TERMS OF REFERENCE
SITING STUDY FOR SANITARY LANDFILL
[],[]
General
The Government of [] has identified solid waste disposal as a priority problem and requires assistance in the
siting of a new sanitary landfill to address this problem. For purposes of this study, sanitary landfill design
guidance and siting criteria are provided in Annex A.
The existing disposal site is located at [] and has been receiving [] solid waste for [] years. The remaining
capacity of the existing site is estimated as [] years.
Following an initial screening of at least 8 potential sites, the siting study shall identify at least 3 candidate
sites which are technically, economically, and environmentally suitable, as well as potentially socially and
politically acceptable for development into sanitary landfill. The sites also need to be feasible to acquire
within the time span required for timely implementation of the proposed project. These 3 candidate sites
shall be further analyzed and 1 site recommended for design.
The siting study shall not be limited to looking only at government-owned lands, as purchase of a privately
owned site might be the most cost-effective solution when considering site mitigation and pollution control
costs and solid waste transportation costs.
To the extent feasible, the siting process is intended to be participatory, so that public opposition to the
recommended site is minimized. To this end, the consultants are advised to encourage the government to
form and convene a steering committee comprised of local authorities as well as representatives of key non
government organizations and citizens groups. The consultants are expected to fully cooperate with the
committee and be available for monthly meetings to discuss progress.
Objectives
The study shall adequately address the following objectives:
1. Determine the service area, waste quantities (including sludge from wastewater treatment plants) and
land requirements for siting of a sanitary landfill which achieves economies-of-scale and cost-effective
transport of wastes.
2. Identify and assess at least 8 sites with regard to site selection criteria (see Annex A) and comparatively
evaluate their environmental, safety, economic, engineering and socio-political feasibility for sanitary
landfill.
3. Identify at least 3 candidate sites that appear to meet most of the site selection criteria, based on
available data, or could be engineered economically to address the intent of most of the criteria.
4. Provide an environmental audit report and economic analysis comparing the 3 candidate sites.
5. Recommend 1 site based on all of the comparative assessment conducted.
Scope of Services
The Consultant shall perform the following services:
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Task 1 -- Review of Available Information: Review relevant feasibility studies and reports concerning solid
waste management, particularly the studies conducted for [] by the []. Review environmental studies
conducted at existing disposal sites, particularly those conducted by the []. Review siting studies already
conducted by the [].
Task 2 -- Develop Baseline for Landfill Planning: Determine the service area to be covered by the sanitary
landfill facility, develop updated waste quantities based on available information, and determine the volume
capacity requirements for a landfill to provide a minimum of 10 years of life. Project the waste quantities
to be produced by [],[] over the next 10 year period starting 3 years from today (assuming that it would
take about 3 years to design and implement a new sanitary landfill). Estimate the size of sanitary landfill
site required for a minimum life of 10 years. For determination of the size of site required, it shall be
assumed that the final in-situ density of solid waste after several years of consolidation will be 900
kg/cubic meter and that the ratio of soil cover volume to solid waste volume will be 1:6. Depth
determined during final design of the proposed landfill will depend upon site specific conditions of the
soil depth to bedrock and topography. However, for purposes of this study, an average depth between 10
to 15 meters may be assumed. Beyond the needs for the landfill's cell development, the site
requirements shall assume to be increased by about 10% for the waste receiving area, 10% for the
leachate treatment and evaporation area, and 10% for the landscaped buffer zone.
Task 3 -- Develop Site Selection Criteria: Develop site selection criteria to evaluate environmental, safety,
economic, engineering, and socio-political feasibility. Sites can be selected even though they do not meet
each of the screening criteria. However, the reason for selecting such sites shall be provided and possible
engineering solutions which would bring the site into conformance with the intent of the unmet criteria shall
be outlined. For purposes of this study, criteria which shall be addressed as part of the screening process
include, but are not limited to, those outlined in Annex A.
Task 4 -- Identify Potential Sites: Review regional information available from private and public sources
which will allow the identification and evaluation of potential sites, including topographic maps, borings
and well logs, soil surveys, geologic studies, climatic/meteorological data, wind data, drainage and
sanitation infrastructure maps, water resource and water supply development maps, stream water quality
data, transmission and power supply maps, road maps, transportation studies, existing and proposed land
use plans, possible development plans and programs for the area and its immediate vicinity, proximity to
residential development, land ownership and land value.
Identify at least 8 potential sites with regard to the above selection criteria and the above regional
information. Explain the reasons for any sites identified wherein the selection criteria have not been fully
met. Outline engineering provisions which would enable selected sites to address the intent of those criteria
which can not be met naturally by the site as is.
Fully collaborate with the local authorities involved in solid waste disposal in the identification process.
