In this paper, fracturing flowback fluids were biologically treated by immobilized chlorella. The individual and interactive effects of three variables (sodium alginate concentration, CaCl₂ concentration, and crosslinking time) on growth of immobilized algal were optimized by response surface methodology combined with Box-Behnken design. The results showed that the SA (sodium alginate) concentration most significantly affected algal density and treatment efficiency. The interaction between SA concentration and crosslinking time was weak, the interaction between CaCl₂ concentration and crosslinking time was modest, while the interaction between SA concentration and CaCl₂ concentration was significant. The immobilized chlorella performed the best when the SA concentration, CaCl₂ concentration and crosslinking time were 2.42%, 2.69% and 16.76 h, respectively, and the COD removal rate of fracturing flowback fluids was significantly higher than that of the free algal (34.70% vs. 8.96%), indicating immobilization could improve growth and organics removal of chlorellas for processing fracturing flowback fluids.

本文通过固定小球藻对压裂返排液进行了生物处理。通过响应表面方法结合Box-Behnken设计，优化了三个变量（藻酸钠浓度，CaCl ₂浓度和交联时间）对固定藻类生长的个体和相互作用影响。结果表明，SA（藻酸钠）浓度最显着影响藻类密度和处理效率。SA浓度和交联时间之间的相互作用较弱，CaCl ₂浓度和交联时间之间的相互作用适中，而SA浓度和CaCl ₂之间的相互作用则较小。浓度显着。当SA浓度，CaCl ₂浓度和交联时间分别为2.42％，2.69％和16.76 h时，固定的小球藻表现最佳，压裂返排液的COD去除率显着高于游离藻类（34.70％）。对比8.96％），表明固定化可以改善小球藻的生长并去除小球藻，以处理压裂返排液。