Wednesday, February 6, 2008

Assabet River and Wastewater Treatment

Whenever I paddle the waters of the Assabet River, I can't help but be conscious of the role that wastewater treatment plays in the river's water quality. One reason for this is that I make my living as a wastewater treatment plant operator. The other reason is that I frequently feel droplets of water splash up from my paddle and contact my face and mouth. At these times, I like to believe that the five wastewater treatment plants that discharge up to 14 million gallons per day of treated effluent directly into the Assabet are being operated at optimum capability.

The State licensed operators charged with the above task have a huge impact on the river's day to day water quality. Most of these treatment facilities are using some of the best available technology to insure that any negative effect is minimal. Every few years the degree of treatment bar is raised, and these operators are challenged to meet even more stringent levels of treatment. I know that I, for one, appreciate their efforts and commend them for a job well done, especially in regards to disinfecting the water of disease causing pathogens.

The reason for the bar being raised is the result of advocacy efforts by groups such as the Organization for the Assabet River (OAR) and the Sudbury Valley Trustees (SVT). Oar has been measuring water quality, using techniques approved by EPA/DEP, at 29 locations since 2000. The collected data helps to demonstrate the need to reduce nutrient levels in the river's water. The nutrient culprits are phosphorous and nitrogen, and cause aquatic plants to grow too well and choke out other living organisms. These two nutrients are in the stuff we spread all over our lawns, and use to wash just about everything we need to get clean.

As of 2010, most of the earlier mentioned treatment plant operators will be required to remove total phosphorous down to 0.1 parts per million (ppm). That is 7.5 times lower than today's requirements. I remember operating a plant that discharged into Spencer Brook back in the 1980s. That plant needed to meet a 1.0 ppm phosphorous limit and I thought that was tough. Just how low is 0.1 ppm? Think of 1/10th of an inch in 16 miles! It is sort of like dancing the Limbo! How low can you go?

To meet these standards, the operators could use all the help we can provide. If we live in the Assabet's watershed, we can help by using cleaners and detergents that contain no phosphorous. There are many on the market and they state clearly on the container that they contain no phosphorous. It takes only a few minutes to check labels on laundry detergent, dishwasher detergent, carpet shampoo, etc.

Another area where the operators can be helped is with nitrogen removal. Because most of the removal techniques utilize biological methods, anything that inhibits the bacteria can throw a wrench into the works. One compound that especially inhibits the bacteria needed to perform nitrogen removal is quaternary ammonium. This compound is often found in floor strippers used in large buildings. Schools and businesses can stress to their cleaning personnel that products containing this compound not be used whenever floors are stripped.

Over the last 5 years I have noticed quite an improvement in the Assabet's water quality. I remember when low river levels in late summer meant nasty odors emanating from just upstream of the Powdermill Dam. In fact, driving down High Street , I'd often regretted not having rolled up my car windows (back when cars still had crank window handles). This past summer and fall saw the water level kept low while work was being done in the area of the dam, and I have yet to notice any negative effect.

If curious about wastewater treatment operations, checkout the website of the Massachusetts Water Pollution Control Association:

More information about river advocacy groups OAR and SVT can be found at the "Relevant Links" section of this blog.

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