Mt. Gilead WWTP
Mt. Gilead, Ohio
The Mt. Gilead WWTP, an activated sludge facility, expanded capacity to include revisions to both primary and secondary treatment processes as well as the biosolids handling for the proposed .82 MGD facility. The Poggemeyer Design Group was asked to evaluate various design alternatives for mixing and aeration of the (2) 62’ and (1) 45’ diameter aerobic digester/sludge holding tanks included in the expansion and upgrade. The Engineer compared complete aeration systems with aeration / hydraulic mixing systems with various combinations of hydraulics and aeration rates. After reaching a decision on his final design, the mixing system manufacturer completed a final design layout after analyzing placement of the diffuser grids in relation to the hydraulic flows required. The final design is now in operation with lower than anticipated operating costs which have resulted in substantial yearly savings along with other significant advantages that will be discussed in this paper. Source: WEFTEC 2008 Proceedings
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Posted: August 27th, 2010 | Filed under: Waste Water Treatment | Tags: Energy Savings, Increased Digester Loading Capability, Operation Savings, Reduced Greenhouse Gas Emissions | No Comments »
Tennessee Valley Authority
Knoxville, Tennessee
National estimates indicate that approximately 80-90% of the electricity utilized at water and wastewater facilities is attributable to pumps and blower motors. The Tennessee Valley Authority and our power distributors are helping our water and wastewater customers and other industrial users save energy by assessing their pumping systems using the US Department of Energy (DOE) Pumping System Assessment Tool (PSAT) which was developed by Don Casada. TVA has partnered with DOE to provide in-depth training in utilizing PSAT at several locations throughout the TVA service region. TVA is also conducting assessments at customer facilities at their request. PSAT identifies energy savings opportunities in pumping systems and quantifies those opportunities in both dollars and electrical energy savings. Although PSAT does not tell how to improve systems, it does prioritize improvement opportunities. When the opportunities are implemented, the results are often decreased maintenance and repair costs and increased production and energy savings. Source: WEFTEC 2008 Proceedings
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Posted: August 27th, 2010 | Filed under: Waste Water Treatment, Water Treatment | Tags: Cost Savings, Energy Savings, Increased Plant Efficiency, Pump Optimization, Reduced Greenhouse Gas Emissions | No Comments »
Fairhaven WWTP
Fairhaven, Massachussets
Many wastewater treatment facilities (WWTFs) in New England reside in one of the costliest electrical energy regions in the country and face a multitude of challenges including high energy costs and limited options for the beneficial reuse and disposal of biosolids. When designed and implemented correctly, an anaerobic digestion process integrated with a combined heat and power (CHP) system can be one of the most effective methods to help large and medium-sized WWTFs overcome these challenges. However, traditional methods of anaerobic digestion are typically not cost-effective for WWTFs with capacities less than approximately 10 MGD. The findings from a feasibility study performed by Brown and Caldwell show that anaerobic digestion with CHP can be developed cost-effectively using co-digestion and lower cost tank construction materials to provide the benefits of renewable energy production and sludge volume reduction for small to medium sized WWTFs. In addition to reductions in annual operating costs, anaerobic digestion and CHP projects can qualify for many new state and federal funding opportunities and incentives for renewable energy production and greenhouse gas reduction. Although recently developed, these programs have been continuously funded and continue to grow. Currently, Brown and Caldwell is applying for new federal funding opportunities as part of the American Reinvestment and Recovery Act, 2009. These include the US Department of Energy grant program for CHP systems under the Clean Energy and Industrial Efficiency Program, the Energy Efficiency Construction Block Grant Program, and the MA DEP Clean Energy State Revolving Fund. Source: WEFTEC 2009 Proceedings
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Posted: August 27th, 2010 | Filed under: Waste Water Treatment | Tags: Cost Savings, Energy Savings, Environmental Impact, Funding Incentives, Reduced Greenhouse Gas Emissions | No Comments »
CFPUA James A. Loughlin, Jr. WWTP
Wilmington, North Carolina
Anaerobic digestion is commonly utilized for wastewater residuals stabilization and generates a methane rich biogas stream. This technical paper evaluates seasonal and lifecycle cost considerations for beneficial utilization of this digester gas stream in the form of a case study at the CFPUA James A. Loughlin, Jr. WWTP. The beneficial utilization of digester gas for electrical power production has been shown to provide the following benefits for the CFPUA James A. Loughlin, Jr. (aka Northside)Wastewater Treatment Plant:
1. Both process configurations, non-CHP and CHP, generate positive economic value based on the lifecycle cost assessment and have an internal rate of return greater than the Owner’s estimated cost of capital (5.5%).
2. The CHP process configuration has the greatest rate of return on invested capital. The marginal rate of return associated with providing full CHP capability is also greater than the cost of capital. An incremental capital investment of $0.14 million dollars was shown
to generate an incremental benefit of approximately $1.32 million dollars. The resultant incremental benefit-to-cost ratio for this marginal expenditure is approximately 9.43 – meaning that each dollar of invested capital is creating $9.43 of present value.
