The conversion of raw sewage sludge into valuable biosolids for beneficial reuse requires a
suitable pre-treatment process. However, traditional technologies are causing high investment
costs, operation costs, and energy demand; or are not fully meeting the demands of the market.
As recent experiences from the world’s largest solar drying and solar-assisted drying plants in
Palma de Mallorca, Spain and Oldenburg, Germany show, solar drying is an effective alternative
for large facilities. Drying costs and energy consumption are less than half, maintenance is low,
and operation is simple and safe at these facilities when compared to traditional thermal dryers.
Also, carbon dioxide (CO2) emissions are reduced by a factor of seven when compared to
conventional dryers. By using waste heat from other processes, the area requirement can be
reduced by a factor of three to five. The final product is suitable as fuel for Waste-to-Energy
(WTE) plants, coal power plants, or cement kilns. It can also be used as a Class-A fertilizer for
agricultural use, or land application.
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Posted: May 20th, 2011 | Filed under: Waste Water Treatment, Water Treatment | Tags: Cost Savings, Decreased Energy Consumption, Plant Sustainability, Smaller Carbon Footprint | No Comments »
Saco Wastewater Treatment Plant
Saco, Maine
The use of novel CSO control, treatment and disinfection systems based on advanced vortex technologies
including Vortex Flow Controls (VFC) and Hydrodynamic Vortex Separator (HDVS) that enable,
Screening, Grit Removal, Sedimentation and Disinfection to be accomplished in one vessel is described.
The application of the technologies at the Saco Wastewater Treatment Plant involves a new generation of
HDVS and vortex flow controls that regulate wet-weather flows to control maximum flows to the existing
wastewater treatment plant to avoid hydraulic overloading and the diversion of excess combined sewage
flows to the new CSO treatment facility.
The wet-weather treatment facility utilizes an advanced HDVS that incorporates a non-powered, selfactivating
and self-cleansing CSO floatables screening system; with the captured pollutants comprising
sewer debris and solids including sediments, settleable organic solids and floatables, being returned to the
headworks at the treatment plant and the clarified, screened and disinfected overflow being discharged to
the receiving environment (Saco River), after de-chlorination.
The ability to perform several essential unit processes (i.e. Screening, Grit Removal, Sedimentation and
Disinfection) all in one vessel resulted in significant savings in the overall project scheme costs on
account of the more compact design of the advanced HDVS system coupled with the elimination of
additional tanks and vessels that would have been required with the conventional approach. Analytical
results from post-construction compliance monitoring have confirmed the efficacy of the advanced vortex
technologies.
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Posted: May 20th, 2011 | Filed under: <50K, Stormwater, Waste Water Treatment | Tags: Cost Savings, Improved Disinfection, Improved Plant Efficiency, Improved Solids Removal, Optimal CSO Control | No Comments »
Green Bay Metropolitan Sewerage District (GBMSD)
Green Bay, Wisconsin
The Green Bay Metropolitan Sewerage District (GBMSD) is a public utility, established in 1931,
that reclaims 38 million gallons of wastewater per day at two treatment facilities in Green Bay
and De Pere, WI. Its service area covers 285 square miles and serves more than 219,000 people.
GBMSD’s mission is to promote public health and welfare through the collection, treatment, and
reclamation of wastewater, while assessing stable, competitive rates. In conjunction with others,
the organization will encourage pollution prevention and support programs to help ensure that
water contaminated by human activity is returned clean to the environment. GBMSD conducts
its business using a sustainable approach within the social, environmental, and economical
values of our customers and stakeholders.
GBMSD initiated the development of a Solids Management Plan in 2008 to address aging solids
handling facilities and the solids loadings from recently acquired De Pere Facility. The existing
solids processing system consists of belt press dewatering followed by multiple hearth
incineration. The solids system is located at the Green Bay Facility. Solids from the De Pere
Facility are transferred by pipeline to the Green Bay Facility for processing. The solids system
was constructed in the 1970s and is reaching the end of its useful life. The multiple hearth
incineration process is now considered an outdated technology. Current incineration technology
uses fluidized beds, which consume less fuel and lower air emissions.
The solids management planning effort was undertaken to develop a long-term plan for handling,
processing, and disposing of solids. The plan included a comprehensive evaluation of numerous
solids management technologies and approaches. This paper describes the process used to
develop the plan, the alternatives that were considered, the alternatives evaluation process, and
the preferred solids management alternative.
