Enhanced Biodegradation of Hexachlorocyclohexane in Soil by Application of Exogenous Amendments

In this study, bioaugmentation and biostimulation were used to explore the efficiency of bioremediation of hexachlorocyclohexane (HCH)-contaminated soil in the laboratory. A complex microbial community (germ A, abbreviated as A) was used for bioaugmentation. The KNO3 and K2HPO4 (NP), wheat straw (JG), and glucose (PU) were used as exogenous amendments for biostimulation. Five treatments were set up: the control (CK), NP, A + NP, A + NP + JG, and A + NP + PU. After 28 days of remediation, the removal rate of total HCH (HCHs) in NP, A + NP, A + NP + JG, and A + NP + PU was 27.0%, 32.2%, 43.4%, and 45.3%, respectively. The results indicated that the removal of HCHs in A + NP, A + NP + JG, and A + NP + PU was higher than NP, indicating that bioaugmentation combined with biostimulation was more effective than biostimulation. Furthermore, compared with A + NP, A + NP + JG and A + NP + PU were more conducive to the degradation of HCHs. Because applying inorganic and organic nutrient substances simultaneously can effectively improve the living environment of microorganisms and increase microbial quantities in HCH-contaminated soil, therefore, the enzymatic reaction of microorganisms is accelerated, resulting in the efficiency of HCHs degradation improvement. The results indicated that bioaugmentation with germ A combine with biostimulation by organic and inorganic nutrients simultaneously constitutes a promising method for restoring soils contaminated with HCHs. This study would provide the basis for improving the bioremediation efficiency of HCH-contaminated soil.

Automated summary

Bioaugmentation combined with biostimulation was more effective in enhancing the degradation of HCHs in contaminated soil compared to biostimulation alone. Simultaneous application of inorganic and organic nutrient substances improved the living environment of microorganisms and increased microbial quantities, accelerating the enzymatic reaction and degradation of HCHs.