WHAT THE STANDARD IS: Splash selects the optimal water purification system for each particular site based on the following criteria in order: water quality, flowrate, local availability of the technology and spare parts, and full 10 year cost.

Water Quality: Splash’s first criterion for water purification system selection is the safety of the water that a system can produce with the local source water.  As part of Splash’s pre-implementation assessment process, a water quality test is performed on the existing drinking water source (see section on water quality testing).  The results of this test provide the local Infrastructure Team with the knowledge of the physical, chemical, and biological parameters of the existing drinking water source that need to be modified or removed in order to make the drinking water safe according to local national, WHO, and Splash water quality standards.  Based on this knowledge, the local Infrastructure Team is able to define the water purification system (including any necessary pre-treatment) that is demanded based on the water quality.

Flowrate: After the water quality needs are established, the local Infrastructure Team must specify a water purification system whose maximum flowrate can meet the demand of the particular site where it will be installed.  The flowrate demand is calculated using the following information: maximum simultaneous population of users at the site (staff and students) (also known as the single largest shift population), Splash’s minimum ratio for drinking taps to users (1:75), and Splash’s minimum acceptable flowrate per tap (3 L/min).  For example: at a school site with 930 daytime students, 70 daytime staff, 600 night students, and 40 night staff, then the single largest shift population is 1,000 users.  The Splash minimum ratio for drinking taps to users is 1 to 75, so we would need to install 14 drinking taps (1,000/75 = 13.3) (Splash always rounds up to meet minimum ratios, so 13.3 becomes 14).  Since the Splash minimum acceptable flowrate is 3 L/min, then we would need to install a water purification system with a flowrate of at least 42 L/min (14 x 3 = 42).  However, in addition to the above calculations, we must also have a conversation with the site leadership to learn if any large expansions or population growths are expected within the following ten years.  If expansion and growth are imminent then we must select a water purification system that will meet the larger flowrate demand.  More details on the drinking tap to user ratio can be found in the Drinking Water Implementation Standard.

Local Availability/Sustainability: After the water quality and flowrate requirements are defined, the local Infrastructure Lead would see if there are any locally available (from established vendors) water purification systems (with all spare parts locally available as well) that meet those requirements.  Splash always seeks to establish local supply chains and to further strengthen the local economy whenever possible.  If no locally available water purification systems can meet the defined requirements, then Splash will import an appropriate water purification system and seek to establish an independently sustainable importer and supply chain for post-MOU service. 

Another key component to sustainability is the system’s ease of (or lack of) maintenance required by the site.  The local WASH Infrastructure Team should select the purification system that minimizes the amount of maintenance that must be completed by the site.

Cost: Finally, once all of the above requirements can be met, the local Infrastructure Team will make the final selection from the list of water purification systems that can fulfill all the above requirements.  This final selection is based on the immediate capital cost plus ten years of annual O&M costs in terms of both money and labor required from Splash and the site.  This means that we look at the initial delivered cost of the system (including shipping, taxes, fees), the money and time cost of installation, ten years of the annual money and time cost of any consumable replacement parts, and ten years of the annual money and time cost of operating the system (electricity, chemicals, labor, increased water usage/storage).  Splash’s goal is to put the lowest time and money cost burden possible on our partner sites.  We always seek to simplify the operations and maintenance requirements of any systems we install.  

The final filter system selection must be reviewed and approved by the Global WASH Infrastructure Lead and the Country Director.