that would meet the needs of this community. The 30 homes in the project, including 84 bedrooms, have a total design flow of 9,240 GPD. Normally, an onsite wastewater system of this size in Massachusetts would require pressure distribution to facilitate dispersal of the effluent to the native soils. However, the performance track record of the En - viro-Septic Wastewater Treatment system from Presby Environmental, Inc. enabled developers to proceed without pressure distribution Due to separation to seasonal high-water table requirements for new construction, the system was designed in an elevated mound configura - tion that included 2 beds for a total of 6,002 feet of Enviro-Septic pipe configured in 66 rows at 91 feet each. A portion of one of the beds (15 rows) slopes at 6 percent to allow the large field to blend in with the terrain and save on the cost of additional fill which would have been required for a level bed. Because of the secondary treatment perfor - mance of the system, the Enviro-Septic system is approved for a 40 percent reduction as compared to conventionally sized systems in Mas - sachusetts. This enabled a much smaller footprint and subsequently much less disturbance to the natural areas of the property. Today, the Cottages at River Hill are fully occupied. The community management association reaps the value of a low-maintenance waste - water treatment system, and the residents enjoy the benefits of a tight- knit community along with the open spaces and natural vistas this type of development provides. Passive CTD Systems Also Excel as Repair Options when Traditional Systems Fail Often, engineers and designers are introduced to passive CTD systems due to their search for a better solution to replace a failing system and soon realize the value and reliability of combining a high level of treatment within the dispersal field. As mentioned earlier, size reductions for certified treatment and the avoidance of relying on native soils for secondary treatment of the wastewater, make passive CTD systems a great solution for sites which prove challenging for conventional systems or not suited to the maintenance demands of mechanical treatment systems. Application in Action Víctor Hernández Elderly Housing Facility in Aguadilla, Puerto Rico Replaces Failed Conventional Wastewater Disposal System with New Combined Treatment and Dispersal System A failed system in poor soil conditions in Aguadilla, Puerto Rico caused the facility to pump the holding tank weekly. The situation made clear the need for a better solution with technology that offered a higher level of treatment to protect and preserve the permeability of the soil. Limited area available for a new system and ongoing maintenance expense were both challenges that steered project designers toward a passive treatment system requiring low ongoing maintenance and as - sociated cost. The small footprint of the system was compatible with the land available and was economical to install and maintain. Also, key to the system selection was the need for superior treatment of the building’s wastewater due to challenging wastewater constituencies typical of these types of facilities.
that achieve certified treatment levels, enable easier siting and use in difficult terrain such as sloping fields. In addition to use for individual wastewater treatment systems, pas - sive treatment systems can be effectively used for a cluster of homes or a community. In this case, there are two basic options to get the wastewater from each individual location to the centralized treatment system. One option is to collect wastewater at each individual location utilizing individual septic tanks. Solids are removed in the tank and the primary treated effluent is then distributed to a central location. The second strategy is to distribute raw wastewater via sanitary sewer lines, cleanouts, and lift stations to larger septic tank(s) for primary treatment and dosing to the dispersal field. This community approach to wastewater treatment and dispersal, as compared to individual sep - tic systems, offers more versatility in site development and allows the wastewater treatment system to be easily managed into the future. Application in Action Innovative Development Where No Infrastructure Exists: The Cottages at River Hill, W. Newbury, MA This project is an excellent example of where a passive combined treatment and dispersal system enabled a new residential community development where no infrastructure was available. One of the most pressing problems with a lack of centralized wastewater capacity is its effect on development within the community the facility serves. However, in areas without centralized sewer, market forces create in - novative solutions enabling unique development opportunities. Such is the case in West Newbury, Massachusetts. The Cottages at River Hill project was developed as a “pocket com - munity” of 30 single-family homes. Rather than develop an entire property with sizable parcels and large secluded houses, pocket com - munities, or neighborhoods concentrate clusters of smaller homes to foster community connections. This leaves the majority of the property as an undeveloped, shared space with walking trails, com - munity gardens, etc., enhancing the quality of life for the residents and greater community. The developers of this innovative project chose an innovative com - bined treatment and dispersal system for onsite wastewater treatment
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september 2021
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