Purification and water resource circulation utilization of Cd-containing wastewater during microbial remediation of Cd-polluted soil

• Published in: Environmental research Vol. 219; p. 115036
• Main Authors: Deng, Yan, Fu, Shaodong, Xu, Menglong, Liu, Hongwei, Jiang, Luhua, Liu, Xueduan, Jiang, Huidan
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier Inc 15-02-2023
• Subjects: Adsorption; Adsorption material; Cadmium - analysis; Cd-containing wastewater; Environmental Restoration and Remediation; Microbial remediation; Purification; Soil; Soil Pollutants - analysis; Wastewater; Water Pollutants, Chemical; Water Purification - methods; Water recycling; Water Resources; Microbial remediation; Cd-containing wastewater; Water recycling; Adsorption material; Purification
• ISSN: 0013-9351; 1096-0953
• DOI: 10.1016/j.envres.2022.115036

The purification and water resource circulation utilization of cadmium-containing leachate is a key link in the field application of microbial remediation in Cd-polluted soil. In this study, through a simulation experiment of microbial remediation of Cd-polluted paddy soil, the feasibility of the purification and recycling process of wastewater derived from microbial remediation of Cd-polluted soil was explored. The results of the microbial mobilization and removal experiment showed that the concentrations of Cd, N, P, and K in the leachate were 88.51 μg/L, 38.06, 0.53, and 98.87 mg/L, respectively. The leachate also contained a large number of microbial resources, indicating that it had high recovery values. To recycle this wastewater, activated carbon (C), humic acid (H), and self-assembled monolayers on mesoporous supports (SAMMS; S) were used as adsorbents. The results showed that the co-existing cations in the leachate had a major influence on the adsorption of Cd. In the ternary system of Fe, Al, and Cd, the removal efficiency of Cd increased to 91.2% when the S dosage was increased to 5‰, and the sorption of Cd occurred after Fe and Al. However, C and H exhibited poor adsorption performances. The isotherm models further showed that the maximum adsorption capacities of S, H, and C were 13.96, 6.41 and 2.94 mg/g, respectively. The adsorption kinetics of S showed that adsorption was a rapid process, and the C–H and O–Si–O of S were the key functional groups. The pH of the leachate significantly affected the adsorption efficiency of Cd. Finally, the purified leachate was successfully applied to microbial cultivation and soil remediation. Overall, the reclamation of Cd-containing wastewater can not only dampen the impacts of water shortages, but also achieve the purposes of Cd removal and resource recovery to lower costs by approximately 1166–3499 yuan per mu.
•The recycling of leachate from microbial treatment of Cd-polluted soil made sense.•Leachate contained nutrients and microorganisms, making it high recovery values.•SAMMS materials showed the best adsorption performance for Cd from leachate.•Purified leachate can be directly used for microbial culture without adding media.•The recycling process can reduce the production cost, about 1166–3499 yuan/mu.