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TO: |
Mayor and Members of Council |
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FROM: |
Stan Bertoia, P. Eng., General
Manager, Construction and Utilities |
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PREPARED BY: |
Stan Lau, Senior Project Manager |
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DATE OF MEETING: |
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SUBJECT: |
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RECOMMENDATION:
That the report entitled “Settlers Park
Landfill Site Management” be received;
That
Beatty & Associates be authorized to carry out a leachate plume assessment
in the vicinity of the Settlers Park Landfill site at an estimated cost of
$12,500;
That
Beatty & Associates be authorized to carry out a detail design for an
Aerobic Landfill Management Plan at the Settlers Park Landfill site at an
estimated cost of $25,000;
That
the cost for the detail design of the Aerobic Landfill Management Plan to an
upset limit of $25,000 be funded from the corporate-wide contingency capital
project and the cost for the leachate plume assessment in the estimated amount
of $12,500 be funded from the Operations and Asset Management 2004 Capital
Budget, Account No. 58-5399-6236-005;
That the
tendering process be waived in accordance with Purchasing By-Law 143-2000,
Section 14(1C) which states “…When the extension of an existing contract would
prove more cost-effective or beneficial; ..”
That the
Operations and Asset Management Department continue to manage and maintain the
Gas Recovery Well System to ensure compliance with the Certificate of Approval;
That
staff pursue partnership funding opportunities with the
And that
staff report back in the spring of 2005 on the consultant’s findings and recommendations.
PURPOSE:
The purpose of this report is to provide
Council with an update on the Settlers Park Landfill Site Management program
and to obtain authorization to retain a consultant to carry out a leachate
plume assessment and carryout the detail design of an Aerobic Landfill
Management Plan for the Settlers Park Landfill site.
BACKGROUND:
Previous Land Use
Previous land uses at the
site included aggregate extraction and a private landfill operation. Extraction
of sand outcrop began in the
Landfill operations by James
Sabiston Ltd. began in the 60’s and ended in 1975. The western portion of the
pit area was filled with a mix of commercial, industrial and residential
refuse. The areas between the un-opened
Groundwater Conditions
Two aquifers exist beneath
Leachate and Methane Gas
Generation
Leachate generated in the waste landfill has
percolated downward to the upper aquifer and eastward toward German Mills
Creek.
The landfill is estimated to
produce 1,000 to 2,000 tonnes per year of methane gas, based on preliminary gas
emission modelling and Environment Canada landfill surveys. This is equivalent
to 20,000 to 40,000 tonnes of carbon dioxide emissions (equivalent of 4150 to
8300 cars) per year.
Gas Recovery System and
Monitoring
After the landfill was completed in 1975,
Sabiston transferred ownership of the property to the Town of
The gas recovery system was rehabilitated in
2001 and Operations and Asset Management continue to operate and monitor the
system.
The
following works and reports have been carried out on this landfill site from
1994 to 2004:
●
December 1994 – Inspection
of the gas and control system by Dames & Moore.
●
September 1996 – Report of
Gas Control System Investigation by Dames & Moore: Damaged gas probes were
replaced and the report recommended repair or replacement of the control
system.
●
October 1999 – Gas
Collection System Preliminary Performance Testing by Beatty Franz &
Associates: The report recommended a
two-stage field investigation be carried out to evaluate the condition of the
buried wells, delineate the extent of possible gas migration and repair the
system.
● March 2000 – Performance of Gas Wells Study by Beatty & Associates: Results of the gas well performance testing indicated that most of the 18 wells need to be repaired or replaced. It was also recommended that the possible distribution of methane gas along the western and northern site boundary should be investigated.
●
June 2000 – As a result of the previous studies
mentioned above, Lantech Drilling Service was awarded the contract to
rehabilitate the gas collection system and construction of new wells.
●
August 2002 - Beatty &
Associates was retained by the Town to carry out a study program to assess
potential environmental impacts at the
Phase I of the study, completed in the summer of 2002, monitored the water quality of the German Mills Creek both upstream and downstream of the landfill site and assessed potential impacts of the landfill on German Mills Creek. Comprehensive water quality analyses showed no measurable impacts in the stream that could be directly attributed to the leachate plume discharge.
·
May 2003 - Beatty &
Associates was retained by the Town to carry out Phase II of the study program.
The Phase II study was to investigate and assess the groundwater flow patterns
and monitor any potential leachate plume that may exist at the landfill site. A
draft report for Phase II was completed in February 2004. The draft report
recommended an on-going monitoring program. It also recommended to carryout a pilot
project to manage the landfill using Aerobic Landfill Technology.
·
June 2004 - Beatty &
Associates was further instructed to monitor and assess the groundwater flow
patterns at the landfill site; analyse groundwater samples and evaluate
leachate attenuation; analysis of stream sample in German Mills Creek to assess
potential impacts; and to carryout an Aerobic Landfill Pilot Test to provide
the data necessary to assess the feasibility of full scale aerobic landfill
management technology.
