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Because the laying of sewers by the open cut method is the most commonly selected construction method, it is obvious that most of the cost data apply to this method. Pecher/Kellner [Peche91b], in an evaluation of the sewer networks of North Rhine-Westphalia (Germany), determined the dependency to the inhabitant-referenced length of the sewers with the number of inhabitants as shown in Bild 5.7.1.1.3. Pecher [Peche92a] presents the increase of the sewer … |
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The attainment of a functional wastewater removal and thus the maintenance and rehabilitation of the sewer networks is a public duty of continuous upkeep. Also in the variants of the transfer of drainage tasks to private entities, the communities still finally have guarantee duties towards their citizens. In most cases, the costs of wastewater removal via the community exchequer are covered in their full extent by the drainage fees received. In other … |
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Construction alternatives for sewer rehabilitation projects often possess different utility periods for different high investment costs. With the aid of the dynamic investment calculation, which makes possible the evaluation of different payment periods, all payments are discounted at a reference point of time, and repeated investments can be considered. If a utility equilibrium of the alternatives is to be assumed, then the viewpoint is reduced … |
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(Image: Dynamic factor with reference to the period of utility and rate of interest [Grunw97] Planning horizont: N = 50 years, Net present value = DFRW · costs) As described in the previous section, there is a large amount of latitude in the determination of the methodical parameters of the dynamic investment calculation. Bild 5.7.1.1.6 shows the dynamic factors for a planning horizon of 50 years on the basis of the statement by Orth [Orth98] for … |
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In view of the prognosis of high costs (Abschnitt 5.7.2) and the fact that sewer rehabilitation is no temporary occurrence but rather a network immanent continuous task, there is the requirement of defining
Almost under the cover of long-term rehabilitation strategies, which can be the base of the medium-term financial planning, there follows the economic … |
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Nov 24, 2004 (Image: Sewer network operating costs with reference to the number of inhabitants [MUNR96]) An indication of generally valid costs for the operation of sewers is hardly possible. The length of the network, the age, the type of discharge and the gradient all lead to widely differing costs. Pecher [Peche94] evaluated calculations of fees requirements from 352 towns with a network length of approx. 92,600 km and arrived at operating costs for the sewer … |
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Nov 24, 2004 The sector of the economy most strongly influenced by sewer construction measures must be the retail trade. Although the national economy is negligibly affected by the influencing of individual businesses because the demand can be satisfied by neighbouring businesses, it cannot be the factual aim to endanger their existence by means of construction measures. This is valid at least then when there is an expectation that alternative construction processes … |
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Nov 24, 2004 Indirect costs as a result of traffic hindrances burden the traffic participants. For practical purposes, statements are selected that have been developed for traffic planning. The "Richtlinien für die Anlagen von Straßen - RAS" [RAS86a] (Guidelines for building of roads), as well as the Federal instructions for traffic planning "Gesamtwirtschaftliche Bewertung von Verkehrsinvestitionen" [NN88b] (Overall evaluation of investment in traffic) contain … |
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Nov 24, 2004 Noise emission changed by construction measures can be caused by changed traffic conditions as well as the noise of the construction machinery utilised. The monetary method used can be that used in many towns as a representative level of rents. Often characteristic rents can be charged for more or less than the traffic noise for particular habitations. The traffic noise, insofar as there are no measurements available or possible, can be estimated … |
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Nov 24, 2004 The pollutant emissions are dependent on fuel consumption as they are determined in connection with the costs of the traffic participants. Points of view of the damage in the following statement are persons, vegetation and buildings. The emissions of fuel-burning motors are converted to carbon monoxide equivalents (COE) and evaluated (in Germany) with resulting costs of 12.00 DEM/t COE (6.14 €/t COE) for damage to health and buildings and 3.50 DEM/… |
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Nov 24, 2004 As sewer rehabilitation measures are, of necessity, mostly carried out in existing roads, there is the question of the influence on the road surface by the open cut method. Several instances can be found in the literature that mention a shortening of the residual utility of road structures of up to 60 % [Beros92] [Thoms95]. Insofar as these are included in the decisions of the indirect costs of the open cut method of construction there must first … |
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Nov 24, 2004 Insofar as excavations, especially for sewer replacement by the open cut method are situated near trees, there is always found damage caused by the cutting of roots or branches or due to the lowering of groundwater or due to consolidating soil (Abschnitt 1.12). If damage is not compensated directly by the carrier of the construction measures, there are often indirect costs, as the affected trees must be replaced early or the trees can no longer fulfil … |
