Enhancing in situ biodegradation in groundwater using pump and treat remediation: a proof of concept and modelling analysis of controlling variables

• Published in: Environmental science and pollution research international 2024-04, Vol.31 (18), p.27356-27374
• Main Authors: Brown, Luther M., Thornton, Steven F., Baú, Domenico
• Format: Article
• Language: English
• Subjects: Aquatic Pollution; Aquifers; Atmospheric Protection/Air Quality Control/Air Pollution; Biodegradation; Biodegradation, Environmental; Contaminants; Earth and Environmental Science; Ecotoxicology; Environment; Environmental Chemistry; Environmental Health; Environmental Restoration and Remediation - methods; Groundwater; Groundwater - chemistry; Groundwater treatment; Injection; Modelling; Models, Theoretical; Organic contaminants; Phenols; Plumes; Pumping rates; Remediation; Research Article; Systems design; Waste Water Technology; Water Management; Water Pollutants, Chemical; Water Pollution Control
• ISSN: 1614-7499; 0944-1344; 1614-7499
• DOI: 10.1007/s11356-024-32662-x

A remediation approach which uses pump and treatment (PAT) to enhance the biodegradation of organic contaminants by increasing dispersive mixing between plumes and groundwater was evaluated for a phenol-contaminated aquifer, using a reactive transport model which simulates kinetic reactions between an electron donor (ED) in the plume and electron acceptor (EA) in the groundwater. The influence of system design and operation was examined in six modelling scenarios. Injection or extraction of groundwater increases biodegradation above no action and the location, pumping rate, and distance between well(s) are important variables which influence biodegradation. An increase in pumping rate, distance of the wells from the plume centreline, and changing the flow direction increase dispersive mixing between the plume and groundwater. This increases plume spreading and the plume fringe interface, providing a greater flux of dissolved EAs for biodegradation. In general, injection of groundwater containing natural EAs enhances biodegradation more than extraction. The enhancement of biodegradation is sensitive to the relative fluxes of ED and EA, as controlled by the arrangement of the wells. In the best performing scenario, biodegradation was enhanced by 128%, compared with no action.