Location

Emalalheni (Witbank) South Africa

Application

Potable water

Capacity

50 MLD

Construction

Aveng Water (Pty) Ltd

End-user

BHP Billiton & Anglo American

Source

Acid mine drainage

Start-up

Phase 1: 2008Phase 2: 2010Phase 3: 2013

background

The Emalahleni Water Reclamation Plant, located in the Witbank coalfields of South Africa’s Mpumalanga province, is the first and only Acid Mine Drainage (AMD) to potable water treatment plant in the world. The desalination plant treats acidic, saline mine waters to a South African National Standard (SANS) 0241 Class 0 potable water. Due to limited water resources, the Emalalheni Water Reclamation Plant plays an important role in meeting the area’s increasing water demand and environmental challenges.

The plant’s three-stage membrane process treats AMD waters from coal mining operations. Multiple ultrafiltration and reverse osmosis membrane systems operate in a series, which offers water recovery rates of > 97 precent. First, a combination of two CSIR processes, namely the limestone/lime neutralization and gypsum crystallization processes, are used as pretreatment, followed by green sand filters to remove residual manganese. 


After this treatment step, the water is processed through X-Flow’s Aquaflex ultrafiltration (UF) membrane modules to remove any microorganisms and suspended solids. The final processing step is performed using reverse osmosis (RO) membranes. The brine (dissolved salts removed from the RO membranes), which is highly oversaturated in gypsum salts, is treated with lime to remove the oversaturation. This last cycle is performed a total of three times to increase the water recovery, maximize the solids removal and minimize the volume of brine.


From 2013 onwards, a total of more than 1.000 Aquaflex UF modules will positively influence all vital aspects of the RO system - ranging from a consistent quality of the RO feed water to a significantly smaller plant design, a better performance and a reduced CAPEX.



water quality

 WATER QUALITY PARAMETER UNITS  FEED WATER (95 PERCENTILE)  TREATED WATER 
 pH 2.7   6.0 - 9.0
 Acidity
mg/l as CaCo3  1050
 Electrical conductivity
 mS/m
460   < 70
 Total dissolved solids     
 mg/l
4930  < 450
 Calcium, Ca
mg/l  660   < 80
 Magnesium, Mg
mg/l
230   < 30
 Sodium, Na
mg/l
130   < 100
 Potassium, K
mg/l  13   < 25
 Sulfate, SO4
mg/l
3090  < 200 
 Choride, Cl
 mg/l
70  < 100 
 Iron, Fe
mg/l  210  < 0.01 
 Manganese, Mn
mg/l  35  < 0.05 
 Aluminium, Al
mg/l  40  < 0.15 

system setup

Pentair X-Flow system Setup WTE Moscow case study

scope of supply

400 x Aquaflex 40 UF Module

695 x Aquaflex 55 UF Module