Reduce 5000 Tonnes of CO2e with Food Waste Diversion by Green Economy North
Mona El Hallak
Jul 23, 2018
The Proposal reads very well. CAPEX and OPEX are well presented.More information on wastewater influents from the system will be helpful and on any other system output. What will be the impact of the system on the wastewater influent characteristics from the site (COB, BOD, TS, TON)? Will the influent characteristics be in compliance with sewer-by –law regulations?
Jul 25, 2018
Organic food waste presents an opportunity for carbon reduction.The biggest challenge may be the benefits to SMEs versus the cost of implementing such a system. Larger scale anaerobic digesters have the benefit of generating bio-gas which might offset natural gas usage. Not the case with the aerobic digester contemplated in this proposal. Some questions to ponder:
Carbon impact: Is there a life cycle assessment of the Carbon footprint for this type of biodigester? All the organic matter gets dissolved and washed down the drain. So what happens to this highly concentrated organic load when it gets to sewage treatment or septic system?
Regulations: What are the regulatory hurdles to discharging this type of wastewater down the sanitary sewer system?
Financials: What is the average cost to send organic waste to landfill across a number of communities? How does this cost compare?
Market research: Which companies stand to benefit the most from the use of a biodigester versus whatever they are doing now? Why would a business do this? How will you convince them? What is the business case that will be pitched to them?
Jul 26, 2018
Hello Mona, thank you for your question! It is a great one!
I have attached two screenshots from a report conducted last year on an LFC biodigester that underwent trial in Melbourne, Australia. The separate screenshots are data from different days. The local water authority administered the test and a third party analysed the samples. The LFC biodigester discharged into a grease trap, into which all other wastewater from the kitchen also discharged. The output from the grease trap was also monitored and found to be worse than the LFC biodigester alone. Meaning, not only does it comply with sewer use by laws, but also the LFC biodigester further positively dilutes the wastewater. For the full certificate of analysis and report, please notify me and I will happily provide you with it!
A screenshot of the “limits for sanitary sewer discharge” from the sewer use by law has also been attached for your convenience. Please notify me if you would like the full document.
Jul 27, 2018
Hello Sandra, more great questions!
You have raised many interesting and important points.
This technology provides a variety of desirable improvements to a commercial kitchen, while consistently reducing emissions. Some of these desirable improvements include the following:
With an aerobic bio-digester, these can all be amended while disposing of their organic waste sustainably.
Although there is no uniform cost for commercial waste disposal, it is always based on weight. Organic waste is extremely heavy and the cost of implementing a biodigester is LESS EXPENSIVE than hauling by truck. This is highly attractive to Food Service business as it saves them money and increases operational efficiencies. Using data from a restaurant that serves approximately 150 plates per day in the Sudbury area, it was determined that the monthly cost for organic waste disposal is over $500 a month. More so, many restaurants in the Sudbury area serve over 300 plates per day and most likely incur over $1000 a month in waste management costs. Meaning, they can reap significant monetary savings by implementing a biodigester.
The highly concentrated organic load produced makes its way to Sudbury’s Biosolids Management Facility. This facility is an environmentally responsible and sustainable plant that turns organic residuals into an agricultural and beneficial soil amendment, used primarily in the agricultural sector and for land reclamation projects. The sale of the biosolids end product generates revenue for the municipality. Please review the comment to Mona in regards to your question for regulations. It is important to note that it does comply with Sudbury’s sewer use bylaw.
From this, it can be seen that biodigesters not only benefit businesses greatly, but also the municipality. It promotes resource recovery and strives to contribute to Ontario’s circular economy.
A biodigester typically uses 150 litres per day, which equates to just over 1 million litres over the biodigesters life. Using appropriate emissions factors, it was determined that processing this water will only emit 0.06 tonnes of CO2e in a 20-year period. Another factor not measured into our GHG emissions reduction assessment is the reduction in garbage truck emissions, which would most certainly be higher than the emissions of treating the wastewater.
Hopefully this response answers your questions!
Jul 27, 2018
To add on to my previous answer Sandra, the Sudbury Wastewater Treatment Plant has an approved rated capacity of 79,625 m3 per day. Using this number and the emissions produced by the Biosolids Management Facility, we can determine the percentage usage by one biodigester, and further prorate for the expected increase in emissions.
A biodigester uses 54 m3 of water in its lifetimes, which equates to 6.78*10-2% of the capacity. Considering the Biosolids Management Facility produce 360 tonnes of CO2e per year, this accounts to 0.24 tCO2e per year. Most likely a very high figure compared to the actual emissions, as the figures used would be in the worst-case scenario.
Adding the emissions from both the Wastewater Treatment Plant and the Biosolids Management Facility equals 0.30 tCO2e per year. This would equate to 6 tCO2e over the lifetime of the biodigester. A very small fraction compared to the total quantity of 1,000-tCO2e emissions curbed over its life.
Jul 28, 2018
I think this is an excellent proposal on a number of levels. Food waste contributes a great deal to emissions both as an "opportunity lost" in terms of high value organic compost, and in it's production, transportation and in generating emissions in landfill. There are educational and lifestyle awareness benefits to this proposal as well.
As the team evaluates life cycle benefits there could also be a side benefit to incorporating a complete waste food awareness campaign. Maybe a website that's provides feedback on landfill diversion by ton...or emissions reduced.
Jul 30, 2018
Dan, thank you for your feedback!
Incorporating an awareness campaign would be of great value.
Initiatives are only as powerful as their scalability, and awareness is an important component in respect to food waste!