Miwatek optimised AMD treatment process eliminates liquid discharge
Miwatek principal process engineer Sebastian Franzsen and MD Herman Grobler discuss the company's AMD treatment technology. Camerawork & editing: Nicholas Boyd. Recorded: 02/04/2014.
Miwatek MD Herman Grobler
JOHANNESBURG (miningweekly.com) – Advanced water treatment company Miwatek has optimised its acid mine drainage (AMD) treatment technology to create a zero-liquid discharge process that only uses a single stage of reverse-osmosis (RO) processing.
The company, along with its partner in the venture – mining solutions company Fraser Alexander – successfully demonstrated this optimised process at its Randfontein pilot plant, which was launched in June last year, Miwatek principal process engineer Sebastian Franzsen told Mining Weekly Online on Wednesday.
Miwatek MD Herman Grobler said traditional AMD processes included up to three stages of pretreatment followed by RO, which then produced a brine that had to be processed, usually through crystallisation.
Miwatek developed a caustic reactor which turned the brine produced in the first stage of RO into a neutralising agent that was then used in the treatment process. The brine was recycled and the process simplified.
The Miwatek process now consisted of pretreatment, RO, and the treatment of the brine through the caustic reactor, with the treated brine then being reused in the RO process, Grobler explained.
“The caustic reactor, which is the centrepiece of the technology, takes the brine stream, reacts it and separates a gypsum-rich stream, and a hydroxide-rich stream which we call the dilute caustic, [which is then used as a neutralising agent],” Franzsen pointed out.
He added that the caustic neutralising agent, when used upstream of the RO, reduced the scaling potential of the membranes significantly.
“[However], caustic [as a neutralising agent] is traditionally a lot more expensive than lime is, therefore, the novelty in the neutralising side is that we are generating caustic from lime and the unconventional aspect of the technology is in the chemical regime we operate,” Franzsen said, adding that the company closed the loop for a zero-liquid discharge process that did not include crystallisation.
He told Mining Weekly Online that while Miwatek had only started with the piloting of this optimised process in January this year, the company started working on the concept more than a year ago. Grobler added that the operation would be easy to scale up for commercial application as it used existing water treatment equipment.
Grobler pointed out that the technology had received a lot of interest from countries such as Peru, Chile and Ghana; however, there had been limited interest from within South Africa.
“In the last year or so, very few tenders of this type have gone out in the [South African] market,” he said.
The Miwatek technology could be applied to water stemming from coal, gold, copper and silver mining as well as water used in industrial processes.
Comments
Press Office
Announcements
What's On
Subscribe to improve your user experience...
Option 1 (equivalent of R125 a month):
Receive a weekly copy of Creamer Media's Engineering News & Mining Weekly magazine
(print copy for those in South Africa and e-magazine for those outside of South Africa)
Receive daily email newsletters
Access to full search results
Access archive of magazine back copies
Access to Projects in Progress
Access to ONE Research Report of your choice in PDF format
Option 2 (equivalent of R375 a month):
All benefits from Option 1
PLUS
Access to Creamer Media's Research Channel Africa for ALL Research Reports, in PDF format, on various industrial and mining sectors
including Electricity; Water; Energy Transition; Hydrogen; Roads, Rail and Ports; Coal; Gold; Platinum; Battery Metals; etc.
Already a subscriber?
Forgotten your password?
Receive weekly copy of Creamer Media's Engineering News & Mining Weekly magazine (print copy for those in South Africa and e-magazine for those outside of South Africa)
➕
Recieve daily email newsletters
➕
Access to full search results
➕
Access archive of magazine back copies
➕
Access to Projects in Progress
➕
Access to ONE Research Report of your choice in PDF format
RESEARCH CHANNEL AFRICA
R4500 (equivalent of R375 a month)
SUBSCRIBEAll benefits from Option 1
➕
Access to Creamer Media's Research Channel Africa for ALL Research Reports on various industrial and mining sectors, in PDF format, including on:
Electricity
➕
Water
➕
Energy Transition
➕
Hydrogen
➕
Roads, Rail and Ports
➕
Coal
➕
Gold
➕
Platinum
➕
Battery Metals
➕
etc.
Receive all benefits from Option 1 or Option 2 delivered to numerous people at your company
➕
Multiple User names and Passwords for simultaneous log-ins
➕
Intranet integration access to all in your organisation