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The Biology of Wastewater Treatment

By Jamie Welch, Worcester Prep, Berlin, MarylandThe upgrades currently taking place at the Berlin Wastewater Treatment Plant are comprehensive, and will allow the plant to fully process all the wastewater that goes through the system down to near drinking water quality.  The technology that the Town of Berlin, MD is installing was made possible thanks to a grant and some low interest Water and Environmental Program loans from the USDA.  These upgrades will help to remove the pathogens, nutrients and other pollutants from the influent.

Technology that is being installed as part of these upgrades is called a SBR or sequencing batch reactor.  I recently spoke with Jane Kreiter, Director of Water and Wastewater for the Town of Berlin, about this new technology and got a look at the lab where the Berlin wastewater officials monitor every stage of the treatment for specific criteria.

The new SBRs being installed at Berlin’s wastewater plant will all work in essentially the same way:  there will be three different SBR tanks installed as part of the ongoing upgrades, and Kreiter says that these will contain different amounts and kinds of bacteria to break down certain types of “bad” nutrients such as nitrogen and phosphorous.  Giant blowers at the bottom of each tank blow varying amounts of oxygen into the tanks, causing the oxygen to slowly bubble to the top.  The oxygen is needed to maintain the biomass inside the tank so that they can be healthy and break down and remove the various constituents in the waste stream.  When the bacteria are young in the biomass, they consume and break down a lot of the nitrogen and phosphorous, but as they begin to get older, they become full and less efficient at breaking down nutrients.  When this happens, they die and fall to the bottom of the SBR.  The dead bacteria are then removed from the bottom of the tank by way of a pump assembly and sent to a digester.  The amount of bacteria and oxygen in the SBR must be constantly monitored to ensure that the right amount of contaminants will be removed at each stage of the treatment process inside the SBR.

After the influent has gone through the entire treatment process it is ready to be sent to the spray irrigation site in Libertytown, Maryland.  Samples of the treated effluent are collected as they are leaving the plant and are taken to the lab.  Kreiter was embarrassed to take me inside the cramped, temporary lab that is located inside the mobile trailer they are currently using while the regular lab is being renovated.  She assured me that this was not what the lab normally looks like and asked to “make sure to come back when we get our new lab,” which will be opening when the rest of the upgrades are completed on site.  In the lab they test for pathogens, nutrients, total suspended solids, PH levels, and biological oxygen demand.

The upgrades to the Berlin wastewater plant, when completed, will break down nutrients and contaminants in the influent to create near drinking water quality effluent. “It’s a better quality than [the water] a lot people get out of their wells,” Jane Kreiter adds.  For a 24-hour time-lapse video of part of the Berlin Wastewater Plant SBR installation, you can visit the following links: for Part 1 and for Part 2.

Jane Kreiter, Town of Berlin, Maryland, Wastewater Treatment Plant Director Jane Kreiter, discusses the biology of the treatment operation with Jamie Welch, student blogger, Worcester Prep.
Jane Kreiter, Town of Berlin, Maryland, Wastewater Treatment Plant Director, discusses the biology of the treatment operation with Jamie Welch, student blogger, Worcester Prep.

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