Process selection for sanitation systems and wastewater treatment in refugee camps during disaster-relief situations

Disasters and emergency situations can disrupt the provision of clean water and hygienic sanitation, which are crucial for maintaining public health. Excreta disposal in emergencies has often been a low priority and this has led to the provision of unsuitable on-site sanitation systems in urban areas. A decision algorithm for the selection of adequate excreta-disposal solutions suitable for different disaster-relief scenarios is presented. The special requirements of a wastewater treatment system for deployment during an emergency are discussed and a semi-centralised system is recommended to serve 5000 refugees under a range of assumed loading conditions. Twenty-three aerobic, anaerobic and natural systems are considered for secondary treatment and a process-selection matrix is presented based around 16 evaluation criteria. A system layout is developed based around several sanitation facilities including sedimentation tanks connected to a centralised roughing trickling filter and an activated sludge unit, which provides optimal performance against the evaluation criteria. The system provides the required treatment performance in an easy-to-deploy, low-cost compact installation.