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18-Env-A6 Solid Waste Engineering and Management · December 2014

Question 26 of 29: Sketch and Label a Landfill

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

Notes on this paper

National Examination, December 2014 — 04-Env-A6 / 18-Env-A6, Solid Waste Engineering and Management. 3 hours duration, closed book, one non-communicating calculator, one letter-sized aid sheet (both sides) permitted. All 29 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.

Note on source parsing

This paper prints marks IN FRONT of the question number on every line (e.g. "5 1. What are the elements…", "4 16. All 29 questions are answered in full.

Question 26: Sketch and Label a Landfill (5 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.

The figure below is a cross-section through one cell of a modern engineered sanitary landfill, labelled with the components required to control the concerns raised in Question 25: the composite base liner and leachate collection system (contamination control), the waste mass placed in lifts with intermediate cover (operational control), the gas extraction well (methane control), the final cover/cap (infiltration and erosion control), and the perimeter/monitoring infrastructure (long-term surveillance).

Native subgrade soilCompacted clay liner + HDPE geomembrane (composite liner)Leachate collection pipe (perforated, in gravel drainage layer)to leachate storage / treatmentWaste lifts, separated by daily/intermediate soil coverLandfill gas extraction well(vents/flares or collects LFG)Final cover: low-permeability barrier + vegetated topsoil capPerimeter berm /access roadGroundwatermonitoring wellwater tableSurface-waterdiversion ditchCross-section of a modern sanitary landfill cell
Cross-section of one cell of a modern engineered sanitary landfill, showing the composite liner, leachate collection layer and pipe, waste lifts with intermediate cover, landfill gas extraction well, final cover/cap system, perimeter berm/access road, surface-water diversion ditch and a downgradient groundwater monitoring well.