The design of this project is based on the general direction that the company divides the wastewater generated in the workshop into "clear and turbid streams" and considers the reuse of water after quality treatment, i.e., the second and subsequent rinsing wastewater (clear water) of the rinsing section which has a large amount of water consumption, the rinsing wastewater with a high concentration in the first rinsing wastewater, and wastewater of the other sections of the process (turbid water) are separated. Separation After the water quality of the workshop is divided, the "clean water" will enter the new system for treatment and reuse, and the "turbid water" will continue to enter the existing sewage treatment system for treatment and external discharge.
System treatment capacity
1）Wastewater treatment system
Design "clear water" wastewater treatment scale: Q = 4000m3 / d, Kz = 1.10-1.15, the maximum controllable risk of water treatment
Maximum controllable risk treatment water Q=4500 m3/d.
Process design
According to the project's actual situation, combined with our practical experience in similar sewage treatment projects and our patented technology, in line with the principle of "two lows and two highs" (i.e., low investment, low operating costs, high removal efficiency, high operability), it is determined that the project adopts "coagulation precipitation + hydrolysis acidification tank + A/O-HBR + coagulation air flotation."
From the perspective of combining economic, social, and environmental benefits, it is determined that this project adopts the treatment process of "coagulation and precipitation + hydrolysis acidification tank + A/O-HBR + coagulation air flotation." The process has the following characteristics:
- A stable operation can meet the water and process maturity requirements, and it has successful operating experience. Coagulation and sedimentation burden of suspended solids, chromaticity and part of the removal of organic matter, hydrolysis acidification tank + A/O-HBR biochemical tank to complete the degradation of organic matter, sedimentation tank for mud-water separation, coagulation shallow air flotation unit to ensure that the effluent SS, organic standards.
- It has physical treatment control and can resist shock load. Sludge has a certain degree of stability, so there is no need for anaerobic digestion of mud treatment.
- Aeration using blast aeration: Set up a high-efficiency aeration system. The system is spread at the bottom of the pool, and it has high power efficiency, low energy consumption, a shallow pool depth, and occupies less land.
- The degree of automation requirements is low, and the operation and management are simple and convenient.
- Covers a relatively small area, a small investment, and a relatively small amount of sludge.
Introduction of the main processing unit (A/O-HBR)
The A/O-HBR process is our self-developed combined denitrification and decarbonization process (Patent No.: ZL201721357507.8,
ZL201721357507.8 and ZL201721359238.9), which is a kind of high-efficiency biological denitrification process with refluxing pre-denitrification of single sludge and multi-sludge mixing, and it also has the functions of A/O, SND, and short-range nitrification and denitrification. This process combines the A/O process and a high-efficiency bio-rope filler. It adopts a multi-point quality water intake to offset the peak, improve the effluent effect, and save carbon sources and alkalinity. The intermediate selection pool is added to enrich the means of bacterial screening, substantially reduce the ratio of mixed liquid and sludge reflux, and adopt the energy-saving gas lift reflux method to save energy effectively. The whole process is integrated into integrated equipment, which can realize unattended operations after the state is stabilized.
The high-efficiency biological rope packing has the following characteristics:
- The filler is microbiophilic and hydrophilic, with a large specific surface area, fast film hanging speed, and easy operation. Under the premise of nitrifying bacteria, it takes only 72 hours to hang the film. The normal time for the system to be put into operation is not more than one month.
- Organic and inorganic composite material, hanging film uniformly, the formation of dissolved oxygen gradient, the outer layer of the biofilm for aerobic bacteria, the middle for anoxic bacteria, and the inner layer of anaerobic bacteria, the formation of n microscopic A2 / O process, the occurrence of synchronous nitrification-denitrification and thus the removal of total nitrogen. The effect of nitrogen removal, carbon removal, and phosphorus removal is greatly improved, and total nitrogen can be reduced from 350mg/L to less than 15mg/L, while ammonia nitrogen is not detected.
