Modelling Of Nitrogen & Phosphorus Removal And Optimal Operation Of Urban Wastewater Treatment Unit

Wastewater treatment system belongs to complex system. Functional microorganisms lived in these complex systems behave intellectively and adaptively. They make responses according to certain rules and change these rules along with new information received form fluky environment. Emulate technology is a useful tool to solve engineering problems existed in complex sytem like wastewater treatment plant (WTP). Take advantage of emulate technology, technical decision, parameter optimization, optimal control and accident analysis can be done effectively and scientifically. As everybody known, activated sludge system modelling is necessary for emulate analysis and reasonable mechanism of nitrogen and phorsphours removal is the key for better model. In this paper, study on mechanism of nitrogen and phorsphours removal was investigated first. Revised model was proposed according to result of experimental research. At last, model application on optimal operation & control of activated sludge process was discussed.Tipical living sewage of southern china city is selected as study object. Real sewage fed, bench-scale, continuous-flow, study and batch tests are carried out with four familiar wastewater treatment processes, conventional activated sludge (CAS), anoxic-aerobic (AON), anaerobic-aerobic (AOP) and anaerobic-anoxic-aerobic (AAO) units, to investigate mechanism of nitrogen and phorsphours removal under conditions similar to WTP. Effect of parameters such as hydraulic retention time, sludge retention time and component of influent on nitrogen and phorsphorus removal is investigated. Transformation of carbon, nitrogen and phorsphorus in different unit is discussed. Amount of functional microorganisms and its characteristic parameter are summarized.Emphasis is placed on mechanism of enhanced biological phorsphorus removal in this paper. Difference of removal process between synthesized and real sewage is studied. Less poly- β -hydroxy-butyrate and poly- β -hydroxy-valerate are found in component of poly-hydroxy-alkanoates generated by phorsphorus accumulative...