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 »
Washington State Parks and Recreation Commission
Olympia, Washington
As part of an ongoing initiative to decrease pollution in Puget Sound, Washington State Parks and
Recreation Commission (WSPRC) identified for replacement lower performing wastewater
treatment systems at five parks. In the interest of producing high quality effluent, particularly with
respect to nitrogen, while minimizing footprint on historic property and maximizing remote
operations potential, WSPRC decided on membrane bioreactor (MBR) technology to replace
existing systems. WSPRC selected a consulting firm to draft a procurement document which
standardized MBR systems across all parks which resulted in an Invitation for Bids (IFB) to select
a single MBR supplier. Flow and load capacity requirements for each park were not developed,
rather, only two MBR system sizes were defined, and representative influent criteria were applied.
This paper provides a brief overview of the procurement process, identifies successes and
challenges associated with this process, and assesses the performance of one MBR at Ft. Flagler
State Park.
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Posted: May 20th, 2011 | Filed under: Uncategorized | Tags: Environmental Impact, Improved Effluent, Increased Nitrogen Removal, Plant Sustainability, Reduced Carbon Footprint, Reduced Greenhouse Gas Emissions | No Comments »
City of North Port Wastewater Treatment Facility
North Port, Florida
Recent societal pressures to reduce the costs associated with energy consumption and the related
greenhouse gas emissions have created a driver that is an inconsistent with the traditional goals
of water quality and environmental protection. The conflict between these goals is particularly
compelling for wastewater treatment facilities (WWTFs), as more stringent effluent requirements
are being promulgated. By and large, it can be said that the greater the required level of treatment
– the greater the energy demand. In addition, both influent concentrations and the type of
biological treatment processes used to meet the regulatory requirements play a considerable role
of the factors that must be considered. In most cases, many facilities over aerate, with no regard
to how much air is required for the process in order to obtain adequate margin of safety against
permit exceedances. The result is that the actual discharge concentrations of these constituents
are well below the permitted discharge concentration, while a significant amount of energy is
wasted in accomplishing this.
Another concern facing utilities are diminishing freshwater supplies, impacts from climate
change, population growth, and more stringent effluent disposal and water quality limitations, all
of which have all placed greater demands on the development of reclaimed water facilities to
supplement the use of this resource in lieu of potable water. Not only can the use of reclaimed
water help conserve potable water by replacing potable water for certain non-potable water uses,
it can also help recharge groundwater supplies. As a result, utilities are finding synergistic
solutions to water supply, wastewater treatment and water resources management issues.
Therefore, the adequacy and protection of our water supplies will be one of the more challenging
issues that utilities will face in the 21st century.
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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, Improved Effluent, Plant Sustainability, Reclaimed Water, Reduced Carbon Footprint, Reduced Greenhouse Gas Emissions | No Comments »
Howard F. Curren Advanced Wastewater Treatment Facility
Tampa Bay, Florida
Although different types of algae have been demonstrated to grow in suboptimal
substrates such as sewage, digested dairy manure and piggery waste (de Bashan et al.,
2008;Wilkie and Mulbry, 2002; Travieso et al., 2006), the potential of biofuel-producing algae to
grow from wastewater has recently gained a lot of interest since it has been highlighted as one of
the most sustainable sources of clean energy (Farm to fuel summit, 2009). Readily available
nutrients, water and carbon make a wastewater treatment plant (WWTP) an ideal location for
cultivation of biofuel producing algae. However, information about the feasibility of
implementing an algal photoreactor in an advance wastewater treatment scenario is limited,
specifically in reference to nutrient recovery, savings on chemical demand and energy
consumption.
In the preliminary stage of this investigation, the green algal species Botryococcus braunii and
Chlorella sorokiniana were used in the lab as prototypes to pursue both nutrient utilization and
biofuel generation in a WWTP in Tampa Bay (Florida, US). Both species successfully
acclimated to NO3 and NH3 rich effluents from different treatment stages of the plant. Results
from microalgae theoretical nutrient and carbon utilization (removal efficiencies) were assessed
to evaluate the carbon footprint and chemical demand reduction, as well as energy savings of the
wastewater treatment process.
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Posted: May 20th, 2011 | Filed under: Waste Water Treatment | Tags: Biofuel Generation, Cost Savings, Energy Savings, Environmental Impact, Plant Sustainability, Reduced Carbon Footprint, Reduced Chemical Demand, Reduced Greenhouse Gas Emissions | No Comments »
In January 2010, the American Society of Civil Engineers conducted a series of
workshops to address problems with infrastructure deficiencies in the United States. The
outcomes associated with these workshops were discussed in Civil Engineering Magazine
(April 2010). Based upon these outcomes, a consensus was reached that the water and
wastewater infrastructure in the United States is in a state of crisis and that the following
recommendations may provide a roadmap to ease that crisis and a vision for
improvement:
• Increase Federal Leadership in Infrastructure;
• Promote Sustainability and Resilience;
• Develop Federal, Regional and State Infrastructure Plans;
• Address Life-Cycle Costs and Ongoing Maintenance; and
• Increase and Improve Investment from all Stakeholders.
