Odor Control Facility for Large Metropolitan WWTP

Dallas, Texas

As part of a larger team, PECI designed the biofiltration odor control systems for the Dallas Water Utilities Influent Pump Station. As part of the 330 mgd pump station project, odor control facilities were needed for the lift station and influent junction box. PECI evaluated the proposed design and determined that an organic media biofilter capable of treating 36,900 cfm would be required. This airflow was carefully determined to include capture velocities for the influent area, screening channels, effluent junction, wetwell, and a large junction box upstream of the facility. To provide ease of maintenance the biofilter was constructed with a manufactured plenum system that can be driven on with construction equipment when the organic media needs to be changed. This project was completed in 2014; the odor control portion of the project was approximately $1.3 million.

Evaluation and Design of Odor Abatement Improvements

Lewisville, Texas

PECI was retained by the City of Lewisville to conduct emissions testing and dispersion modeling for prediction of off-site odor impact from odorous process units at the WWTP. The treatment processes found to cause the greatest off-site odor impact include the influent splitter boxes, fine screens and aerated grit basins.

PECI was also retained to provide design services for odor control improvements at the headworks processes. Foul air from the influent splitter boxes, fine screens and grit removal basins is combined and handled by a single biotrickling filter or bioscrubber.

The foul air flow to effectively capture odorous emissions from the grit removal system was reduced by converting the aerated grit basins to vortex grit removal basins. The vortex grit removal units are being constructed within the existing aerated grit basins, saving on inlet and outlet piping modifications.

Screenings from five existing drum screens were previously directly discharged into five large dumpsters. Screenings disposal was simplified with a dual washer/compactor system. Benefits include reducing the volume and weight of screenings by about 50- to 80-percent and a reduction of odors by removing organics from the screenings.

The project was completed in 2016 for the bid amount of $3.2 million.

Lewisville Dispersion Modeling Results

Odor Control Isopleths Showing Offsite Odor Impact

Evaluation and Design of Odor Abatement Improvements for New WWTP

Hutto, Texas

PECI assisted a larger team of consultants with design of a new, state of the art wastewater treatment facility to serve the City of Hutto. The plant is being built from the ground up and will be operated by the Brazos River Authority when complete.

PECI modeled odor dispersion from the plant’s major process units and assisted with selection of odor control improvements designed to keep detectable off-site odors to a minimum practical level. PECI personnel participated in a public meeting at the site and assisted in developing odor-related language for incorporation into an agreement with nearby landowners, enabling formal permit protests to be withdrawn.

PECI designed an organic media biofilter, ductwork, and a foul air collection system to serve the plant’s headworks structure and dewatering building.

The opinion of probable construction cost for odor control was $400,000. This project was bid in March 2015.

OU Isopleths shown on Aerial Map_Controlled

Odor Dispersion Model Isopleths

Odor Abatement Master Plan

Grapevine, Texas

Perkins Engineering Consultants, Inc. served as a subconsultant to Brown and Gay Engineers, playing a lead role in assessing and prioritizing odor sources at the city of Grapevine’s wastewater treatment plant. The city commissioned this evaluation as a proactive step in addressing extensive residential development in areas immediately adjacent to the facility. This evaluation, completed in 2006, identifies the plant’s headworks facilities, sludge holding tanks, and sludge drying beds as the most cost effective process units to target for initial odor control efforts. The evaluation included training of city personnel for off-site odor monitoring and assessments, and included development of a complaint response protocol or used by city personnel.

Nuisance Odor Prevention Plan Preparation

Blue Water Shores Wastewater Treatment Plant

Aqua Texas, Inc, owner and operator of the Blue Water Shores WWTP, plannned to replace their existing rectangular final clarifier with a new circular final clarifier. Due to footprint limitations, the new final clarifier will be located within the 150 foot buffer zone. PECI drafted a Nuisance Odor Prevention Plan, in accordance with Texas Administrative Code Chapter 309, which addressed existing climatological conditions, surrounding land use, wastewater characteristics in affected units pertaining to the area of the buffer zone, potential odor generating units and proposed solutions to prevent nuisance conditions at the edge of the buffer zone and beyond. Perkins Engineering Consultants has prepared nuisance odor prevention plans for numerous clients.

Odor Dispersion Model and Odor Abatement Improvements

Richardson, Texas

Perkins Engineering Consultants, Inc. was retained by the District to conduct dispersion modeling and to recommend and design specific odor abatement improvements for this plant in Richardson, Texas. Perkins Engineering Consultants, Inc. modeled several different dispersion and improvement scenarios. Design of odor control improvements included full covers on the Plant’s primary clarifier, cover and exhaust improvements to the Plant’s main left station, and addition of a bioscrubber for treatment of foul air. Construction was completed in 2014.

Plant-Wide Rehabilitation Improvements

North Texas Municipal Water District

Perkins Engineering Consultants, Inc. was retained by the North Texas Municipal Water District to assess and prioritize rehabilitation needs throughout the District’s 24 MDG Rowlett Creek wastewater treatment plant. The treatment facilities had been constructed and expanded under numerous contracts, with many facilities over 40 years of age. Corrosion and structural deterioration was a concern in a number of areas.

Perkins Engineering Consultants, Inc. served as prime consultant responsible for detailed design of the highest priority improvements. This project included extensive corrosion repairs to a number of covered concrete structures within the plant, drainage improvements inside the plant’s dewatering building, addition of a 5000 CFM bioscrubber for odor control, replacement of the plant’s aging return and waste activated sludge piping and distribution system, rehabilitation of approximately 3500 square yards of in-plant paving surfaces, and addition of access and security improvements. Construction was successfully completed in 2010 at a cost of $1.6 million.

Odor Control Planning and Design

Wichita Falls, Texas

Perkins Engineering Consultants, Inc. was retained by the City of Wichita Falls to perform and odor source assessment and to develop an odor control master plan for the City’s 19.5 MGD River Road Wastewater Treatment Plant. PEC assisted with design of the first phase of odor abatement improvements, which includes primary clarifier weir covers, junction structure covers, corrosion repairs and a 7500 CFM foul air collection system. Construction was completed in fall of 2008.

Odor Abatement Master Plan and Design

Granbury, Texas

Perkins Engineering Consultants, Inc. served as a subconsultant to Brown and Gay Engineers, playing a lead role in assessing and prioritizing odor sources at the city of Granbury’s wastewater treatment plant. The City commissioned this evaluation as a proactive step in addressing extensive lakefront residential development in areas immediately adjacent to the facility. This evaluation, completed in 2007, identifies the plant’s grit/grease structure and influent lift stations as the most cost effective process units to target for initial odor control efforts. Perkins Engineering Consultants, Inc. designed odor abatement improvements to these two areas, including an upgrade to the BioCube® units at the plant’s existing lift station and a new 1000 CFM AerBios® unit at the new grit basin. The project was completed and successfully passed performance tests in 2010.

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