Annacis Island Wastewater Treatment Plant
Vancouver, British Columbia (Canada)
Annacis Island Wastewater Treatment Plant which is operated by Metro Vancouver, is leading
the way in working within a carbon based regulatory environment. British Columbia has
instituted carbon reduction legislation province wide, a leader in North America. As a result
public entities, such as Metro Vancouver, must be carbon neutral by 2012. In response the utility
is holistically investigating different approaches to achieve the required GHG reductions. One
approach now being actively pursued is the implementation of co-digestion at Annacis Island.
Having developed a the scope for a full co-digestion program at the plant, a pilot facility was
constructed to provide further process controls as well as a start at reducing emissions by codigesting
material at the plant. This project also provided Metro Vancouver a basis of handling
its own sludges from other wastewater treatment plants on an emergency or planned basis by
dual tasking the receiving facility to receive both sludges and co-digestion substrates.
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Posted: May 20th, 2011 | Filed under: 500K-1M, Waste Water Treatment | Tags: Cost Savings, Energy Production, Environmental Impact, Improved Plant Performance, Improved Plant Sustainability, Reduced Carbon Footprint, Reduced Greenhouse Gas Emissions | No Comments »
Milwaukee Metropolitan Sewerage District (MMSD)
Milwaukee, Wisconsin
Significant opportunities exist to increase renewable energy production using existing municipal
anaerobic digesters. Many wastes can be added to co-digest more carbon and produce more
methane. The objectives of this study were to identify and compare potential co-digestates,
determine synergistic, antagonistic and neutral co-digestion outcomes, quantify performance of
co-digestion for selected wastes and estimate economic benefits. Over 80 wastes were identified
from 54 facilities within 160 km of an existing municipal digester. The most promising wastes
(26 wastes) were characterized by biochemical methane potential (BMP) and other testing. A
simple economic comparison identified the greatest benefits for seven co-digestates.
Performance was investigated using bench-scale digesters receiving synthetic primary sludge
with and without co-digestates. Methane production rates in co-digesters were as much as 180%
greater than anticipated from the additional chemical oxygen demand (COD). Therefore,
significant synergism was observed. The VS destruction efficiencies were 49 and 33% higher
when co-digestates were present. Co-digestion is one method to increase renewable energy
production via anaerobic digestion.
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Posted: May 20th, 2011 | Filed under: >1M, Sanitary Sewer, Stormwater, Waste Water Treatment | Tags: Cost Savings, Environmental Impact, Improved Plant Performance, Improved Plant Sustainability, Increased Biogas Production, Reduced Carbon Footprint, Reduced Greenhouse Gas Emissions | No Comments »
Gwinnett County Department of Water Resources
Lawrenceville, Georgia
The F. Wayne Hill Water Resources Center (FWHWRC), owned and operated by the Gwinnett
County, GA, Department of Water Resources (DWR), is an advanced wastewater treatment plant
which currently discharges into the Chattahoochee River and Lake Lanier. The FWHWRC
maximum month design flow is 60 million gallons per day (mgd) and currently about 30 mgd of
wastewater is received.
In light of rising energy costs and declining revenues reflective of the continuing, severe
economic downturn that began in 2007, the Gwinnett County DWR began an initiative to make
the best possible use of resources under DWR control, including renewable energy resources.
DWR retained CH2M HILL to identify and evaluate opportunities to improve resource
utilization and reduce energy costs at the FWHWRC. The results of the evaluations, procedures
for capturing stimulus funding, and technologies employed are discussed in this paper.
The energy types considered for the FWHWRC were biogas derived from anaerobic digestion,
solar, wind, and low-head hydropower. A screening analysis concluded that biogas combustion
to produce power and heat was the optimum alternative.
Next, a Business Case Evaluation (BCE) was conducted to determine if the construction and
operation of a gas-to-energy facility would be economically feasible. The BCE considered
several different scenarios for generating power from biogas, including biogas production with
and without addition of fats, oil & grease (FOG) and high strength waste (HSW) to the existing,
anaerobic sludge digesters.
