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May 16, 2012 The oldest and simplest way to get a general overview of the internal condition of a straight section of inaccessible sewer is to directly look inside of it with the help of a mirror and an additional light source. The mirror, held at a 45° at the opening of the pipe, allows for inspection to take place without the need for direct entry into the manhole by personnel. Additional lighting shun into the pipe section, either at the next manhole or directly … |
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May 16, 2012 The CCTV camera system consists of a video camera that is attached to the end of a telescopic rod which also has a lamp used for the illumination of the section to be inspected. The telescopic rod can be extended up to a length of 12 m. Through the use its optical zoom and additional lighting, the camera is capable of identifying problems (such as blockages, roots and debris etc.) up to 30 m beyond that of a regular visual inspection.
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May 16, 2012 Sewer measuring boat The sewer measuring boat can be used in sewers from DN 700 to DN 2000. It floats on the wastewater and uses sensors to measure the height of the wastewater and the settled deposits in the pipe. The stored sensor data is later processed to obtain a precise determination of the deposit situation within the sewer line. However tough, the sensors do need to be manually re adjusted when the size and shape of the pipe changes. The … |
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May 16, 2012 Culvert pressure unit A special development in the measurement of deposit amounts is the culvert pressure unit. The device uses two pressure sensors connected to an electronic data acquisition system to collect pressure data at two points within the pipe. The data storage unit is located in a watertight plastic capsule that is pulled through the sewer section. (Image: Culvert pressure unit) As shown in the figure, one sensor is located in the capsule … |
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May 16, 2012 (Image: Haltung) Important: The section with the highest problem level should be decisive for the determination of a cleaning priority. In the process of prioritisation the deposit quantity and its composition can both be used as equal assessment criteria. |
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May 16, 2012 Based on the description of the drainage system (technical evaluation) and prioritization of the deposit situation in the drainage system, the blending of the cleaning objectives within the scope of the strategic cleaning planning is made possible.
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May 16, 2012 The results show a prioritisation and area ranking which in addition to a technical assessment of the deposits also include environmentally related, operational, hydraulic, economic and other strategic aspects, such as the sensitivity of surrounding structures (hospital, industrial enterprise, etc.). (Image: District ranking) |
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May 16, 2012 The cleaning intervals for the individual sections or groups of sections are determined on the basis of:
(Image: Determination of the cleaning intervals) |
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May 16, 2012 The Result is a long term strategic cleaning plan that is continually updated based on new operating experience and information
It is highly recommended to increase the cleaning intervals only gradually to minimise the impact of any forecasting inaccuracies. |
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May 16, 2012 Operational cleaning planning is based on strategic cleaning planning. This results in object-related deployment and cleaning plans. They include a prioritisation of the cleaning measures, specifying
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May 18, 2012 (Image: Overview of the drain and sewer cleaning methods as per [Führb1980]) The following information is particularly relevant for selecting the cleaning method according to EN 14654-3:
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May 16, 2012 Practical example of information to be considered.
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May 16, 2012 For an optimisation of the operational or flushing plans the following operational data should be considered: (Table: Operational data of high-pressure cleaning) |
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May 16, 2012 The relationship of the section-dependent and section-independent costs must also be considered in the optimisation process (Table). (Table: Section-dependent and -independent costs incurred in high-pressure cleaning) |
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May 16, 2012 Time distribution of high-pressure cleaning (Image: Limits of variations of required time for operations during sewer cleaning (8-h-day)) (Image: Time required for operations during sewer cleaning (8-h-day) in percent) |
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May 16, 2012 Below you can see extracts from an example flushing plan. The following details can be gathered from the database:
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May 14, 2012 (Image: Arrow Step 03) In step 3, the cleaning planning is implemented based on the developed operational and flushing plans. |
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May 14, 2012 When cleaning, it is important to ensure that coarse material and debris do not end up downstream in the drainage system. It is necessary to remove the debris from the drainage system. In some cases, it is possible to remove the debris at the treatment plant or other suitable locations. If all the sewers in an area are to be cleaned, it is recommended to start with the sewers located at the highest point of the system and then continue the work downstream. … |
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May 14, 2012 Disposal of the collected waste material.
Cleaning – Disposal of the waste material (Waste management) Measures should be taken to minimise the impact of the waste generated during the works. The following hierarchy shall be applied for waste management: (a) measures should be taken … |
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May 14, 2012 Since June 1, 2005, the dumping of biodegradable waste - including the waste material from sewer cleaning procedures - without a prior thermal or appropriate mechanical-biological treatment is only permitted, insofar as the organic portion of the dry residue (measured as loss due to heating) does not exceed the values given:
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May 14, 2012 According to [Billm2002], a maximum of 40 – 50 % of the waste material from sewers, and a maximum of 15 – 25 % of the waste material from catch basins can be classified as recyclable substances. The re-utilisation potential of the waste material from the cleaning of sewers is limited to a fraction of the mineral solids. (Image: Disposal of waste material) (Image: Dewatered waste material in the holding tank of the cleaning vehicle) |
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May 14, 2012 The same applies to the waste material from catch basins. There is an additional re-utilisation potential for the ferrous and non-ferrous metals bound to particles [Billm2002]. (Image: Re-utilisation potential of the waste material from catch basins) (Image: Waste in catch basin) (Image: Disposal of waste) |
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May 14, 2012 Currently, the waste material from sewers and catch basins is, in most cases, dumped or thermally treated. Mineral solids are only recycled in exceptional circumstances and then re-utilised in the following fields:
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May 14, 2012 (Image: Cleaning – Disposal of waste material) |
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May 14, 2012 (Image: Arrow Step 04) After the cleaning measures are completed, quality control is carried out in step 4.
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