This would include preparing from the outset a series of maps which show those areas within the study area
which would not meet selection criteria (exclusion zones) and requesting the appropriate local authorities to
provide views. Then, there should be tours with key local authorities to those areas which are considered
potentially viable, to further solicit their views.
Task 5 -- Select Candidate Sites: Conduct site reconnaissance of each of the potential sites identified above
and review site-specific data which is available. Identify candidate sites which best meet the established set
of criteria and appear to be the most politically/publicly acceptable and, preferably, are closest to the
collection service area so that refuse hauling times and refuse collection costs are minimized. If there are
not at least 3 candidate sites which substantively meet the site selection criteria, propose additional siting
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studies which would supplement those already conducted, including casting of a wider net to look at sites
located further from [].
Task 6 -- Recommend 1 Site for Further Study: Based on best professional judgment and upon the efforts
conducted above, evaluate the 3 candidate sites and recommend which one appears to be the best from
environmental, economic, and public acceptance perspectives.
Reports and Plans
Provide ten copies of the First Interim Report which evaluates alternative sites, with corresponding
site-specific information for each of the sites evaluated, including rationale for recommending the 3
candidate sites. Within 2 weeks of submittal of the First Interim Report, the consultants will provide a full
briefing to local authorities and encourage a discussion of comments and opinions.
Provide ten copies of the Second Interim Report which further evaluates the 3 candidate sites, including
comparative cost analysis and environmental audit review. Within 2 weeks of submittal of the First Interim
Report, the consultants will provide a full briefing to local authorities and encourage a discussion of
comments and opinions.
Provide ten copies of the Final Draft Report which recommends 1 site for further study which addresses
comments and concerns from local authorities regarding the Interim Report. The consultants shall be
available to participate in an open forum conducted by local authorities and their consultants and
representatives to discuss the rationale for recommending this site. Visual aids for the open forum shall be
provided by the consultants to facilitate the discussion.
Provide ten copies of the Final Report which addresses comments and concerns from local authorities and
open forum regarding the Final Draft Report.
All reports shall be in the [] language.
Schedule
The initial phase to identify 8 potential sites shall be completed within a period of 3 months from the date of
the contract, or notice to proceed.
The second phase to complete more detailed economic and environmental analysis of the 3 candidate sites
shall be completed within 5 months from the date of the contract, or notice to proceed.
The final phase to recommend 1 site shall be completed within 7 months from the date of the contract, or
notice to proceed.
This schedule assumes there shall be no delay due to local authorities being unable to agree to the 3
candidate sites at the end of the initial phase of work or to the 1 recommended site at the end of the second
phase of work. The overall study is expected to be completed and all reports submitted within 7 months
from the date of the contract.
Team
The team shall include at least one experienced and qualified geologist with a minimum of a bachelor of
science degree in geology and 10 years of related work experience in geologic and hydrogeologic field
investigations; at least one civil-sanitary engineer with a bachelor of science degree in civil engineering
and 15 years of related work experience in sanitary landfill design; and at least one biologist with a
bachelor of science degree in biology and 8 years of related work experience in terrestrial biology field
survey.
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Annex A
SANITARY LANDFILL SITING CRITERIA
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Adequate land area and volume to provide sanitary landfill capacity to meet projected needs for at least
10 years, so that costly investments in access roads, drainage, fencing, and weighing stations are
justifiable. For siting purposes, land area requirements shall be estimated based on the landfill cell area
required (typically for a depth of 10-25 meters; a final solid waste density of 800-1,000 kg/cubic, and a
minimum soil to refuse ratio of 1: 6), as well as about 2-4 hectares for the receiving area, 2-4 hectares
for the leachate treatment and/or evaporation ponds, and additional 10% land for a landscaped buffer
zone.
Preferably, a site accessible within 30 minutes travel time (a function of road and traffic conditions) is
to be sought, even if it means buying land, because of the need to avoid adversely affecting the
productivity of collection vehicles. At distances greater than 30 minutes travel, for collection
operations to be economic, investment in either large capacity collection vehicles (5 tonnes per load or
greater) or transfer stations with large capacity vehicles (20 tonnes or greater) would be necessary.
If transfer stations are required, the landfill should be accessible within 2 hours of travel time (one-way)
by transfer trucks from the transfer station. Otherwise, for longer distances, transfer by rail or barge
directly to the landfill site needs to be considered. Siting of rail or barge transfer sites within the refuse
collection area may be difficult. Double handling by truck transfer and by rail or barge transfer units
should be avoided because of costs.
Accessible from a competent paved public road which has an adequate width, slope, visibility and
construction to accommodate the projected truck traffic. To minimize landfill development costs, the
requirement for new access road construction generally should be less than 10 km for large landfills
serving metropolitan areas and less than 3 km for small landfills serving secondary cities.