The BCE concluded that a gas to energy facility based on an internal combustion engine (ICE)
was feasible. The proposed system, in addition to continuously generating electrical energy for
use at the FWHWRC, would be capable of producing sufficient heat to keep the anaerobic
digesters operating in the mesophilic temperature range of 95-100 degrees Fahrenheit (F). By
capturing the heat produced by the ICE, in addition to generating power, the system would have
a total energy-recovery efficiency approaching 80%.
The BCE recommended a gas to energy facility of approximately 2 megawatts (MW) in capacity
at the FWHWRC. The biogas requirement at a nominal 600 British Thermal Units (BTU) per
cubic foot (ft3) for an ICE of this capacity is approximately 520 standard cubic feet per minute
(scfm). However, as the FWHWRC is at only about 50% of its total design capacity, the
currently available biogas is considerably less than 520 scfm, and a purchased natural gas fuel
blend would be required to obtain full power generation and heat recovery benefits. To minimize purchase of natural gas, maximize biogas, and as a result improve the return on
investment in the cogeneration system, DWR next investigated addition of FOG and high
strength waste (HSW) to the anaerobic digesters to supplement the solids feed. The project was
made even more attractive by DWR’s successful pursuit of funding under the American
Recovery and Reinvestment Act (ARRA), as administered by the Georgia Environmental
Facility Administration (GEFA), and from the U.S. Department of Energy (DOE).
A schematic design of the system with specifications was prepared for competitive selection of a
design-build contractor. The design-build contract was awarded in October 2009. The contract
value is $5.19 million and includes the installation of a 2.1 MW engine generator along with
digester gas cleaning and drying equipment. The gas-to-energy facility is expected to reach
substantial completion by the end of 2010 with contractual completion in May 2011.
A second RFP for the design and construction of a FOG and HSW receiving facility was
advertised in February 2010. The design-build contract was awarded in June 2010 at a contract
value of $3.16 million. Its completion and startup will closely follow the completion and startup
of gas cogeneration facilities.
Once operational, the FOG/HSW handling and cogeneration facilities will have the potential to
save over one million dollars annually in power costs and generate more revenue in FOG and
HSW disposal fees. When operating at its rated capacity, the resulting power production will
offset the amount of fossil fuel used to generate over 17,000 MW-hours of electrical power
annually.
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Posted: May 20th, 2011 | Filed under: 500K-1M, Stormwater, Waste Water Treatment, Water Treatment | Tags: Cost Savings, Energy Savings, Environmental Impact, Heat Production, Improved Energy Production, Improved Plant Sustainability, Reduced Carbon Footprint, Reduced Greenhouse Gas Emissions | No Comments »
This paper outlines how energy management planning can accomplish dual goals of
energy self-sufficiency and optimum treatment processing, and how this provides robust
performance and acceptable payback on investment, leading to net zero energy
wastewater operations. The energy content of wastewater surpasses the energy required
by treatment, reportedly be a factor of up to 10 times. Nevertheless, conventional
activated sludge plants with advanced treatment consume typically 1,800 kWh/MG of
electricity, but facilities vary from 1,000 to 3,000 kWh/MG. Energy efficiency studies
conclude that the potential for energy use reductions through efficient pumps and aerators
are on the order of 30 to 50 percent, which is a range of about 400 to 700 kWh/MG. For
plants with anaerobic digestion, a rule-of-thumb for electrical production from biogasfueled
generators is 500 kWh/MG. Supplementation of anaerobic digesters with high
strength organic waste and fats, oils and grease is possible where utilities have excess
digester capacity. The experience with supplementation is that facilities have increased
biogas by a factor of two or three times pre-existing conditions, and are able to have a
corresponding increases in electricity production, where generators have been adequately
sized. When thermal heat can be returned for plant processes, overall plant efficiencies
rise even higher. Energy planning studies have also shown that innovative technologies
that build upon anaerobic processes reduce energy usage from typical values, and,
further, energy plans have demonstrated some unexpected results, such as the economic
and environmental justification of anaerobic digestion combined with thermal processing,
such as dryers and incinerators. While local conditions, particularly energy pricing and
government subsidies, likely shape the specific planning objectives and outcomes of any
individual plant, the variety of energy efficiency and production technologies that are
becoming proven can result in a similar endpoint, and specifically net zero energy
wastewater treatment.
