Plant Profile: City of Woodland

Resource Recovery, Technology and Innovation

City of Woodland Water Pollution Control Facility

Story republished with State Water Board permission.

WPCF is a class V Tertiary plant that has recently been updated to an Advanced Treatment facility. The upgrade was completed in December 2016. There were several upgrades including:

  • An upgrade of the secondary treatment process to the Modified Ludzak-Ettinger fine bubble diffuser aeration with an anoxic zone for denitrification.
  • A replacement of the mechanical bar screens at the headwork’s to a band screen system due to excessive ragging and carryover (breakthrough) of solids which improved the facility’s trash capture rate.
  • A 30 inch Secondary Effluent bypass with proportional flow options. This allows WPCF to regulate the flow to the filters for improved effluent quality during plant upsets.

Unique Features: As part of the Davis-Woodland Water Supply Project, starting in June 2016, the Woodland Regional Water Treatment Plant began drawing its water from the Sacramento River (surface water) instead of using well water. Consequently, this change effected the WPCF’s influent as the river water lowered the alkalinity and inhibited the nitrification process. As a temporary fix, while the WPCF’s upgrade construction was being completed, the staff fed pond water into the plants influent to increase alkalinity. Operators needed to be careful because the addition of too much pond water could cause the plant poor settling from algae. The permanent solution is now the addition of magnesium hydroxide into biological process.

City of Woodland Water Pollution Control Facility

WPCF installed new high efficiency, air-bearing turbo blowers, APG-NEUROS, for aeration. After the new blowers were installed, operators saw that the blowers were accumulating too much dust. Staff added polyester filters and decreased the dust issue.

WPCF found that covering the edges of the weir on the clarifier decreased the amount of algae in the weirs. WPCF both lined and added new valves to some of their ponds for better pond control. WPCF has received several awards to recognize their plant including:

  • The American Public Works Association (APWA), Sacramento Chapter, 2007 Project of the Year Award (Small Agency, Environmental Project Category)
  • California Environment Association (CWEA), Northern Valley Section, 2016 Plant of the year medium.