Study On The Domestic Sewage Treatment By Using Suspended Carrier Biofilm Process In The Low Temperature

Microbiological treatment is an important part of the wastewater treatment methods. Themicroorganisms can be found easily around us, the process is simple, the chemical agent isnot necessary, and it won't lead to secondary pollution, for which it is used widely. Theactivated sludge process and the biofilm process are the two primary parts of the traditionalmicrobiological wastewater treatment. The key element is the carrier in biofilm process. Thesuspended carrier biofilm treatment was developed in the nineties of the last century as a newbiofilm technique. The new type carrier was used in it, which improved the efficiency of thewastewater treatment greatly. But in the low-temperature areas of the north, the applicationand study of the suspended carrier biofilm process was seldom. The foreword introduced the fundamental principles of the microbiological method inwastewater treatment, the progress of the suspended carrier and the biofilm reactor research.In the meanwhile, it summarized the low-temperature's influence on the biofilm treatment. The purpose: the two kinds of carrier, plastic artificial suspended carrier and crudemodified touchwood carrier, were used in moving bed biofilm reactor 1 and fixed bed biofilmreactor 2 respectively. The two reactors were combined into a two-phase process. This paperinvestigated the carbonaceous and nitrogenous removal capacity of this process in thedomestic sewage treatment. The content: in the 8¹0℃ low temperature condition, the lab-scale experiment wasoperated for 4 months. It studied the membrance-forming characteristic of the biocarrier. Ittested the removal capacity of the process for COD, BOD, NH₄⁺ -N,TP in the domestic sewagetreatment. This paper studied the membrance-forming characteristic. The artificial plastic carrierinoculated biofilm fast. The biomass concentration was big. It could still be suspending afterbiofilm inoculated and be fluidized easily. The crude touchwood carrier with a coarse surfacewas of great absorption so that it was suitable for the microorganisms to grow on and it wasable to adapt to variable volumetric loading well. The paper studied the capacity of the two biofilm reactors with the two kinds of carrier totreat the domestic sewage. It showed that the reactor1 filled with suspended carrier sustainedthe most organic volumetric loading. While the inlet organic volumetric loading was below 4kg/m3·d, the hydraulic retention time (HRT) was 14 hours, the removal rate of COD wasabove 80%. The reactor2 sustained the most ammonia nitrogen volumetric loading. While theinlet ammonia nitrogen loading was below 0.14 kg/m3·d, the removal rate could be 74%.While COD/NH₄⁺ -H was 2.8, the removal rate of ammonia nitrogen could reach themaximum-56.6%. The two reactors were combined. At the condition of the influent COD 232⁸59mg/L,BOD 87²31mg/L, ammonia nitrogen 23⁶0 mg/L, TP 4¹0 mg/L, the effluent was below50mg/L, 12mg/L, 14mg/L, 4 mg/L, and the mean removal rate was 85%, 90%, 55%, 50%respectively. The conclusion: The 8¹0℃ low temperature condition made small effect on theremoval of COD, BOD. Taking measures of decreasing influent loading, adding the HRTcould get the outcome close to the common temperature condition. The effluent data were allbelow the national standard. The low temperature made big effect on ammonia nitrogendenitrification. But the microorganisms could still live after domestication. The ammonianitrogen removal rate could get to 50%. The two-phase reactor could treat the lowtemperature domestic sewage well. This research applied the new type carrier and process about the problem that thetemperature of the north area in winter was low and that the sewage treating effect inbiological process was bad. The experiment data were valuable in the real design andapplication as a reference.