Comparative study on the effect of SRB and Sporosarcina pasteurii on the MICP cementation and solidification of lead–zinc tailings

• Published in: Chemical engineering journal (Lausanne, Switzerland : 1996) Switzerland : 1996), 2024-09, Vol.495, p.153446, Article 153446
• Main Authors: Yang, Zhenhua, Liu, Longkang, Dong, Yanrong, Gao, Ziqing
• Format: Article
• Language: English
• Subjects: Contrast; Lead–zinc tailings sand; MICP; S. pasteurii; SRB
• ISSN: 1385-8947
• DOI: 10.1016/j.cej.2024.153446

[Display omitted] •S. pasteurii is more suitable than SRB for stabilising tailings particles and heavy metals.•The UCS of the cemented material by S. pasteurii is 4.32 times greater than that of SRB.•SRB achieved a maximum SO42- fixation rate of 95.53 %. The production of tailings sand due to mining and smelting activities is one of the reasons for the accelerated environmental pollution caused by heavy metals, drawing social attention to the management of tailings sand. Microbially induced carbonate precipitation (MICP) is an environmentally friendly soil remediation technique that is gradually becoming the preferred method for soil stabilisation and heavy metal pollution control. To address the issues of heavy metal pollution release and the loose particle structure of lead–zinc tailings sand (LZTS), this study employs a layered MICP approach. The solidification effects of two typical mineralising bacteria, sulfate-reducing bacteria (SRB) and Sporosarcina pasteurii, on LZTS, were compared for the first time. The results show that the maximum unconfined compressive strength (UCS) of SRB cemented solidified lead–zinc tailings sand (SRB-CS-LZTS) specimens is 0.22 MPa, while that of S. pasteurii cemented solidified lead–zinc tailings sand (SP-CS-LZTS) specimens is 0.95 MPa. Compared with the UCS of SRB-CS-LZTS, the UCS of SP-CS-LZTS increased by 3.32 times. The effect of S. pasteurii on the improvement of UCS and immobilisation of heavy metal ions was greater than that of SRB. The immobilisation effect of SRB on SO42- in the LZTS was better than that of S. pasteurii. Compared with SRB, the biological CaCO3 formed by S. pasteurii exhibited stronger adhesion and was more suitable for the cementation and solidification of LZTS. This study uses MICP technology to treat LZTS, aligning with the green environmental concept and providing a reference for the bioremediation of multiple heavy metals in tailing areas.