Journal of Environmental Chemical Engineering, vol.11, no.2, 2023 (SCI-Expanded)
© 2023 Elsevier Ltd.The biodegradation of raw wastewater for an organized industrial zone has been studied by means of dedicated respirometric and analytical experiments. The experimental results indicated that the investigated industrial wastewater contains mainly the soluble (slowly) hydrolysable fraction of chemical oxygen demand (COD) (58 %) while readily biodegradable and soluble inert fractions were in the order of 19 % and 3 %, respectively. Full-scale dynamic modeling results successfully confirmed the validity of estimated COD fraction and biodegradation kinetics. End of pipe wastewater reuse potential studied with a pilot plant revealed that almost 100 % soluble inert organics could be concentrated in reverse osmosis (RO) reject. Expectedly, the concentration was far above the COD discharge limit of 200 mg/L. Subsequently, the application of specific ozone dose around 7 kg O3/(kg COD·hour) on RO concentrates was not sufficient to secure the discharge limit by itself. However, the ozone oxidation converted 85 % of inert COD into the (soluble) slowly biodegradable organic matter. The modeling studies also showed that biodegradable organic matter generated by ozonation has much lower degradation kinetics compared to mainstream sequencing batch reactor system.