described and illustrated in the following examples with reference to the accompanying drawings.

FIG. 1 is a flow chart of the method of the present invention;

FIG. 2 is a schematic cross-sectional view of the structure of the present invention;

fig. 3 is a schematic structural plan view of the present invention.

In the figure: 1. the system comprises a grid 2, an electric cabinet 3, a sewage main ditch 4, a dissolving tank 5, a dosing pump 6, a screen 7, a sediment tank 8, an oil separation tank 9, a water passing pipe 10, an oil separation wall 11, a purifier 12, a stirrer 13, a

slag discharging pipe

14, 20, 21, 25, 26, 29,

valves

15, 16, 18, 19, 22, 24, 28, a water pipe 17, a

water pump

23, 27, 31, 32, a filter 30 and an oil collecting tank.

The invention relates to a restaurant sewage treatment method, which comprises the steps of firstly, pretreating by a physical method, wherein the pretreating comprises a grid 1, a screen 6, a sediment tank 7, an oil separation tank 8 and a sewage, wherein the sewage sequentially flows through the grid 1 arranged on a sewage main ditch to remove coarse floating substances, the screen removes smaller food debris residues and enters the sediment tank 7 to remove the residues with the specific gravity smaller than 2 and larger than 1 which are difficult to settle in the flowing sewage, the residues and the debris flow into a water inlet tank of the oil separation tank 8 through a water outlet which is higher than the tank bottom and is connected with one side of the water inlet tank of the oil separation tank 8, the residues and the debris are settled again and most of floating oil are separated, the oil separation tank 8 is provided with an oil separation wall 10 in the tank to separate the oil inlet tank and the water outlet tank, the central part of the oil separation wall 10 is provided with an ∩ -shaped water pipe 9 with a pipe opening facing downwards, the sewage enters the water outlet tank from the water pipe, only the oil separation pipe can be lighter than water, most of the oil pollution and the oil pollution are separated, the oil separation tank is connected with the wall of the water inlet tank, the oil separation tank is provided with a water outlet, the oil separation tank, the residual oil separation tank is reduced, the residual oil pollution is reduced, and the residual oil pollution is reduced when the residual oil is removed by the physical method, and the residual oil is removed, the oil separation tank, and the residual oil is reduced.

Then the water enters into the chemical purification treatment, the device is mainly a purifier 11, the method is that the water in the water outlet pool of the oil separation pool 8 is sent into the purifier 11 by a water pump 17 through a water pipe 15, the purifier 11 is a cone bottom container, a slag discharge pipe 13 leading to

filters

23 and 32 and two valves 21 are arranged on the cone bottom, the wall above the cone is connected with a water pipe 18 leading to the

filters

27 and 32 and two valves 25, the upper opening wall of the container is provided with an overflow pipe 16 leading to the water inlet pool of the oil separation pool 8, and a stirrer 12 is arranged in the container. Adding strong oxidant bleaching powder and a ferrous sulfate solution with 5-10% of reducing agent into a purifier for chemical purification treatment, wherein the addition amount of the bleaching powder is 0.02-0.1% of the weight of the sewage in the purifier 11, the addition amount of the ferrous sulfate solution is 0.1-0.5% of the volume of the sewage in the purifier, the optimal addition amount of the bleaching powder is 0.04%, and the ferrous sulfate solution is 0.3%, and the action mechanism is as follows: firstly, the inherent components of bleaching powder are decomposed: ca (OCL)₂-CaCL₂+2(O) (1)CaCL(OCL)-CaCL₂Calcium chloride, which is a decomposition product of the formula (1) or (2) of the formula (O) (2), is a strong electrolyte and breaks downThe double electric layer structure of the bad emulsified oil enables the oil to be demulsified and separated from water, and simultaneously realizes the turbidity removal of sewage; the second decomposition product is nascent atomic oxygen, has strong oxidizing property, not only plays a role in decoloring, deodorizing and sterilizing (pathogens) the sewage, but also can oxidize and decompose aerobic organic pollutant animal and vegetable oil in the sewage. Besides the decomposition of inherent chemical components, the bleaching powder also contains free chlorine, and can be dissolved in water to be changed into chlorine water- (CL)₂·H₂O) and in dissociated state in water: (3) dissociative OCL in formula (3)^-Also has strong oxidizing property, and has synergistic effect on the oxidation water purification function of bleaching powder.

