Morro Bay-Cayucos Sewage Treatment Plant and Sea Otter Habitat
The threatened California sea otter numbers just 2,700 statewide. The Morro Bay/Cayucos sewage plant in California has dumped pollutants into the ocean for more than two decades -- directly into bay waters that are a hotspot for sea otter deaths. Although the construction time for the Morro Bay sewage plant upgrade to meet basic federal standards is less than two and a half years, plant officials do not intend to complete the project until March 2014. The plant's own documents show that a faster, more efficient upgrade is not only possible, but would be less expensive as well.
Facts about the Morro Bay-Cayucos Sewage Treatment Plant
- The Morro Bay-Cayucos Sewage Treatment Plant is one of the only treatment plants in California operating with a waiver from federal sewage treatment standards. This means the plant is allowed to discharge primary-treated sewage into the ocean. During primary treatment, wastewater is screened for the removal of solids, grit, and primary sedimentation, then is chlorinated for disinfection.
- The plant treats only part of its wastewater to secondary treatment standards, which utilize special strains of aerobic bacteria (bacteria that need oxygen to grow) to break down the organic waste left after primary treatment. Secondary treatment removes up to 95 percent of suspended solids in the waste stream and is significantly more effective than primary treatment in removing biologic pathogens from sewage. For example, secondary treatment removes 80 to 90 percent of shigella bacterium, 70 to 99 percent of salmonella, and 75 to 99 percent of enteric viruses prior to discharge of the effluent.
- The plant discharges its wastewater just a half-mile offshore, just northwest of Morro Rock, at a depth of 50 feet. The World Health Organization recommends sewage outfalls to be a minimum of one mile offshore and/or at a minimum depth of 60 feet.
- The most recent major upgrades to the plant occurred more than 20 years ago in 1983 and 1985.
- For more information about the plant, you can visit the Morro Bay Public Services Department website.
Facts about the California Sea Otter
- Historically, California sea otters could once be found from as far north as Oregon to Punta Abreojos, in Baja California. At their height, an estimated 16,000 to 20,000 sea otters occupied this range.
- Today, the otters' range is limited to approximately 300 miles of the California coast, ranging from Half Moon Bay in the north to Point Conception and San Nicolas Island. The total population has dwindled to approximately 2,700 sea otters. The California sea otter has been listed as a "threatened" species under the Endangered Species Act since 1977.
- Sea otters are excellent "sentinel" species, meaning they can be early indicators of pollution problems and ecological change. The otter is also a keystone species that helps control the destruction of kelp forests by grazing urchins thereby helping to maintain a diversity of forest inhabitants and ecosystem services, including protection of the coastline from erosion.
Morro Bay Coastal Waters: "Hotspot" for California Sea Otter Infection
- Morro Bay has one of the highest rates of otter infection from the parasite Toxoplasma gondii (T. gondii). T. gondii can cause encephalitis, which affects the brains of infected animals, causing a variety of physical symptoms such as muscle tremors, recurrent seizures and decreased or abnormal motor function. Encephalitis is a major contributing factor in the death of sea otters from both shark attack and cardiac disease.
- California sea otters living in the Morro Bay area are nine times more likely to be infected with T. gondii than sea otters elsewhere in their range.
- The area from Cayucos to Hazard Canyon along the Central Coast had the highest number of otter strandings in the otters' region, 77 in 2004.
- Morro Bay is the only region in the California sea otters' range where primary-treated effluent is discharged into the nearshore marine environment.
- A prominent biologist with the California Department of Fish and Game names "the discharge of primary treated sewage" as a leading factor that may account for the Morro Bay T. gondii hotspot.
- For more information about the sea otter and research regarding potential causes of otter mortality, you can visit the Sea Otter Alliance website.
Facts About Upgrading the Sewage Plant
- The Morro Bay-Cayucos Sewage Treatment Plant has indicated its intent to upgrade to full secondary treatment capacity, but construction is not scheduled to begin until the year 2012. The project is not slated to be finished until at least 2014.
- In contrast, the average upgrade time for sewage treatment plants in the Central Coast region is only five years -- all for plants larger than Morro Bay-Cayucos.
- An environmental expert estimated that the Morro Bay-Cayucos Sewage Treatment Plant could in fact be upgraded in as little as four and a half years.
last revised 1/24/2007
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