Comparison of in-situ bioremediation of soil contaminated with chlorinated hydrocarbons

Abstract: In recent years, due to the continuous development of machinery, electronics, leather, chemical companies and dry-cleaning industry, more and more chlorinated hydrocarbons accumulate in the soil, causing serious harm to the environment. The accumulation of chlorinated hydrocarbons and the teratogenic, carcinogenic, and mutagenic hazards seriously threaten human health. Therefore, the remediation of chlorinated hydrocarbons is imminent. Under this premise, in-situ bioremediation has gradually received attention. For in situ bioremediation of soil contaminated with chlorinated hydrocarbons, the most commonly used methods are biostimulation alone, bioaugmentation alone, and a combination with biostimulation and bioaugmentation. The removal rate of trichloroethylene in the case of using biostimulation products alone is significantly lower than that of using bioaugmentation products alone. The removal rate of trichloroethylene by biostimulation products alone does not exceed 60%, and “DCE pause” occurred, but did not occur in the case of using bioaugmentation products. The removal rate of trichloroethylene by bioaugmentation products is generally higher than 98%, and it will promote the degradation of trichloroethylene or tetrachloroethylene to non-toxic ethylene. Therefore, only cases containing bioaugmentation can achieve non-toxic degradation of chlorinated hydrocarbons and take into account the high removal rate of them. In addition, the biostimulation duration is significantly shorter.