With the continuous development of colleges and universities in China, the amount of school sewage is getting larger and larger, and the call for the treatment of school sewage is getting stronger and stronger. Finding efficient, economical and stable sewage treatment facilities has become an urgent task at present. One.
On April 2, 2015, the "Water Pollution Prevention and Control Action Plan" was reviewed and approved by the Standing Committee of the Political Bureau of the Central Committee. After several rounds of amendments, the "Ten Articles of Water" will be used in sewage treatment, industrial wastewater, and comprehensive control of pollutant discharge. With strong supervision and strict accountability, iron-fisted pollution control will enter a "new normal."
2. Brief description of school domestic sewage characteristics
Source analysis of school sewage: domestic sewage in dormitories, teaching buildings, gymnasiums; canteen catering wastewater; part of rainwater. All have good biochemical properties.
3. School domestic sewage treatment standards
Because the state does not have a clear standard for school sewage, and the main pollutants in school sewage are similar to those in township sewage, the currently implemented standards for school sewage treatment are in accordance with the main reference standards for township sewage treatment:
Discharge Standard of Pollutants for Urban Sewage Treatment Plants (GB18918-2002)
NH 3 -N
≤ 5 (8)
≤ 8 (15)
4. School sewage treatment process
Pretreatment: The catering wastewater of the canteen needs to be oil-proofed. After the sewage is mixed, it is treated by the septic tank. After the septic tank water is mixed, it is filtered through the grille and enters the adjustment tank to adjust the water volume.
Biochemical treatment: In view of the good biochemical properties, there are many optional processes, such as A2O, A / O, etc. It is recommended to use the A / O process in consideration of economical practicality. The biochemical effluent can generally reach the first-level B standard, and some can reach the first-level A standard. standard.
Main process description:
After the sewage is collected by the drainage system, it enters the septic tank of the sewage treatment station, anaerobic decomposition of the feces and macromolecular organic matter, and then enters the adjustment tank for homogenization and uniformity. A level controller is set in the adjustment tank, and the liquid The position controller transmits a signal, which is pumped to the anaerobic tank of the integrated equipment by the lift pump, flows into the disinfection tank for disinfection after aerobic treatment, and the disinfected effluent is directly discharged into the municipal pipe network.
The debris intercepted by the grille is regularly loaded into the trolley and dumped to the garbage dump. The sludge in the integrated sedimentation tank is discharged into the septic tank for sludge digestion. It is regularly sucked out, and the supernatant from the sludge tank is returned to the regulation. Pool reprocessing.
The A / O process is a biological wastewater treatment method derived from the biofilm method, that is, a certain amount of filler is filled in the biological contact oxidation tank, and the biofilm attached to the filler and the fully supplied oxygen are used for biological oxidation. , The organic matter in the wastewater is oxidized and decomposed to achieve the purpose of purification.
In the process, the anoxic section in the front section and the aerobic section in the back section are connected in series, and the heterotrophic bacteria in the anoxic section hydrolyze the soluble organic matter in the sewage into organic acid, decompose the large organic matter into small molecular organic matter, and convert the insoluble organic matter into soluble organic matter. , Ammonia (nitrogen on the organic chain or amino group in amino acid) to free ammonia (NH3, NH4 +). There are aerobic microorganisms and auto-aerobic bacteria (nitrifying bacteria) in the aerobic section. Among them, aerobic microorganisms decompose organic matter into CO2 and H2O. Under sufficient oxygen supply conditions, the nitrification of autotrophic bacteria will change NH3-N (NH4 +). It is oxidized to NO3-, and returns to the anoxic stage through reflux control. Under anoxic conditions, the denitrification of the aerobic bacteria reduces NO3- to molecular nitrogen (N2) to complete the cycle of C, N, O in the ecology. Achieve harmless sewage.
5, A / O process characteristics
(1) The process is simple, the structure is few, the operation is flexible, and the management is convenient.
(2) The province has a low investment in infrastructure and low operating costs.
(3) The treatment effect is stable, and the quality of the effluent water is good, which can realize decarbonization, nitrogen and phosphorus removal.
(4) The amount of sludge is small, the sludge properties are stable, and the sludge treatment cost is low.
(5) Can withstand the impact of water volume and water quality.
(6) The sewage treatment system has high automation and convenient management.
School sewage treatment system accompanied by increasing water pollution is an inevitable product. At present, the integrated sewage treatment equipment is widely used in the sewage treatment process of many schools because of its low investment costs and simple operation.
With the country's increasingly strict environmental protection and sewage treatment standards and the increasing awareness of environmental protection among the people, school sewage treatment is imperative. Constantly innovating the school sewage treatment process and adapting to changing treatment requirements are of great significance to protecting the safety of the environment and the health of teachers and students on campus. It is worth noting that the reuse of water after treatment also greatly improves water utilization efficiency.