- The concentration of microorganisms can be as high as 15-20g/L, 5-6 times the amount of ordinary filler film. The biological items are rich, and there are indicator organisms of good water quality, such as protozoa.
- The effect of this packing on COD removal is also very obvious. Spandex wastewater is used in the A2/O process. Anoxic and aerobic tanks are placed in packing, filling at 70%. The influent water is COD3000mg/L, and the effluent COD can reach 50mg/L below.
- The packing can realize sludge reduction. Compared with the traditional activated sludge method, reducing the remaining activated sludge volume can reach more than 50%.
- The packing material has strong acid and alkali resistance and can be applied to various water qualities. In a low-temperature environment, the ambient temperature of -20℃, water temperature 8-of 12, and water temperature 8-12℃, it can reach the standard of nitrogen removal, and its service life is up to 5-to ten years.
Wastewater system main structure design and equipment
Conditioning tank
Coagulation and sedimentation tank
Hydrolysis acidification tank
A/O-HBR
Secondary sedimentation tank
Intermediate tank
Coagulation air flotation
Discharge Pond
Sludge tank
Dosing system
(2) Water reuse system
The water reuse system is implemented in phases. The first phase is designed to produce water with a volume of Q=1000 m3 /d; subsequent, according to the workshop production capacity's needs and the total sewage control amount, the second phase will be equipped with the system as appropriate.
Reuse system.
Process design of water reuse system
This system is based on the actual situation of relatively low organic matter, suspended solids, and salts in the incoming water of the project, combined with our practical experience in other similar water reuse projects, and based on the principle of "two lows and two highs" (i.e., low investment, low operating costs, high recycling rate, high operability), and from the viewpoint of combining the economic, social and environmental benefits, the system is designed to operate stably and to be able to provide the best water quality. Starting from the viewpoint of combining economic, social, and environmental benefits, and taking operational stability as the assessment system, it is finally determined that this project adopts the dual membrane process route mainly based on "ultrafiltration + reverse osmosis".
Process flow description
After the wastewater is treated, it enters the discharge pool after the water quality reaches the discharge standard. Then, the high-pressure pump elevates it to the water reuse treatment system.
According to the water quality characteristics of treated wastewater, for the current situation of strict requirements for dyeing water in the workshop, this program takes the system's stable operation as the first consideration and chooses the above process route. This route can reach the standard of dyeing reuse water in the workshop after treatment, and the recovery rate reaches 50-55%.
The above main process units are summarized as follows:
(1) Ultra-filtration system
After self-cleaning filtration, water SS can be reduced to <5mg / L and the vast majority of large-size colloidal particles can also be removed, but particles less than 0.1um still partially exist on the operation of the RO membrane are still polluted.
However, particles smaller than 0.1um still exist in part, and the operation of the RO membrane is still a pollution. Therefore
Therefore, it is necessary to carry out pre-filtration before the RO membrane. Hollow fiber membrane ultrafiltration filtration particle size of 0.01um to 0.2um, in principle
Through the hollow fiber membrane ultrafiltration, water turbidity is 0, while bacteria are retained in the water to prevent bacterial contamination of the backstage membrane.
The system's recovery rate is high, reaching more than 90%. Therefore, hollow fiber membrane ultrafiltration is a good pretreatment for RO membranes.
(2) Reverse osmosis systepretreatmentsmosis is mainly used for the pretreatment of small molecular weight organic compounds from the water by applying certain pressure to make the pretreatment water pass through the RO semi-permeable membrane.
The treatment is mainly used to pass the pretreatment water through the RO semi-permeable membrane by applying certain certifications to remove the ions and small molecular weight organics in the water and reduce the conductivity of the water so that the produced water meets the requirements of the water.
(3) Security filter
Security filters are a kind of pressure filtration device mainly composed of a filter cartridge body, filter cartridge cover, quick-opening mechanism, filter element, and other main parts.
