Northeast APCF
Clearwater, Florida
The City of Clearwater, Florida maintains and operates three wastewater treatment plants. The 5 mgd East Advanced Pollution Control Facility (APCF), the 13.5 mgd Northeast APCF, and the 10 mgd Marshall Street APCF. Both Northeast APCF and Marshall APCF use anaerobic digesters for biosolids handling. The biosolids from East APCF is hauled and processed at Northeast APCF. During the early 2000’s the city experienced poor results from their digesters, due to deteriorated heating and mixing equipment. Consequently the City embarked on an initiative to invest in a rehabilitation program for all their digester facilities. The purpose of this paper is to provide data on increased gas production and reduced hauling cost savings after the digesters were rehabilitated in late 2006. The data from the Northeast APCF is presented. The intent of the Clearwater Anaerobic Digester Improvements Project is to improve biosolids treatment processes at the APCFs, to enhance and improve disposal options and operational flexibility, to promote biosolids reuse and energy recovery, and to reduce operating costs as feasible at the facility. Placing the anaerobic digesters back into service reduced approximately 40 percent of the residuals volume. By rehabilitating and utilizing the anaerobic digesters over the past five years WPC has generated O&M savings of $1,711,000. If nothing had been accomplished to reduce the volume of biosolids hauled, the present day annual cost would be $1,424,700. Another added benefit is the reduction in fossil fuel not hauling 14,210 wet tons per year. This equates to 63 truckloads annually. It is also rare to be able to have the opportunity to roll back and reduce costs to a rate lower than they were six years ago while dealing with an increase in unit cost. Source: WEFTEC 2009 Proceedings
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Posted: August 27th, 2010 | Filed under: Waste Water Treatment | Tags: Cost Savings, Energy Recovery, Improved Disposal Options, Reduced Carbon Footprint | No Comments »
23rd Avenue Wastewater Treatment Plant
Phoenix, Arizona
Monitoring of influent loading and plant operating conditions, together with a real-time feedforward control model, allows dissolved oxygen (DO) set-points to be matched in real time to the influent loading. Adjusting DO set-points based on load results in a significant reduction in aeration energy. This paper discusses the monitoring technology, and optimization and control techniques used in an energy savings project at the 23rd Avenue Wastewater Treatment Plant (23rd Avenue WWTP) in Phoenix, Arizona. The plant treats an average of 48 MGD using an MLE process, with a goal of complete nitrification. Load-based feed-forward control of dissolved oxygen in an activated sludge wastewater treatment plant can provide measurable and consistent energy savings through reduced aeration requirements without jeopardizing effluent quality. In the case presented here, aeration energy savings were in the range of 11% to 18%, despite constraints on the controller that prevented it from lowering the DO set-point below an operator defined limit. At Phoenix 23rd Avenue WWTP this represents a savings of 2000 MWh per annum and a carbon footprint reduction of 1,400 metric tons. The results are consistent with savings achieved using the same control methods at plants in different climate zones (Liu, 2003). Source: WEFTEC 2009 Proceedings
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Posted: August 27th, 2010 | Filed under: 100K-500K, Waste Water Treatment | Tags: Cost Savings, Energy Savings, Environmental Impact, Plant Optimization, Reduced Carbon Footprint | No Comments »
California
In 2001 California spent 18,600 Gwh per year only on agricultural and water pumping (http://www.energy.ca.gov / electricity/ consumption_by_sector.html). In addition, pumping is widely used in power industry, HVAC, etc. Considering that each kw*hr of energy saving causes 0.537kg of carbon emission reduction, decrease of energy usage helps not only to improve the bottom line but also leads to reduction of carbon footprint. A new methodology has been developed for pump stations optimization. The methodology uses simultaneously generalized reduced gradient and genetic algorithms. The methodology allows optimization of any combination of constant speed and variable speed pumps. Implementation of this methodology at one pump station yielded reduction of energy usage as much 25% that was equal to more than $50,000 a year. Source: WEFTEC 2009 Proceedings
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Posted: August 27th, 2010 | Filed under: Sanitary Sewer, Stormwater | Tags: Cost Savings, Energy Savings, Environmental Impact, Reduced Carbon Footprint | No Comments »
United Utilities
United Kingdom
This paper will describe the results achieved by applying a Model Predictive Control (MPC) system to an Activated Sludge Plant (ASP) in the UK, with the objective of reducing energy consumption, whilst maintaining compliance within permitted environmental standards. Installation of the MPC system was initially an R&D project to assess if the suppliers performance expectations were valid. The successful outcome of the trial allowed the project to move to a permanent installation assessing the benefits over a longer period. During the R&D Phase the system demonstrated a high availability with an average of 20% energy reduction and peaks of 40% energy reduction when compared to conventional control. To date the system has reliably demonstrated energy savings and offers the potential to contribute significantly to United Utilities objective to reduce its Carbon emissions by 8% by 2012 if the benefits are replicated across the companies asset base of large ASP’s. Source: WEFTEC 2009 Proceedings
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Posted: August 27th, 2010 | Filed under: 50k-100k, Electric, Sanitary Sewer, Stormwater, Waste Water Treatment, Water Treatment | Tags: Cost Savings, Energy Savings, Environmental Impact, Reduced Carbon Footprint | No Comments »
Southwest WWTP and Dillman Road WWTP
Conroe, Texas and Bloomington, Indiana
