The Effect Of Modulation Of The Operational Parameters And Adding Tubificid To Activated Sludge Wastewater Treatment System

With the growing size of the cities and rapid industrial development, the drain of industrial wastewater and domestic sewage is increasingly. Water pollution and sewage treatment problems has become more and more important. The purpose of this study is developing methods of reducing the operational cost and excess sludge production by CODCr, T-P, T-N,SV, MLSS,SVI, SBI for evaluating indicator through modulating the operational parameters and adding Tubificid to active sludge water treatment system,An orthogonal table of 3 factors and 3 levels is applied to the experiment, which includes 9 experimental groups indicating the effect on the processed wastewater of activated sludge treatment system by setting different levels of 3 operational factors:temperature, pH, and influent water CODcr. The indoor modulated experiment demonstrates that the activated sludge treatment system does not work for a long time, the biomass decrease significantly (<50ind/ml) at 10℃.Under the condition of 15℃,weak acidity(pH=5 or 6) and influent water CODCr less than-600 mg/L, the acclimatized activated sludge can ensure the sludge treatment system work regularly, the amount of excess sludge is low, thus it is favorable for post treatment of sludge and reducing secondary pollution. An observation on number and abundance of the protozoan inside the active sludge is carried out, Vorticella, Aspidisca and Epistylis are the dominant species in the active sludge under the condition of low temperature and weak acidity, while under the condition of low temperature and weak alkalinity (pH=8), Litonotus and Epistylis are the dominant species. At 20℃,the number and the abundance of the protozoan increased significantly, Litonotus, Vorticella, Epistylis and Aspidisca are the dominant species in the active sludge system.In aerobic wastewater treatment system, large amount of sludge are produced and the separation, dewatering, treatment and disposal of this sludge takes much cost. In order to avoid cause secondary pollution to the environment, the sludge must be disposed properly. One measure of reducing excess sludge production is to promote the growth of higher tropical organisms in the food chain, which prey on bacteria. During the process of energy changing which transfered from lower to higher trophic level, energy is lost and sludge is reduced because of inefficient biomass conversion. In this study, Tubificid was added to wastewater treatment systems, which lead that the sludge yeild was reduced, MLSS and SV decreased by 16.29% and 10.53%, respectively. SVI was improved, otherwise the CODcr of effluent water reduced by 4.3-7.3%. by inoculating Tubificid.