Increasing the capacity for treatment of chemical plant wastewater by replacing existing suspended carrier media with Kaldnes Moving Bed media at a plant in Singapore

• Published in: Water science and technology Vol. 49; no. 11-12; pp. 199 - 205
• Main Authors: Wessman, F G, Yan Yuegen, E, Zheng, Q, He, G, Welander, T, Rusten, B
• Format: Journal Article
• Language: English
• Published: England IWA Publishing 01.01.2004
• Subjects: Activated sludge process; Biodegradation, Environmental; Biofilms; Biofilms - growth & development; Bioreactors; Carrier mobility; Chemical Industry; Chemical industry wastewaters; Chemical plants; Chemical treatment; Effluents; Filters; Industrial Waste; Load; Organic carbon; Organic loading; Oxygen - chemistry; Oxygen - metabolism; Pretreatment; Singapore; Waste Disposal, Fluid - methods; Wastewater treatment; Water Pollutants - isolation & purification; Water Pollutants - metabolism; Singapore
• ISSN: 0273-1223; 1996-9732
• DOI: 10.2166/wst.2004.0841

The Kaldnes biomedia K1, which is used in the patented Kaldnes Moving Bed biofilm process, has been tested along with other types of biofilm carriers for biological pretreatment of a complex chemical industry wastewater. The main objective of the test was to find a biofilm carrier that could replace the existing suspended carrier media and at the same time increase the capacity of the existing roughing filter-activated sludge plant by 20% or more. At volumetric organic loads of 7.1 kg COD/m3/d the Kaldnes Moving Bed process achieved much higher removal rates and much lower effluent concentrations than roughing filters using other carriers. The Kaldnes roughing stage achieved more than 85% removal of organic carbon and more than 90% removal of BOD5 at the tested organic load, which was equivalent to a specific biofilm surface area load of 24 g COD/m2/d. Even for the combined roughing filter-activated sludge process, the Kaldnes carriers outperformed the other carriers, with 98% removal of organic carbon and 99.6% removal of BOD5. The Kaldnes train final effluent concentrations were only 22 mg FOC/L and 7 mg BOD5/L. Based on the successful pilot testing, the full-scale plant was upgraded with Kaldnes Moving Bed roughing filters. During normal operation the upgraded plant has easily met the discharge limits of 100 mg COD/L and 50 mg SS/L. For the month of September 2002, with organic loads between 100 and 115% of the design load for the second half of the month, average effluent concentrations were as low as 9 mg FOC/L, 51 mg COD/L and 12 mg SS/L.