Comparative Study On Detection Methods Of Activated Sludge On Printing Dyeing Wastewater Biological Treatment System

There are many indicators to evaluate the nature of active sludge of printingand dyeing wastewater in biological treatment system, usually with the mixturesuspended solid concentration （MLSS）, the mixture volatile suspended solidconcentration （MLVSS）, sludge settling ratio （SV30）, sludge volume index （SVI）,sludge age （TS）, and other conventional indexes to measure the activity of sludge.With the development and progress of research and measurement technology,people found that it is not exactly enough to measure the activity of microorganismin activated sludge with MLSS or （MLVSS）, because MLSS （or MLVSS） alsoincludes the non-purification of the active material, that is not to be separate livingcells and the organic residues （such as dead microbial residues）. And whenactivated sludge inflation, to judge the nature of activated sludge by SV30,also havegreater error. So in some conditions these indexes as measures of activated sludgenature are not suitable, it is necessary to supply it.Because of the efficiency ofactivated sludge is related closely to the activity of microorganism in activatedsludge. The bigger the microbial activity, the treatment effect is better, conversely,the effect is poorer. For this, people began to try to use dehydrogenase activity（DHA） and adenosine triphosphate （ATP） and other biological indicators toreflecting microbial activity. In this paper, Comparative Study on the manydetection methods of active sludge and found that the most appropriate testmethods of different growth state.The experiment with the activated sludge of dyeing wastewater in completelyhybrid aeration pool and push streaming aeration pool system as the research object,select adenosine triphosphate （ATP）, dehydrogenase and conventional indexes ofactivated sludge properties to detect, and through research the relation of dehydrogenase activity, ATP content and conventional index with the sludgemetabolic state, and ascertain which method can more accurately detect the activesludge when the sludge in different metabolic state. Select the temperature, settlingvelocity, sludge concentration, sludge volume index, pH value and DO value as themain environmental influence factors of metabolic state in active sludge system, bysingle factor experiment, confirm the optimum detecting method of differentmetabolic state. Use COD removal rate to judge the active sludge of printing anddyeing wastewater treatment results.The results show that：when the SV of activated sludge is chang between20%³5%, with ATP method and TTC-DHA method both can reflect the actualmetabolic state of microbial in activated sludge; when the SV is between35%⁵0%,use ATP method detect the actual metabolic state of microbial inactivated sludge is more accurate. When the MLSS is between1.5².25g·L^-1,wecan both use the ATP method and TTC-DHA method,and when MLSS is above2.25g·L^-1,use the TTC-DHA method is more suitable. When SVI is between125¹50mL·g^-1,use ATP method and TTC-DHA method both can reflect the actualmetabolic state of microbial in activated sludge,and when SVI is above150mL·g^-1,use ATP method is more approximate.When pH value is change between6⁹, use TTC-DHA method detect is more accurate. When DO concentrationbetween2.0⁴.5mg·L^-1, use TTC-DHA methods detecet is more suitable,and whenDO concentration above4.5mg·L^-1,both can detect the activity of sludge.Testing the nature of active sludg in push streaming aeration pool which isprinting and dyeing wastewater treatment system after hydraulic retention time of0h,2h,4h,6h,8h and10h, found the results with ATP method and the TTC-DHAmethod were consist with the removal rate of COD. And when activated sludgehappen expands, the SV of active sludge with MLSS is not obvious, but the testingresult with ATP method and the TTC-DHA method is consist with the change of theMLSS basicly, and consist with the COD removal of active sludge correspondingstate, so use ATP method and the TTC-DHA method to detect the nature ofactivated sludge after different hydraulic retention time is more appropriate. Detect the active sludge properties of different proportion found that the ATPcontent extracted from a certain amount of activated sludge solution and generatedTF content by dehydrogenase is down with the proportion of the water alsodeclined, but the the amount ATP which was extracted by unit concentration ofactivated sludge and the TF which was catalyzed by dehydrogenase were notdescending, however in the concentration of3.0⁵.5g·L^-1is larger. COD removalwould also down along with the proportion, but the unit concentration of activesludge COD removal is lager when the sludge concentration is between2.0³.0g·L^-1. So when activated sludge concentration is small relatively, the metabolism ofmicrobes in active sludge is more exuberant.When aeration amount is more than4mL·s^-1or less than1.5mL·s^-1, ATPabsorbency value will be small, while TF absorbency value change is not obvious.When aeration amount is between2⁴mL·s^-1, the change of TF absorbency valueis consist with the change of COD removal rate, and when the aeration amount isgreater than4mL·s^-1, the COD removal rate is consist with the change of ATPabsorbency value, and the change of MLSS. So when aeration amount changebetween2⁴mL·s^-11, use the TTC-DHA method is more accurately, when aerationamount is more than4mL·s^-1, with ATP method to detect is more close to the truecondition of active sludge.