Water Treatment Plant Austin and Alison

Source Water and Intake Water treatment plants usually draw water from rivers Water may be treated differently depending on where the water is originally from. Surface water generally requires more treatment than ground water. Surface water is also more prone to pollution from pesticides, factories and septic tanks.

Pretreatment and Screening Pretreatment starts by using large screens to catch the large solid debris. They also use a process called aeration which uses air to remove undesired gases, minerals or chemical solvents.

Coagulation and Flocculation Coagulation and Flocculation is an old chemical process in which a coagulating agent, alum, is put into the water. This method helps remove metals, dirt and microbes. The alum causes particles to clump together forming “floc” which sinks to the bottom leaving the water clean.

Sedimentation In sedimentation the water is left undisturbed for a few hours so the floc can settle at the bottom. On average 85% of the floc settles at the bottom.

Filtration Water is run through filters to clean the water. The filtered water is then stored for the next step.

Disinfection At this step the water may look clean but it may still contain harmful microbes. So it has to be disinfected so its safe to drink. The most common disinfectants are chlorine and ammonia. The water is then tested to make sure the harmful microbes are gone.

Distribution and Storage Next the water is pumped into distribution pipes or stored. The distribution pipes consist of fire hydrants, booster pumps, pipes, meters and service lines. The rest of the water is stored in case of emergencies.