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Nov 24, 2004 (Image: Situation-referenced comparsion of direct and indirect costs during the construction of sewers by the open cut or trenchless method of construction with reference to [Grunw97]) The size of the indirect costs resulting from construction measures is to a large extent subject to the local conditions and other input data. Even with the above-mentioned statements the determination is not possible with the same degree of accuracy as with the direct … |
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Nov 24, 2004 The public sewer networks of necessity lie almost exclusively in public areas (Abschnitt 1.11). These areas - mostly in roads dedicated to public traffic - are subject to an extraordinary number of uses. The construction sites required for sewer rehabilitation, depending on the construction process, affect this utilisation to a lesser or greater extent. The continual rise of individual traffic in the towns, combined with exhaust emissions, development … |
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In the previous sections, mention was made of the various technical possibilities, the operational tasks of maintenance and cleaning, the inspection including evaluation of the condition of the sewer and the structural maintenance (sewer repairs) that had to be fulfilled and the sewers to be renovated or replaced by means of investment measures. For this reason, the requirement for economic efficiency can not only refer to the construction measures … |
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According to EN 752-1 [DINEN752-1] rehabilitation is understood to be: All measures for restoring or upgrading the performance of existing drain and sewer systems. With damaged sewers as well as structures of drain and sewer systems that cannot be taken out of operation, i.e. whose function cannot be purposely interrupted for an undefined period in the sense of DIN 31015 [DIN31051:1985], rehabilitation must be undertaken when
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Feb 16, 2011 Rehabilitation and Maintenance of Drains and Sewers Sewers in Water Catchment Areas - Special Requirements for Rehabilitation and Maintenance For sewers in water catchment areas, the interests of environmental protection impose particularly high requirements on the functionality and thus, the planning, execution and rehabilitation and maintenance of these installations. A first step was taken with the ATV-A 142E "Sewers and Drains in Water Catchment Areas" [ATVA142a]. Besides this, some of the States of the Federal Republic of Germany formulated their own regulations or requirement profiles … |
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Nov 24, 2004 Rehabilitation and Maintenance of Drains and Sewers Sewers in Water Catchment Areas - Special Requirements for Rehabilitation and Maintenance In water catchment zone I, the through path of sewers is prohibited in principle. If, in the public interest, sewers must be laid in water catchment zone I, then the draw off of water is to be suspended. The water supply must be maintained in a suitable manner. |
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Feb 16, 2011 The DVGW - working paper W-101 [DVGWW101] lays down the following with regards to a sewer through path and a lowering or seeping of sewage: The following are dangerous and generally not permitted in zone II:
Although the passage of sewage is … |
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In double-walled sewers, the product pipe is placed inside a watertight jacket pipe (casing pipe) whose inside diameter is larger than the outside diameter of the product pipe. The cavities between the double-walled pipes (annular space or ring gap) can be made to be man-accessible or non-man-accessible [ATVM146] |
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According to [MULUF84] the following requirements apply to single-walled sewers:
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In this case the redundancy is achieved by means of a mineral mixture originally developed for sealing waste dumps [Finst90] and this is introduced into the embedment and there, due to its structure, fulfils the role of bedding for the single-walled pipe, on the one hand, and the sealing and pollutant absorbing function on the other hand (Bild 6.4.2.1.3) (Bild 6.4.2.1.3).
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(Image: Section of a single walled sewer with drainpipes [ATVM146]) Wastewater sewers are built into a concrete bed and bedded with drainage gravel whereby the required bedding conditions are fulfilled and a filter body is built up at the same time. Parallel to this, the drainpipes are laid on a profiled concrete layer. The whole gravel body is surrounded by filter stable geo-textile (Bild 6.4.2.1.4). The wastewater sewer and the drainpipes pass in … |
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(Image: Manhole installation for single-walled sewers according to [ATVM146]) The creation of manholes is subject to DIN 19549 [DIN19549] as well as the ATV working sheets A 139E [ATVA139b] and A 241 [ATVA241c] (Abschnitt 1.8). All manhole components including the connections must be able to withstand a continuous internal and external pressure of 0 to 0.5 bar. Corresponding requirements must be agreed upon for higher loads [ATVA142a]. Arrangements … |
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Nov 24, 2004 Rehabilitation and Maintenance of Drains and Sewers Technical Requirements Regarding New Piping, Rehabilitation and Maintenance According to [ATVA142a], the following facts must be considered beyond the special requirements of stability, and operational safety:
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