On-site sanitation systems such as cesspools and septic tanks are widely used in most developing countries. These systems primarily aim to collect and treat toilet wastewater or blackwater. Although septic tanks are commonly used in non-sewered areas, their effluents are still rich in pathogens and other pollutants. The practice of direct discharge of septic tank effluents into the surrounding environment in absence of proper treatment has increased health risks. In order to reduce this problem, a post-treatment unit consisting of nano-silver coated granular activated carbon (NS-GAC) has been developed. The study results revealed that the inactivation efficiency of the NS-GAC unit increased with increasing hydraulic retention times (HRT) from 10, 20 and 30 minutes; however, for economy of scale, the NS-GAC unit could be operated at the 10 minutes HRT to achieve complete removal of Escherichia coli bacteria. The study showed a high feasibility of utilizing the NS-GAC media as a post-treatment unit for pathogen inactivation of septic tank effluent.
- E. coli
- granular activated carbon
- on-site sanitation
- septic tank effluents
- First received 13 February 2015.
- Accepted in revised form 5 July 2015.
- © IWA Publishing 2015