Study On Characteristics And Mechanism Of Integrated Communicative Multi-Influent Process With Five Tanks For Nitrogen And Phosphorous Removal

Contrapose the severe pollution, especially nitrogen and phosphorus pollution in our country, a new municipal wasterwater treatment process, namely integrated commutative multi-inflent wasterwater treatment process with five tanks for nitrogen and phosphorus removal, was developed by Southeast University with the financial support from Department of Science and Technology of Jiangsu..The characteristics and mechanism of integrated commutative multi-inflent wasterwater treatment process with five tanks for nitrogen and phosphorus removal were studied in this paper. The operational parameters, real-time control strategy and nitrogen and phosphorus removal mechanism are as follows:1. The operation condition of commutative multi-inflent wasterwater treatment process is in favor of the growth of PAOs, nitrobacteria and denitrifier. The efficiency of denitrogen and dephosphorus was high after only 20 days of incubation; and the average removal efficiencies of COD, NH4+-N, TN, TP could reach about 83%, 93%, 75% and 85%, respectively.2. Appropriate operation parameters were: phases-time setting was 3h, 3h, 2h, 3h, 3h, 2h; gas/water was 20, sludge return ratio was 30%. Both temperature and hydraulic retention time (HRT) were primary factors that affected the removal efficiency in operation. At the temerature of 23~28℃, 15~22℃,8~14℃, the HRT was 10～12h, 12～15h, 18～20h, respectively; and the volumetric loads of COD were 0.55~0.66 kgCOD/(m3?d), 0.48~0.6kgCOD/(m3?d) and 0.33~0.45 kgCOD/(m3?d), respectively. When typical municipal wastewater was treated by this process under appropriate operational parameters, the quality of effluent could reach the National Discharge Standard GB18918-2002 of Pollutants for Municipal Wasterwater Treatment Plant.3. In SBR system, the sluge of commutative multi-inflent process showed good denitrifying dephosphatation characteristic under certain conditions: denitrifing dephosphatation reaction was difficult to be detected when NO3--N /COD<0.1 while the capability of denitrifing dephosphatation increased when NO3--N /COD≥0.1.4. There were a series of denitrogen and dephosphorus reactions in the process, and the traditinal reaction (i.e. traditional nitrification/ denitrification and anaerobic phosphorus releasion/aerobic phosphorus absorption) was the main reaction. In addition, other reactions such as simultaneous nitrification and denitrification (SND), ANAMMOX, endogenous denitrification and denitrifying dephosphatation were also discovered in this process.5. In SBR system, control parameters (i.e. DO, ORP, pH) correlated to pollutants concentration, each of the controlling parameter can accurately detect the ends of nitrification, denitrification and dephosphatation. In integrated commutative multi-inflent system, DO and ORP could be used to control aerobic phase, i.e. DO and ORP levels in aerobic tanks shold be kept above 3mg/L and 100mv, respectively.