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Posted: May 20th, 2011 | Filed under: Stormwater, Waste Water Treatment, Water Treatment | Tags: Cost Savings, Energy Efficiency, Energy Savings, Environmental Impact, Plant Sustainability, Reduced Carbon Footprint, Reduced Greenhouse Gas Emissions | No Comments »
The development of the Carbon Heat Energy Analysis Plant Evaluation Tool (CHEApet) by
the Water Environment Research Federation (WERF) was in response to the identified need
for a predictive modeling tool that unifies prior WERF research information regarding
quantifying and managing energy consumption. CHEApet was created under OWSO4R07C
of WERF’s Optimization Challenge to model performance and energy consumption of waste
water treatment plants (WWTPs). Energy consumption, along with treatment process
emissions, contributes to a facility’s carbon footprint. CHEApet can be used to create a
baseline scenario, or inventory, of a utility’s carbon footprint for informational purposes as
well as to compare with hypothetical treatment plants. This kind of comparison allows the
user to identify facilities in the utility for energy optimization and the potential for biogas
recovery which can save in costs and improve the footprint of the facility.
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Posted: May 20th, 2011 | Filed under: Stormwater, Waste Water Treatment, Water Treatment | Tags: Biological Phosphorus Removal, Chemical Phosphorus Removal, Cost Savings, Energy Optimization, Energy Savings, Environmental Impact, Heat Drying, High Efficiency Air Diffusers, Improved Biogas Production, Phosphorus recovery, Plant Sustainability, Process Modeling, Reduced Carbon Footprint, Reduced Greenhouse Gas Emissions | No Comments »
Strass Wastewater Treatment Plant
Innsbruck, Austria (Europe)
With increasing operating costs and concerns regarding climate change, most wastewater
treatment facilities are under pressure to reduce the net energy used to treat a gallon of
wastewater. The ultimate goal would be to reduce the net energy use to the point that the
wastewater plant actually “breaks even” on energy use, by a combination of more efficient
operations and production of energy via digestion and power generation. This paper presents a
“roadmap” showing how a wastewater treatment plant can pursue the goal of energy self-sufficiency
via a combination of alternative philosophical approaches and innovations .
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Posted: May 20th, 2011 | Filed under: 100K-500K, 50k-100k, Stormwater, Waste Water Treatment | Tags: Cost Savings, Energy Optimization, Energy Savings, Environmental Impact, Improved Plant Reliability, Plant Sustainability, Reduced Carbon Footprint, Reduced Greenhouse Gas Emissions | No Comments »
Various WWTP's
Various States
Public agencies are increasingly pressured to become more sustainable. Wastewater plants are
significant consumers of energy and correspondingly produce significant quantities of
greenhouse gas (GHG). Reductions in energy and GHG are challenges for wastewater facilities
as flows and loads increase and discharge requirements become more restrictive. The results
highlight some methods to reduce energy and GHG, including the concept of becoming energy
neutral. Energy (as represented by electrical energy or fuels) equate directly to GHG production.
A significant portion of the fuel source for most utilities in the United States is from
anthropogenic sources such as coal, oil, or electric. To achieve energy neutral facilities, the
wastewater plant must implement energy conservation and shift to biogenically derived energy
sources, such as biogas, or alternative energy sources, such as wind. This paper and presentation
describe how wastewater treatment plants can significantly reduce energy to the point of
becoming energy neutral.
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Posted: May 20th, 2011 | Filed under: Stormwater, Waste Water Treatment, Water Treatment | Tags: Best Practices, Cost Savings, Energy Efficiency, Energy Savings, Environmental Impact, Improved Biogas Production, Plant Sustainability, Reduced Carbon Footprint, Reduced Greenhouse Gas Emissions | No Comments »
Various WWTP's
Various States
Energy consumption for municipal wastewater treatment accounts for 15% to 30% of the
operating cost at large treatment facilities and 30% to 40% at small facilities (WEF, 2009).
Energy costs are expected to continue escalating as a result of the rising price of fossil fuels used
for energy production while the energy demand for wastewater treatment is expected to grow as
the use of energy intensive treatment processes increases to meet water quality objectives that
may demand increasingly stringent wastewater discharge limits.
The United States Environmental Protection Agency (EPA) is committed to promoting energy
efficiency and implementation/use of energy conservation measures at municipal wastewater
treatment facilities. EPA, in partnership with The Cadmus Group and HDR, has undertaken a
project to identify and evaluate innovative energy conservation methods implemented at
wastewater utilities in the U.S. and report on their effectiveness in achieving reductions in energy
use and cost associated with wastewater treatment.
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Posted: May 20th, 2011 | Filed under: Stormwater, Waste Water Treatment, Water Treatment | Tags: Cost Saving, Energy Efficiency, Energy Savings, Environmental Impact, Operational Modification, Plant Sustainability, Process Control Enhancements, Reduced Carbon Footprint, Reduced Greenhouse Gas Emissions | No Comments »
Hill Canyon Wastewater Treatment Plant (HCTP)
Thousand Oaks, California
The City of Thousand Oaks’ Hill Canyon Wastewater Treatment Plant (HCTP) is seen by its
City Council and the citizens it serves as a unique community asset. The abstract title, $25.45, is
the City’s monthly sewer service charge for a single family residence, which reflects the City’s
pride in its environmental efforts and in this instance celebrating the creation of an
environmental and financially sustainable community asset at HCTP.
While the authors recognize that monthly sewer service charges can be affected by system age,
topography, varying regulatory requirements, and political priorities, they advocate a monthly
sewer service fee that meets outstanding debt requirements, allows for a proper Operations and
Maintenance budget, and saves money for the future.
The authors’ focus is on HCTP and how energy conservation, facility optimization, and
renewable energy generation has dramatically improved plant operations while keeping the
monthly sewer service charge stable for the foreseeable future.
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Posted: May 20th, 2011 | Filed under: 100K-500K, Stormwater, Waste Water Treatment | Tags: Environmental Impact, Improved Customer Relations, Improved Plant Operations, Plant Sustainability, Reduced Carbon Footprint, Reduced Greenhouse Gas Emissions, Renewable Energy Generation | No Comments »
Owls Head Water Pollution Control Plant
Brooklyn, New York
The Owls Head Water Pollution Control Plant (WPCP) is a 120 million gallon per day (MGD)
secondary level treatment facility serving Brooklyn, New York. As part of a city-wide
environmental sustainability program, extensive renovations are being made to minimize fugitive
greenhouse gas emissions, maximize the utilization of biogenic gas produced during the
anaerobic digestion of wastewater sludge, and conserve energy that is consumed during the
wastewater treatment process. Two projects are in progress. One project will provide supply
side improvements to collect digester gas (digas) and produce usable electrical energy and heat
while the second project provides demand side improvements by reducing the energy
requirement associated with process aeration of the activated sludge process.
These projects are being carried out by the New York City Department of Environmental
Protection (DEP) in cooperation with the New York Power Authority (NYPA). When completed,
the projects will have the net result of a 76% reduction in greenhouse gas (GHG) emissions, a
75% reduction in utility-provided electrical consumption, and operating cost savings of over $1
million per year.
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Posted: May 20th, 2011 | Filed under: 500K-1M, Stormwater, Waste Water Treatment | Tags: Cost Savings, Energy Savings, Environmental Impact, Improved Biogas Production, Plant Sustainability, Reduced Carbon Footprint, Reduced Greenhouse Gas Emissions | No Comments »