Category: Water (page 1 of 6)

Where does Boston’s wastewater go?

This June, the Office of Sustainability organized a field trip to the Deer Island Wastewater Treatment Plant. Current and future Eco-Ambassadors spent a cloudy Friday morning touring the plant and learning about the life cycle of their wastewater, from the drain to Boston Harbor. The field trip encouraged mindfulness about water consumption and showed how wastewater treatment is engineered to maximize efficiency, providing wastewater management for decades to come.

In 1972, the Environmental Protection Agency (EPA) passed the Clean Water Act. The act, among other things, required cities to process wastewater with both primary and secondary treatment. In 1987, Massachusetts created the Massachusetts Water Resource Authority (MWRA) with the goal of updating Boston’s wastewater treatment to comply with the new EPA standards. In 2000, after a decade of planning and construction, the current Deer Island Wastewater Treatment Plant was completed.

Deer Island services 2.5 million people in the Metropolitan Boston area and processes an average of 370 million gallons of wastewater daily. How does wastewater “influent” make it to Deer Island? Gravity drives influent through conveyance tunnels underneath the city.  Massive pumps lift the influent 80 to 150 feet up into the plant. Deer Island has a wastewater capacity of 1.3 billion gallons per day, and on rainy days more pumps are brought online to accommodate increased influent. 

Process Control Project Manager Timothy Beaulieu explains primary treatment to the group

After arriving at Deer Island, influent undergoes primary treatment. Grit is removed and disposed of at landfills, then clarifiers remove pollutants. At this stage, about 60% of suspended solids and 50% of pathogens and toxic chemicals are removed. Gravity separates sludge and scum from the wastewater – scum sits on top of the water while sludge sinks to the bottom.

Once primary treatment is complete, wastewater continues to secondary treatment. Mixers, reactors, and clarifiers remove remaining solids through biological and gravitational processes. Deer Island manufactures oxygen to feed microorganisms which consume dissolved organic matter. After secondary treatment, 85% of pollution has been removed from the wastewater.

Effluent is disinfected and then dechlorinated before diffusing into Massachusetts Bay

The final step before wastewater “effluent” is discharged is disinfection. Effluent is treated with sodium hypochlorite to kill any remaining pathogens, then sodium bisulfite is added to dechlorinate the water. Effluent is released into the Massachusetts Bay through over 50 individual diffuser pipes, ensuring rapid and thorough mixing with ocean water. The effluent is monitored for appropriate chemical and oxygen levels to protect the local ecosystem.

Egg-shaped digestors use bacteria to break down sludge and scum to produce fertilizer

But what happens to the sludge and scum leftover from primary treatment? The solids are first thickened in centrifuges, then added to egg-shaped anaerobic digestors. The digestors are huge, 90 feet wide and 130 feet tall, and carefully maintain a pH and temperature that mimic the human body. Bacteria already present in the waste break down the sludge and scum into methane gas, carbon dioxide, and water vapor. The methane is captured and converted into 95% of Deer Island heating needs and 20% of electricity needs.

Digestion reduces sludge and scum quantities by 55%, and the remaining solids are pumped to the MWRA pelletizing facility in Quincy. The resulting organic nitrogen fertilizer, meeting strict EPA and MA Department of Environmental Protection requirements, is used in agriculture and forestry. Additionally, air from Deer Island is scrubbed of sulfur using filters and activated carbon to prevent sulfur dioxide emissions.

After visiting Deer Island, it’s clear that the plant is designed to operate in the most sustainable way possible. Every output – water, air, gas, solids – is either cleaned to meet environmental standards or repurposed as energy or fertilizer. Residents can rest assured that their wastewater is properly treated thanks to the care and effort of Deer Island planners, engineers, and operators. 

Earth Month at Tufts 2018

Tufts has a month-long series of events planned to educate the community about sustainability issues. The month will culminate with an Earth Day celebration on the Medford/Somerville campus.

