Another use for the seed pods of the Moringa tree is in water purification and treatment processes. The crushed seeds serve as a coagulant that attracts suspended particles in the water and allows them to settle to the bottom, leaving pure, clean water at the top of the treatment container. The process requires mature seed pods rather than the immature ones preferred for cooking purposes. The seeds are removed from the shell and the seed coats are removed; any discolored or misshapen seeds are discarded during this phase, leaving relatively uniform seed kernels. The seeds are crushed and mixed with water to create a paste; this paste is then mixed and thoroughly shaken together with a larger quantity of water to produce a solution. The solution is filtered through cloth or mesh and then mixed together with the water to be treated. The coagulant properties of the crushed seeds allow this solution to attract the particulate matter suspended in the dirty water and to move it safely to the bottom allowing the pure water to be removed from the top; the purification process requires at least two hours for full effectiveness. Because these seeds are safe and nontoxic, the water is ready for use right away rather than requiring a secondary course of purification. One kernel typically can treat up to one liter of the dirtiest water, making this an economically sound means of water purification for distant areas. One drawback of the method is that if the water is left undisturbed for too long, secondary contamination can occur, especially if the water is left uncovered. This form of water treatment does not remove all impurities and should typically only be used in cases where the water supply is presumed to be free of chemical or biological contamination. Water purification is considered to be one of the most important functions of the plant because shortages of fresh, pure water are increasingly worrisome in locations all around the world. This new method of purification can produce wholesome drinking water even in isolated or technologically disadvantaged areas of the world.