CMA Engineering, Inc.


Wastewater Treatment Plants

CMA has designed and obtained approval for many wastewater treatment plants within the State of Texas, and specifically in the environmentally sensitive areas within the Edwards Aquifer.  Below are a few examples of unique wastewater plant projects:

Hays County WCID No. 1

CMA originally designed and permitted the wastewater treatment plant (WWTP) for Hays County Water Control and Improvement District No. 1, serving the Belterra Subdivision.  CMA recently assisted the district with a permit amendment, to expand the facility from 150,000 GPD to 500,000 GPD and convert the permit from land application to discharge. To date, these are the most stringent effluent requirements ever issued by the TCEQ. In addition, the TCEQ requirements for 210 Beneficial Reuse Type I effluent are met. 

The amended design incorporates membrane bio-reactor (MBR) technology into the WWTP. The plant consists of a mechanical bar screen, a pre-anoxic basin, pre-aeration basin, post-anoxic basin, a MBR basin, an Ultraviolet (UV) disinfection unit, associated pumps and piping, aeration diffusers, new blowers, an off-specification tank, treated effluent line and an effluent re-aeration structure, and electrical and controls.  The existing 150,000 GPD WWTP has been converted to a preliminary treatment unit for flow equalization and grit removal.  The new WWTP incorporates odor control for the preliminary treatment unit and on the raw influent headworks/barscreens.  Effluent requirements for Hays County WCID No. 1 WWTP are now 5 mg/L BOD, 5 mg/L TSS, 2 mg/L Ammonia Nitrogen, 0.15 mg/L Total Phosphorus, and 6 mg/L Total Nitrogen.

Hays County WCID No. 1 500,000 GPD MBR WWTP Site Plan

City of Kyle

CMA was contracted by Aqua Texas, Inc. for design of the City of Kyle WWTP expansion, a project that increased capacity from 1.5 MGD to a total of 3 MGD.  The project also included other improvements to address existing operational issues.  CMA was responsible for the design of the additional 1.5 MGD wastewater treatment plant and influent lift station. 

The WWTP is now utilizing fine bubble diffusers, a dissolved oxygen (DO) control system, a new clarifier, two digesters, mechanical bar screening, and improvements to the existing chlorination and dechlorination facilities.  The DO system in the aeration basin utilizes motorized valves on the influent blower butterfly valves and DO meters to reduce electrical consumption. The existing 1.5 MGD WWTP aeration basin was also retrofit with fine bubble diffusers and a dissolved oxygen (DO) control system.  Effluent requirements are 10 mg/L BOD, 15 mg/L TSS, and 3 mg/L Ammonia Nitrogen.

Flat plate membranes units installed in the MBR basin

MBR WWTP concrete structure and equipment room

City of Kyle Wastewater Treatment Plant

City of Kyle 1.5 MGD WWTP Expansion – Testing Fine Bubble Aeration System

City of Kyle 1.5 MGD WWTP blowers

City of Kenedy

CMA performed design services for the City of Kenedy, in Karnes County. The project expanded the WWTP from 0.983 MGD to a total capacity of 1.5 MGD, and included other improvements to address existing operational issues.

Expansion improvements were made in two separate phases: The first phase included installation of fine bubble diffusers in the existing aeration basin and immediately addressed low dissolved oxygen (DO) levels and poor sludge settling in the clarifiers due to the extremely high influent organic loadings.  The second phase included a DO control system, using motorized valves on the influent blower butterfly valves and DO meters to reduce electrical consumption, mechanical bar screening and grit removal, a new clarifier, improvements to the two existing influent lift stations, chlorination system expansion, and new dechlorination facilities.  Effluent requirements are 10 mg/L BOD, 15 mg/L TSS, and 3 mg/L Ammonia Nitrogen.

City of Kenedy 1.5 MGD WWTP Conversion to Fine Bubble Aeration

City of Kenedy 1.5 MGD WWTP Final Clarifier during construction

City of Dripping Springs

CMA assisted the City of Dripping Springs with development of its first organized wastewater system. The process for the South Regional Wastewater Facilities included developing and submitting a wastewater permit application and a Sewer CCN application to the TCEQ for a new wastewater facility. 

The City of Dripping Springs acquired an existing 500,000 GPD WWTP and relocated it to the new WWTP site.  The WWTP is currently rated at 127,000 GPD and utilizes subsurface drip irrigation for effluent disposal.  Most importantly, the WWTP can be easily expanded in the future.  Effluent requirements are 20 mg/L BOD and 20 mg/L TSS.

City of Dripping Springs Relocated WWTP

City of Dripping Springs WWTP Site