Overview

The collection pump station crew is charged with maintenance and repair of our 9 pump stations.  Our entire collection system staff is trained in confined-space entry and rescue, pump maintenance and repair, basic electrical, and basic telemetry troubleshooting (SCADA).  

Routine Maintenance

The collection system has 9 pump stations that “lift” sewage from low points in town.  The collection system is known as a gravity system, meaning it flows downhill and there is no pressure in the pipes.  When it hits a low point it needs to be pumped to a higher elevation where it can continue to flow downhill again.  These pump stations need general maintenance every two weeks to guarantee proper operation.  There are filters to change, pump controllers to check and other mechanical devices to keep in proper working order.

We have two types of pump stations – wet pit, dry pit stations (6) and submerged pump stations (3).  Dry pit stations have all their workings underground in a dry pit and the sewage collects next door in a wet pit or wetwell. 

*Dry pit station

*Submersible Pump Station

Performance Testing         

Once a year our crew does performance testing on our pump stations to check for wear on our mechanical systems.  There is non-routine maintenance done at this time such as oil changes, wear plate tolerances checked, and pump station controllers tested for proper function.

Emergency Response preparedness

Our pump stations have controllers that automate the operation of the stations and are programmed to alarm our standby person in case of an emergency.  Some of the pump stations have their own onsite backup power and others are wired to be powered with a portable generator to provide uninterrupted service during power outages or other related emergencies.

Overview

The wastewater collections division has a two-person crew dedicated to inspection of the wastewater collection.  The staff is NASSCO (http://www.nassco.org/) certified to inspect pipe condition using the industry standard program - Pipeline Assessment and Certification Program (PACP).  The crew is responsible for a variety of types of inspections to assess the wastewater infrastructure condition.

CCTV Sewer Main Inspections

The City of San Luis Obispo has sewer mains currently in use that date from the 1880s to the present.  The older mains may function correctly, but are made of materials that may be considered substandard by today’s criteria.  Mains are inspected with a self-propelled robotic camera system that inspects the condition by travelling through the inside of the pipe.  Defects commonly observed are cracks, missing pipe, roots, grease, offsets, sags and other indications of condition, or failure of pipe materials.  These defects are logged into the IT Pipes inspection database which gives the main an overall condition rating, as well as a structural and maintenance rating.  This information helps determine how soon the sewer main needs replacing.  The goal is to have the entire collection system inspected and logged into a database for use as a long range replacement strategy tool.

The inspection crew responds to sewer main blockages to determine what caused the blockage and assess how to prevent a blockage in that location in the future, either through maintenance, repair or replacement of the affected main.  They also inspect the installation of new sewer mains to ensure the City of San Luis Obispo gets the best possible product installed by contractors, for their customers.

Creek Crossing Inspections

The Collections inspection crew has a program where twice yearly, the sewer mains crossing any creeks get inspected for exposure and condition.  The exposed crossings are visually inspected and photographs taken to document their condition.  Protecting the environment is very important to us and this is a key part of preventing a direct accidental discharge to water bodies, such as a creek.  The information is compiled and entered into our Cityworks database for historical reference and to show compliance if audited by any regulatory agency such as CA Fish and Wildlife.

Infrastructure Inspection Other Than Sewer Mains

The inspection crew inspects any related infrastructure associated with wastewater collection.  This includes manholes, storm water mains, storm inlets, and mutual aid.  Our specialized equipment is suited for many applications for other departments and we assist in locating pipes, inspecting infrastructure for other departments.  We are the “camera guys.”

Sewer Service Lateral Inspection 

The inspection crew has equipment to inspect laterals owned by the City of San Luis Obispo.  These are only facilities as the laterals from commercial or houses are privately-owned.  The crew does review videos of private laterals submitted to the City due to conditions placed by Community Development such as lateral reuse or new replacement of some laterals.

The City of San Luis Obispo requires that all privately owned laterals be kept in a structurally sound condition. We help the private citizen with information on how to maintain their lateral and advice on replacing faulty laterals when asked.