The filtrate flows into the cartridge from the side inlet pipe of the filter shell. The inside of the cartridge is filled with a filter element, and the liquid is permeated to the required fineness level.
The filter liquid flows into the cartridge from the side inlet pipe of the filter housing, and the inside of the cartridge is filled with the filter element. The liquid penetrates through the required fineness level filter element to obtain qualified filtrate, and the filter element intercepts the impurity particles.
Core technology
Reverse osmosis is a high-tech membrane separation technology invented by Loeb and Sourirtajan of the University of California in 1960. Its pore size is very small, mostly ≤ 10×10-10 (10A), which can remove the ionic range in the filtrate and the organic matter with small molecular weight, such as a bacterium, virus, heat, etc. It has been widely used in seawater or brackish water. It has been widely used in desalinating seawater or brackish water, producing pure water for electronics and medicine, drinking water, and space water. It has also been applied to biological and medical engineering.
Reverse osmosis, also known as reverse osmosis (RO), separates solvents from a solution by passing them through a reverse osmosis membrane (or semi-permeable membrane) under a certain pressure. It is called reverse osmosis because it goes in the opposite direction to natural osmosis. According to the different osmotic pressures of various materials, you can make greater than the osmotic pressure of reverse osmosis to achieve the purpose of separation, extraction, purification, and concentration. Pretreatment water enters the reverse osmosis membrane group. Under pressurePretreatment, water molecules and trace amounts of other ions through the reverse osmosis membrane, and after collection, it becomes the product water, which enters the subsequent equipment through the water pipeline; most of the salts and colloids in the water, organic matter, etc. can not pass through the reverse osmosis membrane, and remain in a small amount of concentrated water, which is discharged from the concentrated water pipe. When the reverse osmosis device is out of operation, it is automatically flushed for 3-5 minutes to remove the dirt deposited on the surface of the membrane so that the device and the reverse osmosis membrane can be effectively maintained. After a long operation, the reverse osmosis membrane will accumulate certain dirt that is difficult to flush, such as organic matter, inorganic salt scaling, etc., resulting in a decline in the performance of the reverse osmosis membrane. This type of fouling must be removed by cleaning with chemicals to restore the performance of the reverse osmosis membrane.
In this project, according to the salt content of the raw water and the degree of contamination of the raw water, choose a large water permeability, high desalination rate,
With chemical stability, good anti-pollution performance, and high mechanical strength of the reverse osmosis membrane elements, our company recommends using United States Hydronics products. Considering the energy saving of the equipment, operating pressure, membrane permeability, membrane desalination rate, salinity of the effluent, membrane contamination resistance, and other factors, the RO membrane adopts the electro-neutral contamination-resistant reverse osmosis membrane produced by the United States Hyderabad Energy. The electroneutrality and hydrophilicity of the surface of the LFC3-LD membrane introduced by HYDERNER gives it excellent anti-pollution ability. Then, its reverse osmosis flat membrane is integrated with LD technology, which can effectively prevent colloid and microbial contamination and play a full role in the characteristics of stable performance in wastewater treatment.
Main equipment parameters and selection
Drainage pool
Self-cleaning filter
Ultra-filtration system
Ultra-filtration water tank
Security filter
Reverse osmosis system
Pure water tank
CIP Cleaning System
Dosing system
3）Waste gas system
This project deals with the malodorous gas produced by the company's sewage treatment structures. Hydrolysis is a specific pollution source.
Acidification tank, A/O-HBR, regulating tank, sludge tank, and other four parts of the structure of the malodorous gases generated in the odor produced by the main odor-causing substances for hydrogen sulfide, ammonia, and volatile organic compounds.
To protect the environment, effectively treat the bad-odor waste gas released by the wastewater station, and improve the working and living environment of the company's staff and the surrounding residents, our company will design the treatment system for the bad-odor waste gas released during the operation of its wastewater station.
Main process and equipment description
The waste gas collection unit
Washing tower
