The Town of Cornwall, PEI had concluded that the cost to establish lift stations and force mains to service the southern portions of the Town was prohibitively high. As stated in their 1997 Official Plan: "The objective would be to maintain on-site sewage systems in the area for as long as possible, certainly beyond the period covered by this plan".
However, due to problems with some existing septic systems caused by small lots and poor soil conditions, town council was reluctant to allow further development to proceed. In 1998, the Town retained Engineering Technologies Canada Ltd. (ETC) to carry out an On-site Sewage Treatment and Disposal Servicing Study of the York Point area and Parkview Subdivision.
The study involved an examination of conventional and geographical information system (GIS) maps, GIS modelling, and a comprehensive field and laboratory testing program which assessed the subsurface soil, bedrock and groundwater conditions within the 96 hectare (240 acre) study area.
Thematic maps were produced which graphically depicted the subsurface conditions for each parameter. The data collected during the field program was then analysed in combination with existing provincial GIS database layers to determine an overall potential degree of limitation rating (none, slight, moderate, severe, unsuitable) with respect to the installation of conventional on-site sewage disposal systems.
Finally overall synthesis maps were produced that showed the results of this analysis graphically.
For those sub-areas that can be developed utilizing individual septic systems, ETC provided detailed guidelines for lot sizing and appropriate septic system configurations.
A series of general recommendations were also provided to simplify maintenance and increase longevity of individual on-site systems.
For cluster systems, ETC prepared budget estimates and land-use projections for the Recirculating Sand Filter (RSF) and the PeatlandTM Sewage Treatment systems. Both technologies have a proven track record and can achieve advanced secondary treatment levels without highly skilled operators.
The study completed by ETC has provided the Town with a plan that will allow sustainable and cost effective development to proceed utilizing decentralized systems.