- Population between 1000 and 50,000
- Surface water source with turbidity frequently above 50 NTU (We need to do an economic analysis of the feasibility of using slow sand filters for low turbidity locations.)
- Well organized water board responsible for maintenance and operation of the water supply system
- Community agreement to raise the water tariff to finance the plant operation
- Community agreement to provide labor and materials for construction of the water treatment plant
- Ideally the water supply network is designed such that a single water treatment plant can serve the entire community
AguaClara Water Treatment Plant Requirements
For an AguaClara water Treatment plant there are both technical and social requirements that need to be met in order to ensure its proper functioning and sustainability. The technical requirements ensure that water treatment is necessary, that there is sufficient water, and that after treatment it will be potable. The social aspects look to ensure that the community is interested in this technology as well as organized and committed to the project.
Technical Requirements
- That the community has a water system that provides turbid water (greater than 5 NTU) for at least part of the year.
- While this is the most important requirement it can often be the hardest to verify. At the moment we are in the dry season and most sources are coming clean. While most communities say they have water that comes dirty, it can be difficult to ascertain why or for how long.
- Ideally we would like to leave turbidity meters in all candidate communities for part of the rainy season.
- That the source be able to provide enough water so that each house has water 24/7 and that it be the best source available for the community.
- The capacity of the water source to serve the population is important. When water comes intermittent, users often store the water in open basins in their houses. This provides other routes of contamination.
- If there is not enough water, the population will likely look for other sources to meet the needs of the community. This runs the risk that another source will be found which for various reasons can not be treated by the plant and untreated water will still arrive in the homes.
- That all water sources meet before reaching the community.
- Having the water sources all meet ensures that all water entering the community can be treated. If one source enters untreated it can contaminate the treated water. If there is a case where one source comes clean it is possible to put in a bypass for the plant. However, it is necessary that all water can be routed through the plant.
- That there is a piece of land suitable for the construction of the plant under the control of the water board. The conduction lines for all sources must pass through this site.
- That a water-quality study exists
- A study of the water is needed to ensure that the only contamination is turbidity and the bacteria and parasites that come with it. If there are heavy metals or pesticides the water can still be undrinkable even after treatment from the plant. To ensure that treatment from only the plant will ensure drinkable water a study needs to exist to rule out the possibility of other contamination.
- That the population size exceeds 250 houses
- This requirement is to ensure that the plant is financially sustainable. Often smaller communities aren't as financially stable. This makes it harder for the community to gather the funds for their part in the construction of the plant.
- The economy of scale makes the operation of larger plants more cost-effective. Although chemical costs increase directly with flow rate and population, operator costs do not. The labor required to operate a larger plant is nearly identical to the labor required for a small plant. The salary of a fulltime plant operator causes a smaller increase in the water tariff when it is divided between more users.
Social Requirements
- That the community is conscious of their water quality problems and are motivated to solve them.
- Communities that are already concerned about water quality will be more likely to make the investment necessary to ensure the success of a treatment plant.
- That there is an organization responsible for the operation and maintenance of the water system - Ideally a Junta Administradora de Agua (Water Board)
- This requirement is due to the large turnover in personnel every four years when mayors are elected. If there is a change in political party often entire office personnel are changed. When there is a water board or an organization specifically responsible while there are still political changes the organization has an invested interest in all water projects.
- That the community is willing to raise the water tariff
- Raising the water tariff is necessary in order to keep the plant functioning. Without a raise in the water tariff or some other means to pay an operator and buy chemicals the plant will not be sustainable.
- It is possible that other means to find the economic resources to support the plant can be found, but if not than there will need to be a raise in the water tariff. This varies from community to community, depending on the size of the community.
- That the community enters into a written agreement of the project
- An agreement would be between the community and Agua Para el Pueblo. This agreement will define the roles and responsibilities of each party. It will serve as a guide for the execution of the project and will be used to prevent and settle disputes.
- That the community contributes the unqualified labor and local materials for the construction of the plant
- Having the community contribute part of the plant is necessary to show the interest of the community in the project and to help develop a sense of ownership.
- That the municipality supports the project
- It is important to get the support of the local government for the project. This makes the leaders of the community aware of the project and offers additional funding. This also helps to bring together the local government and the organization responsible for the water system.
- That the water board informs the rest of the community about the project
- It is important to inform the community before, during, and after construction of the plant as they will be the ones financing it.