April 2nd
Tom Thumb Student Garden
Garden Club Tea Swap
8:00-9:00PM, Eaton 203

April 3rd
Tufts University Phone Bank to Defend Transgender Equality
6:00-9:00PM, LGBT Center

April 3rd
Talking 100% renewable energy w. State Reps. Connolly and Barber
7:00-8:00PM, Barnum 104

April 4th
Students for Environmental Awareness -SEA
Chasing Coral Screening and Discussion
7:00-9:00PM, Terrace Room

April 5th
Environmental Studies Program, Tufts University Lunch & Learn:
Land Cover in New Hampshire
12:00-1:00 PM, Rabb Room

April 5th
Tufts University Urban and Environmental Policy and Planning
Building Resilient Communities Networking Night
5:30-7:30PM, 51 Huntington Ave, Boston

April 6th
WSSS Symposium 2018: Water in Humanitarian Emergencies
8:30AM-4:30PM, The Fletcher School

April 6th
Tufts Food System Symposium
10AM-2PM, 51 Winthrop Street

April 6th
TCA x Polykhroma Present: Visions
8:30-10:30, 46 Quincy Street Basement

April 7th
Social Impact Ideation at Tufts
11:00AM-2:00PM, Robinson Hall, Rm 246

April 9th
An Evening with D’Lo
6:00-7:30PM, Crane Room

April 10th
Students for Environmental Awareness -SEA
Startups and App Development: A Talk with Soli’s CEO
7:00-9:00PM, Crane Room

April 12th
Environmental Studies Program, Tufts University Lunch & Learn:
Somerville Immigrant Worker Health Project: Seeing Environmental Justice Through an Occupational Health Lens
12:00-1:00 PM, Rabb Room

April 13th
Demain: Reimagining Community Systems For A Better Tomorrow
2:00-6:00PM, ASEAN Auditorium

April 19th
Environmental Studies Program, Tufts University Lunch & Learn:
The Road to Food Waste is Paved with Good Intentions
12:00-1:00 PM, Rabb Room

April 26th:
Environmental Studies Program, Tufts University Lunch & Learn
Environmental Justice in the City of Chelsea
12:00-1:00PM, Rabb Room

If you are planning any Earth Month events at Tufts that were not included on this list, please contact sustainabilityoffice@tufts.edu and we will add them.

Wolves Impact Ecosystem and Geography of Yellowstone Title Image, background has phases of moon cycle.

In 1995, Yellowstone brought the wolves back to the park. After 70 years without wolves, the reintroduction caused unanticipated change in Yellowstone’s ecosystem and even its physical geography. The process of change starting from the top of the food chain and flowing through to the bottom is called trophic cascades.  According to Yellowstone National Park, here are a few ways the wolves have reshaped the park:

Deer: It’s true that wolves kill deer, diminishing their population, but wolves also change the deer’s behavior. When threatened by wolves, deer don’t graze as much and move around more, aerating the soil.

Grass and Trees: As a result of the deer’s changed eating habits, the grassy valleys regenerated. Trees in the park grew to as much as five times their previous height in only six years!

Birds and Bears: These new and bigger trees provide a place for songbirds to live and grew berries for bears to eat. The healthier bear population then killed more elk, contributing to the cycle the wolves started.

Beavers and other animals: Trees and vegetation also allowed beaver populations to flourish. Their dam building habits provided habitats for muskrats, amphibians, ducks, fish, reptiles, and otters.

Mammals: Wolves also kill coyotes, thereby increasing the populations of rabbits and mice. This creates a larger food source for hawks, weasels, foxes, and badgers.

Scavengers: Ravens and bald eagles fed off of larger mammal’s kills.

Most surprisingly, the land: Soil erosion had caused much more variation in the path of the river. But with elk on the run and more vegetation growing next to rivers, the river banks stabilized. Now, the wolves have changed Yellowstone’s physical geography.

The story of wolf reintroduction demonstrates how crucial every member of an ecosystem is important to a landscape.

Learn more about the wolves in Yellowstone, background wolves in grass

 

Intern, MassDEP (Various Locations)

The Department of Environmental Protection is the state agency responsible for ensuring clean air and water, the safe management of toxics and hazards, the recycling of solid and hazardous wastes, the timely cleanup of hazardous waste sites and spills, and the preservation of wetlands and coastal resources. In an effort to assist MassDEP with its succession planning, MassDEP continues to recruit individuals who are interested in working and utilizing their skills in the environmental field. MassDEP is providing opportunities to undergraduate students, graduate students, law school students, and other individuals who are seeking experience in the environmental field.

Application Deadline: November 25th
Apply Online

Environmental and Sustainability Intern, Schreiber Foods (Green Bay, WI)

The duties of the Environmental and Sustainability intern will be focused on supporting the execution of the environmental/sustainability capital projects and assisting with environmental regulatory programs. This position will be based at Green Bay Home Office location.  This is a paid, year-round internship. Schreiber Foods offers flexible scheduling to accommodate your class schedule.  This position will start Fall 2016.

Apply Online
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