Catch basins, also called storm sewers or storm water catch basins, are openings to the storm drain system. They typically include a grate or inlet at the curb line where storm water enters the catch basin and a sump captures coarse sediment, debris and other pollutants.
Periodic catch basin cleaning is important to maintain their ability to trap sediment, and consequently to prevent flooding. This regular maintenance also minimizes a blocked sewage line and reduces the amount of pollutants entering storm sewers which may eventually end up in local streams and waterways.
Catch basins usually drain well and do not present a problem as far as mosquito breeding; however, some may have structural problems or may be partially blocked, retain water and therefore produce mosquito breeding sites.
Clogged sewage lines and catch basins can also result in the pooling of water along street curbs and parking lots creating annoyances for drivers, pedestrians and businesses.
Debris, chemicals, trash, sediment, leaves, and other pollutants that enter storm drains in streets travel to lakes, rivers, and streams.
Debris left in catch basins can decompose and can create offensive odors and result in complaints from the public. This decomposition process also reduces the amount of dissolved oxygen and may increase bacteria levels in a waterway.
When to Clean
Catch basins need to be inspected annually. Catch basin cleaning needs to be done once the depth of the sediment/deposits reach a ⅓ depth, and at least when they are ½ full. In areas where there’s a lot of leaf debris, fall is usually the best time.
Spring is also a good time for cleaning to remove the buildup of leaves, dirt and other sediment that collected during the winter months.
Catch basin cleaning and maintenance includes the removal of garbage and sediments collected in the sump using a catch basin cleaner with a clamshell bucket, a street sweeper, or a vacuum tank truck.
Combination Machines to the Rescue
Combination sewer cleaners are very popular because they can offer a complete solution for catch basin cleaning, sanitary storm sewer lines. The size and the type of machine chosen depends upon the application.
Dry or Wet Vacuum
Combination sewer cleaner machines feature two types of air movement technologies; centrifugal compressor that use air pressure to move debris up the water suction hose into the vacuum tank truck. PD or positive displacement blowers are a combination of air and true vacuum.
PD or positive displacement blowers are more efficient with liquid from sanitary lines and move the liquid at greater distances particularly horizontally.
Fan machines are used mostly to pick up dry material from and during catch basin cleaning operations. These machines are dual engine units, that is the chassis engine, then the secondary engine powers the jetting and vacuuming machine. PD machines use the chassis engines to drive both chassis and jetting and vacuuming functions.
Boom Hose Size Matters
Smaller combination machines feature a 6 inch diameter vacuum hose, and larger vacuum combo machines feature 8 inch diameter vacuum hose. The 8 inch diameter hose gives almost twice the area of a 6 inch diameter hose, therefore the 8 inch is able to suck up much more and is less likely to clog.
Combination sewer truck manufacturers offer many different brands of water pumps ranging in flow and pressure. Keep in mind for the sewer jetter operation that the higher the pressure (PSI) , the lower the flow (GPM) the pump will deliver.
Sewer Pipe Cleaning
Needless to say that the larger the pipe, the more pressure and flow systems are needed to meet the requirements. Remember that pressure loosens the material, and flow moves the material down the pipe during cleaning operations.
How Long of a Hose Reel?
Most sewer jetter units come equipped with 400 feet of jetter hose and can be fitted with 800 feet of hose. The longer the jetter hose the more pressure drop occurs due to turbulence and friction inside the hose. For instance a pump that delivers 2500 psi at 80 gallons per minute to 500 feet of 1 inch hose loses 1 PSI per foot effectively giving only 2000 PSI at the nozzle.
What Diameter Hose?
Sewer hoses are hard to maneuver and bulky. Therefore, jetter manufacturers offer high air pressure, lower volume pumps using ¾ inch hoses - the trade-off is the drop in pressure at 50 gallons per minute is 2PSI/ft.
Nozzle selection is key to jetting services effectiveness and productivity. Steep sewage grade lines make nozzle climbing difficult therefore you need more flow. The higher the flow the greater the thrust of the nozzle.
Not sure how to specify your machine? Look around your local market and find out what kind of machines they operate? Who are their distributors and how long have they been in business? Distributors will help you find the right kind of machine for the market and also support you after the sale.
Whether you are considering a Vac-Con or Vactor truck or any other vacuum truck manufacturer, a combination sewer cleaner is versatile enough to do anything from catch basin cleaning to vacuum excavation.