Thursday, April 16, 2015

Wastewater Facility at Govs

Did you know that Govs has its own Wastewater Treatment Plant right here on campus? 

This month in the library, we are highlighting the Treatment Plant in our display case as part of our ongoing community theme of WATER. I have to admit that I was skeptical of how fascinating a water plant could be, but it really is worth a closer look. 

The following description of our Wastewater Treatment Plant is courtesy of Wendy Reed, who oversees the facility. Pictures courtesy of Amy Custance.  

The original plant that served the campus was constructed in the 1960s. It was upgraded in the 1990s but despite these efforts, the system was consistently failing to meet the quality standards required. In 2000, the unit was replaced with membrane-based waste treatment technology which was able to increase the capacity of the system without increasing the physical size of the plant. The results have been a success with the facilities 99% compliancy rating. Richard Savage, the CFO at the time put it best, “Our treatment facility represents the Academy’s commitment to environmental stewardship, which is part of our legacy which began in 1763."

Water used in school activities flows through underground pipes to six pumping stations on campus before being pumped to the treatment plant. As it enters the plant, it flows through a grinder which breaks up large solids that can’t be treated by the system like sticks or rags. These pieces are caught on a screen and removed from the influent flow with this auger assembly. They are deposited into the
catch bag and removed daily.

The wastewater coming into the treatment plant is more than 99.9% water. Of the less than 0.1 % solids remaining, about half are organic in nature and can be broken down by the biological treatment process the plant (and most municipal treatment plants) uses. The remaining inorganic solids like sand settle out in this tank. The wastewater is aerated to keep it mixed and oxygen rich before flowing into the biological treatment tank. 

In the membrane biological reactor (MBR), the wastewater is mixed with air and an enhanced mix of bacteria which is called activated sludge and looks and smells like watery mud.  The bacteria use oxygen to decompose the organic material in the wastewater and convert it to carbon dioxide and water. The cleaned water is then drawn out of the tanks through microscopic pores in membrane strands that look like angel hair pasta and into these hoses. The activated sludge remains in the MBR to continue to treat incoming wastewater.

Before being discharged, the treated wastewater must be disinfected to remove any bacteria which may have passed through the membranes and into the MBR hoses. While many traditional treatment plants use chlorine for this step, the Governor’s plant uses ultraviolet light. It is safer than chlorine and extremely effective. It also does not leave a residual level of disinfection agent in the wastewater that might require further treatment or impact the discharge watershed.

The entire system is monitored and controlled by a programmable computer system. This continuously monitors all equipment at the plant and wastewater pumping stations and collects data about tan levels, equipment operation and flow. The data is maintained for EPA reporting purposes and displayed graphically to assist in process control and operation of the plant. The system also alerts the operator if conditions deviate from normal so that the situation can be quickly rectified. 


While most of the water quality testing that is required by the plant’s EPA permit is sent to an outside laboratory, the daily process control testing of the wastewater is done in a laboratory in the plant. This centrifuge is used to measure the amount of solids in the MBR. This is an indication of how well the biological process is working and whether excess solids need to be removed from the tank. The laboratory is also used to monitor pH, dissolved oxygen, ammonia nitrogen and temperature at various points in the treatment process.

Samples are collected daily from different points in the system and analyzed in the laboratory to make sure that the process is operating properly. The one on the left is the wastewater before it enters the MBR treatment tank. The jar in the middle has a sample of the activated sludge in the MBR. The jar on the right contains a sample of the final treated wastewater which will be discharged into the salt marsh.  Because salt water organisms are extremely sensitive to water quality, the effluent from the treatment plant has to be of higher quality than if it was discharged to a lake or freshwater stream. 

Thank you to Mrs. Case and Amy Custance for shedding light on our Water Treatment Plant with this amazing display. Inside the case, you can also find plenty of resources to research water treatment in general. Don't be afraid to ask if you have further questions. While me might not know all of the scientific answers, we can generally point you in the right direction to further your research!

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