Glessen WWTP
Bergheim, Germany
A conventional activated sludge plant for municipal wastewater treatment is retrofitted by using membrane bioreactor technology. The bioreactor and other parts of the infrastructure are incorporated into the new process design. The plant capacity is increased. Stringent discharge criteria are met. After several steps of start-up the plant is in full operation since spring 2008. The efficiency of the treatment process is optimised. In this case study retrofitting the existing CAS as an MBR was beneficial in several ways:
(a) Technologically the membrane filters replace the secondary clarifier and, by increasing the biosolids concentration, the plant capacity was increased significantly without building a new bioreactor.
(b) Economically the cost of building a new second WWTP could be saved.
(c) Ecologically a substantial increase in the nutrient removal and the hygienic effluent quality was achieved. This is an important precautionary measure in the water protection area. It can be said, that MBRs can offer a viable and efficient option for the retrofitting of existing CAS. Source: WEFTEC 2009 Proceedings
Metric Used:
Posted: August 27th, 2010 | Filed under: Waste Water Treatment | Tags: Avoided Building Additional Plant, Cost Savings, Environmental Impact, Increase in Nutrient Removal, Increased Plant Capacity, Optimized Treatment Process | No Comments »
26th Ward WPCP
New York City, New York
The use of crude glycerin was evaluated as an alternative supplemental carbon source to methanol to enhance denitrification in a step-feed BNR process. Two of the four pilots were integrated with separate centrate treatment tanks to oxidize centrate ammonium; centrate was fed to the head of the step-feed process in two other pilot systems. The pilot treatment trains received primary effluent and centrate from the 26th Ward WPCP. Under normal operating conditions, it was demonstrated that crude glycerin could be used to achieve 5-10 mg/L of final effluent TN. Specific denitrification rates determined by the bench-scale batch tests were comparable to that achieved with methanol as the supplemental carbon source. A COD-to-N ratio in the range of 6 to 7 grams/gram was used, resulting in a chemical cost of ~ $1/kg-NOx-N removed with a cost basis of $0.22/L, compared to ~ $1.60/kg-NOx-N for 100% methanol at ~ $0.40/L. Source: WEFTEC 2008 Proceedings
Metric Used:
Posted: August 27th, 2010 | Filed under: 100K-500K, Waste Water Treatment | Tags: Carbon Substitute, Cost Savings, Enhanced Denitrification | No Comments »
Corrosion in sanitary sewer systems occurs when hydrogen sulfide (H2S) is biologically converted to sulfuric acid. Although reducing metals was necessary to protect public health, pretreatment has contributed significantly to increased sulfides, leading to heightened H2S odor and ultimately to accelerated corrosion. As the main contributor to odor and corrosion in collection systems, H2S is typically treated with odor control agents that can be costly and ineffective in providing long lasting H2S removal throughout the collection system. Magnesium hydroxide is effective in eliminating H2S by reducing both dissolved sulfide production and headspace H2S gas, but it also offers additional benefits as well. The introduction of magnesium hydroxide does not lead to the formation of additional unwanted sludge, as often happens with lime and iron salts. Additionally, it provides long-lasting alkalinity, slowly dissolving to increase the pH of wastewater to an optimum pH range that significantly reduces the formation of H2S and prevents further corrosion of sewer lines. Magnesium hydroxide’s pH buffering ability provides effective treatment for miles downstream from the addition point thus reducing the number of chemical injection points needed. In addition to H2S odor and corrosion control and saponification of fats, oils, and greases, adding magnesium hydroxide to the sanitary sewer system provides additional benefit downstream in the wastewater treatment plant. Competing odor control agents do not provide total system treatment as does magnesium hydroxide, making it a more effective solution for municipalities. Source: WEFTEC 2008 Proceedings
Metric Used:
Posted: August 27th, 2010 | Filed under: Sanitary Sewer, Waste Water Treatment | Tags: Corrosion Prevention, Cost Savings, Enhanced Downstream Effluent, Increased Odor Control | No Comments »
Mill Creek WWTP and MWRD's Robert W. Hite Treatment Facility
Cincinnati, Ohio and Denver, Colorado
The business novel The Goal was used as guidance for the optimization/continuous improvement work at the Metropolitan Sewer District of Greater Cincinnati (MSD) and greater Denver’s Metro Wastewater Reclamation District (MWRD). The work at both utilities has been successful. Increased capacity and better and more stable performance has been realized at MSD’s Mill Creek Wastewater Treatment Plant while decreasing operating expenses; better and more stable performance has been realized at MWRD’s Robert W. Hite Treatment Facility. Source: WEFTEC 2008 Proceedings
Metric Used:
Posted: August 27th, 2010 | Filed under: Waste Water Treatment, Water Treatment | Tags: Cost Savings, Energy Savings, Improved Effluent, Improved Sludge Quality, Increased Plant Capacity, Plant Optimization | No Comments »
Metropolitan Wastewater Treatment Plant
St. Paul, Minnesota
