Optimisation of a linear flow channel reactor for semi-passive, simultaneous biological sulphate reduction and partial sulphide oxidation
type: CreativeWork
description: Acid rock drainage (ARD) is a growing concern, particularly in South Africa, as a country already classified as water scarce. ARD is defined as water that has been impacted by mining activities and typically has high levels of sulphate and heavy metals, at acidic pH. Similarly, high sulphate neutral rock drainage is of increasing concern. High sulphate content increases water salinity leading to adverse effects on human health as well as agriculture. Types of ARD and neutral rock drainage can be categorised into those that are produced in high volumes from groundwater rebound, and those that are generated from diffuse sources, as low-flow ARD. Low-flow ARD and neutral rock drainage are amenable to biological treatment of the sulphate component using sulphate reducing bacteria (SRB). Biological sulphate reduction (BSR) generates sulphide, which requires further treatment to remove it from the stream in gaseous form or as a solid sulphur-containing compound. Alternatively, it can also be used, in part, to precipitate metals present within ARD waters. Key challenges associated with SRBbased bioremediation include the cost of the supplemented electron donor needed for SRB to reduce sulphate, as well as the downstream management or treatment of the excess sulphide remaining. This investigation aimed to optimise a semi-passive treatment process which integrates BSR, and concomitant partial oxidation, by sulphur oxidising bacteria (SOB), of the sulphide produced to elemental sulphur. This is generated as a floating sulphur biofilm (FSB). These processes occur simultaneously within a linear flow channel reactor (LFCR), facilitating both treatment of the water stream to a fit-for-purpose water product, and recovery of the sulphur for use within fertilisers or fungicides. The work focused on the effective utilisation of electron donors and a sustainable option thereof, as well as the optimisation of partial sulphide oxidation and sulphur recovery. In addressing the cost of a …
abstract: Acid rock drainage (ARD) is a growing concern, particularly in South Africa, as a country already classified as water scarce. ARD is defined as water that has been impacted by mining activities and typically has high levels of sulphate and heavy metals, at acidic pH. Similarly, high sulphate neutral rock drainage is of increasing concern. High sulphate content increases water salinity leading to adverse effects on human health as well as agriculture. Types of ARD and neutral rock drainage can be categorised into those that are produced in high volumes from groundwater rebound, and those that are generated from diffuse sources, as low-flow ARD. Low-flow ARD and neutral rock drainage are amenable to biological treatment of the sulphate component using sulphate reducing bacteria (SRB). Biological sulphate reduction (BSR) generates sulphide, which requires further treatment to remove it from the stream in gaseous form or as a solid sulphur-containing compound. Alternatively, it can also be used, in part, to precipitate metals present within ARD waters. Key challenges associated with SRBbased bioremediation include the cost of the supplemented electron donor needed for SRB to reduce sulphate, as well as the downstream management or treatment of the excess sulphide remaining. This investigation aimed to optimise a semi-passive treatment process which integrates BSR, and concomitant partial oxidation, by sulphur oxidising bacteria (SOB), of the sulphide produced to elemental sulphur. This is generated as a floating sulphur biofilm (FSB). These processes occur simultaneously within a linear flow channel reactor (LFCR), facilitating both treatment of the water stream to a fit-for-purpose water product, and recovery of the sulphur for use within fertilisers or fungicides. The work focused on the effective utilisation of electron donors and a sustainable option thereof, as well as the optimisation of partial sulphide oxidation and sulphur recovery. In addressing the cost of a …
author: Fernandes, Sarah
keywords: Bioprocess Engineering
date published: 2021
date modified: 2026-07-22T22:23:21Z
provider: University of Cape Town
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: Centre for Bioprocess Engineering Research

PropertyValue
property ID: Handle
value: http://hdl.handle.net/11427/35726