An Analytical Comparison between Secondary Wastewater Treatment Methods; Constructed

Wetlands (CW), Modified Ludzack-Ettinger (MLE), and Sequencing Batch Reactors (SBR)

Jacqueline GermanCBE 555

March 9, 2015

An Analytical Comparison between Secondary Wastewater Treatment Methods; Constructed

Wetlands (CW), Modified Ludzack-Ettinger (MLE), and Sequencing Batch Reactors (SBR)

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 systems7. Conclusion

Secondary wastewater treatment is responsible for removing excess dissolved organics

Animations and youtube videos of the wastewater treatment process

http://www.gbra.org/wastewater-treatment.swf

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) COD500 mg/L NH3-N25 mg/L TN45 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 60-90% 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 Stage NO3-NO2(Nitrate-Nitrite) N2+H2OAeration Stage NH4 (Ammonia)+O2 NO3-NO2

(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) COD500 mg/L NH3-N25 mg/L TN45 mg/L PO4-P 10 (9.88 mg/L)

Removal efficiencies between 83-

100%

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: http://www.constructionweekonline.com/article-19901-dubai-to-crack-down-on-industrial-wastewater/, http://water.usgs.gov/edu/watercyclefreshstorage.html

Slide 4: http://upload.wikimedia.org/wikipedia/en/5/54/ESQUEMPEQUE-EN.jpg

Slide 5: http://www.gbra.org/wastewater-treatment.swf

Slide 6: http://www.hach-lange.ma/countrysites/action_q/download%3Bdocument/DOK_ID/14786173/type/pdf/lkz/MA/spkz/fr/TOKEN/ZnetjKCx8xj3bU3qN6jNAaemUMk/M/LY2QgA

Slide 7: http://www.faqs.org/patents/imgfull/20120187042_02

Slide 8:http://articles.bplans.com/should-i-consider-factoring-to-smooth-out-my-cash-flow/

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: http://environmentalconsultingohio.wordpress.com

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: http://lib.znate.ru/docs/index-35825.html?page=13, http://www.waterdesignbuild.com/water-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: http://www.hazenandsawyer.com/work/services/energy-audits-and-efficiency/,

http://www.aaees.org/e3competition-winners-2013gp-research.php

Slide 2: http://www.erc.uic.edu/energy-efficiency/illinois-energy-now-programs/waste-water-treatment-facilities-program

Slide 26: http://articles.bplans.com/should-i-consider-factoring-to-smooth-out-my-cash-flow/

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: http://www.erc.uic.edu/energy-efficiency/illinois-energy-now-programs/waste-water-treatment-facilities-program