NivaarExam PrepOfficial exam papers ↗

18-Env-A6 Solid Waste Engineering and Management · May 2016

Question 11 of 17: Landfill Design and Operational Plan

Nivaar worked solution (AI-drafted; not reviewed by a licensed engineer)

Notes on this paper

National Examination, May 2016 — 04-Env-A6 / 18-Env-A6, Solid Waste Engineering and Management. 3 hours duration, closed book, one non-communicating calculator (Casio or Sharp), one letter-sized aid sheet permitted. All 17 questions constitute a complete paper (100 marks total).

Reference texts: Tchobanoglous, Theisen & Vigil, Integrated Solid Waste Management: Engineering Principles and Management Issues; Vesilind, Worrell & Reinhart, Solid Waste Engineering; Davis & Cornwell, Introduction to Environmental Engineering (6th ed.); CCME, Guidance Document on Landfill Gas Management; Canadian Environmental Protection Act, 1999.

Question 11: Landfill Design and Operational Plan (10 marks)

Question text not reproduced: the examination questions are © Engineers and Geoscientists BC. Open the official past paper (linked at the top of this page) to read the question, then follow the worked solution below.

Native subgrade soilComposite liner (compacted clay + geomembrane)Leachate collection / drainage layerLeachatesumpLift 1: compacted refuseLift 2: compacted refuseLift 3: compacted refuseDaily / intermediate soil cover (between lifts)Barrier + drainage layer (final cap)Topsoil + vegetationGas ventGroundwatermonitoring wellPerimeterbermAccess road / working face beyond →
A design and operational plan must specify every layer and system shown in this cross section — liner, leachate collection, lift sequencing, gas venting, final cap and monitoring — plus the site-wide programs (traffic, closure funding) that surround it.
  1. Site selection and characterization. Hydrogeology, buffer distances to receptors, and confirmed capacity/service life against the projected waste-generation rate (Q6).
  2. Liner and leachate collection system design. Composite liner (compacted clay plus geomembrane), leachate collection layer, sump and conveyance to treatment (Q2).
  3. Landfill gas collection and control system. Vertical or horizontal collection wells, header piping, and flaring or energy-recovery equipment (Q4, Q5, Q7).
  4. Surface-water and stormwater management. Diversion berms/ditches around the active area and sedimentation controls to keep clean water off the working face.
  5. Cell design and phased development sequence. Sub-dividing the site into cells filled in a planned order to keep the active working face small and to allow progressive final cover.
  6. Daily operating plan. Working-face size, compaction equipment and target lift thickness, and daily/intermediate cover material and frequency.
  7. Final cover (cap) design and post-closure land use. Barrier/drainage layer, topsoil and vegetation, graded to shed infiltration while remaining stable (Q8).
  8. Environmental monitoring program. Groundwater, leachate, landfill gas, surface water and, where warranted, ambient air monitoring, both during operation and post-closure.
  9. Traffic, access and site-security control. Haul-route management, weigh scale/gatehouse operation, fencing and after-hours security.
  10. Closure, post-closure and financial assurance plan. A funded closure/post-closure trust covering the full monitoring and maintenance period (Q8), and an emergency-response/contingency plan for fire or uncontrolled gas migration.