Challenge

The specification for the treated water from the treatment plants was designed to meet existing guidelines and anticipate future drinking water regulations.   Penalties are imposed for excursions from any of the 25 criteria specified.   The water treatment challenge can be summarized as:

• Continuous 2 to 5 micron particle removal and 4-log reduction for cryptosporidium 
• Reliable organics removal (algal toxins, color, taste and odor compounds). 
• No commercial contractual relief due to unforeseen changes in raw water quality  
• Significant penalties imposed for non-compliance over the life of the 25 year operational contract. 

Solution

The Coliban Water Region Water Authority engaged Siemens Water Technologies and Veolia Water-Australia to commission the AQUA 2000 Project, which is a build-own-operate-transfer (BOOT) project. It includes the construction and operation for 25 years of a water treatment scheme for the Coliban Water Authority in Victoria, Southeastern Australia. The system's three water treatment plants, the largest being at Sandhurst near Bendigo, will use MEMCOR® CS microfiltration technology. 

The plants use a combined process of microfiltration, ozonation and biological activated carbon (BAC) to deliver water that far surpasses World Health Organization standards. 

Microfiltration membranes provide a physical barrier, removing particles down to 0.2 micron. The MEMCOR CS plant consists of eight cells (6 duty cells, 2 stand-by cells), each containing 576 submerged membrane modules. Water enters each cell and is drawn through the outside of the porous membranes to the inside by a filtrate pump, producing filtered water. These cells are backwashed intermittently using filtrate and air to scrub the fiber surface. Periodic chemical cleaning is performed when the maximum transmembrane pressure (TMP) is reached.

Results

•  Installing the MEMCOR CS system has increased economies of scale for the Sandhurst WTP. Chemical costs are significantly reduced, and so are related maintenance, storage and disposal.
• Membrane integrity, minimal mechanical repairs and the system’s ability to filter high and variable turbidities and algae loads without chemicals or operator intervention also reduces operational costs by 10-15% over the system’s life cycle, when compared to those of conventional filtration systems.
• The MEMCOR CS system’s smaller footprint has reduced capital costs at the Sandhurst WTP by roughly 20%, allowing Coliban Water to pack greater filtration capacity into a limited space while expanding its potable water production.
• All three plants are currently achieving levels well in excess of 7-log removal/inactivation of pathogens.

Mr. Gordon McKern, Coliban Water Chairman, and his colleagues are very pleased with the resulting potable water. “The quality of water produced is among the best in the world,” he says. “But more importantly, our customers appreciate the difference.”