“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
Note: A person working a regular 40-h work week who
is able to sort 1 ping-pong ball per second would
take 139 years to sort through a billion balls.
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…?
0.25 Mgpd
Wastewater
@7.5ppb lead
 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...
7.5 ppb
Wastewater treatment plant
Sludge + treated effluent
A bigger problem…?
1.25 Mgpd
Wastewater
@7.5ppb lead
7.5 ppb
 A proposed production increase
will increase the amount of
wastewater 500%...
Wastewater treatment plant
Sludge + treated effluent
A potential solution?
“The solution to polution is dilution…”
1.25 Mgpd
Wastewater
@7.5ppb lead
 It is proposed to dilute
effluent to achieve an
acceptable concentration, say
5.75 ppb...
0.4 Mgpd
Clean
H2O
6 ppb
Wastewater treatment plant
Sludge + treated effluent
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