Study On The Commissioning Of Modified ICEAS Technique In Lijiang Wastewater Treatment Plant

The existing process of Lijiang wastewater treatment plant is ICEAS. However, with the improvement of people's living standard and the increasing number of tourist, the city is more and more famous, especially after it is approved as a natural and cultural city by UNESCO. Because of the flourish tourism, water pollution gets more and more serious and the treatment capacity is less than the actual discharge. Thus, increase of the pipeline and expansion of the wastewater treatment plant become imperative.The process of ICEAS has disadvantages of low removal effect of nitrogen and phosphorus under low influent concentration and less sludge as well as sludge aging. To solve these problems, the expansion project adopts Modified ICEAS technique especially to improve nitrogen and phosphorus removal efficiency. In addition, the society development demands the disinfection to the discharge of effluent.Commissioning of the project includes electricity test, PLC test and treatment process experimental operation which consists of removal effect of low influent concentration,process operation model, optimal parameter, SRT, phosphorus removal effect, and comparison of removal effect between modified ICEAS and ICEAS. In addition, economic benefit and society benefit are also analyzed.Under the situation of low influent concentration, the effluent concentration for CODcr ranges from 20 to 44.3 mg / L, and the removal rate is 67.1% ~ 83.3%; The concentration of BOD5 ranges from 8.5 mg /L to 19.1mg /L, and the removal rate is 53.6% ~ 72%; The concentration of NH3-N ranges from 0.3 mg/L to 2.5 mg/L, and removal rate is 84.1% ~ 97.1%; The concentration of TP ranges from 0.8 % to 1.5 mg/L, and the removal rate is 16.7% ~ 69.2%; The concentration of SS ranges from 10 mg /L to 21 mg /L, and the removal rate is 84.2% ~ 91.3%. Under the condition of low-concentration influent, the treatment system operates steadily and the effluent gets to the discharge standard.The optimum operation parameters are determined by orthogonal test. The three factor of DO, sludge load and return rate of sludge are selected for the pilot studies. Since the removal rate of TP is less effective, removal rate of TP is regarded as the major reference factor. According to above, the optimum operation parameters are following: 3 mg/L for DO, 0.2kgBOD5(/kgMLSS·d)for sludge load and 25% for return rate of activated sludge.Under the condition of design sludge age (17d), it can reduce the quantity of TP greatly on the base of good removal effect of CODcr, BOD5 and NH3-N. The concentration of TP in effluent is 0.6 mg/L, which is below the discharge standard.The Modified ICEAS technology has better treatment efficiency of pollutants compared to ICEAS technology, especially for the removal of TP. The removal rates of TP, BOD5 and CODcr are 22%, 7.8% and 8.3% greater than ICEAS technology. In addition, the condition of activated sludge is much better than the former technology.It plays an active and motive role in the development of Lijiang culture. In addition, the implementation of the project will strongly improve people's living environment and promote the development of urban civilization. It can also bring about large social benefits and certain economic benefits which can play an important supported role in the sustainable economic development of this area.