Sewer Cleaning

Last Updated: August 12, 2020

Definition - What does Sewer Cleaning mean?

Sewer cleaning is the process of removing built-up debris, leaves, grease, grit, sand, plastic bags, rags and obstructions such as tree roots from the sewer system. Sewers collect wastewater from laterals connected to homes, offices and industries, which carry different types of wastewater.

Improperly closed or missing manhole covers can also allow surface debris to enter the sewer pipeline. This wastewater has to travel to the sewage treatment plant for treatment before disposal.

To keep the sewer line in working condition and efficiently taking away wastewater, it is necessary to keep the sewer free from obstructions that can prevent optimum flow conditions in the pipes. Improper flow can lead to problems over time such as severely clogged pipes, corrosion, backups, overflows, and unpleasant odors.

Trenchless inspection methods can be used to manage sewer cleaning efficiently. Inspection helps prioritize maintenance activities and also helps detect damaged pipelines that can be rehabilitated before they fail.

Trenchlesspedia explains Sewer Cleaning

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Sewer cleaning has to be systematic in order to ensure that the collection system works properly and minimizes chances of backups and overflows. Generally smaller sized pipes and pipes prone to blockage by grease accumulation and tree root intrusion need to be cleaned more often.

Sewer Inspection

Before undertaking cleaning and repair works, it is essential to undertake a closed-circuit-television (CCTV) inspection. CCTV cameras are mounted on robotic crawlers that are connected to a remote control and a video monitor.

The crawler is inserted into the sewer. As it progresses through the sewer pipes, the CCTV takes footage and relays it to the monitoring computer system. These crawlers are also capable of navigating bends and curves in the pipeline and can accurately capture the internal condition of the pipe.

The pan and tilt options along with rotation capability and lighting options to illuminate its surroundings help inspect suspected problem areas more closely.

Sewer Cleaning

Some sewer cleaning methods are:

  • Hydraulic cleaning - Where blockage in sewers is found, a nozzle is inserted into the access point nearest to the blockage and water is released at high pressure that pushes the blockage into the main sewer system. Sometimes, the blockage includes gravel, roots, sand and other such debris pushed into the sewer system through storm drains during bad weather conditions. In such cases, vacuum trucks are employed that suck up the stuck debris and dirt and dispose them of in a landfill. Flushing operations can be carried out using flush tanks, fire hose, etc., where a sudden flow of high velocity, deep water is allowed through the sewer, cleaning it effectively.

  • Mechanical cleaning - Power rodders, hand rods, and hand-held drain augersare used in this method that can cut, scrape, pull and push the debris out of the pipe. This can effectively cut roots or shred large blocks of collected debris. This operation usually requires a follow up with hydraulic cleaning as mechanical cleaning is more effective in clearing blockages than cleaning.

  • Chemical methods - Chemicals are often used to control root growth, cut through grease, remove odors, eliminate rodents and insects. Only chemicals approved by the local government are permitted when utilizing this method.

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