Metropolitan Syracuse Wastewater Treatment Plant
Syracuse, New York
The 84.2 mgd Metropolitan Syracuse Wastewater Treatment Plant (Metro) has recently
undergone a major upgrade to provide advanced ammonia-nitrogen and phosphorus removal.
Seasonal limits for ammonia are 1.2 mg/L NH3 summer and 2.4 mg/L NH3 winter, and the limit
for phosphorus is a 12-month rolling average of 0.12 mg/L. Biological aerated filters (BAFs) by
Krüger were added for ammonia removal and the ballasted flocculated settling process,
ACTIFLO (also by Krüger) was added for phosphorus removal.
To address the increased biosolids produced at Metro, Environmental Engineering Associates,
LLP (EEA – a joint venture of Stearns & Wheler, LLC, O’Brien & Gere, and Blasland, Bouck &
Lee [now ARCADIS]) was retained to develop the necessary biosolids handling improvements.
The project includes:
• Replacing existing belt filter press dewatering system with high solids centrifuges
• Installing gravity belt thickeners (GBTs) to thicker WAS
• Provide sludge blend tanks to blend thickened primary sludge and thickened WAS prior to
digestion
• Provide a cogeneration system that utilizes digester gas to generate electricity and recover
heat.
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Posted: May 3rd, 2011 | Filed under: 100K-500K, Waste Water Treatment | Tags: Improved Digestion, Improved Sludge Drying, Nitrogen Removal, Phosphorus Removal, Plant Optimization, Reduced Odors | No Comments »
Parkway WWTP and Henrico County WRF
Laurel, Maryland and Richmond, Virginia
Nitrogen removal to increasingly strict discharge standards requires, in many cases, the use of supplemental carbon (methanol, glycerol, acetate, sugar water, etc). The supplemental carbon provides the driving force for further biological denitrification and is typically applied as a polishing treatment such as to a post anoxic zone or a tertiary denitrification filter. The practical use of supplemental carbons has attracted substantial attention from both process optimization and cost minimization perspectives. This paper presents the operational experiences gained with the secondary and indirect impacts of supplemental carbon addition to BNR/ENR treatment facilities at the Parkway WWTP, located in Laurel, Maryland, and at the Henrico County WRF, located in Richmond, Virginia. The focus of the paper deals with the sometimes unexpected beneficial secondary effects of supplemental carbon addition to post anoxic zones in the BNR/ENR treatment processes. This paper has demonstrated secondary impacts from supplemental carbon addition for nitrogen removal. The benefits demonstrated included improved biological phosphorus removal, improved anoxic zone performance, increased biosynthesis for P and N removal, lower residual DO in the internal recycle, and improved utilization of influent rbCOD. Additionally various ways of calculating by the CODadded/Nremoved ratio was developed using effluent TN with and without supplemental carbon. The impact of lower NOx-N load in the RAS when the pre-anoxic zone is not fully utilized was shown to be a significant factor in the resulting CODadded/Nremoved ratio. These impacts illustrate the importance of considering the whole system response rather than an isolated portion of a reactor when evaluating supplemental carbon. Source: WEFTEC 2009 Proceedings
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Posted: August 27th, 2010 | Filed under: 50k-100k, Waste Water Treatment | Tags: Environmental Impact, Improved Anoxic Zone Performance, Lower Residual DO, Nitrogen Removal, Phosphorus Removal | 1 Comment »
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 »
Stable N-removal and successful enrichment of anammox bacteria was achieved over a period of one year in continuous flow granular sludge bioreactor. C. Brocadia was the dominant anammox community in the reactor, likely by virtue of operating conditions including not maintaining excessive control over nitrite concentrations and the possible influx and utilization of volatile fatty acids in the influent centrate. In general, granulation led to a significant improvement in reactor stability and N-removal performance and was paralleled by a significant increase in bacteria related to the Bacteroidetes/Chlorobi phylum. Based on data obtained to date, expression of both hzo and ISR appear to be suitable biomarkers of anammox activity and have potential as predictive tools for anammox monitoring and control. Source: WEFTEC 2009 Proceedings
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Posted: July 6th, 2010 | Filed under: Waste Water Treatment | Tags: Nitrogen Removal, Reduced Carbon Footprint, Sustainable Technologies | No Comments »
Blue Plains AWTP
Washington, District of Columbia
The MBBR process is a relatively new biological attached growth treatment system for denitrification. The results of this research should improve the understanding and quantification of the important kinetic and stoichiometric parameters of the MBBR system. The following conclusions can be drawn from overall test results:
i. Biomass density test indicated an increase in biomass density with decrease in temperature. Observed values ranged widely from 6 – 22 g/m2 for R1 and 5-17 g/m2 for R2 throughout the test period (January through June, 2008) for temperatures ranging from 11oC to 24oC.
