Pilot Study On Operational Adjuctment Of Cyclic Activated Sludge Technology Process Coping With Short-term Shock Loads Base On Factorial Analysis

With the development of economic and our society serious water pollutioncondition in China raises people’s concerns about water resources. Today, It is necessaryto improve the depth of sewage treatment so that it can meet the requirement ofeconomic development; the state has implemented a series of measures to solve theproblem of water pollution. Three Gorges Reservoir areas economically underdeveloped,so it has a high requirement of water environmental protection, urban sewage treatmentplants operating load is low. All these features lead urban sewage treatment becomemore difficult. CAST (Cyclic Activated Sludge Technology) process is the developmentof SBR, which has many advantages, such as small footprint area, no need to set theprimary sedimentation tank and secondary sedimentation tank, a high level ofautomation, higher nitrogen and phosphorus removal efficiency. Due to its ownadvantages in the sewage treatment in the reservoir area, it will occupy a great deal ofthe application prospects. This subject comes from the national "the water body ofPollution Control and the governance Science and Technology major special" in of theThree Gorges project topics Second " the Three Gorges Reservoir Area urban sewagetreatment plants’ function begins with the sludge treatment and disposal technologyresearch with the comprehensive demonstration" sub-topics "the Three Gorges urbansewage in the reservoir area the treatment plant typical process function to enhance thethe thematic of the regulation and control technology research and demonstration "three:municipal wastewater treatment plant CASS Process function to enhance the regulationand control technology research (task numbered:2009ZX07315-002-01-003). thesubject from the CAST process inflow water organic matter and the total nitrogenabnormal to proceed, with a view in order to get the optimal regulation and controlstrategy in the under the conditions of an inflow water abnormal.The study is based on the actual operation of the CAST process in Lijiatuo sewageplant, obtain the basic parameters of the process, and out of the water qualitycharacteristics, and water quality analysis, we found that the sewage treatment plantinfluent inflow water quality fluctuates strongly. This topic at the appropriate time, it ismeaningful Use of the CAST process placed in the sewage Lijiatuo plant pilot plant,and installed in the pilot plant with the pH, DO, ORP0n-line monitoring equipment,PLC for automatic control of the reactor. The pilot experimental reactor model, customization, installation, operational, the sludge training training, no impact on thenormal running conditions to the influent organic matter and total nitrogen abnormalshock system and in-depth study. Through adjusting several key control parameters ofCAST (water inflow ratio, recirculation rate), the analysis of pilot experiment data toget equation of relationship between water effects and regulation factor, Draw waterplant normal operation when the feed water quality abnormal optimal operation schemefor four hours. Then proposed based on the study of the patterns of six hours, and in thepilot model to the model proposed by six hours of practice, After factorial experimentalanalysis equation relationship between the water effects and regulatory factors, andultimately get the optimal control program under the conditions of short-term shockload.Four-hour mode is the normal operation mode of the water plant, so the impact intothe First you must go to this mode of treatment, the need of a great deal of research.Specifically: inflow/aeration2h, sedimentation1h and discharge1h. In the four hoursmode, The equation of relationship between effluent water quality and its control factors,Water rushed into organic matter at the actual factor expression for regression equation:the water quality its regulation factor equation for water by organic matter burst into theactual factor regression equation expressed as: effluent water CODcr (mg/L)=-221.3+7.3×A+8.1×B-0.2A×B, wherein: A-recirculation rate×100(30,50or70);B-inflow ratio×100(15,25or35); influent TN impact on the actual factor Theregression equation is expressed as: effluent water TN (mg/L)=29.4+78.4×A26.7×B, wherein: A-inflow ratio×100(15,25or35).; B-recirculation rate×100(30,50or70)The six-hour mode control mode is raise after, analysis of the experimentalanalysis of the four-hour mode exceptional circumstances, and the six-hour mode:inflow1h, inflow/aeration2h, micro-aeration1h, sedimentation1h, the discharge1h.Water by the impact of organic matter in the six hours mode when the actual factorregression equation expressed as: effluent water CODcr (mg/L)=-118.85+214.3×A+589.8×B-965.1A×B, where: A-inflow ratio×100(15,25or35).; B-recirculationrate×100(30,50or70); the influent TN impact when effluent TN (mg/L)=9.35+30.59×+25.71×B-98.11A×B wherein: A-inflow ratio×100(15,25or35).; B-recirculation rate×100(30,50or70).The results showed that in response to water impact, by reducing the water inflowratio and improving the recirculation ratio can significantly reduce the impact of the shock load for process effluent quality of CAST; the water’s main effect inflow ratio issignificantly stronger than the recirculation ratio. Four-hour emergency mode todischarge the sewage treatment plant of organic water quality impact, and six hours inthe water by total nitrogen impact control mode. However, this adjustment strategy willneed to consider the real-time water flow and return sludge wastewater treatment plantconditions, combined with the mode of operation of the aeration system to get the bestcontrol effect.