Utilities are seeking sustainable solutions for their water and wastewater treatment needs. Engineers and solution providers have always looked to cost-effective solutions, but the new focus dives deeper into what is sustainable, with metrics and goals for achieving a net neutral carbon outcome.
BY REINOUT HOLLAND AND DR HOLLY SHORNEY-DARBY
While sustainability is a goal to set our sights upon, water treatment decisions must also be focused on other metrics, such as the ability to meet water quality objectives, reliability, and robustness in managing challenging feed water. Drinking water treatment is such a critical aspect of public health and community prosperity that any solutions must work well for any society. The goal of producing safe, even palatable, drinking water does not change, but sustainability will play an increasingly important role in evaluating different alternatives for treatment.
Ceramic membranes for filtration have been gaining wider acceptance and usage because they do not succumb to the same challenges as other filter technologies. Sand filters, while still the work-horse of surface water treatment globally, can be compromised allowing harmful pathogens to pass through. Filtration with polymeric membranes, while providing a barrier for pathogens, has had issues with fibre breaks, lesser ability to withstand higher backwash pressures for cleaning, high labour costs and downtime associated with fibre breakage repairs, loss of permeability and in many cases, a shorter-than-expected membrane service life.
Ceramic membranes do not share the issues common to polymeric membranes, but instead, present a challenge for higher initial capital cost. However, utilities that evaluate on a lifecycle cost basis, for example, over 20 years, have discovered that the initial costs of ceramic-based solutions often become less significant because operational costs are often on par or are even less with ceramic membranes. This ties directly into sustainability in the longer term.
CeraMac is a ceramic membrane microfiltration system that was developed by PWNT in the Netherlands to manage the highly-polluted waters of Lake Ijssel and became commercially available in 2009. Multiple ceramic monolith modules are housed in a vessel specially designed for a pressurised membrane system that is operated in dead-end mode. A quick view of a CeraMac system implies durability, due to the industrial look of the steel infrastructure that houses the membranes. A closer examination of the individual sustainability aspects reveals a robust and sustainable solution that is future-proof.
The CeraMac system has been validated and used at full-scale in Singapore (180 MLD), the UK (90 MLD), Switzerland (30 MLD) and the Netherlands (120 MLD).
Reinout Holland is head of business development, and Dr Holly Shorney-Darby is head of technology application and piloting at PWNT.
The full article is available in the latest edition of Water & Wastewater Asia May/Jun 2022 issue. To continue reading, click here.