Adding ferrous sulfate into the sewage, and then carrying out a nascent state oxidation-reduction reaction with the formulas (1) and (2):

(4)

the iron hydroxide sol in the formula (4) has a large surface area, and can adsorb a large amount of aerobic organic pollutants in a suspended fine particle state in sewage, anionic surfactants, animal and vegetable oils and soluble inorganic salts, so that the sol particles quickly grow into coarse floccules, and the coarse floccules are quickly and freely settled in still water to separate the pollutants from clear water.

As the commercial bleaching powder contains calcium hydroxide impurities, the pH value of the sewage is increased to 10-11, which brings about a certain degree of side effect on coagulation and sedimentation effects in the chemical purified water. Such basic impurities may be related to H in formula (4)₂SO₄A neutralization reaction takes place:

(5)

the PH value of the sewage is reduced to 6.5-7.5, and the sewage is neutralized.

The chemical treated sewage enters the terminal treatment of the physical method after the residue thereof is settled, the device mainly comprises

filters

23, 27, 31, 32 and corresponding water pipes and valves thereof, the

filters

27, 32 are containers with two layers of separated bottom plates, the bottom of the bottom plate at the lower layer is communicated with the water pipe 24 leading to the water outlet tank of the inner oil separation tank and two valves 29, the wall between the bottom plates is communicated with the water pipe 18, the bottom plate at the upper layer is provided with densely distributed small holes on which filter media are placed, the wall of the container at the upper surface of the filter media is provided with the water pipe 28 for draining water, the filter media on the filter 27 takes rare earth porcelain sand as a base layer on which columnar granular activated carbon is arranged, the filter media on the

filters

23, 31, 32 are micro-porous ceramic tiles, the bottoms of the

filters

23, 31 are provided with the water pipe 19 leading to the water outlet tank of the oil separation tank 8 for periodically flushing the purifiers and the, the water pipe 22 of tap water or reuse water for flushing and

corresponding valves

14, 20, 26 are also arranged on the sewage, after chemical treatment, the sewage is treated for residue precipitation, and the sewage treatment has two choices according to the requirements of users, the method for obtaining non-drinking reuse water is that the sewage passes through a filter 27 which takes rare earth porcelain sand and columnar granular activated carbon as filter media from bottom to top through a water pipe 24 and a valve 25, the method for obtaining the discharge water which meets the first-level standard of GB-8978-96 Integrated discharge Standard for wastewater is that a filter 32 which takes microporous ceramic tiles as filter media is passed through, the terminal treatment of water-containing residues is that the residues enter a

filter

23 or 31 which takes microporous ceramic tiles as filter media through a residue discharge pipe 13 and a valve 21, the residues and water are separated, and the water enters the water outlet pool of the oil separation pool 8 through a water pipe 19.

The invention also has the electric control box 2, the medicine dissolving box 4, the medicine feeding pump 5 and the pipeline for sending medicine into the purifier 11, the purifier and the filter can be arranged on the top of the oil separation tank in an overhead way, and can also be arranged according to the actual situation, the occupied area is small, the device can also be matched with a computer, an electric valve and the like, and can be operated fully automatically, thereby realizing unattended operation.

