Patent ID: 8002993

Claim:
A method for converting contaminated water into water having a lower turbidity and bacterial contamination level than the contaminated water comprising the steps of: supplying the contaminated water to a water treatment system comprising: an upflow settling unit for at least partially settling a portion of the contaminated water; a filter unit having a granular filtration media selected from the group consisting of sand, anthracite coal, burnt rice husks, diatomaceous earth, gravel pumice gravel and combinations thereof; a sanitation unit comprising an ultraviolet disinfection unit; and a backwash unit, wherein at least a portion of the settling unit is elevated above an inlet to the filter unit and is in fluid communication with the filter unit and the backwash unit, at least a portion of the backwash unit is elevated above the filter unit and is in fluid communication with the filter unit, and the filter unit is in fluid communication with the sanitation unit; settling the contaminated water through the upflow settling unit and filtering the resulting settled water through the filter unit at a flow rate of about 3.5 liters per minute to about 15 liters per minute; selectively directing at least a portion of water exiting the settling unit to the backwash unit after settling; sanitizing water exiting the filter unit in the sanitation unit at a flow rate of about 3.5 liters per minute to about 15 liters per minute; recovering a water having a lower turbidity and lower bacterial contamination than the contaminated water, wherein the contaminated water is passed through the settling unit, the filter unit, and the sanitation unit using gravitational forces; and backwashing the filter unit using the water selectively directed to the backwash unit.