20
Geotechnical News • September 2016
WASTE GEOTECHNICS
Final closure and post closure care of landfill cells:
Lessons learned by one municipality in Alberta
Carol A. Kehoe
Background
The Canadian Public Sector Account-
ing Board (PSAB) has made rec-
ommendations concerning how
municipalities should account for the
long-term financial costs of managing
the liabilities associated with closure
and post-closure care of solid-waste
landfill sites under PS 3270 (Financial
Reporting & Assurance Standards
Canada, n.d.). Closure activities to be
accounted for include final cover and
storm water management, monitoring
of leachate, water quality, landfill gas,
and gas recovery. After final closure,
financial reporting of post closure
care activities should include ongoing
treatment and monitoring of leachate
and landfill gas, monitoring of surface
water and groundwater, and ongoing
maintenance for the full post-closure
care period. Information on the
environmental condition of municipal
landfills is needed to account for these
costs.
The City of Calgary currently owns
and operates three solid waste land-
fills, and has closed an additional six
solid waste landfills over the years.
East Calgary, Shepard and Spyhill
solid waste landfills were originally
permitted under the Provincial Board
of Health and have been receiving
wastes for close to 50 years. Alberta
Environment became responsible for
regulating landfills throughout Alberta
effective September 1996 (Rush,
1996). New operating approvals,
issued between 2001 and 2003, can-
celled the old Board of Health permits.
Blackfoot, Highfield, Manches-
ter Yards, Nose Creek, Ogden and
Springbank were closed during the
time when solid waste landfills were
under the jurisdiction of the Provincial
Board of Health.
The City of Calgary has made finan-
cial provision for environmental moni-
toring and maintenance of its closed
landfills since 1990 (City of Calgary,
1990) and has completed numerous
intrusive investigations and remedia-
tion activities over the years.
Assessing the environmental
condition of municipal landfills
In 2007, The City of Calgary initiated
a program to re-assess its landfills,
coinciding with The Province of
Alberta introducing new guidelines for
the remediation of contaminated sites:
Alberta Tier I Soil and Groundwater
Remediation Guidelines and Alberta
Tier 2 Soil and Groundwater Remedia-
tion Guidelines. Approved facilities
including solid waste landfills hold-
ing an Environmental Protection and
Enhancement Act (EPEA) approval
were to adopt the new guidelines as
outlined in their individual operating
approval (Province of Alberta, 2007).
The program goals were to provide
clarity regarding the environmental
requirements for the landfills, identify
potential environmental impacts at
the landfills, provide clarity regarding
the financial costs of ongoing landfill
management, and to manage the pro-
gram well through the engagement of
internal and external stakeholders and
by meeting corporate records manage-
ment requirements.
The key deliverables for the program
were:
• Historical reviews
• Data gap analyses
• Preliminary conceptual site models
• Intrusive investigations
• Human health and ecological
screening level risk assessments
• Methane gas surface emissions
surveys
• Updated conceptual site models
Achieving the goals of the program
provided addition information on the
landfills that was useful in forecasting
the long term financial costs associ-
ated with closure and post-closure care
of landfills. In 2007, those costs were
$10.9M (City of Calgary, 2009); in the
2015 Annual Report those costs were
$87.5 million (City of Calgary, 2015).
Lessons learned
The program resulted in more exten-
sive groundwater, leachate and landfill
gas monitoring networks to assess
potential environmental impacts;
improvements in landfill gas con-
trols; improved relationships with
both internal and external stakehold-
ers; and, improved documentation of
municipal processes related to historic
landfill development.
Similar programs have been under-
taken by other municipalities, includ-
ing but not limited to the cities of
Hamilton, Ottawa, and Toronto
(Davis, 2011; Geddes, 2004; Griffiths,
2011). Programs identified both the
