chemicals, biological additives, or additional electrical energy. The subsurface location and low maintenance requirements of the system design make it ideal for Newbury and the approach allowed for the continued use of an existing Imhoff tank and significant other existing infrastructure. Ultimately, the Enviro-Septic technology allows the Blodgett Landing WWTF to significantly reduce certain wastewater contaminates, including Fecal Coliform, Total Nitrogen (TN), 5-day Biochemical Oxygen Demand (BOD5), and Total Suspended Solids (TSS).
Preparing for AES install Tuscan Ridge.
GPD bed contains 8,400 feet of AES pipe surrounded by specified sand for a total 33,600 feet of AES pipe. Treated effluent is collected and gravity-distributed to four, UV disinfection units, each followed by a pump tank. These pumps distribute purified effluent to two evapotrans- piration ponds, which allow for possible reuse. The low maintenance, high flow, AES system includes disinfection and allows for full occupancy of the FEMA work housing camp. This provides needed resources close to the devastated community. New building codes and improved street planning are being put in place to prevent similar, future devastation. Expansion of New Hampshire Town Community Treatment Plant Accommodates Growth and Preserves Natural Beauty As the population in the town of Newbury, New Hampshire grew, facil- ity operators began detecting elevated levels of nitrogen in the effluent and groundwater. This catalyzed an update to the Blodgett Landing Community Treatment Plant, a 50,000 gallon per day (GPD) facility. 0riginally designed in 1959 as a seasonal wastewater treatment facility, the upgrade utilizes passive treatment, denitrification, and dispersal to purify the town’s wastewater. A limited budget necessitated finding an effective treatment plant upgrade solution that was affordable both in upfront cost and ongoing operations and maintenance expense. Ad- ditionally, Newbury’s economic dependence on recreational tourism required a solution that would preserve the area’s natural beauty. Several options were explored before the engineers employed by town officials contacted Presby Environmental, Inc. (PEI) for help. PEI recommended incorporating the Enviro-Septic technology into the existing sand filter configuration, which enhances aerobic nitrification and allows for increased denitrification in the recirculation process. The passive treatment performance of the Enviro-Septic technology utilizing naturally-occurring bacteria eliminates the use of harmful
This wastewater treatment solution enables the Town of Newbury to protect its natural resources while allowing continued development within the community unfettered by wastewater capacity restrictions. Moreover, because the system performs well in varying climates, in- cluding freezing temperatures, it is ideal for the location of this project where cold winter months are the norm. Conclusion Decentralized systems offer many benefits for large commercial or community applications and the best approach varies from case to case. Local codes, proximity to water bodies, and anticipated daily flows are additional key factors for individual, commercial, or community systems. New products and applications approaches has broadened the options available to engineers, developers, and communities. In many cases, the decentralized approach may offer a lower cost, high perfor- mance, and versatility when compared to a centralized option. DENNIS F. HALLAHAN, PE has more than 30 years of experience with onsite waste- water treatment systems’ design and construction. Currently Technical Director at Infiltrator Water Technologies, he is responsible for technology transfer between Infiltrator and the regulatory and design communities and consults on product research and testing for universities and private consultants. Hallahan received his MS in civil engineering from the University of Connecticut and his BS in civil engineering from the University of Vermont. He is a registered professional engineer in Connecticut and holds several patents for on-site wastewater products. He can be reached at dhallahan@infiltratorwater.com. DONALD PRINCE holds a Civil Engineering Degree from Vermont Technical Col- lege and is a licensed septic system designer and evaluator. He has provided technical support for AES and other Presby Environmental products since 2012. Presby Environmental is an Infiltrator Water Technologies company. Don lives with his family in northern Vermont. He can be reached at don.prince@presbyeco.com.
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csengineermag.com april 2020
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