Research And Improvement Of Sludge Dewatering System In A Daily-used Chemical Enterprise

Sludge is the byproduct in the wastewater treatment process， which hascharacteristics of heavy in output， high in water content and severe inpollution．Along with the social economic development and the enhancement inconsciousness of environmental protection，the impact of sludge on the environmenthas been received more and more attention．The government has also improved instandardized management in sludge treatment through formulating relevant laws andregulations．The sludge dewatering is the most critical processing step despite ofwhich method will be used．Dewatering of sludge could help to improve the solid content of sludge andreduce the volume as well．Therefore，it could reduce the construction scale of finaldisposal facility and operating cost effectively．The effect of sludge dewateringdepends on many factors such as nature of sludge，process and daily operationmanagement．That is why many factors need to be considered synthetically during thedesign of sludge dewatering system．Recently，a daily-use chemical enterprise faces a problem in sludge dewateringthat a large number of backwashing water need to be retreated when the system inoperation due to the wrong choice of process in preliminary design．The handling ofbackwashing water takes up the capability of the wastewater treatment system and itbecomes more severe with rising in load of production．The enterprise is eager torenovate the current sludge dewatering system to reduce the output of backwashingwater and finally recover the original design capability of wastewater treatmentsystem．In order to ensure the design of renovation can match the actual needs，we madesimulation coagulation reaction test in the laboratory to analyze the relationshipbetween the wastewater quality， quantity of coagulant dosing and dry sludgedischarge and fixed the sludge yield coefficient and the calculating formula ofchemical sludge of renovation according to the study of current wastewater treatmentsystem．Therefore，we can finally to estimate the output of sludge when the systemreaches the design capacity．In order to forecast the excess sludge yield precisely，weused several ways of calculation to make the estimation and analyzed the resultaccordingly．At the same time，we had made the experiment to understand the natureof the sludge which involves organic matter content，moisture content of sludge， specific resistance, and analyzed the change rules of sludge nature．According to the actual operation situation and expect of the enterprise for themodification，we had compared three retrofit schemes by weighted analysis method toget the optimal design．In the renovation program，the sludge conditioning is an important pretreatmentstep in the sludge dewatering system．According to the commonly used method，wedecided to use PAM method as the way for sludge treatment．A variety of PAM product testing involving solubility，flocculation effect andsludge specific resistance has been carried out through beaker experiment in thelaboratory and the test result was compared and analyzed thoroughly to fix theoptimal flocculent and dosing．During the testing phase after renovation，we tested the affecting factors tocentrifuge to determine the optimal operation proposal by means of orthogonalexperiment method．Finally，we compared the operating effect before and after therenovation to test whether the modification can satisfy the expectations of enterprise．...