In 1967 the facility was upgraded to include secondary treatment using Contact/Stabilization. Dis-infection of the effluent flow was also included at this time, using chlorine gas delivered in multiple one-ton steel cylinders.

In 1984 the operation of the primary treatment was discontinued and shut down, as it was discovered that the Contact/Stabilization was able to effectively handle the treatment of the flow.

In the early 1990´s the Contact/Stabilization tanks were refitted from coarse bubble diffusers to fine bubble diffusers.

In the late 1990´s the switch was made from one-ton cylinders of chlorine to chlorine tablets for safety reasons. Then in 2001 we changed over to liquid sodium hypochloride (bleach) for disinfection.

In 2002 and 2003 the Secondary Clarifiers were completely rebuilt, then sandblasted and painted.

In 2003 a Capital Asset Management Plan (CAMP) was initiated to help ensure the City´s ability to accommodate future growth.

In 2004 a new Headworks was designed under the CAMP with construction beginning in mid-2005. Also in 2004 under the CAMP, design was begun for upgrades to the Secondary treatment at the plant.

In October 2004 the EPA issued a new National Pollutant Discharge Elimination System permit (NPDES) effective until October 31, 2009.