A Study on Optimizing BiologicalPhosphorous Removal by Changing

Aerobic Operating Times

Phillip Dixon and Juan Diaz-RoblesCEE 453 Laboratory Research in Environmental Engineering

December 11, 2004Cornell UniversityIthaca, NY 14850

Topics To Be Covered

Introduction to Phosphorous Removal

Experimental Objectives

Materials and Methods

Setup

Procedures

Results and Conclusions

Suggestions

References

Questions?

Introduction to Phosphorous Removal

Phosphorous is a Nutrient Essential to Plant Growth

Responsible for Eutrophication

Interferes with the Health and Diversity of the Water Body

Blooms of Algae

Clouds Water

Underwater Grasses Die

Fish Kills

Introduction to Phosphorous Removal

Very Important for WW Treatment Plants to remove Phosphorous from effluent

Phosphorous Removal Accomplished by

Exposing the WW to an aerobic/anaerobic sequence in a Biological Reactor

Introduction to Phosphorous RemovalAerobic/Anaerobic sequence will cause the reactor to

select for phosphorous removing microorganisms

Anaerobic Sequence Phosphorous Removing Microbes Release Phosphorous to Produce Energy to take up Fermentation Products

In the Aerobic Sequence the Microbes produce energy by oxidizing the fermentation products and simultaneously take up phosphorous

The Phosphorous is Removed from Solution as Intercellular Phosphorous in the Form of Sludge

Introduction to Phosphorous Removal

Phosphorous removal can be optimized by varying aerobic and anaerobic operating times

Something that was Researched throughout this Project

Experimental Objectives

The Research’s Objective was to find the

effect on Phosphorous Removal when Aerobic

Operating Times were changed while

maintaining a Constant Anaerobic Operating

Time

Materials and Methods•Setup

Refrigerator

Wastewater influent

Tap water influent

Samples collected

Materials and Methods•Setup

Peristaltic pump

Air source

Reactor

Pressure sensor

Stirrer

Effluent (Drain)

Materials and Methods•Procedures

States in reactor cycle

Influent wastewater (140 mL)

Influent tap water (2.66 L)

Anaerobic phase (1.5 h)

Aerobic phase (3, 4.5, and 6 h)

Settle (1 h)

Drain (up to 1.2 L)

Samples collected twice a day (minimum of 8 h apart)

Materials and Methods•Procedures

Colorimetric wet chemistry technique

Intensely colored antimony-phopho-molybdate complex

Blue-colored in acid medium (ascorbic acid)

Color proportional to phosphorous concentration

Combined color reagent4.9 N H2SO4 (50 mL)Ammonium molybdate solution (15 mL)Ascorbic acid solution (30 mL)Antimony-tartrate solution (5 mL)

Materials and Methods•Procedures

950 L of E-pure water

50 L of Sample

160 L of Reagent

Results and Conclusions

Removal and “Production” of Phosphorous

Results suggest that there is little evidence of Phosphorous Removal

Tried collaborating with another group

varied anaerobic operating time while keeping aerobic operating time constant

Results suggest little evidence of Phosphorous Removal

We have no recommendations on the Optimum Operating times for Phosphorous Removal

Results and ConclusionsFraction P Removed

-80%

-60%

-40%

-20%

0%

20%

40%

60%

80%

0 5000 10000 15000 20000 25000 30000 35000

Time (min)

Frac

tion

P re

mov

ed

Aerobic 6 hours Aerobic 3 hours Aerobic 4.5 hours

Suggestions

Precise manner in mixing the components for the combined color reagent

Samples should be diluted prior measuring in the spectrophotometer

Collect samples shortly after the draining stage of a cycle has been completed

Collect samples without sludge particles

Analyze samples shortly after collected or refrigerate them before analysis

References

CEE 453 Phosphorous Measurements. “Phosphorus Measurements.” December 7, 2004. http://ceeserver.cee.cornell.edu/mw24/cee453/ Lake Champlain Basin Program. “Phosphorus Pollution.” December 3, 2004. http://www.lcbp.org/phospsum.htm US EPA. “Eutrophication.” September 8, 2003. http://www.epa.gov/maia/html/eutroph.html Wisconsin Department of Natural Resources. “Wastewater Characterization for Evaluation of Biological Phosphorous Removal.” April 29, 2003. http://www.dnr.state.wi.us/org/water/wm/ww/biophos/1intro.htm Pictures of the laboratory setup are courtesy of Sarah.

Environmental Engineers’ efforts are in trying to avoid…