A Fixed Bed Pervious Concrete Anaerobic Bioreactor for Biological Sulphate Remediation of Acid Mine Drainage Using Simple Organic Matter

Sandisiwe Khanyisa Thisani,Daramy Vandi Von Kallon,Patrick Byrne

doi:10.3390/su13126529

Sandisiwe Khanyisa Thisani, Daramy Vandi Von Kallon + Show 1 more

Open Access

https://doi.org/10.3390/su13126529

Copy DOI

Abstract

The development of low-operational-cost and low-operational-complexity active sulphate (SO4) reducing bioremediation for Acid Mine Drainage (AMD) is an ongoing pursuit towards sustainable mining. This study introduces a fixed bed pervious concrete anaerobic bioreactor as a second stage AMD remediation process. The study investigated the pH self-regulation capabilities, SO4 remediation capabilities and the rate limiting parameters of the bioreactor using glucose as an organic matter source. The AMD was pre-treated using a permeable reactive barrier. A 21-day trial comprised of an increase in the SO4 loading rate while reducing the organic loading rate was undertaken to identify performance limiting conditions. A daily average SO4 concentration reduction rate of 55.2% was achieved over the initial 13 days of the experiments. The study found that a COD to SO4 ratio and VFA to alkalinity ratio below 5:1 and 0.5:1 respectively were performance limiting. The bioreactor was capable of self-regulating pH within the neutral range of 6.5 and 7.5. The study findings indicate that the bioreactor design can reduce operational costs and operational complexity of active AMD bioremediation.

Highlights

The mining of sulphide rich mineral ores is associated with the formation of a polluted water stream referred to as Acid Mine Drainage (AMD)
The floc structures obsample with regards to filamentous bacteria and protozoa
This study found that the fixed-bed pervious concrete Anaerobic Digestion (AD) was capable of neutralizing AMD at increasing loading rates as well as the acidity generated by the acidogenic microorganisms within a 24-h Hydraulic Retention Time (HRT)

Summary

Introduction

The mining of sulphide rich mineral ores is associated with the formation of a polluted water stream referred to as Acid Mine Drainage (AMD). The resulting AMD can cause long term impairment to biodiversity, contaminate receiving water streams and aquifers, damage natural habitats and cause other environmental degradation [1,4]. The development of a remediation technology suitable for long term AMD treatment with low operation costs and a high degree of dissolved Sulphate (SO4 ) reduction remains the subject of numerous scholarly works [8,9,10,11]. Active bioreactors are one such attractive solution which can achieve effective AMD remediation for safe environmental discharge with moderate to high operational costs [12,13]. Active bioreactor technologies make use of the naturally occurring sulphur cycle where sulphate reducing prokaryotes convert

Objectives

Results

Conclusion