NivaarExam PrepOfficial exam papers ↗

18-Env-B5 Industrial & Hazardous Waste Management · December 2016

Question 11 of 19: Hazardous vs. Industrial Wastewater — Differentiation and Treatment Strategy

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 11: Hazardous vs. Industrial Wastewater — Differentiation and Treatment Strategy (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.

"Industrial wastewater" is simply the process water generated by an industrial facility — it may or may not meet a regulatory hazard test. "Hazardous waste" is defined by whether it exhibits at least one regulated characteristic (ignitable, corrosive, reactive, toxic) or appears on a listed-waste schedule, regardless of which industry generated it. In other words, hazardous waste generated by an industrial process is a subset of "industrial waste" — not every industrial wastewater is hazardous, but every hazardous industrial wastewater is also an industrial wastewater.

Yes, different treatment strategies are used, because a hazardous designation triggers a completely different regulatory chain of custody (manifests, licensed transporters, licensed treatment/disposal facilities) that ordinary industrial wastewater does not require:

  1. Non-hazardous industrial example — food-processing wastewater high in BOD5/TSS from washing and blanching: treated on-site by equalization, screening and biological treatment (or discharged to the municipal sewer under a permit/surcharge), with no manifest or hazardous-waste facility involved.
  2. Hazardous example — spent hexavalent-chromium electroplating rinse water: cannot go to sewer or a conventional biological plant; it is chemically reduced (Cr6+→Cr3+) and precipitated on-site, and the resulting metal-bearing sludge is manifested to a licensed hazardous-waste treatment/disposal (secure landfill) facility under full chain-of-custody documentation.