City of Roseville – Wastewater Collection Division CCTV Crew
Inspections of the sanitary sewer system are a routine and essential duty for the Sewer Maintenance Division crews. Regular inspections can help troubleshoot and minimize problems with the collection system. Connections to the system and unwanted sources of inflow are identified through sewer inspections. As part of the sewer cleaning process, our crews inspect and report on any problems or deficiencies with the sanitary sewer system. Such items included in the inspection are:
1. Visual Inspections
Visual inspections are performed on the sewer system manholes at a higher frequency than internal inspections because of the relative ease of performance. This type of inspection can give a good indication as to the condition and proper functioning of the collection system and generally includes:
A. Manhole Inspection
Frame & Cover
Manhole Bottom Channels
Structural Integrity/manhole degradation
Inflow & Infiltration into Manhole
Other Miscellaneous Problems
B. Sewer Inspection
Dirt & Stone Brought Back While Cleaning
Abnormal Amount of Debris in Line
Excessive Amounts of Grease in Line
Blockage or Obstruction in Line
Excessive Flow (Relative to Upstream Flows)
Any Miscellaneous Problems
Any of the above items would result in further study of the sewer and include T.V. inspection, sewer repair or manhole repair. Our crew chiefs have the authority to write up anything they deem to be a problem or potential problem to the sewer system.
2. Closed Circuit Television (CCTV) Inspection
Internal sewer line inspections are performed to gather additional information about what is taking place between manhole access points. These typically include using CCTV inspections to photograph the sewer system.
CCTV inspections are performed for a number of reasons including:
Requested by cleaning crew because of a suspected problem.
In connection with Inflow & Infiltration investigation work.
Sewer rehabilitation work.
Routine check on the effectiveness of sewer cleaning.
Sewer inspection prior to street overlay projects .
Inspection of sewer stubs for further development..
The Wastewater Collection Division has two full time inspection crews. A CCTV inspection crew typically consists of one Wastewater Utility Maintenance worker 2 and a Wastewater Utility Maintenance worker 1, Overseen by the Wastewater Collection Supervisor. The inspection data is gathered electronically and brought back to the office from the field and is processed into our CMMS . Preventative maintenance is set up from the data gathered.
3. Smoke Testing
Another form of internal inspection of the sewer system is the smoke test. Smoke testing is performed to determine the following:
Sources of ground water entry into the collection system.
Proof that a building or residence is connected to system.
Location of illegal connections into the sewer system including downspouts, storm water catch basins and yard drains.
Location of broken sewers.
Location of buried manholes or diversion points.
Smoke testing of the sewer system has the potential to affect the occupants of buildings connected to the line being tested. Defects in the sewer system of a building, dry traps, a defective wax ring under commodes, vents terminated in an attic, or cleanout plugs missing from sewers can cause smoke to enter the building. Therefore adequate preparation and advance public awareness is necessary to avoid panic or alarm. Smoke testing letter are usually sent out to each affected resident or business when smoke testing is proposed on the sewer system. A smoke crew consists of a Senior Utility Maintenance worker and three Utility maintenance workers.
4. Dye Tests
Dye testing is a method of internal inspection similar to smoke testing and provides another means of determining connections to the sewer system. Situations where dye testing may be appropriate include:
Locating suspected illegal connections to the sewer system at roof leaders, downspouts, catch basins and yard drains.
Estimating velocity of flow.
Proof that a building or residence is connected to the system.
City of Roseville - Sewer Maintenance Division Construction Crew
Sewer Repair Work
1. Miscellaneous Repair
The City’s wastewater collection construction crew performs routine and emergency repairs on the City’s sewer infrastructure. The Wastewater Collection Division has one full time construction crew. The construction typically consists of three Wastewater Utility Maintenance Worker 2 and a Wastewater Utility Maintenance Worker 1 supervised by a Senior Utility Maintenance worker.
This repair work includes sanitary sewer replacements; spot repairs, lateral and service tap replacements, manhole repairs and manhole replacements. The bulk of the repair work has been in the historic district and the city’s older areas such as old town Roseville. Over the years we have made great strides in getting these sewers structurally secure and are now concentrating on a condition assessment and replacement of the ageing infrastructure.
2. Sewer Rehabilitation Projects
In addition to our normal repair work, we are also committed to doing one or two sanitary sewer rehabilitation projects each year. These rehabilitation projects are generated by our past historical data related to the condition of the sewers.
We are making good use of the City’s rehab funds for sewer rehabilitation projects. The goal of all this rehabilitation work is improves the structural integrity; restore the hydraulic capacity of the pipe and the reduction of Inflow & Infiltration into the sanitary sewer system.
City of Roseville – Wastewater Collection Division Vactor Crew
Sanitary Sewer Cleaning
The Wastewater Collection Division has maintenance and cleaning programs to keep the sanitary sewer system operating efficiently and to minimize the number of main line stoppages and calls for service. Sewer cleaning using hydraulic or mechanical methods performed on a routine basis helps to remove accumulated debris in the pipe such as sand, silt, grease, roots and rocks. If debris/grease is allowed to accumulate, it reduces the pipe capacity and a blockage can eventually occur resulting in overflows from the system onto streets, yards, basements, and into surface waters.
