Phosphogypsum induced electrochemical enhancement of pig manure fermentation: Multi-pathway resource utilization

• Phosphogypsum(1%) induces enhanced electrochemical PM fermentation. • Gas production rate increased by 16% under the induction of phosphogypsum . • Methane content increased by 15.65% under the induction of phosphogypsum. With the continuous development of large-scale farming, pig manure(PM) has become one of the typical organic solid wastes that harm the environment. The fermentation technology of PM has become a key path for its resource utilization due to its ability to produce biogas and organic fertilizer products, but there are problems such as long fermentation cycle, low gas production and heavy metals removal rate. In order to improve the production rate and shorten the fermentation cycle, this study proposed a phosphogypsum(PG) induced electrochemical enhanced fermentation technology, and explored the gas production efficiency, methane content, physicochemical properties of fermentation broth, and removal effect of heavy metals in electrochemically enhanced PM fermentation under different addition. The experimental results showed that when the addition of PG mass ratio was 1%, it could significantly enhance the gas production efficiency of PM fermentation, increasing by about 16% and methane content by 15.65%. The COD content significantly decreased to below 3000 mg/L, the NH 4 -N content increased to above 900 mg/L, and electrodeposition of heavy metals was observed, increasing the richness of microbial populations. This study provides a new solution for the synergistic treatment of PM and PG, expanding the new utilization pathways.