Application Study On Efficient Reduction Disposal Of Waste Activated Sludge Based On Sulfite In-situ Treatment

Aerobic digestion and anaerobic fermentation are two of the most effective methods for sludge treatment at present,but both methods suffer from slow hydrolysis processes due to the sludge’s own characteristics.Therefore,in this paper,in-situ treatment technology is used to enhance the effectiveness of aerobic digestion and anaerobic fermentation of sludge using sulfite in-situ treatment.To achieve sludge reduction and promote resource recover.The main studies are as follows:Firstly,an experimental study on the aerobic digestion of sludge by in-situ sulfite treatment was conducted.The research results showed that the in-situ treatment of sulfite significantly enhanced the aerobic digestion performance of sludge,with the best effect at 500 mg S/L.The sludge lysis was improved,soluble organic substrates were released in large quantities,the lysis of sludge was improved,the VS removal rate was increased by 3.6 times,and the removal rate of E.coli and total E.coli reached 75.3% and 51.6%,respectively,which efficiently promoted the sludge reduction and harmlessness.In addition,the dewatering performance of sludge after aerobic digestion was improved,which was beneficial to sludge reduction and stabilization.According to the microbiological results,sulfite also effectively enriched related microorganisms,such as norank＿f＿Caldilineaceae 、 Exiguobacterium and Glutamicibacter,which led to the improvement of aerobic digestion performance.An experimental study of the anaerobic fermentation of sludge treated with sulfite in situ was conducted.The results showed that sulfite in-situ treatment was the best at 500 mg S/L,with 3.25 times increase in soluble protein and 1.70 times increase in soluble carbohydrate and good inactivation of pathogenic bacteria E.coli,Salmonella,Streptococcus faecalis,and total E.coli,which effectively promoted sludge hydrolysis and enhanced sludge abatement and harmlessness.In addition,the anaerobic fermentation process also produced high-value substances called SCFAs,which can be used as an "internal carbon source" to return to the front end of the biochemical tank for resource recycling and increase the value of sludge resource utilization.Finally,the microbial community analysis revealed that sulfite made the acid production-related functional microorganisms.Finally,the microbial community analysis revealed that sulfite enriched Acinetobacter,Macellibacteroides,and Proteocatelles and inhibited the activity of methanogenic bacteria,which promoted the production and accumulation of SCFAs.A comparison of aerobic digestion and anaerobic fermentation efficacy was performed.The results showed that aerobic digestion was more effective than anaerobic fermentation in terms of sludge reduction,harmlessness,and dewatering performance,but the anaerobic fermentation process could produce high-value substances for resourceful recycling of sludge,and the application value was higher than that of aerobic digestion.