The potential of a semi-decentralised bulk water treatment approach for emergency relief

Humanitarian water treatment interventions vary from package bulk ‘kits’ to household (point-of-use) options. Whereas the former can be perceived to be too complex to operate, the latter, whilst relatively simple and effective, has logistical requirements that may hinder its application during relief operations. This study evaluates the potential of a semi-decentralised water treatment approach for humanitarian emergencies. Its performance was evaluated against the relevant water quality treatment objectives (The Sphere Project) under controlled laboratory conditions using a synthetic test water. Results revealed that whilst the recommended minimum free chlorine residual levels were not attained (possibly due to high chlorine demand of test water), all other treatment objectives were within desired values, namely: <1 colony-forming unit (cfu)/100 mL with regards to thermotolerant (faecal) coliforms and <5 NTU (nephelometric turbidity units) for treated water turbidity. Given the performance of the semi-decentralised approach tested here, it could be expected to attain all treatment objectives when tested in natural surface waters. It has the potential to bridge the gap between centralised (i.e. bulk water treatment kits) and fully decentralised (i.e. household) water supply strategies.