News Details

Odors in Woodland

November 3, 2009

Lately there have been noticeable odors near the east end of Woodland.  City officials believe some of these odors were caused when the City of Woodland Water Pollution Control Facility started drying the un-used wastewater treatment ponds; this is being done in preparation for the conversion of the sewage treatment ponds to storm water storage and treatment ponds.  These ponds are located south east of the I-5/CR 102 interchange.  Most of these nine ponds have completely dried out, leaving just two with a minimal amount of water in them.  However with the recent rains, these ponds have become damp with moisture, causing an odor that is noticeable to residents just west of County Road 102.  The City has received numerous calls about these odors and wants to explain what we are doing to solve the problem.

The reason the wastewater ponds were taken out of service is twofold.

  • First, anticipating future environmental regulatory requirements, these ponds will not be allowed for use in wastewater treatment unless the city puts a lining in each pond.  The anticipated costs for lining one pond would be about $1,000,000 for a total cost of approximately $9,000,000.  The City has determined these ponds are no longer needed for wastewater treatment, since Woodland has a state-of-the art treatment facility that can treat the water to meet the strict limits required by the California Regional Water Quality Control Board.  So the decision was made to dry these nine ponds out and convert them into storm water storage ponds.  To date, seven of the nine ponds are dry, with the other two ponds expected to be completely dry by the summer of 2010.
  • Second, the City of Woodland Public Works Engineering Department estimates it will be more cost effective to retrofit the sewage ponds into storm water detention and treatment ponds for storm drainage management, instead of constructing a new pumping plant that would be located at the South Urban Growth Area and south side of Woodland.  The conversion of the wastewater ponds into storm water management ponds is expected to save $4,000,000.

The new storm water treatment ponds will perform some treatment of the storm water that runs off new development during storm events, reduce pollutants, and peak storm water flows, as the storm water runoff makes its way into the Yolo Bypass.

The city still needs to remove the solids that have accumulated in those ponds over the last 20 years and estimates the cost of the solids removal to be around $900,000 for all nine ponds.  Early next year, the City will go out for bid proposals to get a final cost and award a contract for all of the solids to be removed from the nine treatment ponds, which will be the final stage in abandoning those ponds for wastewater treatment.

Other sources of odors may be a result of the tomato processing at Pacific Coast Producers, during the tomato harvesting season.  The processing season usually runs from July to October each year.  Pacific Coast Producers processes over 500,000 tons of tomatoes, which are grown and harvested by local farmers.  Over 90% of the tomatoes supplied to the cannery come from within 15 miles of Woodland.  Pacific Coast Producers sends the water which is used to rinse and clean tomatoes and sanitize the plant itself; to the farm property they operate about a mile east of County Road 102.  The discharged water is applied by flood irrigation over 750 acres of land, which is then used to grow and harvest forage crops.  Some of the screened tomato skins, peels and seeds are also transported to the site, where it is allowed to dry and then the dried product is plowed under as a beneficial soil amendment.

Pacific Coast Producers has spent over $3,000,000 in recent years to improve operations at the wastewater ranch.  This year, they will employ a new sprinkler irrigation system that will be more effective in spreading the irrigated water on the farm acreage and this new sprinkler irrigation system is expected to reduce the potential for tomato smells.

Any comments or questions on odors can be directed to Mark Hierholzer/WPCF Superintendent for the City of Woodland at 530-406-5100.