Wastewater discharges from the University operate under an EPA issued National Pollutant Discharge Elimination System (NPDES) permit in compliance with the Massachusetts Clean Waters Act. The wastewater discharged into the Cape Cod Canal meets or exceeds all permit requirements. Those parameters that indicate “no limit” are still treated to the best of our ability to protect the environment.
Water Conservation Projects + Buildings Tied into the System
The current WWTP was permitted for use by the EPA in 2001. The NPDES permit has been renewed and approved every 5 years.
The WWTP permit allows for up to an average of 77,000 gallons per day (gpd) of treated water to be discharged with a maximum allowable discharge of 140,000 gpd. The average daily discharge from the WWTP is 55,000 gpd when cadets are on campus. The discharge volume drops significantly on weekends and between semesters and summer the average daily discharge is 10,000 gpd.
All waters flowing down drains and toilets are pumped and treated through the WWTP. Sources of wastewater include dormitory showers, toilet flushings, sinks, locker rooms, dining hall sinks and dishwasher waters, and laundry rooms.
When the TS Kennedy is docked at the pier during the year, the ship is connected to the wastewater collection system and wastewater is treated like all other wastewaters. However, when the TS Kennedy arrives back in port after Sea Term, the holding tank on the ship is offloaded and sent to an offsite treatment facility that can handle sea water.
The WWTP receives the wastewater from lift stations across the campus. The treatment system is a single batch reactor design with disk filter, activated sludge secondary type treatment plant followed by sand filters and ultra violet disinfection facilities, and sludge disposal. The plant was upgraded in 2015 with additional blowers, a new screening unit and additional pumps.
- The blowers handle oxygen depletion during treatment processes
- The screening units remove heavier solids (i.e. mop heads, trash, clothing) that make it into the system via toilets or drains
- The pumps are intended for future treatment to reduce nitrogen
The NPDES permit outlines all of the required testing parameters. Testing includes both the influent and effluent waters. The following is a summary of testing requirements:
|pH||6.5 – 8.5||N/A|
|BOD||30 mg/l||report weekly from composite sample|
|TSS||30 mg/l||report weekly from composite sample|
|Settleable solids||no limit||report daily from grab sample|
|Fecal coliform||14/100 ml||report weekly from grab sample|
|Enterococci||35/100 ml||report weekly grab sample|
|Total Nitrogen||no limit||report quarterly from composite sample|
|Total Kjeldahl nitrogen||no limit||report quarterly from composite sample|
|Total Ammonia (as N)||no limit||report quarterly from composite sample|
|Whole effluent toxicity||LC> 50%||report annually from June composite sample|
BOD (biological oxygen demand) and TSS (total suspended solids) are sampled and tested on both influent and effluent. Composite sample is collected over a 24 hour period.
All testing performed on samples from the WWTP are reported to the MaDEP and EPA per the permit.
The wastewater discharged into the canal meets or exceeds all permit requirements. Those parameters that indicate “no limit” are still treated to the best of our ability to protect the environment.
pH is adjusted using magnesium chloride, or Milk of Magnesia, to ensure a neutral level between 6.5 and 8.5. It is a much better alternative than other hydroxides that are highly corrosive. Magnesium hydroxide is nontoxic to aquatic plants and animals which is why we use it.
The total suspended solids, TSS, has a 98% removal rate in the treatment plant. The permit requires at least 85% removal rate. TSS is the amount of solid particles allowed to remain in the water when it’s discharged.
Biological Oxygen Demand, BOD, has an average removal rate of 96%. The permit requires at least an 85% reduction. BOD is one of the contaminants that can lead to eutrophication along with nitrogen, however the WWTP is very effective at reducing BOD that would not contribute to problems in the canal or area tributaries.
Fecal coliform testing is completed in our lab and the Enterococci is sent out to an independent lab. These results routinely test zero with a rare testing between 2-10 colonies per 100 ml which is well below the permit limits.
The annual toxicity test has been met since the test was required in 2011.
Nitrogen testing is a requirement of the permit but does not include limits on discharge levels. The wastewater is treated to reduce Nitrogen as effectively as possible with average reductions at 35 mg/l.
Treated water is discharged through a dedicated pipe, across from the athletic field, that extends into the flow of the canal current located 12 feet below mean low tide.