Study On The Sludge Reduction Efficiency And Influence Factors Of Metformin Hydrochloride As Uncoupler

At present,the activated sludge process is the most commonly used wastewater treatment technology at home and abroad.Although the effect is excellent,one of the biggest problems in the treatment process is that a large amount of excess sludge is produced.The residual organic matter and its pollutants contained in the sludge,the environment will have secondary pollution,making the remaining sludge treatment and final disposal of sewage treatment plants become one of the most difficult issues.Commonly used sludge reduction technology,such as biological predation technology,enhanced microbial recessive growth technology and membrane bioreactor,most of them have corresponding shortcomings,such as more energy consumption,difficult to control the reaction conditions,higher operating costs.Compared with the above technology,adding a certain degree of uncoupling agent in the activated sludge process can reduce the sludge generation more effectively from the source.Uncoupler agent uncouples the synthesis and catabolism of the organism and fundamentally achieves sludge reduction by inhibiting the synthesis and metabolism and reducing the production of residual sludge.However,most uncoupler agents are toxicologically and also will lead to poor water quality of the system,endangering the environment and human health.In this paper.the cheap and nontoxic Metformin Hydrochloride was selected as uncoupling agent.At different concentrations,different dosage methods and different operating conditions(pH,temperature,influent load),to study the effects of Metformin Hydrochloride on sludge reduction,sewage treatment effect,sludge sedimentation and microbial life activities in sludge.and then to definite the best dosage,dosing mode and the optimal process operating conditions of Metformin Hydrochloride sludge reduction.At last,the economic benefit of Metformin Hydrochloride sludge reduction was calculated,and the economic feasibility of the technology was analyzed.In laboratory-scale SBR process,adding Metformin Hydrochloride had a certain impact on sludge yield and substrate removal rate.The effect of sludge reduction under five different concentrations(10mg/L,20mg/L,40mg/L,60mg/L and 80mg/L)was compared.the results showed that different dosage of Metformin Hydrochloride reduced sludge production.Among them,the optimum concentration of Metformin Hydrochloride was 40mg/L,sludge weight loss reached 58%,did not affect the substrate removal effect,and the sludge settling performance is good.Sludge SOUR and DHA value than the corresponding value of the control group increased by 32%and 25%,better to promote the activity of the system sludge.On the basis of the optimal concentration of Metformin Hydrochloride being 40 mg/L,the effects of two kinds of adding methods(adding 120mg per day and adding 240mg Metformin Hydrochloride every two days)on sludge reduction,sewage treatment effect and sludge performance are compared laterally.The best dosage of Metformin Hydrochloride is determined as a one-time bolus(dosing 240mg every two days)is the most reasonable.The effect of Metformin Hydrochloride on sludge reduction has a great relationship with the operating environment of the system in which it is placed.The increase of pH is conducive to the removal of matrix in sewage,but not conducive to sludge reduction;under normal temperature,the sludge reduction effect and system nitrogen removal effect are the best;increasing the water load makes sludge reduction effect worse,total nitrogen removal rate decreased.Considering sludge reduction effect,sewage treatment effect,sludge performance and other factors,we can draw a conclusion:the optimum operating conditions of Metformin Hydrochloric sludge reduction system is pH=7.0、T=25℃.NS=0.25gCOD/(gMLSS · d)Comparing the economic benefits of conventional SBR system and Metformin Hydrochloride Sludge Reduction System,it can be found that the treatment cost per ton of wastewater(including excess sludge)in Metformin Hydrochloride Sludge Reduction System can be reduced by 0.0022 yuan,reducing the cost of wastewater treatment plant Operating costs.Therefore,it is technically and economically feasible to add metformin hydrochloride to sludge reduction in SBR process.