The Critical Technical Study Of The City Sewage On MUCT Process

Entrophication in water bodies caused by excess nutrients (i.e. nitrogen and phosphorus) is identified as one of main problems in water pollution, therefore, nitrogen and phosphorus removal are very crucial for municipal wastewater treatment. The existing processes for nitrogen and phosphorus removai are:A2/C. modified A2/O. VIP AB. SBR. MSBR. Dephanox. BCFS and UCT. Most of them have problems with complicated operational control and not always being effective for nitrogen and phosphorus removal in practice. however, modified UCT (MUCT) process showed that good nitrogen and phosphorus removal in foreign practice.Hence, this study focused on phosphorus and nitrogen removal from municipal wastewater by MUCT process. The main objectives were to investigate effects of different operational conditions on phosphorus and nitrogen removal by MUCT process. i.e. hydraulic retention time (HRT). solid retention time (SRT) and food to microorganism ratio (F/M), to obtain best nitrogen and phosphorus removal.The optimization of operational conditions were acheived by analysing results of orthogonal test under 9 different conditions to determine major impacts for carbon, nitrogen and phosphorus removal by MUCT process. The results showed that HRT played a major role on COD removal, the predominate effect of TP removal was SRT and interaction between HRT and SRT mainly impacted TN removal. H4--N removal efficiency was all above 90% under 9 different conditions which indicated that the effects of HRT, SRT and F/M on H4--N removal were not significant.The best operational conditions was found at HRT=11h, SRT=10d and F/M=0.357 kgBOD5/(kgMLSS·d)) in MUCT process based on the results of orthogonal test.Moreover, this study investigated effect of carbon on nitrogen and phosphorus removal by MUCT process. The results showed that phosphorus removal efficiency increased with the increase of COD/TP ratio. The relation between nitrogen removal efficiency and COD/TN ratio was not so clear which is recommended for further study.