3. The beneficial utilization of digester gas for electrical power production results in reduced greenhouse gas emissions as a renewable energy power source. Estimated GHG emissions reductions range from approximately 890 tons CO2 equivalents (tCO2e) per year under current conditions for a system configured to operate without combined heat and power capability to approximately 2,670 tCO2e per year under future operating conditions with full combined heat and power capability. In summary, significant economic and environmental benefits should be available for medium sized (10-mgd to 20-mgd) treatment facilities which have anaerobic digestion process equipment that are not currently beneficially utilizing digester gas beyond process heating demands. Source: WEFTEC 2009 Proceedings
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Posted: August 27th, 2010 | Filed under: Waste Water Treatment | Tags: Cost Savings, Energy Savings, Environmental Impact, Funding Incentives, Reduced Greenhouse Gas Emissions | No Comments »
26th Ward WPCP
New York City, New York
Simulation studies were conducted for three scenarios at the 26th Ward WPCP in New York City: no side-stream treatment, side stream treatment with an Advanced Biological Treatment (AT3), and side stream treatment with a physical chemical process, ARP. The models incorporated anaerobic sludge digestion and sludge dewatering to simulate the release of ammonia and organic nitrogen related to sludge destruction and their return to the wastewater treatment process. An extensive literature search was performed to find GHG emission factors for each of the processes. Use of the physical/chemical ARP displayed benefits intrinsic to the use of a non-biological method of nitrogen reduction. The model demonstrates that the two categories of side stream treatment have materially different benefits. Very large emissions of GHG were found for AT3. The physical-chemical processes used by ARP lowered GHG emissions relative to the base case as well as relative to AT3. The ARP alternative will produce about one-quarter (3,500 metric tons CO2eq per year) less direct GHG emissions than the Baseline alternative and 48 percent (9,300 MT/yr) less than the AT3. Source: WEFTEC 2009 Proceedings
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Posted: August 27th, 2010 | Filed under: 100K-500K, Waste Water Treatment | Tags: Environmental Impact, Increased Ammonia Removal, Reduced Greenhouse Gas Emissions, Smaller Carbon Footprint | No Comments »
The algae-to-biofuel industry requires a cost effective means for separating a relatively dilute algae suspension from a large flow of water. Ideally, algae recovery should be economical and result in a thick algae concentrate with minimal extraneous and inert materials that would detract from the value of the resource. To a large extent, the economy of microalgae production depends on the method employed for harvesting and concentrating the algae. This paper discusses some of the possible algae separation techniques with an overview of the advantages and disadvantages of each. Emphasis is placed on the dissolved air flotation process because it still remains the most effective means of separating a relatively low concentration of algae from a large body of water. Some of the important design features of dissolved air flotation that promote effective algae separation and harvesting, as well as thickening of the separated algae, are discussed. The efficiency of recovery is a significant issue because it relates to the economics of the separation technique. However, it is not necessarily of overriding importance since the water from the separation unit can be recycled back to the algae growth units. The efficiency of recovery and operation of the separation technique depends to a large extent on the means by which the algae is conditioned. The paper discusses various inorganic and organic chemicals for algae coagulation, to facilitate algae separation by dissolved air flotation, or by other means. Inorganic coagulants tend to be the most effective, although some natural and synthetic polymers are effective. Chitosan is a natural polymer that does not detract from the animal feed option for the co-product from algae biofuel processing, although it does introduce significant quantities of inert material. Other organic polymers that are GRAS certified should be used preferentially to those products that are not certified. Source: WEFTEC 2009 Proceedings
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Posted: August 27th, 2010 | Filed under: Waste Water Treatment | Tags: Ammonia Removal, Effective Algae Separation Technique, Environmental Impact, Improved Algae Recovery, Improved Thickened Algae Concentrate, Phosphorus Removal, Plant Sustainability, Reduced Greenhouse Gas Emissions | No Comments »
High rate algae ponds fed clarified domestic wastewater and CO2-rich flue gas are expected to remove nutrients to concentrations similar to those achieved in mechanical treatment technologies, such as activated sludge. However, the energy intensity of wastewater treatment with CO2-supplemented high rate ponds (HRPs) would be less than that of mechanical treatments. In conjunction with anaerobic digestion of algal biomass and co-substrates, the algae-based system would produce a substantial excess of electricity. Greenhouse gas abatement from such CO2-HRP/digestion systems would stem mainly from energy conservation and the offset of fossil fuel electricity with biogas-derived electricity. Laboratory experiments showed nutrient removals of >98% for ammonium and >96% for phosphorus with mixed culture microalgae grown on CO2-supplemented primary wastewater effluent. An engineering numerical model for CO2-HRP/digestion facilities (based in part on large-scale algae production under southern California conditions) indicates a potential energy surplus of 330 kWh/ML (1,200 kWh/MG) from biogas-derived electricity, compared to the net energy consumption of about 760 kWh/ML (2,900 kWh/MG) at typical activated sludge facilities with nitrification/denitrification. Considering the net electricity production and energy savings of the CO2-HRP/digestion systems, a greenhouse gas abatement potential of 660 kg CO2eq/ML (2,500 kg CO2eq/MG) treated is expected for a 100-ha facility treating 20 MGD. Source: WEFTEC 2009 Proceedings
