“…COD degradation is limited by various conditions in slaughter wastewater and sludge (Su et al, 2017, Molina et al, 2009, Tamura et al, 2011), which propose that they may have been evolved through adaptation and selective pressure of natural ecosystems, which has resulted in selection of more potentiated organisms in biodegradation. The combination of COD degrading bacteria can degrade a variety of organic species mixture greatly improve the removal rate of COD, due to the presence of strains capable of decomposition and degradation of surfactants, hydrocarbons, phenols, fatty acids, ketones and other easily decomposed organic matter (Samaei et al, 2013, Taheri et al, 2017, Al-Enazi et al, 2018, Gao et al, 2017, Khan et al, 2018, Xie et al, 2018, Hajare and More, 2017). Moreover, Microbial immobilization technology was occure, this technology was beneficial to increase the number of microorganisms in the reactor, facilitate the solid-liquid separation after the reaction, facilitate nitrogen removal, remove high-concentration organic matter or difficult to biodegrade substances, improve system processing capacity and adaptability, and so on.…”