Proceedings of the 14 th International Conference on Environmental Science and Technology Rhodes, Greece, 3-5 September 2015 CEST2015_00265 SIMULTANEOUS APPLICATION OF MEMBRANE ULTRAFILTRATION, ACTIVATED CARBON ADSORPTION, AND ULTRASOUND IRRADIATION FOR FOULING CON- TROL IN SECONDARY WASTEWATER TREATMENT SECONDES M.F.N. 1,2 , NADDEO V. 3 , BALLESTEROS F. 2 and BELGIORNO V. 3 1 University of Negros Occidental - Recoletos, Bacolod City, 6100 Philippines, 2 Environmental Engineering Program, University of the Philippines – Diliman, Quezon City 1101, Philippines, 3 Sanitary and Environmental Engineering Division, University of Salerno, Fisciano (SA), Italy E-mail: msecondes@gmail.com ABSTRACT Water scarcity is a growing global concern and the meager fraction of the remaining renewable water is further reduced by environmental pollution. At present, meeting the world’s water demand entails efforts to protect the remaining fresh water sources from contamination or conserve water by reuse processes. Both actions necessitate advanced treatment techniques to remove hazard- ous substances and improve quality of wastewater effluent. Membrane filtration is one promising technology in the treatment of wastewater. However, the increasing use of membranes necessitates techniques to improve performance especially to con- trol fouling - the main burden to membrane operation. This paper investigates the integration of ultrasound irradiation and activated carbon adsorption to cross-flow membrane ultrafiltration of secondary wastewater treatment plant effluent in a novel hybrid USAMe process. Experiments employing membrane alone, membrane with ultrasound, and membrane with adsorption were also performed. Fouling is analyzed through the continuous monitoring of trans-membrane pres- sure in a constant flux operation and through the measurement of specific resistances obtained during a systematic cleaning process. The influence of ultrasonic frequency to performance and the eco-toxicity of the effluent to Daphnia magna were also studied. All amendment techniques have improved membrane performance and have contributed to the enhancement in the main hybrid process. Superior results were achieved in the USAMe process operated at lower ultrasonic frequency. USAMe permeates produced “no effect” in eco-toxicity tests, denoting the generation of safe effluents. Keywords: adsorbent, anti-fouling, emerging contaminants, flux enhancement, hybrid membrane processes, sonless 1. Introduction Membrane filtration as an advanced treatment method is superior over others in terms of com- pactness, ease of automation, no chemical requirement, full-barrier to bacteria, and non-genera- tion of harmful disinfection by-products (American Water Works Association, 1995; Crittenden et al., 2012). However, the problem of fouling limits its application. Natural organic matter (NOM) present in wastewater fouls the membrane by several mechanisms such as concentration polar- ization, formation of a gel layer or cake layer, by pore blocking, or by adsorption to the membrane and pore walls (Kim et al., 2009; Lee and Cho, 2004). The low pressure membranes more com- monly employed in wastewater treatment are more susceptible to severe fouling since small frac- tions of NOM also enter and adsorb inside the pores, leading to constriction and blocking (Lee and Cho, 2004). Several areas of improvement were investigated to deal with fouling, of which, backwashing and chemical cleaning are the most common techniques in application (Kyllönen et al., 2006). However, besides increasing operational costs by pumping requirements and chemical addition, these likewise decrease productivity by introducing cleaning downtimes, shortens mem- brane lifespan due to chemical degradation, and introduces a load of chemical waste.