1. Sources and characteristics of sewage
1. Sources of rural sewage
Since the reform and opening up, especially since the 17th National Congress of the Communist Party of China, my country has significantly accelerated the development of new The pace of rural construction and the vigorous development of new rural areas or small towns are a major strategy for driving the development of the rural economy or small towns. However, while developing the rural economy or small town economy, it also brings about environmental pollution problems. Controlling pollution and protecting the environment is another major measure for sustainable development.
my country's new rural areas and small towns The environmental protection issues involved in construction mainly include rural sewage pollution and rural garbage pollution. In terms of rural sewage pollution, it is mainly domestic sewage pollution, livestock breeding sewage pollution, pesticide and chemical fertilizer pollution, and there are also some industrial pollution and other pollution. These pollutants are mixed with domestic sewage and discharged outside, so rural sewage is actually the general term for the above-mentioned sewage.
2. Characteristics of rural sewage
⑴. Small sewage-holding area, small sewage volume, large coefficient of variation, and large fluctuations in water quality and quantity.
⑵ In some rural areas, industrial wastewater and domestic sewage are discharged together, causing a certain impact on water quality.
(3) Due to reasons such as poor management and poor management, rainwater is not diverted, and in some cases groundwater infiltrates.
⑷. There may be a leapfrog development in rural areas. The amount of sewage will be relatively small in the near future, but the amount of sewage will be large in the long term.
⑸. Due to funding problems, imperfect infrastructure, and weak technical strength, even if a sewage treatment station is built, the community may have difficulty maintaining a treatment system with high energy consumption, heavy maintenance, and complex management. . Therefore, my country's new rural sewage treatment should choose new sewage treatment processes and technologies that are economical, efficient, energy-saving, simple and easy to implement, have good treatment effects, strong impact resistance, and stable operation.
New rural areas are generally divided into three types: communities of 1,000 people, communities of 2,000 people, and communities of 3,000 people. The per capita drainage of the community is 0.15m?/d, the pollutant concentration CODcr <900㎎/L, and the PH value is 6.5 ~7.5, BOD5<350mg/L, SS<700mg/L, color (dilution factor method)<200, contains a certain amount of nitrogen and phosphorus, and has good biodegradability, but the water quality and water quantity fluctuate greatly. It can be seen that the water quality index of rural sewage is significantly higher than that of urban domestic sewage, and the use of low-load process technology requires a large area, large investment, and high operating costs. Therefore, the high-load sewage treatment process "Diversion Aerated Biological Filter" 》Treat rural sewage, especially suitable for the needs of rural sewage treatment and small town sewage treatment construction in my country.
3. Sewage treatment methods
my country's sewage treatment started late but developed rapidly. The process used in sewage treatment is mainly biochemical treatment. Common processes include contact oxidation method, AB method, A/O method, oxidation ditch, SBR, aerated biological filter, diversion aerated biological filter, etc.
The diversion aeration biological filter is a new sewage treatment process with independent intellectual property rights in my country. According to the different subsequent treatment processes, it is divided into: hydrolysis-diversion aeration biological filter, anaerobic- Diversion aeration biological filter, air flotation-diversion aeration biological filter, rapid sedimentation-diversion aeration biological filter, ultrasonic-diversion aeration biological filter, microwave-diversion aeration biological filter , ozone-diversion aeration biological filter, etc.
The diversion aerated biological filter was upgraded and combined with other processes in terms of nitrogen removal, phosphorus removal, and reclaimed water reuse to develop the AB method - diversion aerated biological filter; A/O method - diversion aeration biological filter; A2/O method - diversion aeration biological filter; oxidation ditch - diversion aeration biological filter; SBR - diversion aeration biological filter; Biological contact oxidation-diversion aeration biological filter and other advanced treatment processes.
II. Introduction to the process technology of diversion aerated biological filter
1. Technology source
The diversion aerated biological filter is a traditional aeration biological filter. On the basis of the filter, we fully draw on the downflow aerated biological filter method, upflow aerated biological filter method, contact oxidation method, biofilm method, artificial rapid filtration method, sedimentation separation method, and pumpless sludge return Eight design methods, including water supply rapid filtration method, sewage treatment process and new technology developed from the secondary or tertiary sewage treatment process. Obtained national patent in 2005, patent number: ZL200420033672.4.
The diversion aerated biological filter has been implemented in Beijing, Shandong, Hebei, Guizhou, Shanxi, Sichuan, Inner Mongolia, Heilongjiang, Jiangsu, Jilin, Henan, Hubei, Tianjin and other places in my country. The cases involve wastewater treatment in hospitals, domestic, chemical industry, slaughtering, food, flax, alcohol, pharmaceuticals, etc. A large number of applications have proven that the effluent water quality CODcr is generally below 20mg/L, with a minimum of 5.95mg/L; BOD5 is generally below 10mg/L , the minimum is 3.50mg/L; SS is generally below 20mg/L, the minimum is 6.55mg/L.
