Nivaar worked solution (AI-drafted; not reviewed by a licensed engineer)
Paper format. National Exams 98-Civ-A3 Environmental Engineering, May 2014 — 3 hours, closed book with one candidate-prepared double-sided aid sheet, approved Casio or Sharp calculator only. Seven questions are offered; any five constitute a complete paper (20 marks each, 100 marks maximum), and only the first five answers in the work book are marked. All seven are solved here, because the set is intended as a study resource rather than an examination script. Section marks are shown in brackets at the left margin of each part, and the marking scheme on page 6 confirms the split.
Reference texts. Davis & Cornwell, Introduction to Environmental Engineering (5th ed.); Mihelcic & Zimmerman, Environmental Engineering: Fundamentals, Sustainability, Design (3rd ed.); Metcalf & Eddy, Wastewater Engineering: Treatment and Resource Recovery (5th ed.); Crittenden et al., MWH’s Water Treatment: Principles and Design (3rd ed.). Canadian regulatory frame: the federal Impact Assessment Act (2019) and the Impact Assessment Agency of Canada, the Canadian Environmental Protection Act (CEPA 1999), CCME Canadian Environmental Quality Guidelines, and Health Canada’s Guidelines for Canadian Drinking Water Quality (GCDWQ).
Check: Henry’s law constant units in Question 1(i). The paper writes the constant as “0.30 (mol/atm)”, which is dimensionally incomplete — a Henry’s constant in the concentration/pressure form must carry a volume in the denominator. It is taken here as 0.30 mol/(L·atm), i.e. the aqueous-concentration form $C_{aq}=K_H\,p$. That reading is confirmed by the published value for ethyl acetate, $H \approx 1.3\times10^{-3}\ \text{atm}\cdot\text{m}^3/\text{mol}$, whose reciprocal is $\approx 0.77\ \text{mol}/(\text{L}\cdot\text{atm})$ — the same order of magnitude. Per NOTE 1 on page 1, this assumption is stated with the answer.
