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Water Reclamation Plant

Follow me on my Environmental Engineering (ENGS 37) adventure to three sites over three days starting with a trip to the water reclamation plant.

Pictured above: cells eat sewage organic matter while in the aerator.

1. Hanover Wastewater Treatment Plant

Wastewater treatment
One of the primary clarifiers.

Before this term, I had never considered what happened to wastewater after it went into the pipes. In ENGS 37, Environmental Engineering, we spent a couple weeks learning about water treatment, including biological wastewater treatment. The system has two parts: primary treatment, which includes physical removal of particulate, and secondary treatment, which includes biological treatment. One type of secondary treatment is an activated sludge system where organic matter in pretreated sewage is consumed by bacteria. The water is then put in a separate settling tank to remove the bacteria. Some of the bacteria is recycled from the settling tank to increase system efficiency.

Empty Clarifier
Duckweed in an empty clarifier.

The setup at the Hanover wastewater treatment plant, which we visited on Monday, almost exactly followed this system, which was exciting to see. At the conclusion of our visit, we got to see some “bugs” under the microscope in the lab on site. It amazes me that these little bacteria can clean water so well. Nature is amazing.

2. Class of 1978 Life Sciences Center

Life Science Center
The Life Sciences Center, a LEED Platinum certified building.

My second stop on Wednesday was the Life Sciences Center, which houses the biology department. I was surprised to learn that the building is actually LEED Platinum certified (super environmentally friendly!). What I found most insightful was that the engineers had built a small test building to try out certain design and construction elements. Research based construction! How cool! We heard from our tour guide about many of the things I had learned in my sustainable design class, like HVAC specifications such as air exchanges. The finale of our visit included a trip to the enthalpy wheel in the basement of the building. This awesome feat of engineering takes heat energy from outgoing air and applies it to incoming air so that the incoming air is preheated or pre-cooled depending on the temperature outside. Less energy is used to heat or cool the building.

Staircase cover at the LSC
Metal staircase cover at the LSC designed to prevent light pollution.

3. Dartmouth Organic Farm

Solar Greenhouse
The solar greenhouse at the O-Farm.

My last stop on Friday was to the Organic Farm! While at the farm, we focused on the construction of the barn, the hoop house, and the solar greenhouse. The barn is a beautiful example of timber frame construction. The hoop house employs a cheaper construction style with a metal hoop framing and two layers of plastic. The solar greenhouse was apparently built by a past engineering class from parts of a recycled old greenhouse. There are big tanks of water in the greenhouse that work as thermal mass to keep the greenhouse warm (and are also used to grow tilapia!). Both the hoop house and the solar greenhouse allow extension of the growing season by creating warmer microclimates. We discussed the cost justifications in terms of increased farm productivity for all of these buildings, which brought us back to one of the concepts of environmental engineering: "green" design if done right can be the more economical option.

Squash
Squash grown at the O-Farm.

For more information on ENGS 37, click here: Introduction to Environmental Engineering

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