Results of this latest study are further discussed below:
OPTIONS/DISCUSSION:
Monitoring Results:
The key results of
site monitoring program include:
·
Water table was a few centimeters higher in August 2004 than in August
2003 due to greater rainfall in 2004;
·
Observation well analyses confirmed the leachate plume that was
identified in 2003;
·
Comprehensive water quality analyses between upstream and downstream of
German Mills Creek indicated no measurable impacts that could be directly
attributed to the leachate plume discharge.
·
Water quality meet MOE Surface Water requirements;
·
Comparison of the August 2004 leachate plume quality with the September
2003 results indicates that some parameters increased in concentration over the
past year;
The
2004 monitoring program has confirmed the development of a relatively
high-strength leachate plume beneath the waste landfill. The plume discharges
into the sandy sediments in the bottom and west bank of German Mills Creek.
The
impact of the leachate plume on water quality in German Mills Creek is
relatively minor, however the presence of relatively high concentration of
ammonia and iron in the leachate plume could impact groundwater seepage on the
streambank and groundwater upwelling in the streambed and may be deleterious to
the aquatic habitat in the stream.
Proposed
Work Program:
It
is proposed to retain a consultant to carry out the following work to assess
the potential leachate plume impacts:
·
Meeting with TRCA to review data collected to date and confirm our work
program, as well as to develop a partnership with TRCA to establish
options/alternatives etc.
·
Mapping and laboratory analysis of groundwater seepages along the
German Mills Creek bank in the vicinity of the leachate plume
·
Identification of groundwater upwelling areas in the bottom sediments
of German Mills Creek by temperature probes and installation of
mini-piezometers
·
Sampling and analysis of groundwater in areas of upwelling for
parameters that may be deleterious to the aquatic habitat
·
Report back in spring of 2005
The
cost for this leachate plume assessment is estimated at $12,500. In the event
that the parameters identified exceed the Provincial Water Quality Objectives
for surface water, a follow-up stream survey by an aquatic toxicologist will be
required.
During
monitoring of gas probes along the landfill boundary this August, in two
occasions, the gas recovery well system was found not fully operating and when
the system is not operating, malodorous landfill gas emission were noted along
the western boundary and methane levels in the boundary gas probes were in the
range of 5 to 15% by volume, well above the MOE compliance level of 2.5 %. A
follow-up investigation indicated that a blockage in the system header may have
prevented effective operation of the western boundary gas recovery wells. Town
staff have inspected the site and is in the process of rectifying the problem.
Site inspection during the first two weeks of September did not notice of any
gas emission in the landfill area.
The MOE regulation for control of landfill gas requires that methane gas concentrations “below the surface of the land at the boundary of the site be less than 2.5 percent by volume”.
Monitoring of the gas recovery wells, after the
2001 rehabilitation works, show that the 2.5 percent compliance level is being
met at the site boundary. However, the system is prone to breakdown and failure
due to ongoing settlement of the gas well header pipe blocking segments of the
system and making the wells inoperable. Also, air leaking into the buried
piping reduces the methane concentration below 10% volume. The low methane
levels prevent the recovered gases from being burned prior to emission to the
atmosphere.
Continuous
operation and maintenance of the perimeter gas collection well system is
required in order to meet the Certificate of Approval (C of A) requirements and
to protect the neighbouring residences. This is being carried out by the
Operations Department.
Proposed
Remedial Action:
Slow decomposition
of the waste materials has caused differential settlement of 4 m or more in
some areas of the landfill over the last 20 years. This has resulted in an irregular
terrain with numerous depressions. This slow and continuous differential
settlement will impact on the plans for development of a more active type of
parkland at this landfill site. Also,
trees are not able to survive on the site because there is no oxygen in the
root zone below the landfill cover due to anaerobic decomposition of the waste.
·
Landfill
Technology – Anaerobic vs Aerobic
Anaerobic:
At present, the Settlers Landfill can be classified as
“Anaerobic” because the existing one metre thick clay and silt landfill cap has
effectively prevented moisture and air from penetrating into the waste material
and created a dry and oxygen-absent environment. The waste decomposition
process under anaerobic condition is very slow and can be expected to continue
generating leachate and methane gas for many decades up to 80 or 100 years.
