Journal of Environmental Engineering Technology•2026•DOI: 10.13205/j.hjgc.202605014
Chlorinated aliphatic hydrocarbons (CAHs) are prevalent groundwater contaminants at industrial sites in China. This pilot-scale study evaluated in-situ anaerobic bioremediation of CAHs-contaminated groundwater in a low-permeability bedrock fracture zone at depths up to 40 m. A self-developed anaerobic dechlorinating culture (BS-1), containing Dehalococcoides, Desulfitobacterium, and Dehalogenimonas, was injected alongside carbon sources (sodium citrate and emulsified vegetable oil) and nutrients. Pressurized nitrogen gas injection enhanced the distribution of amendments, achieving a radius of influence of 5.0 m. Over 399 days of monitoring, the combined use of slow-release and soluble carbon sources maintained anaerobic conditions (ORP < -100 mV) for over one year, providing sustained electron donors. The emulsified vegetable oil reduced injection frequency and operational costs. The BS-1 culture effectively dechlorinated vinyl chloride, cis-1,2-dichloroethylene, trichloroethylene, and chloroform, achieving removal efficiencies exceeding 95%. At times, groundwater quality met the Class IV standard of GB/T 14848-2017. This study demonstrates a green, economical, and effective solution for CAH-contaminated site remediation, with significant engineering application potential.
Chinese Journal of Environmental Engineering•2026•DOI: 10.12030/j.cjee.202512015
The co-contamination of cadmium (Cd), lead (Pb), and zinc (Zn) in agricultural soils near mining areas poses significant risks to ecosystems and human health. Conventional stabilization materials often exhibit insufficient performance for Zn, particularly in multi-metal systems. This study synthesized a novel composite biochar (PFMBC) by loading phosphate and iron-manganese oxides onto biochar via phosphoric acid impregnation followed by secondary pyrolysis at 600 °C. The stabilization efficiency of PFMBC was evaluated against pristine biochar (BC) and iron-manganese modified biochar (FMBC) in a soil collected from a lead-zinc mining area (total Cd: 43.77 mg·kg−1, Pb: 3355.94 mg·kg−1, Zn: 1296.57 mg·kg−1). After 60 days of incubation with 5% PFMBC, the DTPA-extractable (bioavailable) fractions of Cd, Pb, and Zn decreased by 73.44%, 90.10%, and 69.33%, respectively, significantly outperforming BC and FMBC. Sequential extraction indicated that PFMBC promoted the transformation of Cd, Pb, and Zn from acid-soluble and reducible fractions to more stable residual fractions. Characterization via FTIR, SEM, and XRD revealed enhanced surface functional groups and the formation of stable mineral phases. The synergistic effects of phosphate precipitation, iron-manganese oxide adsorption, and surface complexation contributed to the superior stabilization, particularly overcoming the challenge of Zn immobilization. These findings demonstrate that PFMBC is a promising amendment for the remediation of Cd-Pb-Zn co-contaminated soils, offering high efficiency and long-term stability.