18-Env-B5 Industrial & Hazardous Waste Management · Undated paper
Nivaar worked solution (AI-drafted; not reviewed by a licensed engineer)
National Exams — May 2019 — 18-Env-B5: Industrial & Hazardous Waste Management (3 hours, open book). Marks are indicated beside each question for a total of 100 marks; all ten questions are answered in full below as a complete study resource.
Reference texts: LaGrega, Buckingham & Evans, Hazardous Waste Management (2nd ed.); 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.).
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.
Given. A 5×5 reactivity-group compatibility chart for five waste classes, with hazard-code entries below the diagonal:
| No. | Group name | vs 1 | vs 2 | vs 3 | vs 4 |
|---|---|---|---|---|---|
| 1 | Acids, minerals, non-oxidizing | — | |||
| 2 | Acids, minerals, oxidizing | (blank) | — | ||
| 3 | Acids, organic | (blank) | G, H | — | |
| 4 | Alcohols & glycols | H | H, F | H, P | — |
| 5 | Aldehydes | H, P | H, F | H, P | (blank) |
Find. Which pairs of the five groups can be stored together without hazard.
Approach. On this chart a blank cell means no hazard is listed for that pair (compatible); a letter code (G = gas generation, H = heat generation, F = fire, P = violent polymerization) flags an incompatible pair.
Reading the chart, three off-diagonal cells are blank — every other pairing carries at least one hazard code:
All other pairs (1&4, 1&5, 2&3, 2&4, 2&5, 3&4, 3&5) carry an H, F, G and/or P code and must be segregated: mixing non-oxidizing/oxidizing mineral acids with organic acids, alcohols or aldehydes risks heat generation, fire, gas evolution or violent polymerization.
| Pair | Verdict |
|---|---|
| Acids (mineral, non-oxidizing) & Acids (mineral, oxidizing) | Compatible |
| Acids (mineral, non-oxidizing) & Acids (organic) | Compatible |
| Alcohols & glycols & Aldehydes | Compatible |
| All other pairs listed | Incompatible — segregate |
