WASTEWATER TREATMENT

WASTEWATER TREATMENT

Raw sewage includes water from sinks, toilets, and industrial processes. Treatment of the sewage is required before it can be safely buried, used, or released back into local water systems. In a treatment plant, the waste is passed through a series of screens, chambers, and chemicals, and chemical processes to reduce its bulk and toxicity. The three general phases of treatment are primary, secondary, and tertiary. During primary treatment, a large percentage of the suspended solids and inorganic material is removed from the sewage. The focus of secondary solids treatment is reducing organic material by accelerating natural biological processes. Tertiary treatment is necessary when the water will be reused: 99 percent of solids are removed and various chemical processes are used to ensure the water is as free from impurity as possible.