Greywater quality changes in a permeable pavement reservoir

Greywater reuse is becoming popular in water scarce regions, but the key challenges are collection, appropriate treatment and storage. Conceptually, an aggregate base course in permeable pavements can provide both treatment and storage facilities for greywater, particularly in arid regions where urban runoff is not an abundant water resource. A prototype permeable pavement unit was constructed to evaluate this concept. The unit was filled with supply water, ablution greywater and laundry greywater, and various water quality parameters were monitored daily. While most parameters showed an improvement in quality after 1 d of storage, pH and sodium ions were found in excessive amounts in the laundry greywater. In addition, the unit was found to be inefficient in reducing total aerobic and total coliform bacteria. The study revealed that permeable pavements can serve as a treatment and storage unit in greywater reuse schemes subject to the inclusion of appropriate disinfection and sodium ion reduction measures.