Coagulation and sedimentation in lakes, reservoirs and water treatment plants

Coagulation and sedimentation occur naturally in all lakes and reservoirs and, by design, in water treatment plants using surface supplies. Important factors that affect water quality in lakes and reservoirs include nutrient loading, areal hydraulic loading, and detention time together with the concentrations of land-derived (pedogenic) natural organic matter and hardness in waters entering the lake or reservoir. These, in turn, have important effects on the design and operation of potable water treatment systems. It is difficult and expensive to use the good physics to compensate for poor chemistry in water treatment plant design. There are many interesting and useful similarities among the physical and chemical characteristics of lakes, reservoirs, and water treatment plants.