Water & Wastewater Case Story • Treatment • Fish Farming WEDECO ozone system... ...improves conditions at German fish farm The Müritz-Plau GmbH operates several fresh water fish hatcheries with a total fishing area of 27.000 ha. They are producing different fish species for private customers and hotels and operate facilities for further treatment e.g. fish filleting or smoking. The Müritz-Plau GmbH is located in Waren, Germany. Project Motive Supported by Linde Gas, pilot tests were carried out at a small hatchery for trouts. As trouts need clear and clean water the main goal of these trials was the improvement of fresh water quality. When the test started, the water was dirty and turbid, due to the process. Fresh water from a brook, with a consumption of 1000 m3/h was used to feed the channels where the fishes were hatched. For the enrichment of oxygen, 50 % of the water leaving the channels was re-circulated. For water treatment a drum filter was installed. The rest of the water flew back into the brook. The general improvement of the conditions should result in a positive effect on the fishes regarding the utilization of food and the growth of the fish. “The ozone system was used every third day for a maximum of 8 hours” Project Details Caused by bacteria and viruses the customer had a daily loss of approx. 0,1 %. An outbreak of a disease could even result in a loss of the whole fish population. The use of ozone reduced the count of bacteria and viruses to a natural density. This was the second goal of the trials. An average ozone mass of 35 gO3/h was used. This parameter was monitored during the trials by the customer. With a water flow of 1000 m³/h the ozone dosage was approx. 0.035 gO3/m³. The limiting value is 0.05 gO3/m³ for the effluent according to the German “Badegewässerverordnung”. The ozone system was used every third day for a maximum of 8 hours. For the test trials WEDECO installed an OCS ozone system with the following features: » ozone generator WEDECO GSO 30 (capacity: 100 gO3/h) » pump - injector system » catalytic ozone destructor unit » ambient air monitor » ozone measuring device for water phase » degassing vessel (installed by customer) The use of ozone resulted in an improvement of the conditions. The water was clearer and the daily loss decreased to approx. 3 - 4 fish leading to higher profits. The customer calculated a profit (without extra profit by improving) of 4,600.00 €/a. The invest cost for the pilot plant were 14,000.00 €. This means an amortization period of 3.5 years. Better growth of the fish leads to shorter breeding time and better utilization of the food reduces the costs for feed. These facts were not considered in the calculation, therefore the profit will be even higher and the amortization period will be shorter! WEDEO OCS-System Type GSO 30 xyleminc.com © 2012 Xylem, Inc. Xylem Water Solutions Herford GmbH Boschstr. 4 – 14 32051 Herford, Germany Phone: +49 5221 930-0