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Untreated or substandard restaurant wastewater which is directly discharged into urbansewage pipe networks will bring huge pressure to municipal sewage treatment plants. Suchenvironmental problems caused by restaurant wastewater are particularly prominent in theregions with inadequate sewage pipe networks. Besides, the shortage of water resources has alsocaused wide public concern in society. Therefore, this experimental study aims to explore waysof treating restaurant wastewater to get its effluent water quality to reach the secondary standardof Pollutant Discharge Standard (GB8978-1996).The average water quality indices of a university canteen’s restaurant wastewater(theexperimental subject) are COD concentration:2,150mg/L;BOD concentration:1,128mg/L; oilcontent:214mg/L; ammonia concentration:33mg/L; TN concentration:75mg/L; TPconcentration:14mg/L.To treat the restaurant wastewater mentioned above, combined process of magneticcoagulation and SBR are adopted in this study. Study shows as below:(1) After comparison experiments of the3coagulation agents PAC, aluminum sulfate and ferricchloride, it is found that PAC is superior to the other2agents in the coagulation process and hasthe best effluent quality; besides, magnetic coagulation treatment is obviously better than theother conventional coagulation processes,whose average removal rates of COD, BOD, oil,ammonia, TN and TP respectively can be increased by11.3%,12.6%,8.15%,8.89%,7.46%and7.3%.When the dosage of PAC is180mg/L and the magnetic powder is250mg/L, the wastewaterhas the optimal pretreatment effect. After the pretreatment, the removal rates of COD, BOD, oil,ammonia, TN, and TP respectively are85.18%,67.85%,91.86%,60.79%,40.59%and70.45%.(2) By the combined process to treat the restaurant wastewater, mainly aiming to treat oil, theoptimal condition group is A1B2C3D3, namely it is under the condition when the PAC dosage is180mg/L, the magnetic powder dosage is225mg/L, the aeration time is5h and the DOconcentration is2.5mg/L that the effluent water quality of the wastewater treated by the systemcan stably reach the secondary standard of Pollutant Discharge Standard (GB8978-1996). Theremoval rates of COD, BOD, oil, ammonia, TN and TP after the entire combined process arerespectively97%,98%,94%,87%,74%and97%, among which the indices of BOD, ammoniaand TP can meet the first-grade discharge standard.(3) This combined process of magnetic coagulation and SBR for restaurant wastewater treatmentalso has advantages of small occupation space, high processing efficiency, easy operation, stableeffluent water quality, so it can be popularized.
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