2. Technical features
Conduction Current Biofilter (CCB for short) allows sewage to complete aeration → sedimentation → secondary aeration in the same treatment tank Gas → secondary sedimentation and other processes solve other sewage treatment processes that require four pools to complete. Especially under the condition of continuous water inflow, the gap aeration of water inlet → aeration → sedimentation → water outlet is realized. At the same time, sludge return is realized, and the entire operation is not idle. Its advantages are more prominent than other sewage treatment methods, and the treatment effect is excellent. It is remarkable that the diversion aerated biological filter is an updated product for sewage treatment such as AB method, SBR method, A2O method, contact oxidation method, two exposure and two sedimentation methods, and interstitial aeration method. In August 2009, it was listed as an "innovation project" by the Ministry of Science and Technology with the project code 09C26215205564; in December 2009, the Ministry of Environmental Protection listed this product as the "Catalogue of Environmental Protection Technologies Encouraged by the State" (Environmental Development 2009) No. 146; In May 2010, the Ministry of Science and Technology, the Ministry of Environmental Protection, the Ministry of Commerce, and the General Administration of Quality Supervision, Inspection and Quarantine reviewed and identified the "Diversion Aerated Biological Filter" as a "National Key New Product", with the number 2010GR467010; July 2012 In September, the Ministry of Environmental Protection listed diversion aerated biological filters as No. 39 in the “Catalogue of Environmental Protection Technologies Encouraged by the State” (Ministry of Environmental Protection 2012) during the 12th Five-Year Plan period. It has the following characteristics:
1), technologically forward-looking
The diversion aerated biological filter fully draws on eight sewage treatment design techniques and is a typical high-load, With the three-phase diversion of submerged and fixed biological beds and the nitrogen and phosphorus removal reactor, the treated sewage is better than the discharge standard and reaches the quality of reclaimed water, so the technology is forward-looking.
2) Process innovation
The diversion aerated biological filter allows sewage to be placed in the same treatment tank, solving other sewage treatment processes that require four tanks to complete. There was no idleness throughout the run. Therefore the process is innovative.
3) Project investment economy
The BOD5 volume load of the diversion aerated biological filter is 5 to 10 times that of conventional secondary biological treatment, and the microbial load is up to 10~15g/L, and there is no need to set up a secondary sedimentation tank, so the project investment is economical.
4) Stability of treatment effect
l Make the device exist in an aerobic and anoxic environment, which can realize nitrification and denitrification without worrying about sludge expansion and hydraulic pressure. Even if the sewage is reduced by less than half due to load impact and microbial loss, or it is restarted after the water is stopped, it only takes a short time to operate normally, so the treatment effect is stable.
5) Simplification of the treatment process
l Since the diversion aeration biological filtration method combines two aeration tanks, two sedimentation tanks, and two filter tanks into one, Simplify the process, so process simplicity.
6) Economical investment and operating costs
l Due to the short technological process of the diversion aerated biological filter, the small tank capacity, and the small area occupied, the project cost is greatly reduced. In addition, the device uses the filter material to cut, block, and crush bubbles, strengthen the gas and liquid mass transfer effects, and increase the contact area and time between microorganisms and air, resulting in a greatly improved oxygenation efficiency of the filter, making investment and operating costs economical.
7) Simple operation and management
l Through liquid level sensing, dissolved oxygen meter, timer, frequency converter, and PLC program control system, the diversion aeration biological filter can The pool is fully automated, making operational management simple.
8) Typical characteristics of nitrogen and phosphorus removal
l ① Basic principles of nitrogen and phosphorus removal by diversion aeration biological filtration l Principles of nitrogen removal by diversion aeration biological filtration On the basis of converting organic nitrogen into ammonia nitrogen, through the action of nitrification and denitrifying bacteria, ammonia nitrogen is converted into nitrite nitrogen and nitrate nitrogen through nitrification, and then nitrate nitrogen is converted into ammonia gas through denitrification. This achieves the purpose of removing nitrogen from wastewater. The principle of phosphorus removal by diversion aeration biological filtration is that under anaerobic conditions, phosphorus-accumulating bacteria convert organic phosphorus in their cells into inorganic phosphorus and release it. The energy generated in this process is used to absorb the solubility of wastewater. Organic matter synthesizes PHB, so that under aerobic conditions, phosphorus-accumulating bacteria degrade PHB to provide the energy required to absorb phosphorus from wastewater, thereby completing the role of phosphorus-accumulating
3. Diversion Scope of application of aerated biological filters
(1), treatment and reuse of residential sewage, small town domestic sewage, urban sewage, and rural domestic sewage treatment, etc., such as:
1), domestic sewage in cities and towns, villages, rural areas, residential areas and development zones;
2), domestic sewage in hotels, restaurants, nursing homes, hospitals, schools, shopping malls and office buildings;
< p>3), stations, airports, docks and other sewage.(2), Treatment and reuse of organic industrial wastewater
1), Flax wastewater treatment;
2), Milk farm wastewater treatment;< /p>
3), starch wastewater treatment;
4), printing and dyeing water treatment
5), chemical plant high ammonia nitrogen wastewater treatment;
6), alcohol wastewater treatment;
7), food wastewater treatment;
8), slaughtering wastewater treatment;
9), mustard wastewater treatment; < /p>
(3), sewage treatment plant upgrades and sewage treatment with special requirements
1) Urban sewage treatment plants upgrades and reclaimed water reuse projects
2), wastewater treatment with nitrogen and phosphorus removal requirements
3), wastewater that requires advanced treatment, without adding tertiary treatment facilities, the effluent can meet the reuse water standard.