The using process of the invention is that firstly, the bleaching powder of a purifying agent is prepared, 5 to 10 percent ferrous sulfate solution is prepared in a medicine box 4 for standby, all valves are closed, when the water surface in an oil separation tank reaches an outlet communicated with an oil collecting tank, a water pump 17 is started through a starting button of an electric control box 2, the sewage in a water outlet tank of the oil separation tank 8 is sent into a purifier 11, when the liquid level of the sewage in the oil separation tank reaches 10 cm below an overflow pipe, the water pump stops running, the bleaching powder is added into the purifier, a stirrer 12 in the purifier 11 is started again, the stirring is stopped for 5 minutes, a dosing pump is started, after sufficient ferrous sulfate solution is added, the dosing pump is stopped, the stirrer is started again for 2 minutes and stopped, the standing is carried out for 1 to 2 hours, after residues are precipitated, a valve 25 on a water pipe 18 of the purifier 11 is opened, the sewage enters a filter from the bottom of the

filter

27 or 32 and is filtered from, the sewage in the purifier is discharged into a municipal sewage pipe network or recycled non-drinking water by a water pipe 28, after the sewage is discharged, a valve 25 on a drain pipe 18 is closed, a valve 21 on a slag discharge pipe 13 of the purifier is opened, the water-containing residues flow into a

filter

23 or 31 to separate the residues and the water, the water flows into a water outlet tank of an oil separation tank 8 through a drain pipe 19 on the bottom and then the valve is closed, the filter is used alternately, when the residuesof one filter are accumulated to a certain thickness, the other filter is used, the residues in the filter are removed, and the water is washed clean by tap water. The residue is dried into a solid with loose texture, is not bonded with the bottom surface of the filter, is convenient and sanitary to remove, and is enriched with a large amount of organic substances carried in sewage and trace elements necessary for plant growth and development, so that the residue can be used as a base fertilizer for urban greening or other greening plants.

The

filter

27 or 32 and the purifier are washed periodically, a drain valve 29 on the bottom of the filter and a valve 21 on a slag discharge pipe of the purifier are opened, then

valves

14 and 26 on a tap water pipe 22 on the upper part are opened, residues are washed from top to bottom, and slag water flows into a water outlet pool of the oil separation pool 8 through

water pipes

19 and 24, and the steps are repeated. The water after practical treatment is clear and transparent, and the concentration of the main pollutant BOD_FNd is 14mg/l, COD_erLess than or equal to 34 mg/L, 5.4 mg/L animal and vegetable oil, and anionic surface activity nd-1.0 mg/L, NH₃-N nd-5 mg/L, Escherichia coli nd.

In conclusion, the invention has the advantages of small occupied area, simple structure, less investment, short pollutant degradation period, high decontamination efficiency, capacity of discharging water reaching non-drinking reuse water or national first-level discharge standard, lightening the load of urban sewage treatment plants, saving water resources, capacity of using residues for urban greening and planting industry, good social and economic benefits, and is particularly suitable for washing and domestic drainage treatment in catering industries such as hotels, restaurants, hotels, dining halls and the like, residential groups, troops and the like.

Claims

1. A method for treating restaurant sewage comprises three parts of pretreatment, chemical treatment and terminal treatment, and is characterized in that:

the pretreatment part is treated by a physical method, the sewage sequentially passes through a grating (1) arranged on a sewage main ditch (3) to remove coarse floaters, a screen (6) is used for removing small food scraps and residues, the sewage enters a residue settling tank (7) to remove the residue scraps which are difficult to settle and have the specific gravity of less than 2 and more than 1 in the flowing sewage, and then the sewage flows into a water inlet tank of an oil separation tank (8) through a water outlet in an overflowing manner, the residues and the fragments are settled again, most of oily pollutants are prevented from entering a water outlet tank of the oil separation tank (8), and then the sewage enters chemical purification treatment;

