ST. ALBANS — The selectboard gave DuBois & King, Inc, permission to move forward with phase two of the water supply and wastewater system feasibility study last week, estimated to cost around $12,700, after the consulting firm came back with promising results.
The first phase of the study consisted of DuBois & King researching ways to expand upon the current water supply and wastewater disposal options available to the town. The study came back positive for wastewater treatment.
Typical options for the treatment and disposal of wastewater in the state are decentralized and indirect discharge systems. A decentralized approach is useful for individual properties or small neighborhoods, such as cul-de-sacs. An indirect discharge system would be a wastewater treatment facility that collects and treats more than 6,500 gallons of sewage per day.
As of mid-August, the firm had GPS located existing sewer manholes and hydrants on a map, according to Jonathan Ashley of DuBois & King. Soil mapping and parcel mapping were also completed. Ashley said sub-service areas, including growth center, residential, commercial and industrial park, were added to the map as well.
The firm determined that the town could find land to treat wastewater, according to Ashley. At the beginning of September, the firm reviewed 13 soil test pits on two vacant lots in the St. Albans Industrial Park to determine if the area was suitable as a disposal site.
The soil in the test pits had the following profile: the first 12 inches was topsoil, between six and 48 inches was medium to fine sandy loam with evidence of a seasonal high water table and between 26 to 90 inches below grade was very dense sandy loam.
Based on these results, DuBois & King determined the land to be suitable for a mound-type disposal field. The estimated disposal capacity of this area, based on application rates listed in the indirect discharge rules for a glacial till deposit, was determined to be around 238,000 gallons per day. Typical daily use for a home is 450 gallons per day.
The application rate could be limited by aquatic permitting criteria or improved by a site-specific percolation testing and more detailed groundwater mounding analysis of the site, according to the firm.
DuBois & King said based on the disposal capacity estimates and the wastewater design flow estimates, the area may provide sufficient capacity for a majority of the existing wastewater flows from the service area, but would not provide capacity for growth.
Other potentially well-suited soils for on-site leachfields have also been identified in other parts of the service area during the course of the study, such as the Lapierre property, and property owned by Mylan and Ben & Jerry’s within the town industrial park, but have not been test-pitted to evaluate their capacity.
DuBois & King recommended conducting site-specific percolation testing, hydrogeologic analysis and to make a site visit with a representative of the Agency of Natural Resources who can identify the point of compliance with aquatic permitting criteria if they wished to further evaluate the disposal site’s viability.
In the second phase of the study, the firm will delve deeper into two or three municipal water options as well as two or three wastewater options.