New Publications: 

Gunkel, G. & Michels, U (2019) Das neue Arbeitsblatt W 271 – Herausforderungen und Erfahrungen aus der Praxis. 33. Oldenburger Rohrleitungsforum 2019, 118-127, Vulkan Verlag, ISBN 978-3-8027-2885-3.

Michels, u. & Gunkel, G. (2019) Verminderung von Kleintieren in der Trinkwasserverteilung. 33. Oldenburger Rohrleitungsforum 2019, 128-139, Vulkan Verlag, ISBN 978-3-8027-2885-3.

Gunkel, G., Michels, U. & Scheideler, M. (2018) Erfahrungen und Effizienz der Rohrnetzpflege bei Anwendung des CO2-Spülverfahrens - Vorkommen der Wasserasseln in Trinkwassernetzen. gwf Wasser Abwasser, 12/2018, 77-84.

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Gunkel, G., Michels, U. & Scheideler, M. (2018) Kleintiere in der Trinkwasserverteilung – Vorkommen und Anwendung des Arbeitsblatts W 271. Teil 1. Makroinvertebraten. energie wasser praxis 11, 20-27.

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Small animals (water lices, Asellus aquaticus) in drinking water networks – occurrence and evaluation

In drinking water distribution networks, a significant number of small animals (invertebrates) up to a mass development can occur. Besides not visible protozoan (amoebas) and small metazoan (nematodes, copepods, water flies), visible macro-invertebrates such as water lice, oligochaetes and chironomids are common. These macro-invertebrates lead to an aesthetic impact on drinking water supply and a hygienic impact is caused by faeces of the animals as well as by dead animals. 

The observation of small animals (invertebrates) in drinking water networks leads to a spontaneous rejection of the product `drinking water´. But some facts should be considered:

• Drinking water distribution systems cannot be free of small animals, because they have a central function in water treatment, waterworks’ sand filter for raw water treatment are settled by small animals and their activity is used for water purification.
• In a low abundance, small animals should occur in drinking water networks without impact to users.
• The occurrence of small animals in drinking water networks needs to be controlled regularly (= biological drinking water quality).
• In case of increased abundance of small animals, a regulation is needed by adequate pipe network maintenance, several techniques are available (hydro-dynamic modelling, flushing, installation of particle filters).
• An increased abundance of small animals in drinking water networks increases the risk of of human pathogen microbe occurrence; therefore public health departments must be involved. 

New methods for analysis and treatment of drinking water networks have been developed:

• The CO2-flushing method to excavate water lice, the CO2-flushing method is used to sedate the water lice so that they cannot climb to the pipe wall. The CO2 flushing method was awarded with the Professor Adalbert Seifriz Award (2013) and the Zenit Innovation Award (2015).
• Combination of flushing drinking water pipes with a low-pressure high-volume filter system to separate small invertebrates.
• Monitoring of small invertebrates in drinking water networks by hydrant sampling and development of a databank (> 1000 data sets) for evaluation of the occurrence of these animals.  

Referenzen

• Michels, Ute, Gunkel, Günter & Scheideler, Michael (2014) Im Fokus der Wasserversorger – die biologische Trinkwasserqualität. Vom Wasser 112, 3, 93-95.
• Michels, U., Gunkel, G., Scheideler, M. & Ripl, K. (2013) Invertebraten im Trinkwasser - Probenahme, Analytik und Bewertung. Universitätsverlag der Technischen Universität Berlin, ISBN 978-3-7983-2575-3, 98 S
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• Michels, U., Gunkel, G., Scheideler, M. & Ripl. K. (2013) Neues Verfahren zur Probenahme, Analytik und Bewertung von Wirbellosen Tieren in Trinkwasserverteilungssystemen. gwf-Wasser / Abwasser 154, 896-897.
• Gunkel, G. & Scheideler, M. (2011) Wasserasseln in Trinkwasser-Verteilungssystemen - Eintrag, Vorkommen Bewertung und Bekämpfung der Wasserasseln. gwf –Wasser | Abwasser 308-388.
• Gunkel, G., Michels, U., Scheideler, M. & Ripl, K. (2010) Vorkommen und Bedeutung von Kleintieren in Trinkwasser-Verteilungssystemen – Maßnahmen zu deren Regulierung. 3R, 716-724.