Project leader: Dr. Rob Jamieson, Associate Professor, Department of Process Engineering and Applied Science, Dalhousie University

Project team: This project brings together the expertise of six researchers at three universities: Rob Jamieson, Dalhousie University; Doug Joy, University of Guelph; Robert Gordon, University of Guelph; Craig Lake, Dalhousie University; Chris Kinsley, University of Guelph; and Glenn Stratton, Nova Scotia Agricultural College.

The project’s success also relies on the expertise and participation of the following departmental, agency and institutional partners: Nova Scotia Environment; Centre for Water Resource Studies; Colchester County; Wastewater Nova Scotia; Halifax Regional Municipality; Dalhousie University; Nova Scotia Agricultural College; Nova Scotia Agritech Park; Nova Scotia Department of Agriculture and Fisheries; Brookfield Concrete; Ontario Rural Wastewater Centre; City of Ottawa; Rideau Valley Conservation Authority; BioNest Inc.; Berger Environment; Premier Tech Environment; and Ontario Ministry of Municipal Affairs.

Objective: This four-year project is developing the knowledge and tools to manage the risk of surface- and groundwater contamination by decentralized wastewater management systems. The project will produce results that can be used immediately by municipal and provincial government agencies, as well as by wastewater engineers, on‐site system contractors and rural homeowners.

The project will have the following outcomes and conduct the following activities:

1. Provide lifespan estimates for on‐site wastewater management systems and evaluate methods for defining on‐site system failure rates.
2. Quantify on‐site system failure rates and pollutant loading.
3. Develop tools that provide municipalities with the ability to test watersheds for risks posed by decentralized wastewater systems.
4. Improve guidelines for managing, maintaining and replacing decentralized wastewater treatment systems.
5. Construct a facility for training regulators, designers and installers of decentralized wastewater management systems.
6. Train graduate students in decentralized wastewater management and watershed assessment.

Project description: Led by Dr. Jamieson, the project’s activities include conducting both pilot-scale experiments and watershed-scale field studies. The data generated from these studies will be used to develop a risk-assessment framework. The project is divided into three complementary components.

Component 1: Evaluating the long‐term performance of decentralized wastewater treatment technologies
The risk of contamination by pathogens from on‐site wastewater systems is a growing concern, but it remains largely unknown at present. There is little if any information to demonstrate the level of risk of surface and groundwater contamination from soil-based wastewater systems over long periods under controlled conditions. This component of the project involves installing several conventional leaching-bed on-site systems and monitoring their performance over a number of years to quantify the risk of contamination. In addition, researchers are comparing the performance of conventional soil absorption fields with that of several alternative decentralized wastewater technologies, including peat filtration and passive sand filter systems.

Component 2: Quantifying impacts of decentralized wastewater systems on receiving water systems
Field studies are being conducted to assess the loading of microbial and chemical pollutants from decentralized systems to receiving water systems. Quantitative tracer studies are being performed to assess the performance of existing on‐site systems in watersheds in Nova Scotia and Ontario.

Component 3: Development of a risk assessment tool for developing prioritized watershed management strategies for decentralized wastewater management system
This component of the research involves calibrating and testing a risk-assessment tool to conduct watershed-level assessments of the relative risk posed by decentralized wastewater management systems. The model will characterize an area’s risk of ground- and surface-water contamination from on‐site wastewater systems to assess the need for more active management such as requiring operating permits, instituting inspection programs and necessitating planning decisions. The model will be verified by field trials in appropriate settings to demonstrate its viability. Four watersheds – two in Nova Scotia and two in Ontario – will be selected to calibrate and test the tool. Results from project components 1 and 2 will be used to validate the risk assessment framework developed for component 3 of the project.

One of the main goals of this project is to train graduate students in decentralized wastewater management and source water protection planning. Accordingly, this project is linking research activities directly to training and demonstration programs. The project has established an on‐site wastewater research, training and demonstration centre. The full-scale physical models, which will be used to study the hydraulic and treatment performance of on‐site systems, will also serve as a training and demonstration apparatus. The models will be integrated into on‐site training courses and used to demonstrate disposal trench construction details, alternative loading strategies, and trench pretreatment systems.