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18-Env-B5 Industrial & Hazardous Waste Management · December 2017

Question 3 of 28: Basis for Water Quality

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

Notes on this paper

Reference texts: Nemerow & Dasgupta, Industrial and Hazardous Waste Treatment, 2nd ed.; Metcalf & Eddy, Wastewater Engineering: Treatment and Resource Recovery, 5th ed.; Davis & Cornwell, Introduction to Environmental Engineering, 6th ed.; LaGrega, Buckingham & Evans, Hazardous Waste Management, 2nd ed.; CCME, Guidelines for the Management of Biomedical Waste in Canada (1992); Canadian Environmental Protection Act (CEPA), 1999; Basel Convention on the Control of Transboundary Movements of Hazardous Wastes (1989); Canadian Nuclear Safety Commission (CNSC) regulations on radioactive waste; provincial hazardous waste regulations (e.g. BC's Environmental Management Act and Hazardous Waste Regulation).

Question 3: Basis for Water Quality (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.

Water quality is not an absolute standard — it is defined relative to the water's intended use, so "acceptable quality" is set by the most demanding use the water must support.

  1. Intended use — potable supply, industrial process water, irrigation, recreation, or aquatic-life support each has different tolerances (e.g. boiler feedwater needs near-zero hardness; irrigation tolerates moderate salinity).
  2. Regulatory/guideline limits — drinking-water guidelines (Health Canada GCDWQ), receiving-water objectives (CCME Water Quality Guidelines) or a discharge permit set the numeric criteria for that use.
  3. Public health and ecological protection — the underlying purpose of any standard is to protect human health and the receiving ecosystem, which is why criteria differ by parameter (pathogens, toxics, nutrients, DO).
  4. Economic/technical feasibility of treatment — achievable quality is also bounded by what available treatment technology can reliably and affordably deliver.