Feasibility of straw as a substitute carbon source for sulfate reduction system and its influencing factors

In order to reduce the economic cost of the acidic wastewater treatment by sulfate-reducing bacteria(SRB), sodium lactate was used as the control carbon source, the feasibility of three straw extracts replacing sodium lactate as carbon source was analyzed, and the effects of different carbon sources, regular addition of carbon source, ρ(COD)/ρ(SO42-), initial pH, and heavy metal concentration on sulfate reduction system were investigated. The results showed that all the three straw extracts could be used as alternative carbon sources to remove SO42-, among which soybean straw extracts had the best removal effect; adding carbon sources regularly and increasing ρ(COD)/ρ(SO42-)had the original promoting effect on sulfate of each carbon source system; reducing the initial pH and increasing the concentration of heavy metals can inhibit the effect of sulfate reduction; The increase of Mn(II)content has little effect on sulfate removal, at low concentration of Cu(II),Fe(III)conditions, The SO42removal rate of sodium lactate system was higher than that of the three straw systems, and in the relatively high concentration of Cu(II),Fe(III)conditions, the SO42removal rate of the three straw systems was higher than that of the sodium lactate system. Straw extract can be used as a low-cost carbon source to provide an economic and feasible theoretical reference for the treatment of acidic wastewater with high concentration of heavy metals.