A gently sloped topography amenable to development of sanitary landfill by the Cell (Bund), with
slopes which minimize the need for earthmoving to obtain the correct leachate drainage slope of about
2%.
Groundwater's seasonally high table level (i.e., 10 year high) is at least 1.5 meters below the proposed
base of any excavation or site preparation to enable landfill cell development. A minimum depth of 1
meter of relatively impermeable soils above the groundwater's seasonable high level exists (preferably,
less than 10-9 meters/second permeability when undisturbed). If these criteria are not met, use of
impermeable clay and/or plastic liners may be required to protect groundwater quality.
Availability on-site of suitable soil cover material to meet the needs for intermediate (minimum of 30
cm depth) and final cover (minimum of 60 cm depth), as well as bund construction (for the Cell method
of landfill). Preferably, the site would have adequate soil to also meet daily cover needs (usually a
minimum of 15 cm depth of soil). However, daily cover needs can be alternatively met by using
removable tarps, other relatively inert materials (i.e., compost residuals), or by removing the previously
laid daily soil cover at the start of each day for reuse at the end of the same day. For purposes of siting,
assume that at least 1 cubic meter of daily, intermediate, and final compacted soil cover is needed for
every 6 cubic meters of compacted refuse. In most developing countries with highly organic wastes and
warm climates, compacted refuse (after one year of natural consolidation and decomposition within
warm and wet climates) achieves a density of 800-1000 kg/c.m.
None of the areas within the landfill boundaries are part of the 10-year groundwater recharge area for
existing or pending water supply development.
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No private or public drinking, irrigation, or livestock water supply wells within 500 meters
downgradient of the landfill boundaries, unless alternative water supply sources are readily and
economically available and the owner(s) gives written consent to the potential risk of well
abandonment.
No environmentally significant wetlands of important biodiversity or reproductive value are present
within the potential area of the landfill cell development.
No known environmentally rare or endangered species breeding areas or protected living areas are
present within the site boundaries. If this criterion is not met, alternative habitats of comparable quality
for relocation of the species would need to be available.
No significant protected forests are within 500 meters of the landfill cell development area.
No open areas of high winds, otherwise windblown litter will not be readily manageable.
No major lines of electrical transmission or other infrastructure (i.e., gas, sewer, water lines) are
crossing the landfill cell development area, unless the landfill operation would clearly cause no concern
or rerouting is economically feasible.
No underlying limestone, carbonate, fissured or other porous rock formations which would be
incompetent as barriers to leachate and gas migration, where the formations are more than 1.5 meter in
thickness and present as the uppermost geologic unit above sensitive groundwaters.
No underlying underground mines which could be adversely affected by surface activities of landfilling,
or minable resources which could be rendered less accessible by landfilling, unless the owner(s) gives
explicit consent.
No residential development within 250 meters from the perimeter of the proposed landfill cell
development, for reasons of particulates and bioaerosols, in cases where there is landfill gas collection
and flaring. If there is no gas collection and flaring, at least 500 meters are recommended, due to
volatilized organics, heavy metals and other potential toxic constitutents in landfill gas.
Avoid visibility of the proposed landfill cell development area from residential neighborhoods within 1
km. If residents live within 1 km of the site, landscaping and protective berms would need to be
incorporated into the design to minimize visibility of operations. Curving of the access road is
recommended to avoid visibility of the active portions of the landfill from the main road.
No perennial stream within 300 meters downgradient of the proposed landfill cell development, unless
diversion, culverting or channeling is economically and environmentally feasible to protect the stream
from potential contamination.
Avoid siting within areas of significant seismic risk which could cause destruction of berms, drains or
other civil works, or require unnecessarily costly engineering measures, otherwise side slopes may need
to be adjusted to be gentler than the maximum of 2.5:1.
No fault lines or significantly fractured geologic structure within 500 meters of the perimeter of the
proposed landfill cell development which would allow unpredictable movement of gas or leachate.
No siting within 3 km of a turbojet airport and 1.6 km of a piston-type airport. For sites located more
than 3 km and less than 8 km from the nearest turbojet airport (or more than 1.6 km and less than 8 km
from the nearest piston-type airport), no consideration is to be given unless the aviation authority has
provided written permission stating that it considers the location as not threatening to air safety.
No siting within a floodplain subject to 10-year floods and, if within areas subject to a 100-year flood,
must be amenable to an economic design which would eliminate the potential for washout.
Avoid siting within 1 km of socio-politically sensitive sites where public acceptance might be unlikely
(i.e., memorial sites, churches, schools) and avoid access roads which would pass by such culturally
sensitive sites.
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