A review of bacterial indicator disinfection mechanisms in waste stabilisation ponds

Abstract

Waste stabilisation ponds are applied all over the world for treating domestic wastewater. In many developing countries, they constitute the most widely used treatment process, and incorporate the important function of pathogen removal. Because of this wide utilisation, ponds have been extensively studied, resulting in new insights on the disinfection mechanisms, thus leading to more efficient systems and lower land and volume requirements. The previous “black-box” approach for pond design is being substituted by a more conceptual view resulting from a better understanding of pathogen removal mechanisms. This review manuscript aims at gathering previous and current research done on this matter, concentrating on coliforms, and evaluating the following mechanisms and influencing factors: temperature; sedimentation and attachment; dissolved oxygen and pH levels; sunlight-mediated disinfection (in combination with DO and pH) and dark inactivation/repair; biological disinfection (predation, starvation and competition); algal toxins; depth and hydraulic retention time; physical design and hydrodynamic behaviour. Gaps that still need to be filled are identified, which could still lead to further optimisation of waste stabilisation ponds performance.