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Sandblasting is also often used in combination with a hand held HP spray gun in man accessible sewers as a preparatory measure prior to the application of additional coatings. … |
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One of the disadvantages of sandblasting is the accumulation and removal of the abrasive waste material from the channel. Therefore, an alternative method that produces no abrasive residues was developed. The so called “Jetty Robot” system applies dry ice as an abrasive, and is predominantly used for the cleaning of air ventilation ducts ranging from DN 400 to DN 1,300. (Image: Jetty Robot – Track-driven chassis, illumination unit, camera and nozzle) |
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Compared to all of the previously mentioned special apparatus, the sewer robot has proven to be the most effective in practice. (Image: Milling robot HF 100 [FI-Kanala] - For use in nominal pipe sizes from DN 200 to DN 600) (Image: Milling of a protruding lateral connection) (Image: Root removal and milling of the intrusion area) |
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In particular cases, special processes are used for cleaning, such as:
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Physical methods aim at increasing the sewage flow velocity for cleaning purposes by the addition of air or polymers. The effect of the introduction of polymers is the reduction of energy losses of turbulent flow conditions. Using low concentrations (max. 60 ppm), the flow velocity of the sewage can be increased by up to 70%. The effect is not based on a change in the sewage viscosity, but rather on a lowered frictional resistance of to the rough pipe … |
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Another possibility for the removal of agglomerations and deposits in pipe systems is the ultrasonic method, which has been developed and patented in France. It can be used in a range of nominal sizes between DN 20 and DN 600 for drains, sewers and heating water systems [FI-Alben] [Loese1998] [Loese1998a]. According to the manufacturer’s specifications, pipes made of PVC, PE, polymer cement, cast iron, steel or vitrified clay can be cleaned at an … |
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Chemical methods are used to remove:
The first application is generally restricted to industrial pipes and pipelines for oil and gas. For sewers, this method is only used in exceptional circumstances. A detailed example for the removal of incrustations in a water dam drainage system is described in [Siebe1981]. Preconditions for the application of the chemical method include:
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The mechanical root removal methods used today, e.g. by cutting or boring, usually lead to strengthened new root formations requiring re-treatment at relatively short intervals Alternatively, the use of chemical root removal method by applying various herbicides has been tried and tested in several comprehensive studies [Sulli1977] [Ahren1970] [Townl1973]. The respective line is taken out of service, and the herbicide is injected into the line as a … |
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Biological cleaning methods are used to decompose fats and fibres in the biofilm, as well as phenols, proteins and mineral oils. They are also applied to eliminate or reduce odour nuisances [Baig1976] [Jense1977]. A two-components detergent is mainly used in sewage systems of hospitals, kitchens, large cafeterias and the food processing industry [FI-Aladi]. |
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The first component comes in a liquid form and is composed of a mixture of fatty acid esters, fatty acid amides and urea. It is fed into the sewage system via kitchen drains, floor inlets, etc. and then flushed with lukewarm water. After a reaction time of about six hours, the second component, containing microorganisms, is mixed with the lukewarm water. A soaking time of about 10 to 15 minutes is required, and the mixture is then fed into the sewage … |
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Feb 04, 2013 This module focuses on the different possibilities for mechanical cleaning of sewers. In this context, a wide range of mechanically operating cleaning equipment is presented, and a practical impression is given. After completing this module, you will have knowledge regarding:
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(Image: Sequence of operations work flow for pipe bursting) |
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(Image: Condition acquisition of a sewer via a TV-inspection) (Image: Maintaining the drainage capability) (Image: Exposing a lateral connection using the open cut method as part of the bursting process) Pre-construction survey: The pre-construction survey includes a walkthrough of the to be renewed pipeline section at ground level, determining the location of existing pipelines and utilities in the surrounding area, and acquiring a visual assessment … |
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Cleaning of the pipeline, removal of obstructions: Cleaning is not required as long as the pulling-in of the winch cable or the pulling rods is possible. Obstructions which prevent this, such as pipe collapse, positional deviations, roots, etc. must be cleared first. Preparation of the manholes: For the manholes within the section to be replaced, the invert and connection areas must be prepared or modified in such a way that the insertion, pulling-through, … |
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(Image: Documentation) Inspection and storage of the pipes on the construction site: Upon arrival at the site, the pipes are to be inspected for faults. In addition, the delivery papers are also to be checked in order to ensure that all of the information corresponds with the original order details. These checks are to be documented as part of the quality assurance procedure. (Image: HD-PE discrete long pipes DA 500) |
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(Image: Bursting head with a directional guide) Bursting procedure: Introduction of the new pipeline under the consideration of the permissible tensile forces and bending radii. There must be an overlap between the external diameter of the expander head and that of the new pipeline in order to reduce the frictional forces during the pulling through procedure. The tensile forces acting directly on the new pipeline during the bursting procedure must … |
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(Image: Realisation of pipe bursting from the insertion manhole to the reception manhole) Manhole to manhole: Utilization of discrete pipes and bursting equipment suited to the size of the manhole structure. (Image: Realisation of pipe bursting from the insertion manhole to the reception pit) Manhole to pit: Utilization of discrete pipes and bursting equipment suited to the size of the manhole structure. Installation of the pulling equipment in the pit. |
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(Image: Realisation of pipe bursting from the insertion pit to the reception manhole) Insertion pit to manhole: Installation of the pulling equipment in the manhole or above it. The discrete pipes or the continuous pipeline, together with the bursting unit, is inserted through the insertion pit. The size of the bursting unit is accordingly dimensioned as to allow for its removal from the target manhole. (Image: Realisation of pipe bursting from insertion … |
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(Image: Connection of the new pipeline to the manhole) Connection of the new pipeline to the manhole: The connection between the new pipeline and the manhole structure must be properly sealed so that water cannot infiltrate into the surrounding soil. A leaktight joint must be created between the manhole wall and the new pipe. The manhole channel and benching must be accordingly fitted to the new pipeline. (Image: Re-connection of a lateral to the new … |
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Dec 20, 2013 (Image: Gravity pipeline) The following materials are commonly used in the production of gravity, protection and product, pipelines: (Table: Commonly used types of new pipelines for the pipe bursting of gravity systems with reference to [DWAM143-15]) |
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