the chemical purification treatment is carried out in a purifier (11), when the water in the oil separation tank is about to reach a communication port with an oil collecting tank (30), the sewage in a water outlet tank of the oil separation tank (8) is conveyed into the purifier (11) by a water pump (17) through a water pipe (15), the pump is stopped until the position 10 cm below an overflow pipe opening, then aerobic organic matters, animal and vegetable oils, which are capable of oxidizing and degrading aerobic organic pollutants in the sewage, anionic surfactants, animal and vegetable oils, soluble inorganic salts and soluble solids in a suspended fine particle state in the sewage are adsorbed and degraded in large quantity are added, sol particles are rapidly grown into coarse floccules and rapidly settled in the water, so as to realize the purposes of turbidity removal, color fading, deodorization, sterilization, emulsion breaking, neutralization, coagulation and settlement of the sewage, and achieve a strong oxidant bleaching powder and a 5-10% ferrous sulfate solution of a reducing agent in the water purification process of solid-liquid separation and the like, firstly, adding bleaching powder, stirring uniformly by a stirrer (12), stopping, adding a ferrous sulfate solution, stirring uniformly, stopping for 1-2 hours until residues are completely precipitated, and performing terminal treatment. The adding amount of bleaching powder is 002-0.1% of the weight of water in the purifier (11), the adding amount of 5-10% ferrous sulfate solution is 0.1-0.8% of the volume of the water in the purifier (11), the optimal adding amount of bleaching powder is 0.04% and 5-10% ferrous sulfate solution is 0.3%, the stirring time is that bleaching powder is added, the stirring is carried out for 5 minutes, 5-10% ferrous sulfate solution is added, and the stirring is carried out for 2 minutes;

the terminal treatment part is a physical method, namely, the process is carried on through filter and corresponding water pipe, valve, close all valves at first, prepare purifying agent, the water treatment has two kinds of choices according to the needs of users, the method to obtain non-drinking reuse water is to make water flow through the water pipe (18) and valve (25) of the clarifier (11) from bottom to top and use rare earth porcelain sand as the filter (27) of the basic unit and column granular activated carbon as the filter medium on it, in order to obtain the first class emission standard discharge water which accords with GB8978-96 "comprehensive discharge Standard of wastewater", its method is to make water flow through the water pipe (24) and valve (25) from bottom to top and use the filter (32) of the filter medium of the micropore ceramic tile, close the valve after finishing the treatment, the terminal treatment of the residue is that the water-containing residue in the clarifier (11) enters the filter (23) or (31) which uses the micropore ceramic tile as the filter medium to use alternately through the slag discharge pipe (13) and valve (21), and (2) carrying out slag-water separation, enabling water to enter a water outlet tank of the oil separation tank (8), closing the valve after treatment, flushing the purifier (11) and the filters (27) and (32) regularly, opening a valve (21) on a flushing slag discharge pipe, flushing a valve (29) on the bottom of the filter and valves (14) and (26) on a tap water pipe (22), closing the valves (21) and (29) after flushing, and cleaning the filters (23) and (31) only after scraping residues.

2. The special device for treating restaurant sewage as claimed in claim 1, comprising a grid, a screen, a sediment tank, an oil separation tank, a purifier and a filter, and is characterized in that:

A. the purifier (11) is a cone bottom container, a slag discharge pipe (13) leading to filters (23) and (31) and two valves (21) are arranged on the cone bottom, a stirrer (12) is arranged in the container, and an overflow pipe (16) leading to a water outlet pool of the oil separation pool (8) is arranged on the upper opening wall of the container; the wall above the cone bottom is connected with a water pipe (18) leading to the filters (27), (32) and two valves (25);

B. the filters (27), (32) are a container with two layers of separated bottom plates, the bottom of the bottom plate at the lower layer is communicated with the water pipe (24), the wall between the bottom plates is communicated with the water pipe (18), the upper layer bottom plate is provided with densely distributed small holes on which the filter medium is placed, and the wall of the container on the upper surface of the filter medium is provided with a water pipe (28) for draining water;

C. an oil separating wall (10) which separates the oil separating tank into a water inlet tank and a water outlet tank is arranged in the oil separating tank (8), an ∩ -shaped water passing pipe (9) is arranged at the central part of the oil separating wall (10), the pipe orifice faces downwards, one surface of the water inlet tank is connected with the water outlet of the sediment tank (7), is higher than the bottom of the sediment tank and lower than the other tank walls, an outlet communicated with the oil collecting tank (30) is arranged on the tank wall of the water inlet tank, and the outlet is lower than the water outlet of the sediment tank;

3. the special equipment as claimed in claim 2, characterized in that a tap or return water pipe (22) for flushing residues and valves (14), (20), (26) are arranged above the filters (23), (27), (31), (32) of the purifier (11).