Wastewater Treatment Strategy
Class EA Update and
Biosolids Management Master Plan
INFORMATION BRIEF
JUNE 2005
Introduction. . .
Class EA Update
The City of Guelph is undertaking an update to the Wastewater
Treatment Strategy that was developed through the Class
Environmental Assessment (EA) process in 1998. The City is
also undertaking a related study to develop a Biosolids
Management Master Plan. This Information Brief provides a
summary of the progress made on these two studies.
Decision-Making Process. . .
Study Purposes. . .
The studies are following the Municipal Engineer’s
Association Class Environmental Assessment process. The
decision making processes are being carried out to be
transparent and repeatable. Consultation with the community
and regulatory agencies is integral to both studies.
Municipal Class EA Planning and Design Process
Class EA Update
The 1998 Wastewater Treatment Strategy addressed treatment
needs to the year 2016 and recommended expansion of the
Wastewater Treatment Plant (WWTP) in two stages. The Stage
1 expansion is complete and the WWTP is currently operating
at a rated capacity of 64 million litres per day (MLD). The
Stage 2 expansion will increase capacity of the WWTP to 73.3
MLD. The purpose of the Class EA Update is to review and
select emerging treatment technologies for pilot testing and
incorporation in to the design of the Stage 2 expansion.
Biosolids Management Master Plan
The 1998 Class EA included a recommendation to develop a
master plan for the management of the increased volume of
biosolids that would be generated by the WWTP Stage 2
expansion. The purpose of master plan is to identify a
plan for the management and end use of biosolids
generated at the WWTP. This study is following the Class
EA process for master plans and the first public information
Centre to present the need for the study was held in February
2002. Since that time, the City has evaluated options for
biosolids management, disposal, and end use.
Biosolids Master Plan Decision Tree
These Studies are Related…
Both of these studies involve activities and programs at the
WWTP. The Class EA Update is focused on technologies to
treat the liquid stream of the wastewater conveyed to the
WWTP. The technologies will generate biosolids which will
require further treatment, management and disposal. This
information is important to the Biosolids Master Plan. The
de-watering processes evaluated for the management of
biosolids will produce sidestream wastewater that will be
recirculated back to the liquid treatment processes. This side
stream will have quantity and quality characteristics that will
need to be considered in the evaluation of innovative
treatment technologies.
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WASTEWATER TREATMENT STRATEGY CLASS EA UPDATE AND BIOSOLIDS MASTER PLAN
INFORMATION BRIEF – JUNE 2005
The Existing WWTP
Biosolids Master Plan
Compost Utilization Opportunities. . .
With the Stage 1 expansion complete, the existing WWTP
consists of four treatment plants. Wastewater received
primary treatment (including screening and grit removal).
Partial secondary treatment in achieved in Plants 1 to 3
followed by tertiary treatment in rotating biological reactors
to remove additional ammonia. Wastewater flow treated in
Plant 4 receives full nitrification. The combined wastewater
flows are then passed through tertiary filters, received
disinfection and final treated effluent is then discharged
through an outfall pipe to the Speed River.
Class EA Update
Evaluation of Innovative Technologies. . .
The evaluation of potential innovative technologies included
a long list of 10 treatment technologies. The 10 technologies
were then screened and four technologies were short listed
and evaluated in more detail, along with the base case
existing treatment processes at the WWTP.
The evaluation process identified Bioaugmentation as the
treatment technology recommended for pilot testing at the
WWTP.
An important step in the biosolids master plan decision process
was to determine the potential opportunities to utilize the
biosolids compost produced at the WWTP. A market
assessment was conducted to identify markets with viable end
uses including, landscaping, soil blending, sod farms, mining
reclamation, golf courses, etc. The assessment concluded that
potential revenues from the sale of compost could be
approximately $400,000 per year. Demonstration trails and
regulatory approvals would first be required.
The City has been unable to carry out composting
demonstration projects due to equipment and processing issues
at the WWTP. As these issues are addressed the City wishes to
proceed with the evaluation of other biosolids management
alternatives. The composting alternative will continue to be
evaluated as a feasible option for the remainder of the
operational lifecycle of the existing facilities.
Biosolids Master Plan
Screening the Long List. . .
The long list of 102 treatment technologies and the long list of
six biosolids end uses were screened using “must have
criteria”. The screening results in a menu to feasible
technologies, biosolids products, and end uses were then
combined to develop seven Biosolids Management Strategies.
WASTEWATER TREATMENT STRATEGY CLASS EA UPDATE AND BIOSOLIDS MASTER PLAN
INFORMATION BRIEF – JUNE 2005
• Option 4: Expand Existing System with Heat Drying and
Phased Digestion
• Option 5: Expand Existing System with Primary Solids
only, Digestion, and Heat Drying
• Option 6: Expand Existing System with Alkaline
Stabilization
• Option 7: Expand Existing System with Alkaline
Stabilization and Phased Digestion
Biosolids Management Strategies. . .
All seven strategies include digestion treatment, biosolids
dewatering and further processing and result in a product that
has multiple potential end uses.
• Option 1: Expand Existing System
• Option 2: Expand Existing System with Phased Digestion
• Option 3: Expand Existing System with Heat Drying
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Evaluation of Biosolids Management
Strategies. . .
The biosolids management strategy options were evaluated
using a Multi-Attribute Analysis. The Multi-Attribute Utility
Analysis (MUA) approach conducts a structured evaluation
of the risks and benefits of a decision compared to costs.
The evaluation identifies Option 1 (Expand Existing System)
and Option 2 (Expand Existing with Phased Digestion) as
rated the highest among the alternative strategies.
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WASTEWATER TREATMENT STRATEGY CLASS EA UPDATE AND BIOSOLIDS MASTER PLAN
INFORMATION BRIEF – JUNE 2005
Next Steps . . .
Class EA Update
Biosolids Master Plan
• Modify recommended
pilot testing options
based on public
comment
• Finalize recommended
technology pilot test
• Modify recommendation
based on public
comments
• Confirm recommended
strategy (Preferred
Solution)
• Document EA Update
• Document Biosolids
Master Plan
• Inform Council
• Publish Notice of Update
• Implement Pilot Test
• Inform Council
• Publish Notice of Master
Plan Study Completion
For additional information, please
contact:
James Etienne, P.Eng.
Director of Environmental Services
Environment and Transportation Group
City Hall, 59 Carden Street
Guelph, ON N1H 3A7
Phone: (519) 837-5604
Fax: (519) 822-6194
e-mail: james.etienne@guelph.ca