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Posted: May 20th, 2011 | Filed under: 100K-500K, Sanitary Sewer, Stormwater, Waste Water Treatment | Tags: Environmental Impact, Minimized Life-Cycle Cost, Plant Sustainability, Reduced Carbon Footprint, Reduced Greenhouse Gas Emissions | No Comments »
DC Water and Sewer Authority (DC Water)
Washington, DC
The DC Water and Sewer Authority (DC Water) is implementing new sludge and biosolids
processing facilites at the 1.4 million cubic meters/day (370 million gallons per day [mgd]) Blue
Plains Advanced Wastewater Treatment Plant (AWTP) in Washington D.C. The program
involves thermal hydrolysis (TH) followed by anaerobic digsetion and includes a major
cogeneration facility to provide electric power for the treatment plant and steam for the TH
process.
Decision and development criteria for DC Water’s biosolids program have evolved over recent
years and now include a broad range of factors with strong emphasis on sustainability criteria. A
major link between high-performance digestion and renewable energy production has been
forged. Key criteria for decision-making now include renewable power and energy production,
climate change issues, biosolids product quality, digestion performance, and site efficiency, as
well as capital constraints and economics.
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Posted: May 20th, 2011 | Filed under: 100K-500K, Waste Water Treatment | Tags: Biosolids Minimization, Economic Benefits, Energy Management, Improved Digestion Performance, Plant Sustainability, Reduced Carbon Footprint, Reduced Greenhouse Gas Emissions | No Comments »
Pine Creek WWTP
City of Calgary, Alberta (Canada)
The 100 ML/d Pine Creek WWTP is a state-of-the-art BNR facility that serves the City of
Calgary, Alberta. A delay in the construction of the primary sludge fermenters allowed a
comparison of the performance of the BNR process with and without fermentation for
extended periods of time, and facilitated a life-cycle cost analysis in which the cost of
primary sludge fermentation was compared with alternative forms of primary sludge
thickening and meeting the effluent total P limit by chemical addition. Data from the first 20
months of plant operation indicated that, with primary sludge fermentation, the plant is
capable of reliably meeting its stringent effluent total P target of <0.3 mg/L. Without
fermentation, the plant required the in-plant addition for approximately 50 mg/L of alum to
meet this same effluent quality standard. The life-cycle cost comparison between primary
sludge fermentation and enhanced biological phosphorus removal (EBPR), and two
alternative forms of primary sludge thickening and chemical P removal, indicated that
primary sludge fermentation is a cost-effective method of reliably meeting a stringent
effluent total P standard. Using a 20-year net present value (NPV) analysis, primary sludge
fermentation was found to be approximately 8 percent cheaper than mechanical primary
sludge thickening and chemical P removal, and 22 percent cheaper than gravity thickening of
primary sludge and chemical P removal.
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Posted: May 20th, 2011 | Filed under: 100K-500K, Waste Water Treatment | Tags: Biological Nutrient Removal, Phosphorus Removal, Sludge Handling | No Comments »
Humber Treatment Plant (HTP)
Toronto, Ontario (Canada)
The Humber Treatment Plant (HTP) was experiencing severe settling problems. An opportunity
to improve the performance of the HTP was seized by the plant’s Senior Engineer by developing
and implementing a program of repair, continuous assessment, analysis, and tuning to ensure
optimal operation of the aging infrastructure. Through the strategic utilization of existing inhouse
expertise and resources, a new benchmark of excellence, serving the community through
improved and consistent effluent quality with accompanying odour reductions, was established.
This achievement was accomplished paradoxically using less energy and chemicals, thus,
significantly reducing the Humber’s environmental footprint. The direct delivery of these
services by City staff, while further enhancing in-house knowledge, skill, and stewardship,
eliminated the delays associated with project delivery using external contractors and made it
possible to reap the immediate rewards. The monetary benefits to the City are savings in
operating costs of $550,000 per year and capital savings of $6,000,000.
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Posted: May 20th, 2011 | Filed under: 500K-1M, Waste Water Treatment | Tags: Capital Savings, Decreased Energy Consumption, Improved Plant Sustainability, Operating Cost Savings, Reduced Carbon Footprint, Reduced Odor Problems | No Comments »
Massaponax WWTP
Spotsylvania, Virginia
Spotsylvania County embarked up an aerated static pile composting program in 2002 to manage
undigested dewatered wastewater treatment plant (WWTP) residuals cake from their
Massaponax WWTP in conjunction with brush collected through a convenience center and at the
Livingston Landfill. The initial compost facility included a covered aerated static pile process
that provided intermittent positive aeration only. The quantity of dewatered residuals being
composted has increased from approximately 8,800 tons per year in 2003 to in excess of 12,600
tons per year in 2009. Even with this rapid increase in quantities, all regulatory process criteria
have been met and offsite odor impacts have been non-existent. Howeverer, residuals cake
continued to be landfilled from a second WWTP, the FMC plant, in the amount of 5,000 – 6,000
tons per year. The County embarked upon a compost facility expansion program in 2006 with
three main goals.