The above information and the predicted infrastructure rehabilitation and replacement
needs expected in the next decade prompted the USEPA to commit to promoting
sustainable infrastructure practices. If successfully implemented, these practices would
help reduce the predicted gap between infrastructure needs and infrastructure spending
(USEPA, 2006). Disinfection is one of the key unit processes for the protection of public
health. In order to fully implement the four pillars of the USEPA sustainable
infrastructure model, approaches must be taken to incorporate sustainability into
engineering design and operation of disinfection unit processes for water and wastewater
infrastructure systems.
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Posted: May 20th, 2011 | Filed under: Stormwater, Waste Water Treatment, Water Treatment | Tags: Environmental Impact, Green Infrastructure, Improved Disinfection, Improved Infrastructure, Increased Federal Leadership, Plant Improvement, Plant Sustainability, Reduced Carbon Footprint, Reduced Greenhouse Gas Emissions | No Comments »
City of Sunnyvale Water Pollution Control Plant
Sunnyvale, California
At wastewater treatment pond facilities where removal of algae suspended solids is
required, the harvested biomass is often returned to the ponds for disposal. This biomass
is potentially valuable as a biofuel feedstock, and in the context of wastewater treatment
plants, biogas is currently the most practical biofuel to produce. While future algal high
rate pond treatment facilities, which maximize algae production for nutrient removal,
would integrate algae digesters, existing pond facilities may benefit in the immediate
future from algae digestion or co-digestion to increase production of renewable energy.
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Posted: May 20th, 2011 | Filed under: 100K-500K, Stormwater, Waste Water Treatment, Water Treatment | Tags: Algae Digestion, Cost Savings, Energy Savings, Environmental Impact, Green Infrastructure, Increased Renewable Energy Recovery, Reduced Carbon Footprint, Reduced Greenhouse Gas Emissions | No Comments »
Woodward Avenue WWTP
Hamilton, Ontario (Canada)
The City of Hamilton, Ontario is faced with increasing pressure from growth and
development, greater wet weather treatment needs, and stringent effluent targets. In
order to address these challenges, the City of Hamilton initiated an ambitious program
to identify alternative upgrade options for the Woodward Avenue WWTP. Two
alternative treatment strategies were short-listed for further study. The first option,
termed Parallel MBR / MF, included a more conventional style membrane facility with
a MBR facility treating approximately half of the primary effluent in parallel with a
membrane filtration facility filtering nitrified secondary effluent from the existing
secondary treatment plant. The second option, termed Tertiary Nitrifying MBR or TMBR,
involves installing a membrane bioreactor using feed consisting of non-nitrified
secondary effluent from existing high rate secondary treatment plants. A detailed triple
bottom line (Economic, Social, and Environmental) evaluation was carried out on the
two alternatives. The evaluation revealed that the two options are very similar in most
respects, with the exception of energy efficiency. More specifically, the T-MBR option
was found to require significantly lower energy, primarily due to reduced oxygen
demand and more efficient oxygen transfer characteristics within the MBR processes.
Annual savings with T-MBR are expected to be $500K. In addition, the additional
biogas production with T-MBR is expected to result in additional revenues approaching
$600K annually. These factors drove the selection of the T-MBR strategy as the
preferred alternative for the expansion of the Woodward Ave. WWTP.
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Posted: May 20th, 2011 | Filed under: 100K-500K, Stormwater, Waste Water Treatment, Water Treatment | Tags: Cost Savings, Energy Savings, Increased Biogas Production, Increased Energy Efficiency, Plant Enhancements, Plant Sustainability, Reduced Carbon Footprint, Reduced Greenhouse Gas Emissions | No Comments »
Green Bay Metropolitan Sewerage District (GBMSD)
Green Bay, Wisconsin
The Green Bay Metropolitan Sewerage District (GBMSD) used the principles presented in
Effective Utility Management, a Primer for Water and Wastewater Utilities in development of its
Strategic Plan and Solids Management Plan. The self-assessment and attributes of a Highly
Effective Utility were crucial to the successful development and implementation of these plans.
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Posted: May 20th, 2011 | Filed under: 100K-500K, Sanitary Sewer, Stormwater, Waste Water Treatment, Water Treatment | Tags: Effective Utility Management, Environmental Impact, Improved Strategic Planning, Optimized Self-Assessment, Plant Sustainability, Reduced Carbon Footprint, Reduced Greenhouse Gas Emissions, Solids Management Planning | No Comments »