18-Env-A6 Solid Waste Engineering and Management · May 2017
Nivaar worked solution (AI-drafted; not reviewed by a licensed engineer)
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; ISO 14040/14044, Environmental Management — Life Cycle Assessment.
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) Collection frequency and scheduling — how often each route is serviced (once, twice, or more per week) trades off directly against truck-fleet size, storage-container capacity at the generator, and nuisance (odour, vector attraction) from waste sitting uncollected; residential frequency is usually set by public-health regulation as a floor. (2) Collection method and level of service — curbside vs. backyard/alley pickup, and manual vs. semi-/fully-automated (cart-tipping) collection, sets both labour cost per stop and the crew size and vehicle type required; automated collection cuts labour cost substantially but requires standardized carts and adequate curb/alley clearance. (3) Vehicle routing and haul distance — route design (using network routing methods, e.g. the "Chinese postman" arc-routing heuristic) minimizes deadhead travel and total collection time, while haul distance to the disposal/transfer point sets whether direct haul or a transfer station is more economical. (4) Container type, size and storage — the storage capacity provided at each generator (bag, can, cart, bin, compactor) must match the generation rate and collection frequency chosen, since undersized storage causes overflow and litter between visits while oversized storage wastes capital.
These four levers are not independent: automated collection (item 2) requires standardized carts (item 4), and route optimization (item 3) is only as effective as the collection frequency (item 1) allows, since a route re-run for a second weekly pass duplicates travel regardless of how efficiently it is sequenced. A defensible design is therefore set once as an internally consistent package rather than four separate decisions — for example, a community switching to automated collection should reconsider frequency and container standardization in the same design pass, not retrofit automation onto an unchanged twice-weekly manual-can system.