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Posted: August 27th, 2010 | Filed under: Waste Water Treatment | Tags: Energy Savings, Environmental Impact, Improved Algae Recovery, Nitrogen Removal, Phosphorus Removal, Plant Sustainability, Reduced Greenhouse Gas Emissions | No Comments »
Joint Effort by California Department of Water Resources and California Energy Commission
Sacramento, California
In 2005, California, led by the California Energy Commission, began a serious look at the waterenergy-greenhouse gas relationship in the state. Saving water saves energy. Saving energy saves water, both where there are cooling towers on buildings and at thermal power plants which use water for cooling. You save more in Southern California than in Northern California because of the energy attached to imported water. Saving water used outdoors is good (pumping, treatment and delivery), saving water used indoors is better (no waste removal, treatment and discharge) and saving hot water is still better (no energy to heat the water too). This paper will build on the work done by the California Energy Commission by presenting information on both sides of the connection: energy for water and water for energy. Source: WEFTEC 2009 Proceedings
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Posted: August 27th, 2010 | Filed under: Electric, Waste Water Treatment, Water Treatment | Tags: Energy Savings, Environmental Impact, Plant Sustainability, Reduced Greenhouse Gas Emissions, Smaller Carbon Footprint, Water Conservation | No Comments »
Metropolitan Water Reclamation District of Greater Chicago
Chicago, Illinois
The District’s mission includes the protection of our water environment, specifically the water
quality of Lake Michigan, the region’s drinking water source, at all times in compliance with our
NPDES permits. All of the energy management measures listed above were implemented
without compromising or diminishing our ability to meet our primary goal. As an environmental
organization, the District has a responsibility to not only to achieve its primary function of
treating wastewater, but also to do so in an environmentally responsible manner.
The measures discussed above ultimately result not only in O&M cost savings but energy use
reduction. The decrease in energy use reduces the emissions of greenhouse gases, which has
taken on a new significance with the current concern regarding global warming and its predicted
dire effects on the planet and its ecosystems. They also demonstrate how vigilant maintenance of
public systems can have benefits above and beyond the immediate results.
The success of any initiative is directly dependent on the knowledge, dedication and efforts of
personnel involved not only in establishing protocol, but also in implementing and performing
the associated tasks on the daily basis. The District’s success, as measured by the cost savings
and energy reduction shown in the tables above, demonstrates the ability of District personnel to
work collaboratively as a team. The District will continue to seek additional measures to be
implemented at all facilities to not only save taxpayer money but also to operate more efficiently
to better improve the overall environment.
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Posted: August 24th, 2010 | Filed under: >1M, Sanitary Sewer, Waste Water Treatment, Water Treatment | Tags: Energy Savings, Environmental Impact, Improved Plant Sustainability, O&M Cost Savings, Reduced Carbon Footprint, Reduced Greenhouse Gas Emissions | No Comments »
Stormwater runoff from urban and suburban areas can damage the environmental health of
receiving streams from increased flow rates during rain events, reduced base flow, and increased
loading of pollutants associated with the runoff. Low-impact or green infrastructure techniques
that are decentralized or dispersed throughout the watershed can mitigate these impacts. The
U.S. Environmental Protection Agency, Office of Research and Development, Sustainable
Environments Branch (EPA) developed a field research project to measure the effects of green
practices on stream hydrology and quality on a watershed scale.
The suburban watershed selected for this study includes both single-family residential land use
and a forested park. The hydrology and water quality of Shepherd Creek have been monitored by
EPA and some reaches were found to be affected by urbanization. The use of dispersed Best
Management Practices (BMPs) that infiltrate or detain runoff were planned and implemented for
this area, with continued monitoring during and after the implementation to measure the effects
on Shepherd Creek.
In 2007, Tetra Tech, as contractor to EPA, implemented a reverse auction to solicit participation
by area residents and then installed 50 rain gardens and 100 rain barrels on the selected
residential sites. This presentation summarizes the methods and results of both the site selection
and construction activities to date.
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Posted: August 24th, 2010 | Filed under: Stormwater | Tags: Environmental Impact, Reduced Carbon Footprint, Reduced Greenhouse Gas Emissions, Sustainable Infrastructure, Water Conservation | No Comments »