WATERLOO U PROJECT LOOKING TO MAKE SMALL WASTEWATER PLANTS MORE ENVIRONMENTALLY SUSTAINABLE
This story is brought to you in part by Waterloo Biofilter Systems
By Stuart Smith
A large wastewater plant will employ many strategies to make use of the residual sludge at the end of the treatment process. It could be used to produce methane gas, as fertilizer for agriculture, or transformed into pellets to make artificial soil. All of these methods help make use of a by-product which would otherwise have to be disposed as waste. By utilising the sludge, a more sustainable system is created.
But when it comes to sludge handling and biosolid management, Wayne Parker - Professor of Civil and Environmental Engineering at Waterloo University told WaterToday that smaller wastewater treatment plants were not receiving the same kind of attention that larger plants were. This is particularly relevant for Ontario, because many of the plants are small-scale.
"We want to understand what practices are being employed, certainly from a technology implementation standpoint, but especially how they are being operated, how they're performing, and how they would look if you evaluate them against sustainability and performance indicators.
In this study, a small plant does not use anaerobic processing and deals with less than 10,000 cubic meters of waste a day. A plant such as this will not have many employees manning it, and therefore requires different solutions to create a more sustainable system.
He explained to us that once the results of the 10-plant comparison are released, a site can pinpoint where they are falling short compared to other similar wastewater treatment centers. They can then make changes to improve their sustainability.
"We' re going out to the plants, we're measuring their actual energy consumption, we're looking at qualities and quantities of solids that are moving through the systems, and the quality of product."
Parker points out that this does not just include the operations in the plant – they're looking outside the fence" as well. A plant which has to transport dewatered biosolids by truck rather than dealing with them on-site will incur extra GHG costs, which the study seeks to account for.
If all goes to plan, Parker told us the next part of the project would be looking at processes and technologies which could help improve the plants' sustainability. These are expected to be the more passive processes which do not require more personnel. Options such as these are more appealing to plants who may not otherwise have the operator capacity. But exploring these options is stage 2. For now, quantifying and qualifying these smaller plants is the focus.