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18-Env-B5 Industrial & Hazardous Waste Management · December 2015

Question 8 of 18: Management Strategy for Waste Pharmaceutical Products

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); provincial hazardous waste regulations (e.g. BC's Environmental Management Act and Hazardous Waste Regulation).

Question 8: Management Strategy for Waste Pharmaceutical Products (6 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.

Management strategy (steps):

  1. Characterize and inventory the waste streams — distinguish off-spec/expired finished product, process residues and rinse waters, and determine RCRA-type hazardous characteristics or listed status of each active pharmaceutical ingredient (API) present.
  2. Segregate at the source — keep concentrated API residues separate from general process wastewater so the small, high-hazard fraction is not diluted into (and does not contaminate) the much larger low-strength flow.
  3. Minimize generation — tighten inventory/batch control and pursue return-to-manufacturer or take-back agreements to reduce the volume of expired/off-spec product generated in the first place.
  4. Prevent discharge to the sanitary sewer — conventional municipal wastewater treatment is not designed to remove APIs, so concentrated pharmaceutical waste must never be sewered; it is manifested and shipped to a licensed hazardous-waste facility.
  5. Select and implement a treatment/disposal option from those below, matched to the specific compound's properties.
  6. Document and track every shipment under a cradle-to-grave manifest system, with staff trained on segregation and handling procedures.

Treatment options:

  1. High-temperature incineration at a licensed hazardous-waste facility — the primary option, since it thermally destroys the API regardless of its biodegradability.
  2. Solvent/reverse distillation and recovery for process solvents that carry a low residual API load, recovering the solvent for reuse and concentrating the API residue for incineration.
  3. Chemical hydrolysis or advanced oxidation for specific compound classes amenable to chemical destruction in aqueous residuals.
  4. Return-to-manufacturer / take-back program for unopened or off-spec finished product, avoiding the need to treat it as waste at all.