“gilbane gold” phil/engr 482 ethics & engineering gilbane gold case study
Post on 19-Dec-2015
227 views
TRANSCRIPT
“Gilbane Gold”“Gilbane Gold”
PHIL/ENGR 482
ETHICS & ENGINEERING
Gilbane Gold Case Study
Taxonomy of Obligations
To whom does an engineer have obligations?To self?To others?
Family and friends Employer and fellow employees Fellow professionals Clients/Consumers/3rd Parties Public; including future generations
To the environment?
Gilbane Gold Background
Allowable Lead and Arsenic Concentration in Wastewater
A person working a regular 40-h work week whois able to sort 1 ping-pong ball per second wouldtake 139 years to sort through a billion balls.
Note:
Assumptions:
250,000 gal/day wastewater before expansion Old test methods indicated 5 ppb lead, ok. New test indicates 7.5+ ppb lead Legal limit is 7.5 ppb lead
Planned expansion will cause 500% increase in wastewater (and lead) volume
Impact of proposed expansion...
Wastewater Current: 250,000 gal/day Future: 1,250,000 gal/day
Lead Current: 250,000 g/day @ 7.5 ppb = 5.7 lb/day Future: 1,250,000 g/day @ 7.5 ppb = 28.5 lb/day
A problem…?
When trying a new and more accurate test method, we discover that the plant is discharging wastewater concentrations at or above the legal limit of 7.5 ppb lead…
Regulations do not require the new test method be used...
0.25 MgpdWastewater
@7.5ppb lead
7.5 ppb Wastewater treatment plant
Sludge + treated effluent
A bigger problem…?
A proposed production increase will increase the amount of wastewater 500%...1.25 Mgpd
[email protected] lead
7.5 ppb Wastewater treatment plant
Sludge + treated effluent
A potential solution?“The solution to polution is dilution…”
It is proposed to dilute effluent to achieve an acceptable concentration, say 5.75 ppb...1.25 Mgpd
[email protected] lead
6 ppb Wastewater treatment plant
Sludge + treated effluent
0.4 MgpdClean H2O
Annual cost of 0.4 Mgpd water...
Fresh water purchase (@ $0.25/1,000 gal) = $35,000
Incremental sewage charges (@ $0.75/1,000 gal) = $105,000
Total annual cost = $140,000
Potential solution 2?Ion Exchange
Potential solution 3?Artificial Wetland
Summary of three possible solutions
Method Est. Annual Cost
Dilution $140,000
Ion exchange $270,000
Artificial wetland $150,000