Toronto Dufferin Details   

Background

In 1999, spurred by their rapidly diminishing land fill capacity, the City of Toronto (City) made a strategic decision to apply resources to the development of a residential and commercial organics diversion solution. Selected from 19 processing proposals was the BTA® Process owned by CCI. From September 2002 through March 31, 2014 the Dufferin Organics Processing Facility (DOPF) was the processing cornerstone for the Green Bin Program. 

 

Commissioned in May 2002, the City owns the facility. It was developed under a fixed price, guaranteed, design/build/operate/maintain agreement with CCI and our partners.  CCI and partners operated the facility under contract to the City. The site is urban and also houses one of the City’s seven transfer stations and a material recovery facility. The DOPF accepted the first Source Separated Organics (SSO) in September 2002 to coincide with the start of the Green Bin Program rollout in which residential and commercial sources are separately collected for processing. The facility was temporarily closed in the spring of 2014 and will reopen in 2017 when the second step of a 2 phase expansion plan is completed. 

 

Today, the City collects over 130,000 metric tonnes of residential and commercial SSO annually, of which up to 55,000 metric tpy will be processed at the DOPF when the facilty is re-opened. A second BTA footprint at Disco Road with a 75,000 metric tonne annual capacity began converting a portion of the repatriated volumes in December 2013. The remaining tonnage is composted by external service providers. Once the DOPF expansion is completed, more than 130,000 metric tonnes of SSO will be converted at these 2 City owned AD facilities.

 

Document Link

Dufferin Case Study

 

Processing Highlights

The facility initially operated two shifts daily, Monday through Friday, for receiving and processing. In the early life of the facility there were several extended intervals when the City had asked for a third shift and some weekend processing to manage the lack of reliable external capacity to process the remaining volumes collected in the program. In 2009 this practice became permanent when a third shift was added.

 

The waste feedstock, which is characterized by a high plastic content due to the collection in plastic bags, was directly fed to the BTA® Hydromechanical Pre-treatment system without any prior treatment. The anaerobic digestion methodology implemented is a single-stage wet digestion process in the mesophilic range with full mixing using compressed biogas.

 

The digestate was dewatered using screw presses and the solids were sent for aerobic finishing at an off-site composting facility. Due to the virtually non-existent inert contamination, the final Class AA quality compost was distributed into the high-value markets. The liquids from dewatering, primarily made up of the liquids inherent in the waste, plus any fresh water used for cleaning was reclaimed and recycled in the process using a closed-loop process water management system. The BTA® Process Control system monitored and controlled all equipment, including subsystems such as the biofilter.

 

Dufferin Expansion - 5,100 m3 Digester
         Biogas Collection

Delivery Team Partners

CCI was an equal partner in the joint venture responsible for both the initial build and the 2012 capacity expansion under a design, build, operate, maintain (DBOM) approach the City used to develop and operate the project. Equipment and services directly delivered by CCI under this structure included:

 

  • Delivery of the process design
  • Advise & assist for basic and detail engineering
  • Waste receiving designs & equipment
  • Procurement, installation & warranty of the BTA® Waste Pulpers / Grit Removal System (GRS) & Process Control System
  • Procurement & installation of the solids/liquids separation system
  • Design of the reclaimed process water management loop
  • Detail engineering of the digester, including non-mechanical mixing
  • Commissioning, start up & continued operations
  • Performance guarantees
  • On-line monitoring & technical support

Performance Achievements

A broad acceptable waste profile helps maximize diversion achievement and the production of community based bioenergy. According to the City, the residential participation rate is running at greater than 91% and is primarily due to the ability for generators to use plastic bin liners to mitigate the "yuk factor". These liners account for close to 50% of the inert contamination, which averages 14%, as per the actual audited findings.  Some compelling facts about the history and performance of the facility include:

 

  • 1st large scale AD facility in Canada – 2001
  • 1st municipally owned AD plant in North America – Toronto 2001
  • Initial design capacity was 25,000 metric tpy - historically operated at 145% of design capacity
  • 360,047 total metric tonnes converted 
  • Up to 55,000 metric tonnes will be converted annually starting in 2017
  • 110 m3 of biogas per metric tonne of incoming organics is produced
  • Dewatered digestate was used as a feedstock to make high quality Class AA compost products
  • Just under 99% of incoming contaminants are removed at the front end
  • Over 93% of the organic fraction in the Green Bin is captured and diverted from landfill
  • Odour complaints averaged less than 2 per year 

Doubling Capacity Started In 2012

The consistent results and reliable operations have birthed an expansion plan to double conversion capacity to 55,000 metric tonnes annually. In August 2012 a second digester was started-up, signifying the completion of the first step in the expansion plan.  In step two in 2015 a City decision will be made to double the pre-treatment system capacity. The biofilter will be expanded and a new tip floor and other building and site improvements are planned. A cogeneration system will be installed to produce electricity and heat for the organics facility, the transfer station, and other buildings on the site. The robust, open architecture of the BTA® Process Control System allows for the integration of the monitoring systems of these types of modular subsystems. 

Toronto Green Bin Program Details

Toronto Disco Road Details