Conroe Central Wastewater Treatment Plant – City of Conroe

Conroe, Texas

LAN provided preliminary engineering, final design, and construction phase services for a new 6-MGD greenfield wastewater treatment plant that will ultimately be expanded to 12-MGD. The major project components included a diversion structure, influent lift station, influent force main, headworks with screening and grit removal, B-Stage secondary treatment, B-Stage clarifiers, tertiary filtration, ultraviolet light (UV) disinfection, non-potable water system, effluent outfall, RAS/WAS pumping system, sludge thickening, digestion, and dewatering, odor control systems, complete electrical system, SCADA control system, emergency generators, administration building, maintenance building, compete site drainage system, access roadways, and planning for a future carbon diversion system.

A hybrid design was developed to allow future incorporation of carbon diversion and anaerobic digestion. The expansion plan is for future phases to incorporate carbon diversion, allowing the B-Stage aeration basins to be utilized without expansion. The anticipated initial loading increase resulted in larger B-Stage blowers than required if carbon diversion was initially executed. Without carbon diversion or primary clarification, the most practical treatment process was activated sludge with aerobic digestion. Digestion tankage was designed to allow future anaerobic digestion. The digesters will initially be constructed without covers and be aerated. Based on staffing limitation, it was decided that sludge dewatering would not be conducted on a 24-hour basis, leading to an increased digested sludge flow rate requiring larger centrifuges.

At a glance

New 6-MGD greenfield plant

$60M construction cost


Hybrid process design

Activated sludge with carbon diversion


Treatment plant design

Process design


City of Conroe

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