NivaarExam PrepOfficial exam papers ↗

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

Question 4 of 17: Variables Governing Landfill Gas Production

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 4: Variables Governing Landfill Gas Production (3 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.

(1) Moisture content of the refuse mass — water is required both as a reactant/transport medium for the anaerobic hydrolysis and methanogenesis reactions and to move nutrients and microorganisms through the waste. (2) Waste composition, specifically the biodegradable organic fraction (putrescibles, paper, wood) — only organic material generates gas, so a higher biodegradable fraction increases both the rate and total yield. (3) Temperature within the landfill — governs the rate of the microbial reactions, with generation typically maximized in the mesophilic range (roughly 30–40 °C) that a deep, insulated waste mass tends to self-sustain.