ii. SDNR was estimated between 1.3 to 2.0 g N/m2/d expressed in terms of total biofilm carrier area. The SDNR expressed as g/m2.d had very little relationship with temperature suggesting a resilience of the overall process to temperature changes. The SDNR expressed as g-NOx- N/g biomass-d was observed to decrease with decreasing temperature. This suggested an Arrhenius relationship, and the Arrhenius constant was calculated as 1.09 for R1 and 1.07 for R2 for a temperature range of 11 – 18 oC, similar to those observed for the activated sludge process using methanol as a substrate. The biomass accumulation at colder temperatures may have contributed to temperature-stable SDNRs when expressed as g/m2.d. This is of practical significance for use of MBBRs in colder climates.
iii. Stoichiometric COD/N ratio was observed in the range of 4.6 mg COD/mg NO3-N to 5.3 mg COD/mg NO3-N and 4.4 mg/mg to 6.1 mg/mg for R1 and R2 respectively. This range is similar to the range observed for denitrification in suspended growth processes.
iv. A model was developed to predict half saturation constant for the MBBR biofilm. The model was based on the non-linear Monod kinetic model and operated on a Microsoft Excel Platform. The model predicted a similar range of KsNOx-N between 0.6 and 2.6 mg N/L for R1 and R2. These values seemed insensitive to changes in temperature with a weak relationship with biomass density. Source: WEFTEC 2009 Proceedings
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Posted: July 6th, 2010 | Filed under: Waste Water Treatment | Tags: Nitrogen Removal, Sustainable Technologies | No Comments »
Valued qualities such as portability, small footprint, fast start up, and high effluent quality have made package membrane bioreactor (MBR) systems a preferred technology for decentralized wastewater treatment applications. Package MBR systems have many advantages which make them ideal for decentralized wastewater treatment applications, particularly those looking for high effluent quality including total nitrogen removal. However, the selection of a package MBR system can be overwhelming for decision makers given the wide variety in available package MBR systems today and if not evaluated properly can lead to selection of a system that cannot meet the low flow challenges often encountered by decentralized wastewater treatment applications. Therefore it becomes important for decision makers to recognize whether the package MBR system is designed with features that allow it to maintain treatment conditions during low flows. This includes a properly designed flow equalization system capable of handling low influent flows which can be done using multiple pumps with VFDs or an influent flow splitter configuration. The package MBR system should also be designed with system turndown through the use of multiple treatment trains and/or use of multiple pumps and blowers. Lastly the package MBR system must be able to maintain control of oxygen delivery during low flows. Selecting a system which incorporates these low flow design methods into the design of the package MBR system will lead to selection of a system that will reliable meet total nitrogen limits at low flow conditions. Source: WEFTEC 2009 Proceedings
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Posted: July 6th, 2010 | Filed under: Waste Water Treatment | Tags: Nitrogen Removal, Reduced Carbon Footprint, Sustainable Technologies, Water Reuse | No Comments »
Washington Sanitary Suburban Commissions Seneca WWTP
Germantown, Maryland
This paper examines a full scale, real time nitrogen load and nitrogen removal profile along the aeration basin via an online analyzer at the Washington Sanitary Suburban Commissions Seneca WWTP, Md. Six months of full scale experiments provide firsthand experience with a control strategy based on DO and air flow set point, ammonia and NOx measurements and aerated swing zone volume for maximizing nitrogen removal. During the test period, ammonia, nitrite, nitrate and total phosphorous concentrations were monitored instantaneously. Parallel laboratory data agrees well with online analyzer measurements. Ammonia and NOx concentrations near the head of the aerobic zone and at end of the aeration basin were critical to achieving TN below 3 mg/l. Manually controlled swing zone on/ off and air flow adjustment responded well to nitrogen load variation, resulting in overall improvement of nitrogen removal. The Seneca experience and successful application of the control strategy in European WWTPs could provide an opportunity for future process control automation based on continuous online DO and nutrients. This paper also evaluates operational data at Seneca WWTP and summarizes experiences with operation strategies and BNR process optimization gained during the last few years. Simultaneous nitrification and denitrification (SND) was also observed based on nitrogen mass balance data which accounted for about a 53% nitrogen loss in the WSSC Seneca system. Source: WEFTEC 2009 Proceedings
