An electrical failure at The Dalles Wastewater Treatment Plant resulted in the discharge of about 2,100 gallons of fully treated but undisinfected wastewater.  The failure occurred at about 9:07 a.m. Sunday and lasted for about a minute and 20 seconds.   Failure of a motor starter tripped an electrical breaker, shutting down the plant’s ultraviolet light disinfection system.  Plant staff  reset the breaker to bring the system back online by 9:09 a.m.  The failed unit is locked out and will be replaced as soon as possible.  City officials say Oregon Department of Environmental Quality officials have been notified of the event and DEQ guidance is being followed in response to this incident.