Jacqueline German CBE 555 March 9, 2015
Water is essential for life with one of the most important sectors relating to water that helps sustain life on earth being wastewater treatment
Overview 1. Background of Secondary Wastewater Treatment 2. Constructed Wetlands (CW) 3. Modified Ludzack-Ettinger (MLE) 4. Sequencing Batch Reactors (SBRs) 5. Evaluation Matrix on basis of cost, and phosphorus removal efficiency for a 100,000 gallon/day plant 6. Research on SBR systems 7. Conclusion
Secondary wastewater treatment is responsible for removing excess dissolved organics
Animations and youtube videos of the wastewater treatment process
Focus on nitrogen removal due to the severity of ammonia toxicity to fish from even extremely small levels
Phosphorus removal is important due to its characteristics of being a good fertilizer ingredient (e.g. for algae) Phosphorus Accumulating Organisms (PAOs) are obligate aerobes. They can store food, but not process it.
Average Inflow Values (Secondary Treatment System) COD 500 mg/L NH3-N 25 mg/L TN 45 mg/L PO4-P 10 (9.88 mg/L)
Constructed Wetlands (CW)
Constructed Wetlands (CW) generally contain five principal concepts: (1) substrates with various rates of hydraulic conductivity, (2) plants adapted to water- saturated anaerobic substrates, (3) a water column, (4) (in)vertebrates, and (5) aerobic and anaerobic microbial populations, assisting in this (Hammer, 1989)
Constructed Wetlands (CW) can require 10 times more land
From Brix (1993) From Shutes (2001) “These systems efficiencies have been documented to reach 77% for ammonia nitrogen and 82% for total phosphorus (yearly mean),” (15) 98% reduction of BOD and 90-98% suspended solids, averages of % nutrient removal Cost analysis concluded that constructed wetlands cost start around 51,700 US$ (Oppelt, 2000) 10 mgP/L*0.18=1.8 mgP/L
Modified Ludzack-Ettinger (MLE)
The MLE process involves a series of tanks Anoxic StageNO 3 -NO 2 (Nitrate-Nitrite) N 2 +H 2 O Aeration StageNH 4 (Ammonia)+O 2 NO 3 -NO 2 (Nitrate-Nitrite)
MLE process should be built with a two train minimum
From Song et al. (2003) “Application of sludge ozonation to the [MLE with] MBR system was significantly effective for the minimization of excess sludge production as well as for the enhancement of nutrient removal,” (359). Cost analysis concluded that the MLE method had a total cost around 1,069,400 US$ (Hartman and Cleland, 2007) 10 mgP/L*0.46=4.6 mgP/L
Sequencing Batch Reactor (SBRs)
Sequencing batch reactors operate with many of the process that the MLE tanks due in series in one tank Benefits include Decreased variation in construction Decreased variation in operation Decreased space necessary
Much like the MLE process, it is necessary to implement this system in parallel
Wilderer et al. (2001) This method can more easily tolerate hydraulic or organic “shock” loads with its flexible aeration design (Mikkelson, 1995) overall aeration efficiency enhanced to 30% Sequencing batch reactors are documented to have a total cost around 1,066,000 US$ (Hartman and Cleland, 2007) Mikkelson (1995) “Based upon 1986 EPA cost comparison of a 1.0 MGD facility, the installation of an SBR represented 10% cost savings as compared to a flow-through [e.g MLE] system,” (38) 10 mgP/L*0.15=1.5 mgP/L
Evaluation Matrix
Evaluation of CW, MLE, and SBRs yield SBR as the most optimal solution
SBR Wastewater Research
Background on Research Has been running for around 4 years Two Liter system Five phased systems Aeration levels around 0.2 mg/L during aerobic phase
Research on lowering aeration levels while still keeping nutrient removal efficiencies high
Average Inflow Values (Secondary Treatment System) COD 500 mg/L NH3-N 25 mg/L TN 45 mg/L PO4-P 10 (9.88 mg/L)
Removal efficiencies between % For COD =98.9% For NH3 =92.8% For P =82.9%
However while nutrient removal is stable, TSS/VSS is not
Conclusion
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Bibliography/Graphics Slide 2: wastewater/, Slide 4: Slide 5: Slide 6: lange.ma/countrysites/action_q/download%3Bdocument/DOK_ID/ /type/pdf/lkz/MA/spkz/fr/TO KEN/ZnetjKCx8xj3bU3qN6jNAaemUMk/M/LY2QgA Slide 7: Slide 8: Slide 10: Brix, H. (1993). Wastewater treatment in constructed wetlands: system design, removal processes, and treatment performance. Constructed wetlands for water quality improvement, 10. Slide 11: Slide 14: Vidal, N., Poch, M., Martí, E., & Rodríguez ‐ Roda, I. (2002). Evaluation of the environmental implications to include structural changes in a wastewater treatment plant. Journal of Chemical Technology and Biotechnology, 77(11), 1207 Slide 15: design-build-projects/robindale-wwtp-renovation-expansion/ Slide 18: Wilderer, P. A., Irvine, R. L., & Goronszy, M. C. (2001). Sequencing batch reactor technology. Intelligence Water Association (IWA) Alliance House, London, UK, 29 Slide 19: 20, Wilderer et al., 2001
Bibliography/Graphics Slide 25: Slide 2: facilities-program Slide 26: Hammer, D. A. (Ed.). (1989). Constructed wetlands for wastewater treatment: municipal, industrial and agricultural. CRC Press. Hartman, P. and Cleland, J. (2007). Wastewater Treatment Performance and Cost Data to Support an Affordability Analysis for Water Quality Standards. Prepared by ICF international for Montana Department of Environmental Quality. Oppelt, T. (2000). Constructed Wetlands Treatment of Municipal Wastewaters Enivonmental Protection Agency (EPA) Manual. Cincinnati, Ohio Slide 34: facilities-program