12/20/2012 SEWER COMMISSION Minutes

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r � to treat the seasonal increases, with some bacteria growing slowly, an issue that would not occur with shellfish as they would remove nitrogen in algae from summer increases. Regarding quantification of the nitrogen removal, treatment plants were typically sampled monthly but the eight of all shellfish harvested commercially is recorded electronically when sold to dealers. The nitrogen content of oysters from the Mashpee River has been measured, with some preliminary data from quahogs received, confirming Mr. York's figures. Regarding the total nitrogen removal required, Mr. York stated that the total amount needing removal from both bays totaled 29.4 tons per year and the Mashpee portion estimated to be 9 tons from the Popponesset Bay and 9 tons from wauoit Bay areas. In Popponesset Bay,the Mashpee River would require the removal of .01 tons of nitrogen per p � g year, while Shoestring Bay would be 4.04 tons, Ockway Bay would be 0.87 tons and Popponesset Bay itself would be 1.46 tons. Regarding the-draft MEI'Report for wa uoit Bay, conversion from kilograms of nitrogen per day to tons per year gives a total load of 42 tons in the watershed with 18 tons requiring removal. Mr. York noted that a stable,, giant seaweed bed located in the center of the bay was removing 25 tons of nitrogen per year. Mr. York also discussed consideration of the bottom of the bay and the grater column as part of the end result, adding that some of the nitrogen was being pulled from one part of the systenn.,.which originated from another part of the-system. Mr. York stated that the Estuaries Report recommended that the nitrogen load from septic systems in the watersheds be removed from the sub-estuaries where the largest loads existed. Those Waquoit Bay sub-estuaries in Mashpee are Little River-, Jehu Pond, Hamblin Pond and Great River needing a total of 6 tons of nitrogen removed per year. Mr. York would propose addressing that area with the shellfish project. The-nitrogen reduction needed in these sub-watersheds was broken down in the estuaries report into 3.3 9 tons in Hamblin Pond, 0.32 in Little River, 1.05 in Jehu Pond and o.9 in Great River_ These sub-estuaries are designated as shelIfxsh growing area SC 16 by the Division of Marine Fisheries.in harvest records. The Moonal is River sub-estuary in Falmouth is not a good area for shellfish remediation because shellfrshing is prohibited in most of it. The Moona is River is in the Quashnet River watershed with the upper part in Mashpee. Sewer ing and/or other solutions would be needed there. Mr. Yor'k proposed utilizing oysters in the Mashpee River, noting that, to 2008, 525,000 oysters were harvested and removed 260 lig of nitrogen, representing %of the clean-up of the riv r. There have been no fish kills since the establishment of the oyster project. Mr. York st ted that the project was initiated in 2004 and has not been impacted by diseases and predators due to the lower salinity of Mashpee River waters. It has been conservatively estimated that the oysters filter twice their weight of algae out of the water. The Chair inquired about the amount of nitrogen reproved during the filtering process and Mr. York responded that about twice the weight of nitrogen in the oyster_ 'Mr. York sued that the Town project provided recreational fishing but that the Tribe had a commercial oyster farm at the mouth of the river, with plans to continue increasing their farm. The Town's fishery oyster production would be increased,,. doubling the oyster seed production capacity in May of 2013, with the Delp of Ain ricorps, in an effort to increase the oysters to 1 million harvested. Mr. York reported that the Tribe had received an environmental award from the EPA for growing oysters, and planned to increase their seeding from 750,000 to 2 million in 2013 with increased seeding'n the future to harvest 4 million oysters. The denitrification by bacteria in the oyster beds combined with the oyster