Serving public and private clients across Texas


2023 | HEB Austin 33 WWTP & Irrigation Field Design

Parra & Co was engaged by HEB to perform the Engineering Design of their Wastewater Treatment Plant (WWTP) and Irrigation field for their new Austin 33 store. 

For Phase I of this project, the Parra & Co team researched the site with the intent of providing a conceptual sizing of the drip field for a 14,000 gpd on site WWTP that will serve the new HEB store and produce our Preliminary Engineering Report (PER). This PER included a comparison between a conventional activated sludge system and a sequence match reactor that complies with the existing Texas Land Application Permit. (TLAP)

During phase II, Parra & Co provided the performance specifications and Construction Documents for the WWTP system and Irrigation Field. Our team also provided assistance with permitting, construction inspection, startup, and post-construction/warranty. Parra & Co received approval of the system from TCEQ in October 2021. This endeavor concluded successfully with the plant opening on June 20, 2023 and the new HEB Austin 33 store opening to the public the following month on July 6.

2019 | City of Mercedes W/WW Facilities Conditions Assessment

As the City of Mercedes had been engaging the services of a third-party operator to run the Water Treatment Plant, the City wanted to understand what level of effort was required for them to take on that responsibility. The first step for that was to perform a Due Diligence Study that analyzed where the City was at that moment, what gaps existed, and what impact it would have on the City to transfer the duties to a City-run Utilities Department.

Parra & Co was engaged to perform the Water / Wastewater Facilities Conditions Assessment. We started with a 2–3-day site visits to obtain a proper inventory assessment of: list of all fixed assets for the utility, Water Treatment Plant data (stats, figures, records, etc.), Wastewater Treatment Plant information, collect any/all assessments and analysis performed to date, current Chart of Accounts, amount of payments for Utility Operations for the last three years, record of Lift Stations, record of all vehicles, all designated equipment, miscellaneous equipment & machinery, and all technical components (computers, laptops, communication equipment, etc.). Our team also requested utility bills (electricity, water, gas, phone, internet, etc.), copy of any maintenance/operations agreement separate from the Main Operations Contract (already provided) paid directly by the city, and current job classifications, job descriptions and pay ranges. 

Parra & Co’s Water / Wastewater Facilities Conditions Assessment provided recommendations on: Estimate number of staff needed to run current facilities, Conceptual Chart of Accounts, Draft Organizational Chart for Utilities, necessary Minimum Qualifications for new staff, commentary on the need of a separate Department of Utilities or a Combined Public Works/Utilities Department, Proposed Implementation Timeline, Conceptual Budget, Commentary on Levels of Operation & Quality Control, and Commentary on Assumed Risk. Parra & Co also assisted a Workshop with the City of Mercedes to go over additional questions/changes to the report.

2021 | Zacate Creek WWTP TPDES Permit Renewal

Parra & Co was engaged by the City of Laredo to provide professional engineering services for the Texas Pollutant Discharge Elimination Systems (TPDES) permit renewal for the Zacate Creek Wastewater Treatment Plant (ZCWWTP).

Our team completed the appropriate application forms and prepared the required application attachments to renew the TPDES permit. While the application was being processed, our team assisted with responses to the Texas Commission on Environmental Quality (TCEQ) questions during the reviews. 

Parra & Co also provided Legal Permit Assistance regarding the renewal application and any possible issues raised by the existing compliance issues at the Zacate Creek Wastewater Treatment Facility (ZCWWTF), as well as any necessary legal analysis and evaluation during the preparation of the renewal application. Under the permit legal assistance, our team performed quality assurance and regulatory review of the draft permit renewal application, including identification of any suggested revisions, prior to its submission to TCEQ. 

2020 | Preliminary Engineering Report for 60,000 GPD WWTP

Parra & Co has been engaged by a private party to prepare the Preliminary Engineering Report, System Engineering Design and Permitting of their Wastewater Treatment Plant (WWTP) for their 30-acre upcoming development. (Corpus Christi, TX.) 

During the preliminary review, our team noticed a few conditions related to discharge and drainage from the site that require further review and attention. Parra & Co prepared a Preliminary Engineering Report that provided a conceptual understanding for the project, as well as an Order of Magnitude Construction Cost. Our team also assisted on the Texas Pollutant Discharge Elimination System (TPDES) and other permitting processes. 

On the design stages Parra & Co provided the performance specification for pre-selection of the conventional system and Construction Documents for the WWTP system. Moreover, we provided assistance with permitting, construction inspection, startup, and post construction/warranty. Once the Preliminary Engineering Report was completed, our team delivered a Technical Memo with Engineer’s recommendations for the WWTP. 

Parra & Co provided a plan for future tasks as well, including: TPDES New Permit Application, Preparation of Plans & Specifications, Assistance/Support with Local Building Permitting, Assistance with Bidding & Construction, TCEQ Submittals & Approvals or Plans & Specifications, Construction Administration Assistance, Operation & Maintenance Manual, additional site visits, and post-construction warranty assistance/limited remote support.

2022 | SLWWTP Operation & Maintenance Manuals & Training

Parra & Co, in collaboration with the City of Laredo and the South Laredo Wastewater Treatment Plant staff, developed an Operations & Maintenance Manual that fulfilled the requirements listed on the Texas Administrative Code Title 30, Part 1 Chapter 217, Sub-chapter A, Rule §217.16.

Based on the background information provided by the City of Laredo, (Preliminary Engineering Report, equipment manufacturer’s manuals, SCADA manual, Emergency Response Plan, Risk Management Plan, Hazardous Mitigation plans, as-built drawings, applicable change orders, applicable communication letters, and any other necessary information) Parra & Co segmented the process into logical sub-units. 

Examples of these sub-units being the normal start-up, routine, emergency, and shutdown procedures for the aeration basins (including the basins themselves); the diffusers, blowers, and power control systems, along with the hydraulic, air valves and piping associated with the basins. Similarly, the procedures for the clarifiers would include the RAS, WAS and scum pumps associated with the clarifiers along with any instruments, power, and controls.

These manuals were also delivered in a searchable pdf format for ease of use for the operators. Further, the Parra & Co team was composed of engineers and operators, creating a final product that was technically accurate and easy to use.






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