Abstract
Introduction
Ensuring the availability of clean and safe water is a challenge in Divisional Headquarters Hospital, Dera Murad Jamali, Pakistan. The available water is delivered from a local canal through a municipality pipeline. It arrives with a turbidity of <50 nephelometric turbidity units (NTU) and contains pathogens and small white maggots. It is not fit for any purpose in the hospital currently but is nevertheless used for washing and cleaning. This innovation project aimed not only to clean the water for drinking (to below 5 NTU and hence fit for chlorination), but also to do so in an economical and sustainable manner.
Methods
The water treatment system we developed used gravitational water flow within a water tank. Water was tested for turbidity before entering the system, using a turbidity tube. Water passed through sand, activated charcoal bags, brick pieces and gravel before entering a perforated PVC 12” diameter pipe enveloped by a fine screen, set at the bottom of the tank. Water was then drawn from the PVC pipe to round flocculation tanks by a pump and tested for turbidity. Using a jetting action, water was then swirled in the tanks. If water tested at >5 NTU, flocculation would be performed. Water was then drawn through a vertical perforated and screened PVC 8” diameter pipe and delivered to the clear water tank. It was disinfected before being transported to storage tanks. A pool tester was used to check the free residual chlorine levels, to assess suitability for drinking.
Ethics
This innovation project did not involve human participants or their data; the MSF Ethics Framework for Innovation was used to help identify and mitigate potential harms.
Results
Over the course of one day, water was tested before entering the system at 35 NTU. Six water samples were tested for turbidity from each of two flocculation tanks at an average of 4.0 NTU (range 3-4.5 NTU for 12 samples), meaning that flocculation was not necessary. After disinfection, pool tester readings recorded an average chlorine level of 0.3 mg/litre (range 0.1-0.4 for 7 samples) and water was deemed fit for consumption following each test.
Conclusion
This evaluation showed that it was feasible to provide safe drinking water through a gravitational water filtration system of this design, and this design may be adaptable to other contexts with similar water quality issues. The costs for installation were £19675 (including installation of eight 2000 litre storage tanks) and ongoing maintenance / running costs are expected to be no more than £70 per month. This implies not only that this is an economical and efficient design for MSF and other actors, but that it could be adapted for domestic household settings using only locally available materials for construction and minimal maintenance / running costs (estimated to be ~£2 per month).
Conflicts of interest
None declared.
Farooq Khan
Farooq Khan is a professional engineer, with a degree from the University of
Engineering and Technology, Pakistan. Farooq earned a postgraduate scholarship to study further in the USA, and has about 14 years of experience working in water, sanitation and hygiene, including with the International Rescue Committee, Terra des Hommes, Norwegian Refugee Council, Save the Children, International Medical Corps, and MSF. He has also done engineering work in the USA, in Qatar, and in Pakistan.
