Where it All Goes: Our Tour of the Wastewater Treatment Plant

As you drive down Highway 33 and exit the Ojai Valley you can get a glimpse of our community’s wastewater treatment plant that is operated and maintained by the Ojai Valley Sanitary District. Members of the Ojai Valley Green Coalition toured the plant recently to learn about this vital environmental service.

Bradshaw Pruitt, CS/TP Operations Supervisor for the District, enthusiastically guided us through the plant and explained the different treatment processes that transform wastewater into water safe for discharge to the Ventura River.

Through over 120 miles of pipe, an average of 1.6 million gallons of water per day enter the Plant, which has the capacity to treat up to 3 million gallons per day. Equalization basins following secondary treatment, the composting area, and the old digesters are available to handle surges in flow that often occur during extreme wet weather events. Customers should verify they do not have any property drains or gutter downspouts plumbed into the sewer system as it creates problems with plant operation such as poor solids settling resulting in water with higher turbidities being discharged into the Ventura River.

Another issue the plant experiences is excessive maintenance due to customers disposing of “flushable wipes” into the sewer system. Please do not do this as it causes multiple problems in many areas such as service area lift stations pumps, plant influent pumps, grit pumps, and the return activated sludge pumps. They also build up in the plant’s biological system, and cause fouling of process monitoring probes. As we learned: never flush wipes.

The plant’s most interesting feature is that it is like a giant liquid compost pile. All the various bacteria in the wastewater decompose the organic material into simple molecules like carbon dioxide and nitrogen gas. Some bacteria thrive in an oxyge-rich environment while others in a low oxygen environment. The different bacteria living in the different environments assimilate and transform nitrogen, phosphorus, and organic carbon materials into carbon dioxide, nitrogen, and compostable biomass. Dead microorganisms along with inorganic particulate matter leave the plant as biosolids and get sent to a composting facility operated by Synagro in Lost Hills, CA. 

Biosolids are being sent for off-site site composting because of concerns with staff time and resources to run the compost operation. This takes away from the resources needed to monitor and operate the plant so the discharge meets the compliance requirements central to the core mission of discharging safe water to the Ventura River.

Composting of biosolids and the land application of the finished compost has been in the news recently. Since the discovery of micro- and nano-plastics in our wastewater, as well as forever chemicals like Per- and Polyfluoroalkyl Substances (PFAS), it has become a dilemma as to what to do with the biosolids that could be used as a soil nutrient on farms. To produce healthy living compost that can be recycled into our food supply system be conscious of what is put into the sewer.

Consider alternatives that do not introduce plastics and PFAS into our wastewater such as all-natural fiber clothing and linens, non-coated cookware, glass storage containers, etc.

And never dump any toxic/hazardous materials or pharmaceuticals into the sewer! We can contribute to efficient and environmentally friendly operation of our wastewater treatment processes through small changes in our life.