1. To manage the ever increasing quantities of residuals cake generated from both County
WWTP’s over the next 20 years.
2. To enhance and automate the compost process performance.
3. To accomplish this expansion with no offsite odor impacts.
Construction of the new facilities was completed in March, 2010. This paper presents data on the
process flow, process controls, and the odor management system of this successfully expanded
aerated static pile composting operation.
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Posted: May 20th, 2011 | Filed under: Waste Water Treatment | Tags: Cost Savings, Environmental Impact, Plant Sustainability, Reduced Carbon Footprint, Reduced Odor | No Comments »
Polk County Utilities (PCU)
Polk County, Florida
To assure that Polk County Utilities (PCU) is ready for coming changes in regulations and ever
increasing solids production from ten treatment facilities geographically dispersed throughout the
County, the County wanted to develop a proactive long term biosolids management plan that
integrated residuals management approaches among the various treatment plants. Geographical
dispersion and capacity diversity combined with a desire for an integrated long-term
management plan gave rise to a number of possible alternatives to be included in the evaluation.
The landfill disposal alternative investigated met PCU’s objectives which were to identify a cost
effective method for managing current and future biosolids generated at PCU’s facilities that
would represent a viable plan for the next twenty years. An agreement developed between PCU
and Polk County’s Solid Waste Division to mutually address disposal of leachate and biosolids
resulted in significant cost savings for both these County agencies.
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Posted: May 20th, 2011 | Filed under: Stormwater, Waste Water Treatment | Tags: Biosolids Management, Cost Savings, Environmental Impact, Plant Sustainability, Reduced Carbon Footprint | No Comments »
Little Rock Wastewater (LRW)
Little Rock, Arkansas
This paper reports on the use of a two cell 30-million-gallon (MG) equalization basin and diesel
engine-driven pump station as a means of mitigating sanitary sewer overflows (SSOs). The
ultimate capacity of the pump station, which utilizes vertical turbine solids handling pumps
(VTSH) arranged in a self-cleaning trench-style wet well, is 68 million gallons per day (MGD).
Configuring the pump station with diesel engine-driven pumps provided a 20-year, $1 million
present worth savings in comparison to a conventional electrical motor driven pump station
arrangement. The use of diesel engine-driven pumps eliminated the peak electrical usage of 450-
horsepower (HP) electrical motors, as well as the need for variable frequency drives and
redundant power generation needs during electrical outage time periods. A supplemental 150-
kilowatt (kW) generator was installed to provide emergency power needs for SCADA, seal water
systems, influent screen, and a 50-HP maintenance pump for wetwell cleaning.
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Posted: May 20th, 2011 | Filed under: 100K-500K, Sanitary Sewer, Stormwater, Waste Water Treatment | Tags: Cost Savings, Decreased SSO Volume, Energy Savings, Improved Plant Efficiency | No Comments »
Miami-Dade Water and Sewer Department
Miami, Florida
Difficult times require an extra effort when it comes to communication. With all of the talk
about layoffs, budget cuts and salary reductions, utilities face an uphill battle against the internal
“rumor mill”, declining morale during the current economic downturn, and external pressures to
do more with less. A well-developed communication strategy is one key to sustaining
performance in the face of these challenges.
The Water Distribution and Transmission Division of the Miami-Dade Water and Sewer
Department is meeting these challenges “head-on” with an aggressive communication program
that has been developed and refined over a number of years. This presentation will highlight that
program from the perspectives of the Division Chief, managers and supervisors, and employees.
Extensive interviews at various levels of the organization identified key communication
strategies and tactics that are helping this agency maintain a high level of performance through
the most significant economic crisis the US has faced since the Great Depression. These
strategies and tactics will be discussed in detail and results will be presented as a “business case”
for optimizing communication during challenging times.
Focus of Study and Results:
This presentation will include discussion in communication topic areas including:
1. General overview of communication strategies and tactics
2. Types, frequencies, and styles for effective communication
3. Directional communication – up, down, and across the organization
4. Formal and informal communication methods and tools
5. Strengths and weaknesses of various communication approaches
6. Value and results from effective communication programs
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Posted: May 20th, 2011 | Filed under: >1M, Sanitary Sewer, Stormwater, Waste Water Treatment, Water Treatment | Tags: Effective Communication, Improved Customer Relations, Improved Plant Efficiency, Improved Work Morale | No Comments »