1. Technical Criteria:
The water delivered need to require the standard quality (both chemical and bacteriological) and required quantity, throughout the various seasons.
Technologies should be reliable and robust, with little possibilities for faults due to weakness or obvious user error. In our case, it is a prerequisite that the technology is protected against overdraft for instance.
The technology is not allowed to have any adverse effects on the environment. One of the big advantages of in situ treatment is that there is no waste as is the case with many of the technologies of arsenic removal.
2. Socioeconomic Criteria:
Economic considerations - Everyone should agree that safe drinking water is a basic human right and that national governments and society at large should ensure that all members of society have equitable access to meet basic needs for safe drinking water. The costs of technologies are of great importance. If the there are no water cleaning stations using sand to remove iron from the water in the neighbourhood, it is the option of iron coated sand is not feasible.
Institutional considerations - Awareness raising, technology identification and verification, application and monitoring of arsenic mitigation which will all require
coordination and understanding by various public and private representatives.
Gender considerations - The technology should not put and extra burden on women, that are in most developing countries responsible for the provision of water,
and the technology should at least be gender neutral in terms of ergonomic, culture and time.
Convenience and Social Criteria - implies a necessary level of convenience required for the users and the existing social regulations. The effort required to go to the safe communal source and wait in a queue for one�s turn to collect water should to take into account and the amount of effort that the users are willing to put into it.
The technology should be socially accepted, preferably blend into the existing water supply, suitable and sustainable in terms of the local topography, hydrology, socio-cultural conditions, settlement pattern and population density.
3. Site Selection Criteria:
For all designs, the obvious assumption is that the SAR (Subterranean Arsenic Removal) works at that particular location where:
� Sufficient underground iron is present,
� Soil structure at filter depth not too coarse (which would lead to no absorption surface)
� No strong groundwater flows overloading the absorption zone.
� Moreover, we assume a delivery factor at the safe side, namely 1:4. For every 4 litres pumped up, 3 can be used for drinking water and 1 is needed for recharge.
4. Cost elements:
Assuming the SAR technology works, one of the decisive factors for its success will be the costs. All the materials needed for the designs are locally available and the costs of the materials are relatively low.
