Adelaide’s water quality has been the subject of adverse media comment in regard to taste and odour for years. At times, algal taste and odours are evident due to the majority of water being sourced from the River Murray plus reservoirs in the Adelaide Hills – a primary agricultural area. Further, customers complain about chlorinous taste and odour in the distribution systems. Despite all reticulated water being treated by conventional processes, the high dissolved organic carbon (DOC) requires high coagulant doses and increases the chlorine decay rate which necessitates a higher dose (or doses) of chlorine to maintain a residual.
Any future deliberations on treatment processes to improve taste and odour would, following the Sydney water crisis, be expanded to include removal of Cryptosporidium and Giardia although the present risk is considered quite low for these protozoa. Supplies to most metropolitan areas are filtered therefore any process changes have to be retrofitted
to existing operating plants.
Further, an holistic view which encompasses a ‘source water – consumer’ scope is essential. This includes catchment management, reservoir management, treatment processes and distribution system management.