Bowker & Associates, Inc.
Services Qualifications Odor Information
Consulting Engineers
Specialists in Odor Control & Corrosion Control in Sewer Systems & Wastewater Treatment Plants
PROJECT EXAMPLES
Identification of Odor
Sources and Optimization of Odor Control Systems
at the
In March of
1997, a series of odor episodes prompted the City of New Bedford, Massachusetts
to study potential odor sources at the new 30 mgd wastewater treatment
plant. Bowker & Associates, Inc. was
retained to conduct an independent assessment of 
odor
emissions, to evaluate the adequacy of the design of odor control systems, and
to make recommendations to control odors and reduce complaints.
A
comprehensive series of odor emissions inventories led to the conclusion that
the major sources of odor complaints were the solids handling scrubber,
fugitive emissions from the solids handling building, and trucks hauling
dewatered sludge.
Recommendations
included reducing sludge inventories to control the generation of reduced
sulfur compounds, improving scrubber monitoring and control systems, using
fixed covers instead of fabric covers on sludge trucks, and minimizing fugitive
emissions through better management and scheduling of dewatered sludge
containers. A series of meetings were
held with local residents that led to the formation of an odor control task
force.
Assessment and Control
of H2S Corrosion in the
Bowker &
Associates, Inc. worked closely with O’Brien & Gere Engineers to
conduct a major study of sewer corrosion in the 
Recommendations
included using a novel process involving upstream addition of iron salts to
control hydrogen sulfide generation in the force mains, with downstream
hydrogen peroxide addition to regenerate the iron. Measures for sewer rehabilitation and
protection of concrete interceptors from further corrosion were also
recommended.
Development of a Master
Plan for the Blue Plains WWTP
Mr.
Bowker was retained as an expert peer reviewer by Camp Dresser & McKee for
the development of an odor control master plan for the 350 mgd Blue Plains WWTP
serving Washington, DC. This
comprehensive project involved liquid and air stream sampling, extensive odor
dispersion modeling, and prioritization of odor sources based on an innovative
economic analysis of unit costs for controlling the major sources. Mr. Bowker participated in three workshops with
the Client at various stages of the project.
A phased approach to controlling the priority odor sources was
recommended.
Comprehensive Assessment
of Odor and Corrosion Control Alternatives for the
Mr. Bowker was
retained by Camp Dresser & McKee as an expert consultant for a
comprehensive study of odors and corrosion in the Collier County, Florida sewer
system. Due to the warm climate and flat
terrain, the extensive force main system generates large quantities of hydrogen
sulfide that causes odor complaints and sewer system corrosion.
A detailed sampling program was implemented involving measurement of dissolved
sulfide, temperature, and pH of the wastewater, and measurement of H2S
in the headspaces of sewers, manholes, and wet wells. The performance of existing odor treatment
system was assessed by inlet and outlet measurements of hydrogen sulfide and
odor concentration. Continuous H2S
dataloggers were installed at multiple locations to measure diurnal variations
in H2S concentrations.
The
alternatives evaluation investigated chemical addition to the wastewater and
collection/treatment of odorous air. A
decision matrix was developed to assist the County in selecting the most
cost-effective odor and corrosion control technique for the conditions
encountered. Similarly, guidance was
provided on the best techniques for rehabilitation of manholes and wet wells,
and the most effective techniques for protecting against future corrosion.
Independent Review of
Sewer Odor Control Program for the City of
Bowker & Associates was selected by the City of Los Angeles, the
State of California, and the U.S. EPA to conduct an independent review of the
City of Los Angeles’ sewer odor control program. This review was required as part of a
Court-ordered 
settlement regarding odor emissions from the City’s sewer system.
The project involved multiple tasks, including a review of previous
studies and on-going monitoring efforts, an assessment of existing and proposed
odor control measures, an evaluation of odor complaint tracking and response
procedures, and a comparison of the City’s sewer odor control program
with those of other major cities.
Recommendations were prepared to improve odor monitoring and complaint
tracking, enhance the chemical addition and air treatment programs, and improve
the effectiveness of the Odor Advisory Board.
Control of Odor
Emissions at the
Bowker
& Associates participated in two comprehensive assessments of odor emissions
and their control
at the 80 mgd Syracuse Metro WWTP.
Detailed air and liquid stream sampling programs were implemented in
1992 and 2002 to characterize and rank the sources of odor emissions. In both projects, dispersion modeling was conducted
to assist in prioritizing the sources based on downwind impacts. Major improvements resulting from the first
study included optimization of upstream chemical addition programs, and
collection and treatment of air from two headworks buildings, all open influent
channels, and primary effluent weirs.
The second project evaluated multiple odor control scenarios that
addressed odors from the alkaline sludge stabilization system and the quiescent
surface of the primary clarifiers.
Control of Odor and
Noise Emissions at the
In response to a
lawsuit over odors and noise form a solid waste transfer station, Bowker &
Associates and Webster Environmental Associates conducted a comprehensive assessment
of emissions that included odorous air sampling, community odor surveys, and
ambient noise surveys.
Dispersion
modeling was conducted to verify existing odor impacts and evaluate various
control scenarios. Recommendations
included 1) capturing and treating air around the main doorway to prevent
escape of fugitive odors, 2) installation of roof-mounted, high-velocity
dispersion fans, and 3) installing engine mufflers and acoustical baffles.