Overview

There are approximately 138 miles of sewer main in the City of San Luis Obispo’s collection system.  The age varies from the 1880s to present and made of a variety of materials.  Predictive and preventive maintenance is done to extend the useful life of the main and prevent stoppages. Common problems are root intrusion, grease build-up, and grit settling into sags in the sewer main.  We address these problems with a specialized truck that can clean the lines with high-pressure water and also vacuum the debris from the system.

Predictive Maintenance

Predictive maintenance is recurring scheduled maintenance to address known problems in our collection system.  Our main goal is to prevent stoppages and overflows from occurring.

The sewer mains that have known problems have been inspected and evaluated by our CCTV inspection crew and placed on a cleaning schedule.  These recurring schedules are created in our Cityworks database and can automatically generate schedules for the crew on a monthly basis.  We have mobile computers on our trucks that highlight the mains on a GIS map with all the pertinent data to get the job done correctly.  While cleaning, the operators do a visual inspection of what they get back in the manhole while cleaning the main.  If there are substantial amounts of debris, roots or grease, the crew will vacuum the manhole and make note of the conditions.  If there’s justification, they will adjust the cleaning schedule (longer or shorter) to optimize the effectiveness of the cleaning.  Work orders are updated and completed in the field. 

Preventive Maintenance

Preventive maintenance is performed the same way, but with different goals.  Preventive maintenance is done on mains not currently experiencing problems.  The lines without problems are cleaned about every five years. Mains are cleaned by drainage basin and work orders are generated by the crew in our Cityworks database.  While cleaning the main is evaluated for problems. If amounts of debris or roots are observed, the crew will make a CCTV work order to have the main inspected and evaluated.  It may be put on a predictive maintenance schedule depending on the result of the inspection.

Overview

The construction and repair crew repairs defects found in the mains, conduct manhole repairs, and make repairs to concrete collars around manholes.  Concrete collars get broken regularly due to heavy traffic from trucks and buses, and mains incur damage due to age, material failure and getting hit by contractors.

Conventional repairs

Most repairs to the sewer system are done with conventional repair methods.  Asphalt streets are cut and the mains are exposed by excavating with a backhoe.  Defective pipe is removed then replaced with more modern materials.

Pipe patch

Pipe Patch is a brand name of a pipe lining process we use to repair pipe from the inside using a resin repair kit.  The pipe patch is wrapped around an inflatable plug and inserted into the main where the defect is located.  The inflatable plug is inflated to a specified pressure and then left in place for the resin to cure (usually two hours +/-).  Then the plug is deflated and removed leaving a cured-in-place fiberglass pipe repair, restoring the host pipe back to new condition.

Overview

The Stormwater Collection System consists of inlets, storm mains, manholes, rock guards, grates and other collection points.  The wastewater collection division works in conjunction with the public works department to maintain the stormwater system.  Staff cleans the inlets, mains, and manholes,  as well as inspections on the buried infrastructure, because we have the specialized equipment and expertise to perform these duties.

 Inspections

The inspections are performed by two crews depending upon the infrastructure being evaluated.  The storm cleaning crew does visual inspections of the manholes, inlets and some short storm mains.  Some inspections can be performed with a specialized camera called a “quickview” camera, capable of video or capturing still photographs of defects.

Example: http://ww1.prweb.com/prfiles/2010/10/18/4137384/quickview01.jpg

Storm mains which have bends, or are longer in length are inspected by the Collections CCTV camera crew and documented in videos and defects are entered into an inspection program, and documented in Cityworks for future reference.

 Cleaning

The Storm crew cleans inlets and manholes by pressure-washing the structure and vacuuming the debris from the structure.  They have a specialized truck similar to the wastewater combination truck, but higher capacity.  To clean the mains they use a high-pressure nozzle that breaks up debris and drags it back to the manhole or inlet they are working from and the large amounts of debris are vacuumed and trucked to a disposal site.