Model unit of industrial wastewater treatment plant DUSLO Šaľa Inc. with membrane module Blšťáková Andrea*, Bodík Igor*, Németh Peter**, Vilím Daniel***, Buday Mikuláš****, Drtil Miloslav* * Institute of Chemical and Environmental Engineering, Slovak University of Technology, Radlinského 9, 812 37 Bratislava, Slovak Republic (E-mail: igor.bodik@stuba.sk) ** DUSLO Inc., 927 03 Šaľa, Slovak Republic (E-mail: nemeth@duslo.sk) *** ENVI-PUR Ltd., Kpt. Jaroše 358, 390 09 Tábor, Česká republika (E-mail: vilim@envi-pur.cz) **** VUCHT Inc., Nobelova 34, 836 03 Bratislava, Slovak Republic (E-mail: mbuday@vucht.sk) Abstract Significant improvement of treated water quality was proved in wastewaters from organic chemistry production by using membrane separation of sludge. This phenomenon was observed in laboratory scale and also in pilot plant. On the basis of positive results from laboratory tests with membrane separation, which are being carried out in Duslo Šaľa Inc. since 2005, in 2008 pilot plant was installed. Pilot plant fully copies existing processes complemented with progressive wastewater treatment methods. One of the most important goals is setting up of optimal operational parameters for membrane separation technology in conditions of Duslo Šaľa Inc. Keywords Membrane bioreactor, wastewaters, organic chemistry production, nitrification, permeability Membrane processes are well known for some decades and they are successfully utilised in many branches of industry. Concerning particularity of activated sludge, membrane processes were not used in industrial waste water treatment plants (WWTPs). First pilot plant experiments were carried out in 80 – 90 ´s, when production of membrane materials had reached certain development. Despite of that, membrane price, capital and operational costs of this technology did not allow its wider application. Since the end of the last century, the membrane technology has started to apply in WWTPs and first real applications of membrane reactors could be found in WWTPs. By 2006, around 100 municipal full-scale plants with a capacity > 500 p.e. were in operation in Europe, and around 300 large industrial plants with a capacity > 20 m 3 /d (Dohman et al., 2000; Aprica Studi, s Rondi, 2005; Mislang, 1998; Theilen, 1999; Lesjean and Huisjes, 2007). Industrial wastewaters (WWs) are generated mainly from production of pharmaceutical products, fertilizers, fibres, dyes, pulp and paper etc. Sample of membrane applications are food industry using tube modules (Kellogg, Great Britain; Dairygold, Ireland; Dairy Crest, Great Britain), malthouses and animal carcass disposal using immersed capillary modules (Sobelgra n.v., Belgium; Saria, France), chemical industry and pharmaceutical industry using immersed plate modules (Raiso chemicals, Belgium; Sandoz/Biochemie, Spain) and etc. (Pinnekamp and Friedrich, 2003). Reported organic loading rates range between 0.25 – 16 kg COD/m 3 d with corresponding removal efficiencies of 90-99.8 %. Feed concentrations of 68 000 mg/L COD (Kempen et al., 1997) for a brewery effluent and 29 430 mg/L COD for oily waste (Zaloum et al., 1994) are typical examples (Stephenson et al., 2000).