  We present the technical and engineering design of a medium energy (10 MeV)
and high average power (1 MW) electron beam accelerator intended for
irradiation treatment of high volume industrial and municipal wastewater. The
accelerator uses superconducting radiofrequency (SRF) cavity technology for
producing the high average beam power with $>$90% RF to beam efficiency. The
design of the accelerator is simplified and tailored for industrial settings by
adopting the cryocooler conduction-cooling technique for the SRF cavity instead
of a conventional liquid helium bath cryo-system. The technical design is
supplemented with a detailed analysis of capital and operating cost of the
accelerator. The designed accelerator can treat up to 12 million gallons per
day of wastewater, requires capital of $\sim\$$8M for construction, and has
$\sim$13.5 cents/ton/kGy in material processing cost.
