Article from IMIESA April 2017

Removing suspended solids and dissolved matter prior to the reverse osmosis (RO) process is vital. It enables RO to do the work of dissolved solid removal with less biofouling and solids blockage in the spacers. Ultrafiltration (UF) is the best way to do this, explains Herman Smit, managing director of Quality Filtration Systems (QFS).

QFS specialises in advanced treatment technologies, such as UF and RO, which are essential for wastewater reuse and desalination applications. Key to UF is the trademarked Memcor CP II system, which is a pressurised, pre-engineered membrane system with a modular building-block configuration that simplifies design and operation and reduces installation costs. The enhanced PVDF membrane is 20% to 25% more permeable, which translates into lower transmembrane pressure thereby reducing energy usage and ownership costs.

Case studies

QFS has successfully utilised these technologies in a number of applications. One example is a 3 Mℓ/day wastewater treatment plant that supplies potable drinking water to the Ballito community in KwaZulu-Natal. Here, the water is fed to sand filters and goes through the Memcor UF system before being dosed with SMBS, biocide and antiscalant and undergoing RO treatment for the salt removal.

A more intricate system has been utilised in De Doorns, Western Cape, where QFS produced a 1.5 Mℓ/day reuse plant for irrigation purposes. The wastewater filters through the inside of a drum screen to the outside by gravity pressure and flows into the UF feed tank. From here, the water is pumped through the UF, granular-activated carbon filters and UV light into the final water tank. The QFS systems used ensure that these plants will have the longevity to continue to provide water security for their communities, operating effectively and with minimal maintenance.