Effect of activated persulfate on gas production from food waste anaerobic digestion

Anaerobic digestion (AD) is an effective way to improve the utilization of food waste (FW). Activated persulfate is a powerful oxidant. This research investigated the effect of activated persulfate on gas production from FW AD. Three activation methods including heating, lighting, and ultrasonication were used. The results showed that the addition of activated persulfate promoted gas production from FW AD. And the main biogas composition were CH4, CO2, and N2. The difference in SO42− concentration further verified the effect of activated methods on producing sulfate free radicals by heating, lighting and ultrasonication from persulfate. The activated persulfate enhanced gas production by improving the organic hydrolysis. Relatively, lighting and ultrasonication were better than heating in persulfate activation. At the same time, the accumulated gas volumes from ultrasonication (587 mL) and lighting (574 mL) were significantly higher than that in heating (478 mL). The environmental impact assessment and economic assessment suggests that the addition of activated persulfate in FW AD is beneficial because of the lower secondary pollution, lower cost and higher additional value.