Environmental Engineering Reference
In-Depth Information
and need for separate actions. As part of this process, the initial EIS con-
firmed that establishing the location of the treatment facilities was the key
issue, and all other decisions revolved around the siting of the wastewater
treatment plant. All of the other issues and questions listed above were con-
sidered in light of where the plant would be sited and a determination made
as to the constraints this would put on each of the other issues. No fatal
flaws or unmanageable constraints to future decisions were identified to first
determining the site for the wastewater treatment plant in the initial EIS and
using a tiered approach for subsequent decisions.
Thus, the environmental and engineering evaluation of alternative sites
was initiated. There were four primary alternatives considered:
r A number of satellite wastewater treatment plants located through-
out the service area.
r A centralized facility at the existing Nut Island Wastewater
Treatment Plant site that currently served the southern portion of
the service area.
r A new location in Boston Harbor, such as Long Island in the center
of the harbor, for a centralized facility.
r The wastewater treatment facility at the existing Deer Island
Wastewater Treatment Plant site that currently served the northern
portion of the service area.
A comprehensive evaluation of alternatives was conducted consider-
ing the environmental, engineering, economic, and community impacts. In
addition to these factors, the initial EIS evaluated the potential constraints
to the other aspects of the Boston comprehensive wastewater management
plan (e.g., residuals management, level of treatment, discharge location) in
the comparison and selection of alternative sites. The satellite wastewater
treatment plant sites had several advantages, including retaining the treated
effluent in each watershed as a water resource. This was important because
many of the outlying communities derived their drinking water from local
ground water sources that were in short supply. Consequently, there were
frequent water use restrictions and extreme low low stresses to the rivers
in these communities. However, it also had several disadvantages including
limiting the options for effluent discharge and management of residuals. The
Nut Island and other Boston Harbor locations had constraints of available
space and compatibility with the sewage collection system without any sig-
nificant advantages. In the final analysis, the existing Deer Island Wastewater
Treatment Plant site was identified as the preferable alternative because it was
equal or superior to the other sites in almost every category analyzed.
Another advantage of the Deer Island selection was that it produced the few-
est constraints on the range of alternatives available for the other aspects of the
comprehensive wastewater management plan. But all parties acknowledged
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