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 »
City of Newton WWTP
Newton, Mississippi
The case study described in this paper demonstrates that the nitrifying trickling filter (NTF) is a
reliable and robust bioreactor. The studied NTF was designed to oxidize ammonia-nitrogen
(NH3-N) remaining in the effluent stream of an aerated lagoon that is located in Newton,
Mississippi, USA. NTF performance data was collected during a period beginning in June 2007
and ending in January 2010. An analysis of the data demonstrated that the NTF consistently met,
amongst other permitted criteria, a moderately stringent permit limit requiring an annual average
NH3-N concentration less than 2.0-mg/L remaining in the effluent stream. Comparison of
operating costs revealed that the NTF evaluated in this study required approximately one-third of
the power required to meet the same treatment objective with a moving bed biofilm reactor
(MBBR). However, the NTF required a slightly more foot print than the MBBR (e.g. 90 vs. 80
m2) to meet the treatment objective. The studied NTF was designed using generally accepted
criteria defined throughout this paper. The NTF used medium-density modular plastic trickling
filter media comprised of corrugated plastic sheets. The required biofilm surface area, and
therefore bioreactor volume, was defined based on a 0.65-g NH3-N/m2/d zero-order nitrification
rate and a 0.1-kg/m3/d five-day biochemical oxygen demand (BOD5) load at 12oC. The method
for calculating NTF ventilation is demonstrated. Implementation of the NTF design and
construction included some unique features: (1) the NTF influent pumps were located to provide
NTF effluent recirculation (which provides proper media wetting, controls biofilm thickness and
minimizes macro fauna accumulation), (2) use of influent pump(s) speed control to optimize the
NTF superficial hydraulic application rate (or Spülkraft), (3) the ventilating area was
conservatively designed to maximize airflow, and therefore process oxygen, for the nitrification
process (i.e., 0.1-m2 (1.0-ft2) open area per 2.4-m (8.0-ft) of NTF periphery), and (4) the
application of a column and pier support system to facilitate simple installation and increased air
flow.
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Posted: May 20th, 2011 | Filed under: Stormwater, Waste Water Treatment | Tags: Cost Savings, Effective Tertiary Process, Energy Savings, Environmental Impact, Improved Plant Reliability, Nitrifying Trickling Filter, Plant Sustainability | 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 »
Gloversville-Johnson Joint Wastewater Treatment Facility (GJJWWTF)
Johnstown, New York
The lack of effective large-scale designs and inexpensive electrode materials has limited
the real-world applications of MFCs. This paper aimed at addressing these problems by
developing a multi-anode/cathode MFC and MnO2 (OMS-2) cathodes. The results
demonstrated that the multi-anode/cathode MFC substantially increased the total power
production of MFC since the average power density per anode/cathode channel did not
significantly change when the MFC was operating with 12 and 4 channels (575 mW/m2
vs. 635 mW/m2) at an organic loading rate of 0.5 kg/m3/day. Meanwhile the power
density increased from 300 to 380 mW/m2 as the organic loading rate increased from
0.19 to 0.66 kg/m3/day. MFCs achieved 80% of COD removal at HRT of 20 hours while
the COD removal at HRT of 5 hours was 66% and fluctuated greatly with the shock in
influent COD. MnO2 cathodes produced power density as high as Pt cathodes. A decrease
in the power density (from 400 mW/m2 to 150 mW/m2) and an increase in Rin of MFCs
(175 Ω to 225Ω) was observed due to the cathode fouling. Analysis revealed that the
interior fouling was mainly caused by calcium precipitation (89%) and the exterior
fouling was mainly caused by diffusion of sodium (83%) through the cathodes.
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Posted: May 20th, 2011 | Filed under: 50k-100k, Waste Water Treatment | Tags: Cost Savings, Efficient Contaminant Removal, Energy Savings, Environmental Impact, Plant Sustainability | 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 »
Donald C. Tillman (DCT) and Los Angeles-Glendale (LAG) Water Reclamation Plants
Los Angeles, California
The principal source of nitrogen compounds in the Los Angeles River is from the City of Los
Angeles upstream plants, Donald C. Tillman (DCT) and the Los Angeles-Glendale (LAG) Water
Reclamation Plants (WRP’s). These WRP’s were major contributors, with up to 75% of the total
dry weather nitrogen load during dry weather periods. In 2007, the City has completed a nitrogen
removal program to reduce the nitrogen mass discharge from its WRP’s. As part of the process, a
comprehensive research effort was undertaken involving bench, pilot and full scale testing to
identify the most effective way to upgrade and optimize the existing WRP’s. The combined
findings were then used to upgrade WRP’s to “full” BNR plants without derating, carbon and
alkalinity addition utilizing the MLE (Modified Ludzack Ettinger) process. This paper will focus
on the MLE process design and treatment practices successfully implemented at the City’s
WRP’s.
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Posted: May 20th, 2011 | Filed under: 100K-500K, 500K-1M, Stormwater, Waste Water Treatment, Water Treatment | Tags: Environmental Impact, Improved Nitrogen Removal, Improved Nutrient Removal, Plant Optimization, Plant Sustainability | No Comments »
Bureau of Sanitation, City of Los Angeles
Los Angeles, California
The goal of this research study is to enhance the efficiency and economy of carbon scrubbers in
controlling odors and VOCs at the wastewater collection and treatment facilities of Bureau of
Sanitation, City of Los Angeles. The objectives are: 1) to use carbon life expectancy and
breakthrough methods for monitoring carbon towers; 2) to reduce harmful impacts of pollutants
on public health and the environment; 3) and to recommend efficient active carbon application.
The butane activity and hydrogen sulfide breakthrough capacity of activated carbon were
assessed. Air streams were measured for odorous gases and VOCs. Single-stage wet scrubbers at
some wastewater treatment processes, while removing moderate levels of reduced sulfur
compounds, showed low to negative removal of VOCs when compared to carbon towers alone or
in series. Regular monitoring of activated carbon has resulted in useful information on carbon
change-out frequency and packing recommendations to enhance odor- and VOC-removal
capacity.
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Posted: May 20th, 2011 | Filed under: >1M, Stormwater, Waste Water Treatment, Water Treatment | Tags: Cost Effective Odor Monitoring, Cost Effective VOC Monitoring, Cost Savings, Efficient Active Carbon Application, Environmental Impact, Increased Public Health, Odor Control, VOC Reduction | No Comments »