Study On The Effect Of Sodium Ferrous Chlorophyllin Combined With Peroxydisulfate On The Treatment Of Excess Sludge

Excess sludge is an inevitable byproduct in the sewage treatment process,which enriches a large number of complex organic pollutants,heavy metals,pathogens,etc.from the sewage,and has the dual characteristics of severe pollution and resource utilization.Reasonable treatment and disposal of excess sludge is a difficult issue that troubles the industry.Sodium ferrous chlorophyllin(SFC)is a typical metal organic complex that is non-toxic,harmless,and free from secondary pollution;Peroxydisulfate(PDS)is a stable,easy to store,and safe oxidant that does not cause secondary pollution to the environment.The combination of the two can produce free radicals with strong oxidation activity,which has great potential in sludge treatment.It provides a new approach to solve the problem of excess sludge treatment and disposal.The production of excess sludge is enormous,and conventional technologies such as sludge dewatering and anaerobic fermentation(digestion)have lower treatment efficiency.Especial ly,volatile fatty acids(VFAs)generated during anaerobic fermentation have higher and more widespread application value compared to methane.In order to increase the production of VFAs during anaerobic fermentation and prevent their conversion to methane,this study applies the SFC combined with PDS system to the field of sludge treatment,exploring the effects of-the combination of the two on the pretreatment,anaerobic fermentation,and dehydration of excess sludge.The main conclusions obtained are as follows:(1)The dosage of SFC and PDS was studied using COD,TOC,SC,SP,and TN as characterization parameters.The results showed that PDS had better effects on sludge decomposition and organic matter dissolution than SFC;The optimal dosage for SFC and PDS pretreatment of excess sludge is:PDS=2.0 mmol/g TS,SFC=0.025 mmol/g TS.(2)The anaerobic fermentation experiment was conducted using the optimal dosage of pretreatment sludge to monitor the hydrolysis,acid production,and methane production processes of anaerobic fermentation.The results showed that PDS was gradually activated in an anaerobic environment,and the activation effect of SFC on PDS was not significant.The strong oxidizing activity of PDS activation makes anaerobic fermentation tend to synthesize acid types with relatively stable structures,with a total acid production of about 2600 mgC/L,with acetic acid>nbutyric acid>n-valeric acid.(3)The methane production of surplus sludge treated with SFC alone can reach 954.99 ml,which has a certain promoting effect on methane production.The low pH and high ORP environments generated after PDS activation have inhibitory effects on methanogens,reducing their consumption of VFAs and accumulating VFAs.(4)The combination of SFC and PDS pretreatment of excess sludge can promote the destruction of floc structure,release capillary water,adsorbed water,and intracellular water,and improve the dehydration effect;Simultaneously,a large amount of organic matter is dissolved,resulting in a small increase in CST.After the completion of anaerobic digestion,it was found that SFC+PDS had the best sludge dewatering effect,organic matter utilization was the most sufficient to minimize CST,Zeta potential was the smallest,and the average particle size became larger than PDS.After the completion of anaerobic digestion,the order of sludge dewatering performance from excellent to poor is SFC+PDS>PDS>RS>SFC.