Experimental Study On The Synergistic Purification Of H₂S By Biological Leaching Of Sludge

In recent years,with the increasing improvement of people’s quality of life,the rapid advancement of urbanization and national attention to sewage treatment work,sewage collection and treatment capacity has increased sharply,and sludge production has also increased.Surplus sludge is enriched in a large number of organic matter,nitrogen,phosphorus,potassium and other nutrient elements,is a very good raw material of organic fertilizer,but at the same time there are a lot of water,heavy metals,pathogenic bacteria and other toxic and harmful substances in the sludge,affect the subsequent disposal and resource utilization,and through various ways to human physical and mental health threats.Therefore,the safe treatment and disposal of surplus sludge is very important.Biological leaching as a kind of sludge conditioning technology emerging in recent years,it is through the physiological function of compound sulfur bacteria,reduce sludge p H,change sludge bacterial flora composition,reduce microorganisms extracellular polymer production,improve the dewatering performance,and can be dissolved out of heavy metals in addition to,and at the same time guarantee the sludge nutrients almost does not suffer losses,after the sludge conditioner without adding the additional depth of dehydration,can be realized after the sludge can be recycling use,such as land improvement,landscaping and without the presence of chloride ions,the effect of drying when burning on the equipment also decreased obviously.In the process of treating sewage and sludge in the urban sewage treatment plant,the sewage carries on the anaerobic reaction in the pipeline to produce odor,which has an increasingly prominent impact on the surrounding environment and the normal operation of sewage treatment plant,and the treatment of odor is extremely urgent.Hydrogen sulfide is one of the main components of odor gas.It is a kind of toxic gas with strong pungent smell and corrosiveness.Biological desulfurization technology is becoming an important method to eliminate H₂S pollution at medium and low concentration due to its unique advantages over dry desulfurization and wet desulfurization.According to the principle of biological leaching and biological desulfurization technology,it is possible to treat H₂S cooperatively in the process of biological leaching of sludge.In this paper,the acclimation and purification culture experiments of biological leaching strains were carried out to study the biological leaching experiment under the optimal conditions,explore the possibility of biological leaching and H₂S treatment,and analyze the mechanism of biological leaching and H₂S treatment.The specific conclusions are as follows:（1）In this experiment,the optimal conditions for biological leaching reaction were initial p H 2,inoculation amount of 30%,substrate concentration of 4g/L sulfur powder and 14g/LFe²⁺,acidification time of 48h.（2）Both the static flask shaking experiment of biological leaching and the biological leaching reactor can improve the dewatering performance of sludge and remove heavy metals in sludge,but the effects of the two are slightly different.（3）Different ventilation conditions have different effects on the leaching effect of biological chain.Under the condition of ventilation for 2h,the biological leaching reaction could not be carried out,and the process of biological leaching was promoted by ventilation for 1h and 1.5h.（4）After H₂S is introduced into the sludge,the solid content of the sludge will increase,the content of S and heavy metals in the sludge will increase,the content of iron will decrease,and the concentration of Fe²⁺in the solution will increase,and the change range will decrease with the decrease of p H.