Identification & Evaluation of Resource Recovery Opportunities (036-1)
Discussion Paper Summary
Wastewater is a resource containing rejected energy (organics, heat and nutrients); it also contains reclaimable water for non-potable use. Recognizing wastewater as a resource and not a waste product lies at the heart of a resource recovery focus in the CRD secondary treatment program. Recovery of these resources can:
- reduce fossil fuel use
- reduce greenhouse gas emissions
- reduce the demand on our drinking water systems
Five potential areas of opportunity exist for resource recovery in the CRD.
- Energy and residuals from organic solids
- Wastewater heat energy
- Water reuse (use of treated wastewater in a beneficial manner)
- Nutrient recovery
- Pressure energy
This paper focuses on heat energy recovery and water reuse opportunities in the CRD. For more details on these processes, read about the CRD's environmental strategies. Water reuse in this paper was incorporated whenever an efficient and effective energy recovery opportunity existed, allowing for both water reuse and energy recovery to be used together.
Where is the CRD's heat demand?
Demand for heat is largest near district heating systems (boilers systems), where the temperature of wastewater would be sufficient to heat buildings to a comfortable level for most of the year. Boiler systems make the most sense when utilizing wastewater heat because their large scale can more effectively use the heat. When analyzing heat demand, land use, floor area ratios and energy demand for buildings were used to create a map of potential heating opportunities.
Where will energy recovery take place?
Heat recovery works best when situated in a location where there is sufficient heat in the wastewater system to supply energy and where there are a number of consumers who can benefit from the heat. These areas tend to have:
- High density (commercial or residential development)
- Institutional structures (such as hospitals or universities)
- Redevelopment potential
- Presence of hot water boilers (not steam)
Based on these characteristics, 38 energy recovery areas were selected. Details on the areas can be found in the full version of Discussion Paper 036-1. Once selected, these areas were analyzed for greatest potential. Areas were ranked based on a number of criteria, including:
- Supply of source heat
- Amount of heat demand
- Boiler availability
- Demand development timing
- Number of parties involved
- Treatment and energy recovery potential
- Reuse production
- Suitability of reuse demand
- Combined environmental considerations
Some of the 38 areas have great potential for resource recovery, while others may not be as successful.
Next Steps
The next step will be to determine how to create viable distributed treatment plant facilities that can take advantage of the most promising of these 38 areas. This will involve creating a number of distributed treatment plant scenarios and evaluating them for greatest success. Success will be measured based on the CRD's triple bottom line methodology, which takes into account financial, social and environmental factors, as well as potential revenue from resource recovery.
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