Studies conclude the aeration process in an activated sludge wastewater treatment plant consumes 40 to 60 percent of a plant’s power usage. With the dramatic impact of the aeration process on the overall operational expenses of a plant, the last three decades has seen increased focus on the design, implementation, and operation of high efficiency single-stage centrifugal blowers and aeration control systems. State and local agencies offer a variety of funding options that favor energy-minded aeration systems due to the increased global emphasis on energy conservation. This paper will discuss the different types of high efficiency single-stage centrifugal blowers used in wastewater treatment plants, along with blower and aeration system control methodologies to maximize the overall aeration process efficiency. In addition, this paper will detail two case studies where alternative funding options allowed the implementation of high efficiency single-stage centrifugal blowers and aeration control systems, which yielded significant energy and operational savings. Source: WEFTEC 2009 Proceedings
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Posted: August 27th, 2010 | Filed under: <50K, Waste Water Treatment | Tags: Cost Savings, Energy Savings, Environmental Impact, Plant Optimization, Reduced Carbon Footprint | No Comments »
Malabar Wastewater Treatment Plant
Trinidad and Tobago
Sustainable wastewater solids management constitutes a serious challenge to the overall initiative of improvement of the wastewater systems by the local authorities in Trinidad and Tobago. The solids treatment approaches must be focused on the effectiveness of the processes and its durability. The selected approach must also integrate local and regional settings, as well as current and future environmental limiting conditions. It is concluded that the proposed process of solar drying will allow measurable scientific, environmental and economic benefits. Based on the analysis of the local weather conditions and estimated solids production rate of 17,600 tonnes per year, a total of 6 solar dryer cells covering an area of 7,450 m2 are required. The biosolids produced from the process is expected to have a minimum solids content of 70% and to have a significant vector attraction reduction. This fully automated and simple technology will enable minimum operator’s attention. Source: WEFTEC 2009 Proceedings
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Posted: August 27th, 2010 | Filed under: Waste Water Treatment | Tags: Cost Savings, Energy Savings, Environmental Impact, Reduced Carbon Footprint, Reduced Solids | No Comments »
Town of Sturbridge WWTF
Sturbridge, Massachusetts
The Town of Sturbridge, MA WWTF has experienced steadily increasing flows over the last 20 years due to significant population growth in the community. Plant loading rates are now above design levels, and NPDES permit requirements are becoming more stringent for both nitrogen and phosphorous. Furthermore, a limited footprint is available for expansion. The Town and its consulting engineer, Tighe & Bond, considered many potential solutions to address these issues, including a system upgrade using Membrane Bioreactor (MBR) technology. During an evaluation of treatment alternatives Tighe & Bond recognized that while MBRs can provide high level treatment in a small footprint they can also be energy intensive, relatively expensive to own and operate, and subject to membrane fouling, cleaning and replacement issues. Based on these issues the Town decided to explore an emerging ballasted biological treatment technology called BioMag. The results of this successful full scale demonstration show that BioMag is a promising new technology for upgrading many activated sludge treatment facilities. Existing systems can be reconfigured to implement biological nutrient removal, and/or to operate at higher flows and loadings without adding new aeration tanks and/or clarifiers. BioMag proved to be a stable, reliable, operator-friendly process. The Town concluded that the demonstration was a success, and is moving forward with the design and installation of a full scale BioMag system in Sturbridge. Capital costs for the BioMag upgrade were determined to be substantially lower than those of a comparable MBR upgrade. O&M costs for BioMag are also expected to be lower than those of a comparable MBR system, resulting in a substantial lifecycle cost savings of nearly 30 percent for the Town. Source: WEFTEC 2009 Proceedings
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Posted: August 27th, 2010 | Filed under: <50K, Waste Water Treatment | Tags: Cost Savings, Energy Savings, Environmental Impact, Innovative Technology, Reduced Carbon Footprint | No Comments »
Membranes, which provide a number of significant benefits, have become cost-effective for many water, wastewater, and desalination treatment applications. They are rapidly replacing conventional and traditional processes, providing benefits for new construction, upgrades, and retrofits of existing facilities. Every type of conventional water, wastewater, desalination, and water reuse treatment has a membrane alternative. Membranes have become a commodity in water treatment, as more and more applications are found to replace conventional technologies. When used in combination with different technologies, membranes may address removal of mineral and organic compounds in the water, including volatile-type compounds such as the 42 endocrine disruptors (EDCs) found in the U.S.A., pharmaceutically active compounds (PhACs), and personal care products (PCPs). Membrane treatment offers a number of advantages, including higher effluent water quality, a more compact foot-print, and often times simpler operations as compared to conventional treatment. With the industry’s acceptance of membrane technologies and the rapid growth in the number of operating facilities, the costs of membrane systems are now approaching those of conventional systems. Sooner or later, membranes are likely to be in your future, either for upgrading existing facilities or considered as the preferred choice for new water reuse needs. Source: WEFTEC 2009 Proceedings
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Posted: August 27th, 2010 | Filed under: Waste Water Treatment | Tags: Cost Effective Treatment Process, Higher Effluent Water Quality, Increased Removal, Reduced Carbon Footprint | 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 »