Importance of Clean Drinking Water Every 15 seconds, a child dies from a water-related disease ( > 2,000,000 per year or 180 children during this class) Approximately 443 million school days are lost each year due to water-related illness. For children under age five, water-related diseases are the leading cause of death. At any given time, half of the world’s hospital beds are occupied by patients suffering from a water-related disease. 1.8 million children die each year from diarrhea–4,900 deaths each day. Source: Water Partners International
Water is CHEAP! Source: United Nations Human Development Report 2006
How do we treat the water? Flocculation Sedimentation Filtration pH Control Disinfection
Flocculation Flocculation is the process of forming “floc”, or large particles, by bringing small particles together. Most particles (including sediment and microorganisms) have a negative charge. Aluminum sulfate (alum) has a positive charge
Sedimentation Sedimentation is the process of slowing the velocity of water and thus allowing these large particles to sink to the bottom. Sedimentation basins collect the solids at the bottom and allow the clean water to flow over a weir.
Why do We Spend So Much Effort to Remove All of the Particles? What kinds of things can be attached to sediment? –P–Protozoa –B–Bacteria –C–Chemicals Pesticides Herbicides
pH Control Alum (used in flocculation) is acidic Why would we need to adjust the pH of the water before it enters the distribution system? –Acidic water can cause corrosion of pipes and cause harmful substances to become dissolved in your water.
Disinfection Disinfection kills or inactivates disease- causing organisms Many disease causing micro-organisms are too small to be removed through the sedimentation and filtration processes Residual disinfection is required
Watershed What is a watershed? –An area of land that drains water, sediment, and dissolved materials to a common body of water. How big is the Beaver Lake Watershed? –1193 square miles or 763,246 acres –Located in parts of six Arkansas counties