PROJECT DESCRIPTION
BACKGROUND
The food industry is an important industrial sector throughout the European Union, however food processing consumes a considerable amount of fresh water and generates waste water which has to be discharged into a sewage treatment plant. The application of water recycling processes could contribute to a better environmental management for food processing companies.
OBJECTIVES
The objective of the project was the operation of a modular designed demonstration plant for the treatment of low-contaminated process water from the agri-foodstuffs industry to obtain closed water cycles by means of innovative treatment processes. The low contaminated wastewater stream could be treated by the treatment plant to such an extent that the water could be reused in production.
RESULTS
The feasibility of the project was proven by using three examples of low-contaminated process water streams from the food industry (chiller shower water from the meat processing industry, vapour condensate from milk processing and soaking water in bottle washing machines in the beverage industry). A demonstration plant with a capacity of 1-2 m3/h was built up and experiments were performed for study. The technology developed consisted of a combination of treatment steps: pre-treatment, membrane filtration and disinfection. Through the completed research, it could be shown that the waste waters from the agri-foodstuffs industry, containing organic contamination of a COD smaller than 700 mg O2/l (e.g. fats, proteins, organic acids and aromatic compounds) as well as in some cases large concentrations of inorganic components (e.g. Na+, K+, Cl-) could be treated to such an extent that water with drinking water quality was obtained which met the requirements of standards in all EU countries (limitation for the concentration for inorganic, and organic components, as well microbiological parameters). Recycling wastewater using the technology could reduce fresh water consumption and wastewater generation in food processing companies to an equal extent. Taking an average drinking water price of approx. 1-2 EUR/m3 and wastewater charges of approx. 3-4 EUR/m3, the total water costs of an industrial enterprise is roughly 5 EUR/m3. The pay-back time for a treatment plant with adequate flow rates would be approx. 2-3 years at water treatment costs of 1,5 EUR/m3. The technology produced water whose quality (e.g. boiler make-up water, water for cleaning purposes etc) permitted various possibilities of water reuse. Because of the drinking water quality of the treated process water and the high reliability of the technology, the treatment process was submitted for authorisation in 1998, at the Ministry for Health of the Saarland, Germany and was granted approval for water reuse. Due to the high degree of flexibility of the process combination, the technology could also be transferred to other industrial sectors (e.g. the textile industry, electroplating companies) where low-contaminated process water has not previously been reused. The feasibility of the project was proven by using three examples of low-contaminated process water streams from the food industry (chiller shower water from the meat processing industry, vapour condensate from milk processing and soaking water in bottle washing machines in the beverage industry). A demonstration plant with a capacity of 1-2 m3/h was built up and experiments were performed for study. The technology developed consisted of a combination of treatment steps: pre-treatment, membrane filtration and disinfection. Through the completed research, it could be shown that the waste waters from the agri-foodstuffs industry, containing organic contamination of a COD smaller than 700 mg O2/l (e.g. fats, proteins, organic acids and aromatic compounds) as well as in some cases large concentrations of inorganic components (e.g. Na+, K+, Cl-) could be treated to such an extent that water with drinking water quality was obtained which met the requirements of standards in all EU countries (limitation for the concentration for inorganic, and organic components, as well microbiological parameters). Recycling wastewater using the technology could reduce fresh water consumption and wastewater generation in food processing companies to an equal extent. Taking an average drinking water price of approx. 1-2 EUR/m3 and wastewater charges of approx. 3-4 EUR/m3, the total water costs of an industrial enterprise is roughly 5 EUR/m3. The pay-back time for a treatment plant with adequate flow rates would be approx. 2-3 years at water treatment costs of 1,5 EUR/m3. The technology produced water whose quality (e.g. boiler make-up water, water for cleaning purposes etc) permitted various possibilities of water reuse. Because of the drinking water quality of the treated process water and the high reliability of the technology, the treatment process was submitted for authorisation in 1998, at the Ministry for Health of the Saarland, Germany and was granted approval for water reuse. Due to the high degree of flexibility of the process combination, the technology could also be transferred to other industrial sectors (e.g. the textile industry, electroplating companies) where low-contaminated process water has not previously been reused.
