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16-Civ-B5 Water Supply and Wastewater Treatment: May 2013

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

  1. Question 1 Water and wastewater quality parameters
  2. Question 2 Settling regimes and the mechanisms of coagulation
  3. Question 3 Effluent phosphorus limit from receiving-water assimilative capacity
  4. Question 4 Primary clarifier volume, overflow rate, and the choice between a second tank and a deeper tank
  5. Question 5 Trickling filter — principle, working, and operating problems

Start with Question 1 →

Paper format. National Examination, May 2013 — 98-Civ-B5 Water Supply and Wastewater Treatment. Three hours, closed book, one aid sheet written on both sides, approved calculator permitted. Question 1 is compulsory and the candidate attempts any three of the remaining four; every question carries 25 marks, so the examinable total is 4 × 25 = 100 marks. Page-1 Note 2 invites the candidate to submit a clear statement of any assumption made where a question is open to interpretation, and Note 6 makes clarity and organisation part of the mark. All five questions are solved here, because this set is a study resource rather than a timed sitting.

Reference texts. Metcalf & Eddy | AECOM, Wastewater Engineering: Treatment and Resource Recovery, 5th ed. (wastewater characterisation, primary sedimentation, attached-growth processes); J. C. Crittenden et al., MWHʹs Water Treatment: Principles and Design, 3rd ed. (coagulation, flocculation, settling theory); M. L. Davis & D. A. Cornwell, Introduction to Environmental Engineering, 5th ed. (water-quality parameters, unit operations); J. R. Mihelcic & J. B. Zimmerman, Environmental Engineering: Fundamentals, Sustainability, Design, 3rd ed. (mass balances on receiving waters); Health Canada, Guidelines for Canadian Drinking Water Quality (GCDWQ) and CCME, Canadian Environmental Quality Guidelines (CEQG) for the Canadian regulatory frame; Wastewater Systems Effluent Regulations, SOR/2012-139 (WSER) for national effluent limits.

Check — conventions used throughout this paper. Concentrations in mg/L are treated as g/m3 throughout, which is exact for dilute aqueous solutions and is what makes the load arithmetic in Questions 3 and 4 one-line conversions. Wastewater flows quoted as m3/d are converted to m3/s with 86 400 s/d and are taken as steady average-day values, since the paper gives no peaking factor. Where a Canadian regulatory number is quoted (WSER, GCDWQ, CEQG) it is named at the point of use; the exam itself sets no jurisdiction, and none of the numerical answers depends on the citation.