Basics Wastewater disposal
Sewage water is wastewater and/or stormwater runoff from urban areas. Both can be heavily polluted and must be treated.
The German Federal Water Act (WHG) defines sewage water as follows: "Wastewater is water that has been altered by domestic, industrial, commercial, agricultural or other uses and dry weather flows (wastewater) and runoff collected from built-up or paved areas (stormwater)."
-domestic wastewater from toilets, bathrooms, kitchens and washing machines
-wastewater from business transported to the public sewer system
-stormwater from uncritical source areas that does not need to be treated
-stormwater runoff from problem or critical source areas that contains dissolved dirt particles pollutants and that must be treated
Generally, separate sewage systems should be used to transport wastewater and stormwater and not, as was the case in the past, in a combined sewer system.
Germany has achieved a high internationally recognised standard in wastewater disposal. Pollution of water bodies and soil has been considerably reduced and has been going a long way towards more environmental sustainability. On average, sewer systems in Germany are 41 years old. If a service life of 80 years is assumed, half the time has elapsed. Approximately one fifth of the sewer systems need repairs/redesign in the short or medium term (according to DWA survey). The most commonly encountered damage pattern are broken pipes and defective connections. More recent sewer systems – in particular those made of plastic – have probably not yet been inspected and analysed. They will most likely improve the status quo of the total network due to significantly less damage. According to the DWA, their number is constantly increasing.
Requirements and goals
-high-quality, reliable sewer systems that satisfy long-term operating requirements
-permanently leak tight and corrosion-resistant sewer systems to prevent environmental damage
-maintaining and ensuring the technical infrastructure and preserving the value of a national wealth grown over generations
DIN EN 13476 and EN 476 are the most important standards regarding wastewater disposal. In addition, numerous standards, guidelines and regulations must be complied with in connection with planning, dimensioning and installing drains and sewers.
DIN EN 13476
"Plastics piping systems for non-pressure underground drainage and sewerage – Structured-wall piping systems of unplasticized poly(vinyl chloride) (PVC-U), polypropylene (PP) and polyethylene (PE)." („Kunststoff-Rohrleitungssysteme für erdverlegte drucklose Abwasserkanäle und -leitungen – Rohrleitungssysteme mit profilierter Wandung aus weichmacherfreiem Polyvinylchlorid (PVC-U), Polypropylen (PP) und Polyethylen (PE)") DIN EN 13476 comprises 5 parts. Part 3 applies to structured-wall pipes such as robukan SMR: "Specifications for pipes and fittings with smooth internal and profiled external surface and the system, Type B." The standard applies to non-pressure underground drainage and sewerage and defines both requirements and test procedures and test parameters.
"General requirements for components used in drains and sewers for gravity drain systems" („Allgemeine Anforderungen an Bauteile für Abwasserkanäle und -leitungen für Schwerkraftentwässerungssysteme“)
ATV-DVWK-A 110 worksheet
"Hydraulic dimensioning and performance verification of sewers and drains" („Hydraulische Dimensionierung und Leistungsnachweis von Abwasserkanälen und -leitungen“)
DWA-A 118 worksheet
"Hydraulic dimensioning and performance verification of drain and sewer systems” („Hydraulische Bemessung und Nachweis von Entwässerungssystemen“)
DIN EN 752
"Drain and sewer systems outside buildings" („Entwässerungssysteme außerhalb von Gebäuden“)
"Directive relating to road construction – Part: drainage" („Richtlinie für die Anlage von Straßen – Teil: Entwässerung“)
DIN EN 1610
"Construction and testing of drains and sewers" („Verlegung und Prüfung von Abwasserleitungen und -kanälen“)
DWA-A 139 worksheet
"Installation and testing of drains and sewers" („Einbau und Prüfung von Abwasserleitungen und -kanälen“)
ZTV A-StB 97
"Additional technical terms of contract and guidelines for earthworks in trafficked areas" („Zusätzliche Technische Vertragsbedingungen und Richtlinien für Aufgrabungen in Verkehrsflächen“)
ATV-DVWK-A 127 worksheet
"Statistic calculation of drains and sewers" („Statische Berechnung von Abwasserkanälen und -leitungen“)