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Posted: July 6th, 2010 | Filed under: Waste Water Treatment | Tags: Cost Savings, Environmental Impact, Nitrogen Removal | No Comments »
Littleton-Englewood WWTP
Englewood, Colorado
Littleton-Englewood and Brown & Caldwell worked to meet the new TIN permit by enhancing nitrate removal with a new in-plant recycle and new denitrification filters. Advanced control strategies and instrumentation were included to improve reliability in meeting a daily permit. The final design included eight deep bed filters, each 3.6 meters by 29.3 meters, containing 2.4 meters of 2-3 mm rounded sand. A formal Process Performance Guarantee was required. Only partial denitrification was needed at certain times of the year. However, denitrification filters work best when fully denitrifying. Otherwise, partially converted nitrogen in the nitrite form discharges from the filter and causes a very high chlorine demand downstream. To solve this, the filter plant was designed with individual methanol feed to each filter. Each filter could be controlled individually to produce full efficient denitrification in some filters, while others simply provided solids filtration. This produces a blended effluent quality as chosen by the operators. Filtration of a majority of the plant flow was envisioned to aid phosphorus removal that might be required in the future. Each filter was equipped with two inlet gate valves that feed evenly dividing cut-throat flumes. Filters not being used for denitrification can be run with both flumes open to allow for doubled filtration rates. Source: WEFTEC 2009 Proceedings
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Posted: July 6th, 2010 | Filed under: Waste Water Treatment | Tags: Environmental Impact, Nitrogen Removal | No Comments »
East Greenwich WWTP
East Greenwich, Rhode Island
The nitrogen removal system utilizes a tertiary two-stage, biological filtration process where ammonia is oxidized to nitrate (nitrification) in the first stage and the nitrate is subsequently reduced to nitrogen gas (denitrification) in the second stage. The nitrogen removal system initiated operation in April 2006 and the data collected during the three compliance periods of 2006, 2007, and 2008 indicate that the process performance of the system has been excellent. In 2001, the average total nitrogen discharge to Greenwich Cove was 10.3 mg/L. Since the upgrade, the WWTP has consistently met the 5 mg/L total nitrogen permit limit, with a 51% reduction in the total nitrogen discharge. The East Greenwich WWTP Upgrade project improves the water quality of Narragansett Bay and Greenwich Cove. Source: WEFTEC 2009 Proceedings
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Posted: July 6th, 2010 | Filed under: Waste Water Treatment | Tags: Environmental Impact, Nitrogen Removal | No Comments »
This modeling study of nitrogen removal and its impacts upon whole plant carbon footprint clearly show the importance of biogenic N2O production in the secondary treatment system. This production accounted for between 35% and almost 65% of the total plant footprint. In this model, N2O release is primarily by stripping in the aerobic zone by the fine bubble aeration system. As a result the lowest N2O production levels were seen in systems that minimized the amount of N2O entering that first aerobic zone. The last anoxic zone nitrate/nitrite level was used as a surrogate for N2O levels since it is more easily measured. Essentially if there are significant nitrate/nitrite levels in the last anoxic zone, the denitrification intermediate, N2O, is also likely to be present at higher levels. If the designer’s, or operator’s, goal is to minimize their plant’s carbon footprint, the goal should be to minimize the concentration of nitrate leaving the plant’s anoxic zones. While the plant influent COD/N ratio is not under the control of either party the design and operation of the nitrogen removal system can be adjusted for the desired goals. On a whole plant basis, the production of N2O in the bioreactor system is the single largest variable on the plant carbon footprint, with it accounting for between 25% and 65% of the total. This paper has shown that this carbon impact can be minimized during design and operation of the facility. Source: WEFTEC Proceedings 2009
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Posted: June 25th, 2010 | Filed under: Waste Water Treatment | Tags: Environmental Impact, Nitrogen Removal, Reduced Carbon Footprint | No Comments »