Balancing the technological dependent solutions to mitigating climate change, WA 7th Graders spent Earth Day April 22, 2010 at Walden Pond in Concord, MA (click) for the day. Thoreau challenges our own intrinsic capacity for regeneration and transformation: “We must learn to reawaken and keep ourselves awake, not by mechanical aids, but by an infinite expectation of the dawn, which does not forsake us in our soundest sleep. I know of no more encouraging fact than the unquestionable ability of man to elevate his life by a conscious endeavor.” Students take the long view above, tapping into their ability to observe closely the world around them. The park interpreter explains 1) how the isolated kettle pond has flooded over the sandy beach shore due to heavy March rain and that the water line will remain high through the summer while the water slowly percolates through the pond bottom to the groundwater below 2) the decline of one prominent Chesnut Trees in New England due to fungus infection, wherein the tree can grow a short height and sent off offshoots before dying, and 3) White Pine secondary succession patterns. Students surround a replica of Henry David Thoreau, a devout walker and master pragmatist, while listening to a park ranger. Ghost like memorial of Walden’s original cabin inspires the imagination.

This past fall the Upper Blackstone Water Pollution Abatement District (UPWPAD)began operating at increased rated capacity (up to 150 MGD from 56 MGD) and with tertiary treatment methods wherein specific bacteria break down phosphate and nitrate compounds (decreasing effluent levels by a factor of 10), which can lead to eutrophic and hypoxic aquatic environments. Ann Cohen instructs the students above on the topic. As well students observe the final output of treated water to a canal that flows directly into the Blackstone River near Route 20 and 146. The recent record rains had a volume of wastewater flow into the plant peaking near 190 MGD, which the plant was able to manage.

The farm has a polyculture of fruits and vegetables as a well as a diverse selection of apples and peaches. With “Westfield Seek-No-Further” apples in hand, Ken Nicewicz explains to students the role of traps in Integrated Pest Management (IPM). Given the both risks of pesticide residues on apples and with organic approaches to managing pests, studies have claimed IPM be the optimal strategy. Diversity of species is an important element in sustainable agriculture, and one that enriches our eating experience and sense of narrative as well as preserving agro-cultural heritages. Out of the 1,000′s of known varieties worlwide, a few of the American apples that start with “W” include the “Wolf River”,”Winter Banana”, and “Winesnap”. Ken also points to a ruined corn crop due to early winter weather in October. Last, Ken explains how fruit species are grafted. Corn was reported to be a nitrogen hungry crop whereas apple trees’ demand for nitrogen tapers off during the growing season. Ken also explained the role of weather, geography, and microclimates in influencing crop growth along the hill-top to valley spectrum of the farm.

AP Environmental Science students visited the farm this fall. Coopers operates at equilibrium capacity with its local community: retail sales match consumer demand. Retail means, however that Coopers must handle the bottling on its own which includes modern, mechanized milk production practices such as pasteurization ( raising the milk temperature to 145 degrees F for disinfection), homogenization (even mixing of cream/fat to appeal to consumer preferences), and bottling (plastic and reusable glass). James Cooper gave the students a tour of the farm highlighting 1) the practice of pasture farming wherein grazing is managed through rotation to ensure that the grass stays above 3 inches to maintain growth vitality and below 8 inches to avoid the plant from going to seed, 2) the need to maintain proper N-P-K soil ratios through monitoring and corn crop rotation 3) Coopers lack of capacity to make feasible waste to energy production due to scale 4) lowered corn yield due to heavy rain last summer. Pictured above right is a “cycle of life” image of a calf born the day of the trip, reminding us all of the wonder of life.

Worcester manages wastewater and run-off by three means: sanitary sewer system, surface sewer, and combined sewer system. Students travelled to the Upper Blackstone Water Pollution Abatement District’s Upper Blackstone Wastewater Treatment Facility (UBWWTF )in Millbury to study how Worcester and surrounding towns manage and treat their waste water (“sewage”). While the surface sewer system in Worcester directs stormwater to the nearest waterway, the combined sewer system collects both sewage and stormwater sewage in 4 square central miles of the city and directs it along with sewage from homes and businesses to the UBWWTF. The plant averages 30+ million gallons a day using “primary”, physical treatment (settling through gravity), “secondary” biological treatment ( decomposition and absorption of organics, fine solids, dissolved metals, ammonia, phosphorous by microbes living in the aeration tanks followed by a second round of settling), and chemical treatment (chlorine disinfection). Treated water flows into the Blackstone River, making up over 60% of the total headwater flow volume at points in the summer. In 2007, the plant removed 6,238 tons of suspended solids from the waste stream. Sludge is incinerated on-site using various air pollution controls (scrubbers, electrostatic precipitation, oxidation). Other systems data include annual heat energy demand (2007) of 69 million cubic feet of gas and 16.2 million kWh. Currently, the plant is undergoing a $ 180 million renovation to deal in part with EPA regulations regarding phosphorous and nitrogen pollution.

In the event of heavy rain the combined sewer system can become overwhelmed leading to Combined Sewer Overflows (CSOs) that pollute local waterways. In 1980, Worcester built the Quinsigamond Ave Combined Sewer Overflow Treatment Facility (QACSOTF), which pumps sewage from the combined system to the UBWWTF during dry periods and treats the sewage during heavy rains by using bar screens, settling, and disinfection before capacity exceeding flow is discharged into the Blackstone River.

For more information on the UBWWTF go to UBWPAD

For more information on the QACSOTF go to DPW (click on city departments-public works-combined sewer overflow treatment)

Environmental Science students visit the city’s water filtration plant in Holden, MA. Pictures above display i) the role that computers play in monitoring and managing each treatment step, ii) plant manager Bob Hoyt fielding a question from upper school science teacher ,Paul Elkins – in the room for coagulation (fast mixing of aluminum sulfate and cationic polymer binds to debris, forming flocs, which after going through slow mixing, or flocculation, will be filtered out by the top layer of the direct filtration beds (comprised of 5 feet coal, 1 foot sand, 1 foot gravel) and de-ozonation (excess ozone needs to be converted back to O2 before being released outside)- and iii) students peering over the direct filtration beds (filtering water at a rate of about 6 gallons/sf/minute). Typically, the plant reaches it annual maximum during the summer, with 32+ MGD, well below its maximum capacity of 50 +MGD. If and when a water main breaks, the plant will have to compensate for the water pressure drop and lost water by increasing filtration rates by a few MGD. The city is working to mitigate the contamination threat from “cross connections” which is when non-potable water (contaminated with pesticides, chlorine, industrial materials, etc.) back-flows into the water distribution systems due to negative pressure. For more information click on the Water page above and previous water post