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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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May 14, 2012 (Image: Picto Fakten) The manner in which the cleaning performance is to be accepted and verified should be determined before the start of the cleaning (tender document / performance specification). This should include the following points:
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May 14, 2012 Important: Performance indicators should be selected so that they can be used to clearly show whether the required performance has been achieved. Especially suitable are easily quantifiable parameters, such as:
EN 14654-3 recommends the following further indicators:
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May 14, 2012 The diagram below shows the relationship between the performance indicators, the description of the cleaning result and the assessment methods. (Image: Quality control – Diagram)
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May 14, 2012 (Image: Picto Liste) Cleaning report The cleaning measures should be comprehensively documented in the form of a cleaning report (acceptance protocol). It should be noted that a simply structured reporting system supports the operating processes and ensures compliance with legal requirements. The cleaning report should be carried out either immediately after cleaning or after clearly defined time intervals. The following information should be included … |
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May 14, 2012 The following techniques/methods are available as assessment methods for determining compliance between the tendered and executed services:
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May 14, 2012 (Image: Frage) The following questions should already be considered with regard to quality control and documentation:
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In summary, through the optimization of the cleaning activities the following objectives can be achieved:
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Important: As a result of the dynamic optimization process, it becomes clear that the task of cleaning sewer systems goes beyond the previous practice of ensuring the functionality of the drain and sewer system and makes a significant contribution to maintaining value and optimising operating costs. (Image: Cleaned, accessible sewer made of natural stone, and channel made of vitrified clay) |
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To further optimise sewer cleaning, the chosen strategy should be evaluated retrospectively. The following indicators can be used for this purpose:
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Congratulations! You have successfully finished this module. Next you will have the opportunity to review the newly acquired knowledge with an interactive questionnaire. You can of course still navigate back to any point in the modules if you wish to review a specific point or subject. Stay curious! |
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