Wastewater Clarifier

After preliminary treatment the wastewater enters three clarifiers where the flow stream is allowed to slow down. This allows the solids (Sludge) to settle out and the clear water (Supernatant) to rise to the top. The clear supernatant then flows to the chlorine contact chamber where it is treated with Chlorine, followed by de-chlorination with Sulphur Dioxide in order to discharge into Cibolo Creek.

Some of the effluent is processed at the Reclaimed Water Station that further filters the water through a series of sand media filters which allows bulk water sales of effluent to be used for irrigation purposes.

Wastewater Clarifier

Sludge Treatment

The "Sludge" that settle out in the clarifiers is pumped to one of two places, returned to the aeration basin to "Re-seed" the process, this is called Returned Activated Sludge or RAS. The remaining "Sludge" from the bottom of the clarifiers called Waste Activated Sludge or WAS is pumped into the anaerobic digesters which also help break down the solids. The remaining solids are then pumped to the belt press or one of three solids holding tanks and then land applied as soil enhancers in a hay field. 

A belt press is used in the event there is no storage space and/or the fields are unable to be worked and then hauled to an approved landfill.

Wastewater Treatment Diagram


The WWTP has the capacity to treat up to 6.2 million gallons per day (MGD) and has started an expansion project to raise that to 10 MG.