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
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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
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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
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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 »
San Jose/Santa Clara Water Pollution Control Plant
San Jose, California
The San Jose/Santa Clara Water Pollution Control Plant (“Plant”) is an advanced wastewater treatment facility with a rated capacity of 167 MGD. Over the past year it implemented three major energy savings projects: optimization of pump station operation, optimization of operation of the dissolved air floatation system and replacing continuous aeration of mixed liquor channels and anaerobic/ anoxic compartments of the BNR process with pulsed (intermittent) aeration (Patent pending). Estimated energy savings is $1.3 million dollars. Cost of the projects was less than $300,000. Project cost was refunded to the Plant by the Electrical Utility. The following results were achieved: 1. More than 20% energy savings was achieved by optimization of scheduling of pumps and speeds of VFD motors.
2. More than 60% energy saving was achieved by optimization of operation of dissolved air floatation.
3. More than 50% energy savings was achieved by implementing pulsed aeration in the anaerobic compartments.
4. No deterioration of treatment performance was observed. Source: WEFTEC 2009 Proceedings
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Posted: August 27th, 2010 | Filed under: >1M, Waste Water Treatment | Tags: Cost Savings, Energy Savings, Plant Optimization | 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 »
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 »
Yucaipa Valley Water District's Henry N. Wochholz WWTP
Yucaipa, California
IFAS process is a relatively new technology for controlling nitrogen discharges from wastewater treatment facilities in the United States. There is widespread interest in this technology, especially for retrofitting existing plants. Wochholz WWTP selected IFAS to expand its capacity from 15140 m3/d (4 mgd) to 30280 m3/d (8 mgd). To meet an annual effluent TIN limit of 6 mg/L, a post anoxic zone with methanol supplementation was provided in addition to a preanoxic zone and a 400% mixed liquor recycle stream. Performance data has shown that the plant can consistently achieve a TIN of less than 6 mg/L with methanol addition. Effluent ammonia has been below 0.5 mg/L and effluent nitrates below 4 mg/L with trace amounts of nitrites once the biology was stable. Methanol is added at the headworks due to lower than expected influent BOD. Methanol is also added at the post anoxic zones to polish effluent nitrates. By taking proper measures surface foaming in the IFAS basins has been controlled to less than an inch. Source: WEFTEC 2009 Proceedings
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Posted: August 27th, 2010 | Filed under: Waste Water Treatment | Tags: Environmental Impact, Increased Plant Capacity, Plant Optimization | No Comments »
Dublin San Ramon Services District Wastewater Treatment Plant
Dublin, California
While the implementation of enhanced biological phosphorus removal (EBPR) may appear to increase the complexity of the activated sludge process, the improvement and stabilization of activated sludge quality and performance afforded by EBPR actually simplify operational requirements. Moreover, there are design features that can be included to further simplify operation. Presented is a discussion of the design features included in the expansion and upgrade of the Dublin San Ramon Services District Wastewater Treatment Plant, in particular the mixed liquor surface-wasting system for mean cell residence time (MCRT) control. Comparison of operations and performance data before and after the expansion and upgrade project confirm the design intent to simplify operations and improve and stabilize activated sludge quality and performance. Mixed liquor wasting has several benefits compared to conventional RAS wasting. Mixed liquor wasting is effective for precise and accurate MCRT control needed to allow EBPR and minimize nitrification in high-rate activated sludge systems, such as used at the DSRSD WWTP. For any type of activated sludge system, mixed liquor wasting provides a simple means of MCRT control – the aeration tank volume and target MCRT are all that are needed to calculate the waste sludge flow rate. Combined with a classifying selector, nocardioforms are quite effectively controlled. Operations and performance data from the DSRSD WWTP following EBPR implementation demonstrate that average effluent total phosphorus concentrations less than 1.0 mg/L are easily achieved with concurrent low effluent suspended solids concentrations. The design features included for MCRT control and nuisance foam and scum control have simplified activated sludge operations. Although granular media filtration for recycled water production was not considered during design of the plant expansion and modifications, the EBPR system produces a high-quality, filterable effluent. Source: WEFTEC 2009 Proceedings
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Posted: August 27th, 2010 | Filed under: Waste Water Treatment | Tags: Biological Phosphorus Removal, Environmental Impact, Increased Plant Capacity, Plant Optimization | No Comments »
A newly developed automatic cleaning method for Potentiostatic sensors lowers the operational costs and improves the reliability of disinfectants measurement/dosage in safety critical applications. The newly developed Potentiostatic sensors for the most common disinfectants like Free Chlorine, Chlorine Dioxide, Ozone and Peroxide are least affected by coating in surface water and waste water applications, preventing safety critical incidents, such as over dosage of chemicals. In combination with the patented automatic cleaning system (ASR), maintenance and operational costs are kept to the minimum. The overall system has unrivalled high measuring availability, operates fully automatic and has long service intervals, which makes it ideal for installation in unmanned water works, cooling towers and safety critical applications, such as gate warning systems in industrial waste water treatment plants (figure 4) or desalination plants to protect sensitive instrumentation or processes against intolerable disinfectants concentrations. Source: WEFTEC 2009 Proceedings
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Posted: August 27th, 2010 | Filed under: Waste Water Treatment | Tags: Plant Optimization, Reduced Operational Costs, Reliable Disinfectant Monitoring | No Comments »
The Hopewell Regional Wastewater Treatment Facility
Hopewell, Virginia
The Hopewell Regional Wastewater Treatment Facility (HRWTF) treats waste streams originating from multiple large industrial sources which make up 85% of the influent to the plant (with the balance made up of municipal waste). In the past, the HRWTF has experienced random toxic upsets due to unidentified causes. Because of this, the HRWTF began using in June 2006 LuminUltra Technologies Ltd’s ATP (Adenosine Triphosphate) monitoring technology with the goal of detecting and preventing impending upsets.
The benefit of ATP monitoring was not fully understood until January 2009 when a significant toxic upset event occurred. This paper will discuss how the ATP testing along with other routinely collected plant data revealed the onset of the 2009 upset, helped identify the source of the problem, assessed the degree of damage done, and facilitated troubleshooting in the aftermath of the upset. Rather than relying on TSS or VSS measurements that contain many components other than living cells, ATP monitoring isolates the living population from dead biomass, inert solids, and other interferences. This 5-minute test shows the active population’s response to stimuli (good and bad), and therefore gives operators the ability to immediately detect changes in the process and determine the source and severity of toxic events. Source: WEFTEC 2009 Proceedings
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Posted: August 27th, 2010 | Filed under: Waste Water Treatment | Tags: Plant Optimization, Reduced Plant Interruptions, Reliable Toxicity Monitoring | No Comments »