1 wastewater treatment process improvement program
The 25 thousand day of slaughter duck feather, produce large amounts of wastewater every day in the duck in the process of sewage emissions of about 2500m3/d.
According to the state promulgated the "integrated wastewater discharge standard" (GB8978-1996), combined with the duck farm wastewater treatment and recycling of water quality requirements, considering the development of the domestic wastewater treatment technology and technological economic support ability.
2 Determination of new wastewater treatment process
According to the actual situation of the enterprise, according to the original process shortcomings, combined with the design scale, characteristic, wastewater effluent quality requirements, local actual conditions of enterprise and the actual economic situation, to achieve water recycling and energy saving effect, design process of the new transformation scheme.
3 the new treatment technology of duck wastewater characteristics
The combined process of wastewater treatment mainly includes pretreatment process, air flotation process, hydrolysis acidification process, CASS aerobic biochemical treatment and advanced treatment process.
Pre treatment of mixed wastewater from the field through the grille to remove the sewage in the large floating debris and fibrous material, to ensure the normal operation of a building and effectively reduce the processing load, provide a guarantee for the normal system. The grid is provided with a grid gap for the 3mm mechanical grid. After the treatment of the sewage, the sewage is mixed into the regulating tank by adding medicine, and a pre aeration device is arranged in the regulating tank, and the oxygen is mixed and stirred to regulate the water quantity and the uniform water quality, so as to prevent the sludge accumulation in the regulating pool.
The air of wastewater after adjustment for elevating the pump to the flotation tank, continuously adding flocculant by measuring container (polyaluminium chloride), the dosage is determined by the water quality of the wastewater, colloid agglomerate, and the dissolved air release method , the dissolved gas releaser to form tiny bubbles as a carrier. When suspension has been condensed in the sewage in the rising process, micro bubbles attached to the suspension, make up soon, so the sewage in the suspended matter all floating on the water, and then through the upper part of the flotation foam scraper to scrape into the tank, discharged to the hydrolysis acidification pool and pool bottom the treatment of wastewater, air flotation equipment after treatment, can greatly reduce the CODcr, BOD5, SS, oil.
The hydrolysis acidification process of flotation effluent flowed into the hydrolysis tank, the sewage in anaerobic conditions, using anaerobic or facultative bacteria hydrolysis acidification process, further acidification organic macromolecules in sewage, difficult to decompose into organic small molecules, so that the biodegradability of the wastewater conditions further improve [2-3] among them, organic carbon material by water dissolution of monosaccharide, hydrolysis of proteins into peptides and amino acids, fat is hydrolyzed into glycerol and fatty acids.
The CASS aerobic biochemical treatment of sewage flowing into the CASS hydrolysis pool pool. The CASS pool is divided into two parts: the pre reaction zone and the main reaction zone. In the pre reaction zone, through the rapid transfer mechanism of enzyme microorganism can rapidly adsorb most of soluble organic matter in sewage, through a high load matrix fast accumulation process, the good buffer effect on water quality and quantity, pH and toxic and harmful substances; followed by a low load matrix degradation process in the main reaction zone. CASS process in reaction, precipitation, drainage in one, the degradation of pollutants is pushing flow process on a time, microbial in aerobic, anoxic and anaerobic periodic changes, has the function of nitrogen and phosphorus removal is better, at the same time in anoxic and aerobic conditions alternately for microbiological screening, inhibitory effect on the growth of filamentous bacteria, which can effectively prevent sludge bulking .
The depth of treatment using activated carbon adsorption process. CASS pool water flow to the disinfection tank, waste water mixed with disinfectant can be discharged.
The reclaimed water is further purified from the pump to the sand filter and the activated carbon filter, and the effluent of the filter is used for the reuse of the reuse water pool. After the treatment of deep water has reached the level of colorless and transparent, its COD value of less than 70mg/L, to meet the national sewage discharge requirements.
It is produced by the sludge flotation tank and CASS tank sludge by the pump to the sludge tank, after concentration by sludge pump lifting type filter press to take, dewatered sludge cake Sinotrans sale.
4 benefit analysis
The enterprise through the sewage treatment not only makes the company's discharge of sewage and recycling of renewable resources to be successfully implemented, but also reflects the considerable environmental benefits, economic benefits and social benefits, to ensure the long-term development of enterprises.
5 environmental benefits
The implementation of duck wastewater treatment improvement program, with a rate of about 90% is expected to return to wastewater, COD emission reduction of 723.6t/a, SS 450.8t/a BOD5 emission reduction, emission reduction 545.7t/a, NH3-N emission reduction of 53.38t/a emission reductions of 821250t/a wastewater.
After biochemical treatment sludge can be sold as agricultural fertilizer, reduce pollution. After the project is completed, the local ecological environment can be effectively improved, and the pollution load of Huaihe and Weishan Lake can be reduced.
6 economic benefits
After the completion of the project, the direct benefit is to save sewage charges 912 thousand and 500 yuan, can save water costs: *2.35 yuan / ton =192.99 yuan / ton. After treatment, the sludge produced by biochemical treatment can be used as agricultural fertilizer, and the direct economic benefit is 300 thousand yuan / year. Therefore, after the completion of the project, some of the proceeds can be offset by the cost of wastewater treatment.
7 social benefits
After the implementation of this technology, we can improve the local ecological environment, so that the pollution load of Huaihe and Weishan Lake has been reduced. As a large emitter of organic matter in the whole basin, the water ecological environment of the basin will be greatly improved, and the difficulty of the protection of the clear water corridor of the south to North Water Diversion Project will be reduced.
At the same time, improve the development and competitiveness of enterprises, to promote local economic development and local industry nurturing agriculture are meaningful. The improvement of the local ecological environment will improve the investment environment and the development of local economy in the surrounding areas, and promote the sustainable development of the local economy.
At present, the technology of air flotation, hydrolysis and CASS aerobic biochemical combination is mature, and its operation control system mainly adopts programmable automatic control, and is equipped with safety protection and alarm device. The implementation of the program does not require too many operators, is conducive to the improvement of product capacity and quality, easy operation and control, so that the overall energy consumption. The depth of the treated effluent has reached a colorless and transparent degree, the COD value is below 70mg/L, achieve the sewage discharge requirements prescribed by the state, and to achieve 90% of the wastewater reuse rate, sludge can be sold as fertilizer, which brings great economic benefits to the enterprise, while reducing light pollution load of local water basin and the huge effect to improve the local ecological environment has.