Council Bluffs Water Pollution Control Plant
Council Bluffs, Iowa
The Council Bluffs Water Pollution Control Plant (WPCP) added a high-rate, integrated, fixedfilm,
activated sludge (IFAS) process in 2007 to increase the organic removal capacity of their
conventional trickling filter plant. Plant staff uses an innovative approach to estimate the fixed
biomass on the IFAS media through strategically placed miniature textile-media coupons. These
coupons were used to evaluate the performance of the high-rate IFAS system at design
conditions during cold-weather operation in 2009. Results showed that the system could operate
within permit limits at design conditions; however, the effluent quality was less than predicted
target values. Results also showed that the average IFAS media biomass loading was only 40%
of the manufacturer’s design value. Additional testing is needed to evaluate options for
improving effluent quality at design conditions such as increased mixed liquor, increased solids
retention time (SRT) or even increased hydraulic retention time (HRT).
KEYWORDS: Trickling Filter; Integrated, Fixed-Film, Activated Sludge; IFAS
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Posted: May 20th, 2011 | Filed under: 50k-100k, Waste Water Treatment | Tags: Achieve Permit Limits, Improved CBOD Removal, Increased Plant Capacity | No Comments »
Patapsco Wastewater Treatment Plant
Baltimore, Maryland
The State of Maryland Enhanced Nutrient Removal (ENR) Program sets effluent goals of 3.0
mg/L total nitrogen (TN) and 0.3 mg/L total phosphorus (TP) for plants that discharge to the
Chesapeake Bay tributaries. To meet ENR Program goals, the City of Baltimore will construct
new ENR treatment facilities downstream of the existing secondary clarifiers at the 81 MGD
Patapsco WWTP. The new ENR facilities include biological aerated flooded filters (BAFF) and
denitrification filters. The performance of the ENR processes and the ability of the plant to meet
ENR effluent goals will depend directly on the performance of the secondary clarifiers. This
paper will discuss the design efforts for modifications to the secondary clarifiers to incorporate
energy dissipating inlet (EDI) and will provide step-by-step approach in the evaluation and
selection of the design. Construction of this project will begin in 2011.
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Posted: May 20th, 2011 | Filed under: 100K-500K, Waste Water Treatment | Tags: Environmental Impact, Improved Clarifier Performance, Improved Process Performance, Increased Plant Capacity, Reduced Nutrient Load | No Comments »
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
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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 »
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 »
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 »
The performance of secondary clarifiers is critical to ensure that stringent nitrogen and phosphorus limits are met in Biological Nutrient Removal (BNR) and Enhanced Nutrient Removal (ENR) treatment plants. Additionally, these plants rely in slow growth microorganism populations that are difficult to restore in the event of solids washout that could happen in wetweather storm flows. Secondary clarifiers are a key unit to ensure retention of the solids inventory. This paper illustrates the application of computational fluid dynamics (CFD) modeling to four different BNR/ENR case studies covering a wide variety of clarifier geometries, internal configurations and loading conditions. In Case Study 1, the model was used for the validation of step feed as a wet weather strategy to prevent solids washout during storm events. For Case Study 2, the model was use to evaluate the impact that the tank depth can have on clarifier performance and capacity. In Case 3, the model was used to compare the performances of peripheral-feed and center-feed circular clarifiers; and Case 4 presents the evaluation of rectangular clarifiers. In all cases, the model was used to identify improvements and operating strategies that result in improved reliability, increased capacity and reduced capital cost. Source: WEFTEC 2009 Proceedings
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Posted: August 27th, 2010 | Filed under: Waste Water Treatment | Tags: Cost Savings, Improved Reliability, Increased Plant Capacity, Increased Plant Efficiency | No Comments »