| The method of activated sludge is an effective and promising technology forwastewater treatment, the process is commonly used in wastewater biologicaltreatment. However, no matter for which an improved activated sludge process,sludge bulking (Sludge Bulking) phenomenon from the activated sludge processsince the advent of the operating management in the suppression of that problem, soit is also called "the cancer of activated sludge ".sludge bulking phenomenon isperplexing, though research in this respect has achieved great results, but theseresults are only some scattered results, but did not form a complete system, and nowon the DO, organic load, nutrient balance and factors such as sludge expansionFor sludge bulking definition has many kinds, but in general are the same,compared with a full description is:1poor settling performance, regional subsidencerate less than1.2m/h (MLSS=3.5g/L);2sludge loose, not dense, sludge index SVIis greater than150(or200mL/g);3of sludge bulking caused by filamentousbacteria filamentous length more than104m/g.The purpose of this experiment is to find and verify the occurrence of activatedsludge bulking and its running environment and different conditions, in the course ofthe experiment by changing operating conditions predisposing sludge expansion,then through the system is restored to its original state to study the effective controlmethods of sludge bulking. This experiment uses the SBR process, using syntheticwater as water nutrients, by changing the different operating conditions andconclusions.In the present experiment, the beer waste water as the research object, usingSBR method to study the water of different organic matter and total nitrogen andtotal phosphorus concentration ratio (BOD/N and BOD/P) on activated sludgebulking effect Through a lot of. experimental research the following conclusions canbe drawnThe traditional organic load on sludge bulking effect point of view, low organicloading caused by filamentous sludge bulking is one of the main factors, but in the present experiment, the water inlet nutrient adequacy condition, when the organicload is reduced gradually in the process, sludge settling properties remain good, andno sludge expansion. When the influent BOD/N of100/2under nitrogen starvation,in normal organic loading that occurs when the high viscous zoogloea causedexcessive growth of filamentous sludge bulking. While at low organic loading,sludge concentration is reduced substantially, microbial catabolism of their cellularmaterial for microbial growth provides a nitrogen source, therefore, the SVI valuedid not rise further, no sludge expansion. When the influent BOD/N of100/0.94conditions, in the normal organic loading conditions by high water content viscouszoogloea excess growth caused by severe non filamentous sludge bulking, at loworganic loading SVI up to200mL/g above, also produced non filamentous sludgebulking. Due to the low organic loading sludge concentration decreased rapidly,microbial cell catabolism substance makes the surplus sludge volume reduction,metabolites of nutrients to alleviate on certain level the water nitrogen lack of impact,so the sludge settleability deterioration degree is not very serious.When the influent BOD/P of100/0.8conditions, sludge settling performancegood, and effluent suspended solids less. When the influent BOD/P is respectively100/0.6and100/0.3, occurs from high moisture viscous zoogloea excess growthcaused by non filamentous sludge bulking, and by the expansion of the controlledstudies found, influent organic loading in the more and more high, sludge bulkingphenomenon recovery faster. When the influent BOD/P of100/0.4conditions, theoccurrence of serious non filamentous sludge bulking, at the same time, theemergence of a large number of high water content of extracellular polymericsubstances, but the seriousness of the non filamentous bulking in adding sufficient,under normal conditions can be effectively controlled. |
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