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Investigation and optimization of passively operated compost-based system for remediation of acidic, highly iron- and sulfate-rich industrial waste water

journal contribution
posted on 2023-05-16, 22:18 authored by Dann, AL, Cooper, RS, John BowmanJohn Bowman
A passively operated multi-stage bioremediation system utilizing composted agricultural waste products and an artificial wetland system was found to be effective for purification of acidic, iron- and sulfate-rich waste water derived from titanium mineral processing. The main microbial players involved in the remediation system processes and the dynamics were investigated; mineral processing waste water-filled sludge dams possessed stable microbial communities that included Acidithiobacillus, Desulfurella, and acidophilic, anaerobic fermenters of the order Bacteroidales. These groups were enriched in a subsequent potato waste-based iron mobilization pre-treatment stage. Within downstream reduction treatment stages ("reduction cells"), compost/straw decomposition and associated sulfur/sulfate and iron reduction were carried out by a complex mix of aerobic and anaerobic bacteria. The efficaciousness of the system without replacement of the compost was found to steadily decline following 2 years of operation and corresponded with the reduction cell communities becoming simultaneously more diverse and homogenous. Microcosm-based experiments demonstrated that operational declines were due to unsustained supply of suitable labile carbon sources combined with spatial heterogeneity within the layered design of the reduction stage of the system resulting in inadequate redox conditions. Temperature was not found to be a critical performance factor in the range of 10-25 °C. Application of a combined emulsified oil/molasses amendment was found to be highly effective in promoting a microbial community capable of remediating waste water with high iron and sulfate levels. Acidophilic members of the order Bacteroidales were found to be critical in the investigated remediation system, providing organic donors for subsequent metal and sulfur transformations and could have a broader ecological significance than previously suspected.

Funding

Australian Research Council

Echo Remediation

History

Publication title

Water Research

Volume

43

Issue

8

Pagination

2302-2316

ISSN

0043-1354

Department/School

Tasmanian Institute of Agriculture (TIA)

Publisher

Elsevier

Place of publication

United Kingdom

Rights statement

The definitive version is available at http://www.sciencedirect.com

Repository Status

  • Restricted

Socio-economic Objectives

Evaluation, allocation, and impacts of land use

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