| Water resources are the root of human survival and development. It is also the life blood of the normal running of the economy. What’s more, it will be the foundation of future generations to continue. This experiment was carried out on the low temperature conditions on the sewage effluent water quality situation analysis.CASS process is an effective process of activated sludge waste water treatment. At present, in order to get the experts, scholars worldwide recognition, and it is widely used in many countries, such as Japan and USA.Which achieved a sewage treatment effect. In China, CASS technology is the most common sewage treatment. Its flexible control, simple operation, small occupation area, less capital investment, convenient management, nitrogen and phosphorus removal effect is good wait for an advantage.And it is very suitable for processing work for small and medium-sized city sewage. In this experiment, combining with the natural conditions in the north winter cold season characteristics.Let’s take a further research on CASS process. Inquiry under different temperature conditions,simulation of CASS waste water treatment process in the biochemical reaction tank for water environmental characteristics, CASS process, water quality indexes were detected, which was observed and summarized the northern cold area with a model of construction way. The water quality dynamic change a rule that before and after the CASS process treatment of cold north sewage sludge CASS process could change rules of CASS process’ s improvement and development to further deepen according to the discussion.The following conclusions are: 1. In the test control and drainage ratio of about 1/3, influent flow 200-900 L / h, influent time(1h, 4h, continuous water), aeration 4h, precipitation 1h, drainage 1h, sludge reflux ratio 50%, the last paragraph of dissolved oxygen aeration control at 2-3.0mg / L, SRT 15 d conditions CASS sewage effluent treatment process and increase with increasing temperature, but the low temperature(5 ℃, 15 ℃) affect its water quality. 2. At temperatures of 5 ℃, under 15 ℃, 25 ℃ conditions, the average value of the effluent COD removal were 86.69%, 88.09%, 91.54%; effluent COD was 65.47 mg / L, 61.9 mg / L and 44.17 mg / L; SS effluent removal averages were 88.48%, 89.30%, 92.63%, and the effluent of the SS were 22 mg / L, 22.3 mg / L, 16.7 mg / L; effluent ammonia removal efficiency of averages were 32.35%, 30.13%, 76.19%, and the effluent ammonia were 16.14 mg / L, 15.34 mg / L, 5.37 mg / L; the mean effluent total phosphorus removal were 65.21%, 64.13%, 84.03%, total phosphorus effluent were 1.9 mg / L, 1.65 mg / L and 0.98 mg / L. The water temperature was 5 ℃, 15 ℃ effluent COD, SS, ammonia nitrogen, total phosphorus did not reach the level of the class B standard GB18918-2002. 3. When the water temperature is 5-15 ℃, CASS process running in winter should control range of each parameter is generally: SRT θcn system in 30-12 hours; total remaining dry sludge system(Stp) at 35521-14709 kg; sludge concentration(MLSS) in: 5680-2350 mg / L, the sludge layer thickness(H) in: 3.55-1.47m; weekly time(h): 8-4h; discharge ratio: 2.7: 1-5.4: 1; cycle sludge load: 0.05-0.1; Cs: 12.8-9.17 mg / L;: 14.52-10.4 mg / L; R0: 182.7-191.6 kg / h; GS: 73304-76632 m3 / d; aeration time 12- 16h; hourly air volume required: 6300-4725; n = required air volume per hour biochemical pool: 3150-2362 m3 / h; excess sludge: 296-306.4 m3 / d.The results show that: Although low temperature(5 ℃, 15 ℃) will affect CASS water quality and waste water treatment processes, but by adjusting the process parameters, can be resorted to water quality to achieve "urban sewage treatment plant emission standards"(GB18918-2002) a class class B standards. |
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