Pakse Urban Environmental Improvement Project: Solid Waste Landfill Improvement Works

LOAN NO.: 2876-LAO
Executing Agency: Dept. of Public Works & Transport-Champasack Prov.
Nature of Contract: Construction
Contract No.: PUEIP-01
Contract Description: Solid Waste Landfill Improvement Works

Improvement of the existing solid waste landfill located at Km 17 along National Road 13S at Bane Yong Village, Xanasoumbon District. The Works is within the 13 hectares fenced property of Pakse Urban Development Administration
Authority (P-UDAA), and comprise the following:
Landfill cells – Two cells are to be constructed with soil confining embankment bunds. Cell A is an old cell which will be improved by raising its embankment bund by about 4.0 m to accommodate old garbage and incoming waste during construction. Cell B will be the major cell which will have an embankment bund height of 7 to 8 meters, equipped with HDPE basal liner and compacted clay liner.
Leachate collection – Since Cell A will contain old garbage, leachate collection laterals shall be provided with conveyance pipe discharging the liquid into the facultative pond. Cell B will have new leachate collection network over the liner with gravel and sand drainage layer. To minimize generation of leachate, uncontaminated runoff shall be intercepted and discharged directly to the surroundings.
Gas vents – Cell A shall be closed and capped soon after Cell B is completed and accordingly, vertical gas vents shall be installed at appropriate spacing to diminish the threat of accumulation of gases within the Cell A landfill mound. For Cell B, connections for vertical gas vents shall be constructed and pipes shall be erected vertically upwards as the garbage is piled up. The gas vent pipes shall be surrounded with gravel for more efficient migration of gases.
Septage pits – Two septage pits shall be sited to accept discharges from de-sludging trucks that are servicing people’s septic tanks in Pakse.

Treatment Ponds – Leachate from the landfill as well as liquid from septage pits shall first be discharged into the facultative pond and later to the aerobic pond. Leachate recirculation shall be done prior to the exceedance of the capacity of the ponds and the leachate quality is found to be still non-compliant to discharge standards. A sump tank shall be constructed at the corner of aerobic pond to house a submersible pump that will pump back liquid back to Cell B.
Access roads – An access road shall be developed within the facility that will serve as the main route of trucks that will deliver waste into the landfill. Another road shall be  improved at the south the landfill which can serve as construction route and for other purposes.
Capping and Closure Layer – Cell A shall be capped with topsoil, sand drainage layer and clay cover. This same layer shall be installed also by P-UDAA on Cell B at its closure.