This paper presents mr optimization analysis of the remedial pumping d
esign for a contaminated aquifer located in Elmira Ontario, Canada. Th
e remediation task presented in the paper is to remove two ground-writ
er contaminant species, NDMA (N-nitrosodimethylamine) and chlorobenzen
e to such extent that the specified ground-water quality standards are
met. The contaminants, NDMA and chlorobenzene, have different initial
plume configurations and retardation characteristics. The required qu
ality standard for NDMA is five orders of magnitude smaller than the i
nitial peak concentration. The objective is to minimize total pumping
and the constraints incorporate ground-water quality requirements on t
he maximum and the spatially averaged residual concentrations, with co
ntaminant source control being considered. On the combination of simul
ation and optimization, the results of this study indicate that the pe
rformance of an optimization algorithm based on gradient search is con
troled by the specified cleanup levels, and that contaminant concentra
tions can be nonconvex and nonsmooth for some pumping schemes.