Sulfate affects the anaerobic digestion process treating nitrogenous fertilizer wastewater

Massive demand of nitrogenous fertilizer in agriculture led to large amount of nitrogenous fertilizer wastewater during its production in recent years. Anaerobic digestion process could remove the organics and produce biogas for energy recovery from the nitrogenous fertilizer wastewater. However, the sulfate may impact this process. In this study, the short- and long-term effect of sulfate in 200-1600 mg L-1 on the COD removal, biogas production and microbial characteristics were investigated. Results showed that the sulfate slightly improved the COD removal, and promoted the biogas production. Methanothrix and Methanomassiliicoccus were detected as the main methanogens. Sulfate in 400-1600 mg L-1 suppressed the proportion of Methanothrix, but enhanced Methanomassiliicoccus. For actual application, anaerobic digestion could be adopted for treating sulfate-containing wastewater, not just nitrogenous fertilizer wastewater, and achieving carbon recovery.

Automated summary

The massive demand for nitrogenous fertilizer in agriculture has resulted in the production of a large amount of nitrogenous fertilizer wastewater. This study investigated the effect of sulfate on the wastewater treatment process and found that sulfate slightly improved the COD removal and promoted biogas production, but also affected the proportion of methane-producing bacteria.