The Wastewater Collection Division has three full time cleaning crews. The Collection division has an up to date map of the collection system. The map is broken into grids. Each grid is set up for scheduled maintenance into or CMMS based on past history. As the grids come up for scheduled maintenance or cleaning each crew is assigned to one of the grids in the city. A cleaning crew typically consists of a Wastewater Utility Maintenance Worker 2 and a Wastewater Utility Maintenance Worker 1, overseen by the wastewater Collection Supervisor. We use high-pressure sewer jet trucks (Vactors), and a trailer mounted mechanical Rodder or Eel.
Our high-pressure sewer jet trucks carry between 1,500 and 2,000 gallons of water depending on the truck. The vehicle’s high-pressure pump can pump out up to 85 gallons of minute at around 3,000 psi for cleaning out the sewer pipes. A typical truck can carry 700 feet of 1 1/2inch diameter high-pressure hose, which is inserted into the sewer during cleaning operations. The sewer jet can power a variety of sewer cleaning apparatus.
The following is a list of sewer cleaning methods presently in use by our division:
1. High Pressure Flushing
This method uses high-pressure water to flush out stone, sediment or other unwanted material from the sewer. Our sewer cleaning trucks can generate 3,000 psi of water pressure with a flow rate of 85 gallons or more per minute.It is the combination of high pressure and high flow rates that cleans the pipe. A flushing nozzle is installed on the end of the Vactor truck’s hose and the hose is lowered into the downstream manhole of the sewer section being cleaned.
There are a number of rear facing jets in the circumference of the nozzle that allow the high pressure water to move the nozzle and sewer hose up the sewer main to the next manhole, which is typically 500 feet away. As the nozzle moves up and down the pipe, it dislodges sediment, stone, grease and other debris and flushes it downstream to the manhole, where it is removed by vacuum from the system.
We use a variety of cleaning nozzles, each are tailored for removing certain materials from the sewer system. Some examples are penetrating nozzles, which have one frontward facing nozzle to penetrate a blockage and break it up and spinning nozzles, which spin and scour the pipe walls during cleaning. A culvert nozzle is used to clean pipes 15 inches in diameter and larger.
High Pressure flushing is typically used to clean sewers with polyvinyl chloride (PVC) pipe, reinforced concrete pipe (RCP), vitrified clay pipe (VCP) and Ductile Iron Pipe (DIP) Although high-pressure flushing is good at cleaning sediment and stones out of the sewer system, it cannot cut roots, which are typically found in the older areas of the Town.
2. Root Cutters
This method uses the high-pressure water from the sewer ‘Vactor” truck to operate a hydraulic root cutter. The high-pressure water turns a hydraulic motor, which has a root cutting chain attached to the motor shaft. As with the cleaning nozzles, there are rear-facing jets on the root cutter assembly, which propels the cutter up and down the sewer pipe. All cut up roots and debris is flushed down to the manhole where it is removed by vacuum from the sewer system.
3. Sewer Vacuum Trucks
Sewer vacuum trucks are used to vacuum out sediment, sand, stone, grease, bricks rocks or other debris cleaned out from the sewer system. The vacuum truck can be used in conjunction with the sewer jet during cleaning operations when the sewer is too deep to clam out the material by hand or when an abundance of material is brought back to the manhole. The sewer vacuum trucks also reduces the need for confined space entry.
4. Hand Rodders
Hand rodders are also used to cut roots, grease and dislodge debris in sewer mains that are located in areas (such as back yard easements) that are not accessible to our “Vactor” truck. Cutter heads are attached to a flexible shaft that is attached to a gas powered motor. The flexible shaft is inserted thru a guide tube and then into the manhole which protects the cable from kinks or operator entanglement. The Gas powered motor turns a 1 1/4” self feeding flexible rod thru the sewer main from 50 to 1000 rpms. The cutter head reduces the debris or obstruction to small pieces which are then washed downstream with large volumes of water.
Sometimes it is necessary to work upstream especially in cases where the distance between manholes exceeds the cable length. Running the cutter head upstream or against flow is often most effective in removing sand silt and other sediments because it augers the deposits back towards the operator where it can be removed.
City of Roseville – Wastewater Collection Division Maintenance Crew
The City of Roseville has over 45,000 services, 14 neighborhood lift stations, and over 9300 manholes to maintain.
The Wastewater Collection division has maintenance and cleaning programs and schedules to keep them operation efficiently and to minimize the number of service line stoppages, lift station failures. and the calls for service.
The Wastewater Collection Division has five full time employees dedicated towards maintenance on services lines minor manhole repairs and neighborhood liftstation. There are typically two crews. One crew typically consists of one Wastewater Utility Maintenance worker 2 and a Wastewater Utility Maintenance Worker 1 supervised by a Senior Wastewater Utility Maintenance Worker. This crews Job duties are as follows.
Routine maintenance and inspection of lift stations
Eeling and CCTV inspection of services
Manhole repair and coating
Coating of Protecto 401 pieces and repairs
Prep D.I. Transition pieces
Traffic control setup on an as needed basis
Confined space entry on an as needed basis
Application of chemical root control
The second crew typically consists of one Wastewater Utility Maintenance Worker 2 supervised by a Senior Wastewater Utility worker.
Application of chemical root control
Prep D.I. Transition pieces
Eeling and CCTV inspection of service Lines