Question 3 of 7: Environmental Ethics and Water Treatment

Question 3: Environmental Ethics and Water Treatment (20 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.

(i) The Proper Ethical Course of Action on the Chlorine Storage Hazard

The engineer here is not employed by the tank’s owner and has no contractual or design responsibility for it — but obligation (a) is not scoped to a project or an employer, it is a paramount, career-wide duty that applies whenever an engineer becomes aware of a genuine risk to public health, safety and welfare. A chlorine storage tank sited dangerously close to residential homes is a serious hazard: chlorine gas is acutely toxic, and an uncontrolled release (from a leak, corrosion failure, or an accident during handling) could cause mass casualties among nearby residents with essentially no warning. Having personally identified this hazard and investigated it far enough to confirm the tank’s owner, the engineer already carries the knowledge that triggers obligation (a): the risk must be treated as paramount over any other consideration, including the inconvenience of pursuing it further or the fact that it is “not his project.”

Obligation (b) then defines what “treating it as paramount” requires in practice: appropriately reporting the hazard, and if a significant risk remains unresolved after reporting, the engineer may ethically escalate to making the concern known publicly. Raising the issue once with the provincial authorities and being told “there is nothing they can do” does not discharge this obligation — a single rebuffed inquiry to one authority is not the end of the reporting chain when a credible, serious, unresolved public-safety risk remains. The proper course is to escalate through the available channels that do have jurisdiction or influence: the local fire department/emergency-management authority (which needs to know regardless of zoning jurisdiction, for emergency-response planning alone), the workplace/occupational-safety regulator, the municipality (land-use/bylaw enforcement, if the siting itself violates a setback requirement), and the engineer’s own professional licensing body for guidance. Documenting each step (what was found, who was told, and the response received) protects both the public and the engineer’s own professional standing. If, after genuinely exhausting these avenues, a significant and credible risk to nearby residents still remains unresolved, obligation (b)’s final clause explicitly and affirmatively permits — it is framed as an ethical option, not merely a tolerated last resort — making the concern known publicly (for example, informing the affected residents directly, or the local media), even though doing so may create friction with the tank’s private owner or with the authorities who declined to act. Simply accepting the provincial authorities’ response and taking no further action would not meet the paramountcy standard obligation (a) sets, given the severity of a potential chlorine release near occupied homes.

(ii) Key Strategies for Consistently Potable Water from a Surface (Lake) Source

Surface water sources are more variable than groundwater (turbidity spikes from runoff, seasonal algal blooms, temperature-driven stratification and turnover), so consistent potability depends on more than a single treatment step. Four key design/operational strategies:

1. A complete multi-barrier treatment train sized for the source’s worst-case, not average, water quality. Coagulation–flocculation–sedimentation (or dissolved-air flotation) followed by granular-media filtration and disinfection, each barrier designed around the lake’s peak turbidity/organic-loading events (e.g., spring runoff or an algal bloom) rather than its average condition, so no single upset event can pass contaminants through the whole train.
2. Watershed / source-water protection. Managing land use, buffer zones and pollutant discharges in the lake’s contributing watershed reduces the pollutant and pathogen load reaching the intake in the first place — the first, and often most cost-effective, barrier in the multi-barrier approach, since it is always easier to keep a contaminant out of the source than to remove it downstream.
3. Real-time raw- and finished-water monitoring with automated process control. Continuous monitoring of raw-water turbidity, algal/cyanotoxin indicators and UV₂₅₄/dissolved organic carbon (a disinfection-byproduct precursor indicator), paired with automated coagulant-dose and filter-run adjustment, lets the plant respond to a changing lake condition (e.g., a bloom or a storm-driven turbidity spike) within hours rather than discovering the upset only after compliance sampling.
4. Redundant, multi-barrier disinfection with a distribution-system residual. Combining a physical/UV disinfection barrier (effective against chlorine-resistant Cryptosporidium and Giardia, both realistic risks in a surface-water source) with chemical disinfection (which additionally provides a persistent residual protecting the distribution system against regrowth and intrusion) ensures no single disinfection technology’s specific weakness becomes the plant’s single point of failure.