Potable water from wastewater and beyond

The Holy Grail of water technology is a full recycle of all wastewater as potable water (or water of a similar quality) after treatment by enhanced separation. Traditional wastewater treatment systems, mainly based on activated sludge treatment, have a high water loss through the sludge produced, generate a large volume of secondary waste and have insufficient quality of the product water. Newer technologies – often based on membranes – may be of help in increasing the water recovery. However, those membrane processes that yield a good water quality (typically better than with traditional processes) in fact suffer intrinsically from low water recoveries. Reverse osmosis, for example, might result in a loss of 50% of water. This depends on the kind of feedwater, but using wastewater a high water recovery is difficult because of the risk of membrane fouling. Thus, combined or hybrid solutions are needed. This presentation will describe three potential approaches based on membranes: