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 »
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 »
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 »
Fayetteville Public Works Commission
Fayetteville, North Carolina
Fayetteville Public Works Commission (PWC) is implementing a number of renewable energy
projects. These projects include digester gas cogeneration at their Cross Creek Wastewater
Treatment Plant, solar panels to be installed as part of an innovative, sustainable design for a new
elementary school, and smart grid technology for their power distribution. These technologies
will allow PWC to reduce their power demands, reduce their carbon consumption and emissions,
and take advantage of renewable energy sources to meet the requirement for renewable energy
portfolio standards required by North Carolina Statutes. This paper will provide a description of
the smart grid and solar panel projects, and a more detailed discussion of the digester gas
cogeneration project. Cogeneration technologies that were evaluated include engine generators,
microturbines, and fuel cells. A comparison of technologies, capacities, implementation plans,
alternatives analyses, and cost evaluations will be discussed.
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Posted: May 20th, 2011 | Filed under: 50k-100k, Stormwater, Waste Water Treatment, Water Treatment | Tags: Cost Savings, Energy Savings, Environmental Impact, Green Infra, Improved Biogas Production, Plant Sustainability, Reduced Carbon Footprint, Reduced Greenhouse Gas Emissions, Solar Energy Utilization | No Comments »
Victoria, BC WWTP
Victoria, British Columbia (Canada)
A part of the planning effort for two green field secondary treatment plants that will service the
Core District of Victoria, British Columbia, a modified triple bottom line analysis was conducted
to identify technologies that meet the Province’s goals of cost effective, environmentally
sustainable socially responsible wastewater treatment. One element of this analysis was to
evaluate the impact of a combination of solids stabilization and end use alternatives on the net
greenhouse gas (GHG) emissions of the future utility. If managed appropriately, biosolids
production and utilization is a way to offset emissions from wastewater treatment operations and
accrue carbon credits. Long-term benefits to Capital Regional District (CRD) include compliance
with municipal carbon neutrality goals as well as potential revenue from the development of
carbon trading markets.
Analysis revealed significant carbon credits could be achieved with sludge stabilization by
anaerobic digestion and biosolids utilization in mine reclamation. The greatest reduction in GHG
emissions was achieved when the biogas from digestion was cleaned to natural gas line quality
for introduction to the commercial grid. Co-generation proved to be less beneficial due to the low
GHG intensity of the commercial power source available in the region. Additional carbon credits
are obtained from mine reclamation due to improvement of soil productivity and carbon
sequestration potential. However, it was also found that all of the end uses which capitalized on
either the fertilizer value or energy content of biosolids can provide significant benefits to a
wastewater utility.
Results of this analysis enabled the CRD to make an informed decision about how to produce
and use biosolids to maximize benefits from a sustainability perspective. However, it should be
noted that the findings of this study are contrary to other studies in the published literature. This
is attributed to the low GHG intensity associated with the power utility in the region (0.000022
tonne-CO2e/kWh). This observation suggests that utilities and engineering practitioners should
be conducting site specific inventory analysis and use great care when evaluating literature
reported results to make process decisions.
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Posted: May 20th, 2011 | Filed under: 100K-500K, 500K-1M, Waste Water Treatment | Tags: Cost Savings, Energy Savings, Environmental Impact, Green Infrastructure, Plant Sustainability, Reduced Carbon Footprint, Reduced Greenhouse Gas Emissions | No Comments »
Sugar Creek WWTP
Charlotte, North Carolina
When complete, the Sugar Creek WWTP Expansion Project increases the capacity of a 90-year old facility
from 20 mgd to 34 mgd in two sequential phases. Considering the uncertainty associated with rising
energy costs, regulatory requirements for greenhouse gas (GHG) emissions, and the desire to be a leader in
environmental stewardship, Charlotte-Mecklenburg Utilities (CMU) integrated carbon footprint analysis
into the Project. This analysis determined the base case carbon footprint – a 20 mgd facility, and measured
that against each of the incremental expansions – first to 28 mgd and subsequently to 34 mgd.
Completing the carbon footprint analysis for the Expansion Project:
- Provides a baseline for GHG for potential regulatory requirements.
- Drives energy optimization and energy efficiency into the design process.
- Considers GHGs in the alternatives evaluation.
- Quantifies a success story for CMU for this Expansion Project.
This analysis looked at the relative GHG emissions of process configuration alternatives considered and
discusses ideas for reducing the overall carbon footprint impact of the Sugar Creek WWTP expansion. In
addition, this paper quantifies the GHG emissions related to wastewater process components in general.
As a result of the Sugar Creek WWTP Expansion Project’s energy efficiency initiatives, CMU avoids an
estimated 1,595 metric tons of carbon dioxide equivalent emissions by 2014. Reduced emissions continue
to increase as influent flows increase over time, thus further reducing CMU GHG emissions on a unit flow
equivalent basis. Continued expansion to the Sugar Creek WWTP West Side process facilities can be
expected to reduce GHG emissions by nearly 30% (over alternative locations for treatment) by 2034. As
expected, indirect emissions associated with electricity purchases comprise over 80% of the overall
emissions for the Sugar Creek WWTP. Thus, the most significant impact that CMU can make is to
continue to focus on energy efficient design and operation.
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Posted: May 20th, 2011 | Filed under: 100K-500K, Stormwater, Waste Water Treatment | Tags: Cost Savings, Energy Savings, Environmental Impact, Green Infrastructure, Plant Sustainability, Reduced Carbon Footprint, Reduced Greenhouse Gas Emissions | No Comments »