Environmental Science/Gulf of Mexico Dead Zones
QUESTION: We are working on a science project where we have to explore various environmental issues and come up with solution plans. For that purpose, we've specifically chosen to investigate the presence of dead zones in the Gulf of Mexico. From our research, we now know that eutrophication caused from agricultural runoff and human activity led to the exhaustion of oxygen in several areas along the coast of the gulf.
Part of our assignment requires us to reach out to professionals in this field of study to gather information. We would really appreciate if you could fill us in with the statistical data, and perhaps some possible solutions for this situation.
Thanks so much for your time and effort, we look forward for your reply!
ANSWER: Unfortunately for you, I'm not the one to be able to help out. There is a scientist/ researcher at the University of Georgia who mobilized and was out on the water collecting samples after the Deepwater Horizion Incident. I suggest that you contact her: her contact information is below. Sorry, but I cannot help because I don't study that area.
Dr. Samantha (Mandy) B. Joye
Athletic Association Professor of Arts & Sciences
Dr. Mandy Joye
Department of Marine Sciences
University of Georgia
Athens, GA 30602-3636
Office Phone: (706) 542-5893
Lab Phone: (706) 542-6818
FAX Number: (706) 542-5888
The Joye Research Group
Dr. Joye is studying the water column and seafloor impacts of the 2010 BP Gulf of Mexico oil spill. Please visit the 2010 Macondo Well Blowout research for details.
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Thank you anyways, we appreciate your reference.
We were wondering if you have any information about sewage treatment that removes nitrogen and phosphorus. Is this possible? If so, how much approximately does one treatment facility cost?
Once again, thanks for help!
Bill and Angel
ANSWER: About Nitrogen and Phosphorous removal:
All bacteria have nitrogen and phosphorous in their cellular makeup. The approximate ratio of Carbon:Nitrogen:Phosphorous is about 120:20:1 depending upon how the Carbon is measured. There are many ways of removing N & P from sewage. Perhaps the easiest is by focusing on the ammonia (NH3) and getting rid of that first. In biological processes, there are any number of ways of reducing N & P. The most popular is by providing an anaerobic front end which forces the bacteria in the biomass into a luxury uptake of phosphorous. Then the water is supplied with a very small amount of oxygen and this changes the chemistry slightly causing the nitrogen to be released to the atmosphere. (The entire process is quite complex and the chemistry is quite detailed, MS level in environmental engineering type detail, so I won't go into it here. I can supply references, if you want to go further, but be warned the chemistry involves ORP). From there, the sewage is aerated to remove the carbon and convert it into biomass which is removed.
For even a relatively small plant the costs of biological treatment are quite high. A plant for a city of 5000 people can handle wastes of 600,000 gallons per day (2.2 million liters/ day) and the cost of a plant would be in the millions of dollars, probably about 2-5 million dollars including the land and everything else, and it is heavily dependent upon the treatment train (the steps involved ) and the type and number of tanks, and the sludge processing equipment.
I hope that helps. If you have further questions, please contact me directly:
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QUESTION: I was going to send you an email, but I opted to ask here, hope that you don't mind.
Your resources are extremely helpful, thank you so much!
However I'm wondering if you happen to know the projected data of nitrogen and phosphorus content after implementing the sewage treatment facility.
After treatment to remove Nitrogen and Phosphorous, the approximate levels of each should be less than 3 ppm (parts per million or milligrams per liter) total nitrogen, of which less than 0.2ppm should be Ammonia or NH3 Nitorgen.
Again, depending on treatment levels, the Phosphorous level can be as low as 0.02 ppm, but more realistically 0.05 ppm. The level of less than 0.2 ppm is somewhat critical because below that there is not enough Phosphorous to trigger an algae bloom. Note that most algae and some other organisms can absorb Nitrogen directly from the atmosphere which is about 79% Nitrogen.
Actually the water from an advanced waste water treatment plant can be pure enough to recycle into groundwater and lakes which are drinking water sources.