All plants have an obligation to ratepayers to deliver the best wastewater treatment service at the lowest cost. As polymer prices started to soar even faster than energy costs, plants have needed to find new ways to reduce its dewatering polymer use. Some improvements are capital intensive, such as installing newer equipment. Others cost very little; they are simply improving the way we do things, such as putting the operators in charge. Most plants change operating goals passed down to operators intermittently as specific directives: “Try not to use more than 15 GPM of polymer, and keep the cake at least 27%.” This sort of instruction is OK, but usually not done often enough to account for changes in the dewatering processes. In the Minneapolis-St Paul Metro Plant the control system displays, operators are empowered to make changes independently, hour by hour, so the dewatering costs can be constantly minimized. We are looking into on line analyzers, to continuously monitor the blend ratio. The instruments for continuous solids measurement were unreliable ten years ago, but are now proven. Since polymer has now surpassed electricity as the largest expendable for solids processing (Table 1), another enhancement will be to combine energy and polymer costs on a real-time solids management screen. This would be incorporated into the already developed energy cost/conservation screen (Figure 8). MCES is also investigating ways to reduce the sludge yield in the winter (when most of the secondary sludge is produced). A 25 dryton-per-day reduction of secondary sludge production could save $400,000 in polymer while costing $200,000 in extra energy netting a savings of about $200,000 per year. Source: WEFTEC 2008 Proceedings
Metric Used:
Posted: August 27th, 2010 | Filed under: >1M, Waste Water Treatment | Tags: Cost Savings, Improved Organization, Plant Optimization | No Comments »
Metropolitan Water Reclamation District of Greater Chicago's Calumet Water Reclamation Plant
Chicago, Illinois
As part of an ongoing capital improvement plan, the Metropolitan Water Reclamation District of Greater Chicago (MWRDGC) plans to construct twelve 47.2 m (155-ft) diameter circular primary settling tanks (PST) at its Calumet Water Reclamation Plant (CWRP). The new PSTs are intended to receive flows up to 75,700 m3/h (480 mgd). Due to the magnitude of the proposed facilities, the MWRDGC partnered with the design consultant and researchers at the University of Illinois to use computational fluid dynamic (CFD) modeling of the PSTs in order to optimize the design of the tanks. A three dimensional, multi-phase, turbulent flow model was developed. The model was used to optimize the arrangement of the inlet pipe and feedwell to maximize removal efficiency. In addition, the model allowed the design team to select a tank sidewater depth and tank diameter that are estimated to save the MWRDGC $2 million in construction cost without adversely affecting performance. Source: WEFTEC 2008 Proceedings
Metric Used:
Posted: August 27th, 2010 | Filed under: Waste Water Treatment | Tags: Cost Savings, Increased TSS Removal Efficiency, Optimize Inlet and Feedwell Dimensions, Plant Optimization | No Comments »
City of Taft POTW
Taft, California
One solution to address overloaded collection and treatment systems is to develop satellite units for wastewater treatment. The challenge is to implement a treatment system of such efficacy that these satellite units can exist throughout an area without a large footprint. Membrane bioreactors are one option; electrocoagulation is another. Ecolotech systems are designed to meet effluent criteria that allow the non-potable reuse of the effluent, while solids are transmitted to the centralized wastewater treatment plant. The system can create an unobtrusive water recovery facility by replacing tradition treatment equipment. A small footprint can be used to effect a 95% reduction in wastewater effluent to the collection system, an odor-free system, rapid implementation, and a source of emergency non-potable water. This paper describes the electrocoagulation process, Ecolotech system components, and case study results providing proof of concept for use in small wastewater treatment and water recovery facilities. Pilot testing of the Ecolotech system has demonstrated that that electrocoagulation is a viable technology and that each unit can treat up to 250 gallons per minute (gpm) of wastewater. The Water Recovery Treatment Center is a viable option for communities that want to offer wastewater treatment to new development without having to invest heavily in new or upgraded infrastructure. Reusing treated wastewater will reduce the use of potable water for non-human consumption uses, therefore conserving a valuable resource for the community. Small-scale (<2 mgd) MBR systems typically cost about $10 million per mgd capacity. The Ecolotech system is estimated to be approximately 40% to 60% of the MBR cost, depending upon site conditions and other factors. Source: WEFTEC 2008 Proceedings
Metric Used:
Posted: August 27th, 2010 | Filed under: <50K, Waste Water Treatment | Tags: Achieving Greater Throughput, Cost Savings, Energy Savings, Improved Treatment, Increased Treatment Capacity | 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
Metric Used:
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 »
Water Works and Sewer Board of the City of Prichard
Prichard, Alabama
To comply with a State issued Consent Decree, the Water Works and Sewer Board of the City of Prichard, AL had to replace or repair 1,000 private sanitary sewer laterals to reduce inflow and infiltration that was leading to sanitary sewer overflows (SSOs). The anticipated cost of this effort was expected to be between $800,000 and $1 million, a significant amount for a community with a median household income of less than $20,000. Early struggles with excessive paperwork, inadequate equipment, and inexperienced personnel led to concerns by the State about the lack of progress. A revised strategy that simplified analysis and streamlined work was developed. The results were a 30 percent reduction in inflow and infiltration at a cost of $550,000. Overall SSO volumes were reduced by 95% and the number of recurring SSOs dropped from eight to one. Source: WEFTEC 2009 Proceedings
Metric Used:
Posted: August 27th, 2010 | Filed under: Sanitary Sewer, Water Treatment | Tags: Cost Savings, Reduced Inflow and Infiltration, Reduced Sanitary Sewer Overflows | No Comments »
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
Metric Used:
Posted: August 27th, 2010 | Filed under: Waste Water Treatment | Tags: Cost Savings, Energy Recovery, Improved Disposal Options, Reduced Carbon Footprint | No Comments »