钠盐对高负荷餐厨垃圾和剩余污泥中温厌氧混合发酵过程的抑制作用

针对高负荷餐厨垃圾和剩余污泥混合发酵系统在实际应用过程中存在的盐度抑制问题，通过批次试验探究了不同钠盐（CH₃COONa、NaCl和Na₂SO₄）对中温混合发酵体系的影响，考察了添加不同浓度钠盐时混合发酵体系的甲烷累积产量、有机物去除率、挥发性脂肪酸（VFAs）累积量及水解、酸化、乙酸化和产甲烷速率的抑制作用.结果表明，随着CH₃COONa浓度的增加，相应的甲烷产量逐渐增加，但在高浓度时理论甲烷产量降低，当Na⁺浓度为8 g·L^-1时，对产甲烷抑制率为21%.此外，NaCl和Na₂SO₄对甲烷累积产量具有抑制作用，相同Na⁺浓度下，Na₂SO₄对混合发酵体系甲烷产量的抑制作用更大；当SO₄^2-浓度为8.3 g·L^-1时，相应甲烷抑制率为23%.相反，Cl^-浓度为3.1~6.2 g·L^-1时，对混合发酵过程中甲烷抑制率为4.6%~7.7%；但随着Cl^-浓度增至9.3~12.3 g·L^-1时，甲烷产量提升了14.5%~37.6%.分析认为，NaCl对混合发酵过程有机物去除率的抑制作用主要是Na⁺的影响，而Na₂SO₄的抑制作用主要来源于SO₄^2-和Na⁺的协同作用.NaCl和Na₂SO₄对水解速率和产甲烷速率的抑制作用较大，而对酸化速率和乙酸化速率抑制作用较小.

Inhibition effects of sodium salinity on the high-rate mesophilic anaerobic co-digestion of food waste with waste activated sludge

To ascertain the salinity inhibition effect on the practical application of high-loading anaerobic co-digestion process, the effects of different types and concentrations of sodium salts on the mesophilic anaerobic co-digestion of food waste and waste activated sludge were investigated through batch experiments. Through adding different sodium salts (CH₃COONa, NaCl, and Na₂SO₄), the changes of cumulative methane production, organic removal rate, volatile fatty acids (VFAs) concentration, and the conversion efficiencies of hydrolysis, acidogensis, acetogenesis, and methanogenesis processes were analyzed. The results showed that the methane production improved with the increase of CH₃COONa concentrations. However, the theoretical methane production was not achieved at a high CH₃COONa concentration, with 8 g·L^-1 Na⁺ showing an inhibition rate of 21%. NaCl and Na₂SO₄ both had inhibition on methane production, with Na₂SO₄ showing higher inhibition than NaCl at the same Na⁺ concentrations. On the other hand, the inhibition rate of SO₄^2- at 8.3 g·L^-1 on the methane production was 23%. Moreover, the inhibition of Cl^- on the methane production ranged from 4.6% to 7.7% with Cl^- concentrations of 3.1~6.2 g·L^-1, however the methane production enhanced by 14.5%~37.6% with Cl^- concentrations increasing from 9.3 to 12.3 g·L^-1. Furthermore, the experimental results also showed that the effects of NaCl and Na₂SO₄ on the organic removal efficiency during the anaerobic co-digestion were mainly due to the inhibition of Na⁺ and synergistic effects of Na⁺ and SO₄^2-, respectively. The inhibition effects of NaCl and Na₂SO₄ on the efficiencies of hydrolysis and methanogenesis processes were greater than those of acidogensis and acetogenesis processes.