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Morro Bay Water Reclamation Facility Project:  Issues, Concerns, and Solutions

The collection system, consists of sewer lines and lift stations.  The treatment plant, the sewer lines, and the lift stations (also known as pump stations) are part of an integrated system.  Yet, collection system issues have not been thoroughly investigated and addressed as part of the WRF project.

Most of Morro Bay’s sewer lines are gravity lines, meaning that the sewage moves downhill, by force of gravity, to the current treatment plant.  However, some of the lines, primarily larger ones, must convey sewage uphill.  This requires lift stations.  A lift station collects sewage and, when a certain level is reached, the pumps are activated and force the sewage uphill through the line.  A line that carries sewage uphill from a lift station is called a “force main”.

WRF Force Main Issues

The current plan is to leave the sewer line configuration essentially as it is, with the lines converging at the location of the existing treatment plant, and to pump the sewage from there to the inland plant via a large force main.  There are two serious issues associated with this plan.

• The longer the line, the more likely some portion of it could be damaged in an earthquake, making it impossible to move sewage to the treatment plant, and thus causing the entire system to fail.
• The recently-completed draft facility master plan made no provision for any sort of leak detection system.

WRF Lift Station Issues

The City currently plans to put a massive lift station at the site of the existing plant where the sewer lines converge. The “wet well”, where the sewage would be collected, is projected to be 30 feet long, 16 feet wide, and 26 feet deep.  This area does not include the space required for generators and other associated infrastructure.  This massive lift station would pump all of the City’s sewage through a large force main to the new plant.  There are major issues associated with this plan.

• The area where the lift station is to be built is subject to liquefaction in an earthquake.  However, this issue was not addressed in the recently-completed facility master plan draft.  If the station were significantly damaged in a liquefaction event, it would be impossible to move sewage from town to the currently-planned South Bay Boulevard treatment plant site.  
• Pumping all of the City’s sewage a considerable distance uphill, 24/7, will greatly increase overall WRF operating costs, as the electric power required will be substantial.  Thus the system, as planned, would not only be expensive to build, but very expensive to operate.

Leaky Sewer Line Issues

Clear evidence of sewage contamination of the City’s Morro Basin drinking water aquifers has been documented and reported, but the City refuses to take action to fix the dilapidated sewage collection system.  For many years, residents have been reminding City officials that the City’s own video inspections show that the sewer lines are in terrible condition and leaking sewage into the ground all over the town.  Residents have also presented significant evidence that the sewage is contaminating some of Morro Bay’s drinking water wells.

WRF operating cost is another issue related to the leaky collection system.  Just as sewage can leak out in dry weather, water can enter (infiltrate) the damaged lines during wet weather.  This increases the volume of “sewage” that the plant must process, and thus increases the operating costs.  

Infiltration of rain water also increases the risk of “surcharging” -  overloading of the sewer beyond its design capacity, and even exceeding the capacity of the treatment plant, resulting in spills and environmental damage..

The City has refused to take corrective action and recently a senior staff member stated that the most problematic (by its own assessment) of the leaky lines will not be fixed for four more years.

Existing WWTP flow data has been used in development of capacity requirements for the WRF.  However, infiltration and exfiltration issues, The flow data is unreliable.

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