Pre-Treatment of Algal-Laden Water using Volcanic Ash in a Dual Media Filtration System

H.M. Kalibbala (Uganda), E. Plaza, O. Wahlberg (Sweden), and R. Kaggwa (Uganda)


Pre-treatment, algae, dual media filtration, filter-run length, volcanic ash


With increasing pollution of the available water resources, development of safe drinking water supplies is increasingly becoming a challenge, both for the developing and developed countries. In order to alleviate the prevailing difficulties, approaches should focus on sustainable water supply and treatment systems that require minimal maintenance and operator skills. It is important that these technologies are affordable and preferably use locally available materials. In this study, a pre-treatment of surface water containing algae using a combination of volcanic ash and sand in a dual media system was assessed. The results indicated that volcanic ash and sand in a dual media filter system performed better in the removal of algae than sand alone. However, it was noted that different algae genera were removed at different rates within the two types of media arrangement. In addition, there was an increase in the filtration run length of the dual media with volcanic ash on top of sand of about two and half folds compared to the mono medium system. It is therefore anticipated that pre treatment of raw water laden with algae using dual media systems would probably improve on the performance of the subsequent conventional processes in algal removal and thus reduce operation costs with regard to chemicals.

Important Links:

Go Back