Aerobic:
Aerobic Landfill Technology is a proven approach for
reducing methane emissions by adding air (oxygen) into the landfill to promote
aerobic activity, alter the decomposition process and accelerate waste
degradation and stabilization. When oxygen is present, bacteria, fungi and
aerobic organisms consume oxygen and convert organic material to carbon dioxide
and water. On-site reduction of methane is achieved without the need for gas
collection, treatment and burning. Aerobic conditions also allow vigorous
vegetation growth and reforestation of the site. It would also reduce the
long-term care requirements for monitoring a gas migration and gas collection
system maintenance. This system was successfully applied at the Donlands
landfill site in the City of
Partnership with other Government Agencies
Applying the aerobic landfill technology to this
landfill site will have many positive impacts to the environment such as,
accelerated waste decomposition and settlement; eliminate the emission of
methane and gases; and allow for vigorous vegetation growth. It may qualify for
funding contribution from the Green Municipal Enabling Fund (GMEF)
established by the Federation of Canadian Municipalities and other funding
opportunities.
The
·
Feasibility of
an Aerobic Landfill
Data collected in the aerobic pilot test has
demonstrated that it is feasible to reduce methane at this site to
non-hazardous levels. Implementation of an aerobic landfill would achieve a
major reduction in greenhouse gas emission in
Proposed Work Program:
It is proposed to retain a consultant to perform the
following work:
·
Carry out a
detail design of an aerobic landfill management plan;
·
Prepare cost
estimate for construction, operation and monitoring of the aerobic landfill;
·
Evaluate the
benefits of aerobic landfill technology, including annual reduction in
greenhouse gas emission and eligibility for Emission Reduction Credits etc;
·
Report back in
spring of 2005
The estimated cost for this Aerobic Landfill design is
$25,000.
RECOMMENDATIONS:
·
That Beatty & Associates be authorized to carry out a leachate plume
assessment in the vicinity of the Settlers Park Landfill site at an estimated
cost of $12,500;
·
That Beatty & Associates be authorized to carry out a detail design
of an Aerobic Landfill Management Plan at the Settlers Park Landfill site at an
estimated cost of $25,000;
·
That the cost for the detail
design of the Aerobic Landfill Management Plan to an upset limit of $25,000 be
funded from the corporate-wide contingency capital project and the cost for the
leachate plume assessment in the estimated amount of $12,500 be funded from the
Operations and Asset Management 2004 Capital Budget, Account No.
58-5399-6236-005.
·
That the tendering process be waived in accordance with Purchasing By-Law
143-2000, Section 14(1C) which states “…When the extension of an existing
contract would prove more cost-effective or beneficial; ..”
·
That the Operations and Asset Management Department continue to manage
and maintain the Gas Recovery Well System to ensure compliance with the Certificate
of Approval.
·
That staff pursue partnership funding opportunities with the
·
And that staff report back in the spring of 2005 on the consultant’s
findings and recommendations.
FINANCIAL CONSIDERATIONS:
That the cost for the detail design of the
Aerobic Landfill Management Plan to an upset limit of $25,000 be funded from
the corporate-wide contingency capital project and the cost for the leachate
plume assessment in the estimated amount of $12,500 be funded from the
Operations and Asset Management 2004 Capital Budget, Account No.
58-5399-6236-005.
Approximately
$22,000 was included in Account No. 58-5399-6236-005 for Urban Design to
develop Park Development scenarios.
These will assist with the public consultation process for the landfill
management plan.
The
costs for monitoring the Gas Recovery Well System header and purchasing of
monitoring equipment is funded in the 2004 Operations and Asset Management
Department’s Operating Budget.
ENVIRONMENTAL CONSIDERATIONS:
The
concept of aerobic landfill technology has been introduced to various
stakeholders including municipal governments, Environment Canada, the Ontario
Hydro Generation Company, as well as representatives of pilot greenhouse gas
emission reduction trading programs to solicit feedback on the technology and
the potential for emission trading. There is interest at all government levels in
promoting landfill methane emissions reduction as a viable way to meeting
greenhouse gas reduction targets. The use of aerobic landfill technology may
assist the Town in its commitment to meet the objectives of the Kyoto Protocol.
It will also allow enhanced use of land in a passive or active manner by the
public.
BUSINESS UNITS CONSULTED AND AFFECTED:
The
Legal Department has been involved in the discussion, provided input and have
reviewed this report.
ATTACHMENTS:
Attachment
1 – Site Plan
Attachment
2 – Plan: Groundwater Flow (Fig. 2)
Attachment
3 – Plan: Leachate Attenuation Zone (Fig.3)
Attachment
4 – Plan: Landfill Geological Cross-Section A-A (Fig. 4)
Attachment
5 – Plan: Landfill Geological Cross-Section A-A (Fig. 2)
Attachment
6 - Photo: Iron-stained Groundwater Seepage (German Mills Creek, August 2002)
Attachment
7 – Memorandum Re: Council Resolution
_____________________________________
Stan Bertoia, P. Eng.
General
Manager, Construction and Utilities
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Peter Loukes, P. Eng. Director of Operations and Asset Management |
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Jim Sales Commissioner of Community Services and Fire |
Q:\Commission Share\Operations
and Asset Management\Reports\2004\C & U\Capital Works R.O.W\Settlers Park
Landfil Site Management 2.doc
