Engineering HDR Seminar Series 28_2013: Integrated Treatment Process of Pulp and Paper Mill Effluent using Coagulation and Heterogeneous Photocatalysis

Ms Wennie Subramonian, Chem Eng postgraduate student

Date: 2013-05-30
Time: 15:00 to 16:00
Venue: Engineering Meeting Room 1, 5-4-22


The pulp and paper industry generates 30-180 m3 of wastewater per ton of manufactured pulp and 20-70 m3 of wastewater per ton of manufactured paper and paperboard. Toxins present in pulp and paper mill effluent (PPME) include chlorinated compounds, extractives, waxes, sterols, suspended solids, fatty acids, diterpene alcohols, tannins, lignin and its derivatives. PPME causes eutrophication, exhibits strong mutagenic effects and physiological impairment to living organisms, thermal impact, and scum formation. Generally, primary clarification followed by biological treatment systems are employed in treating PPME. However, conventional biological methods exhibit unsatisfactory performance due to certain setbacks. The objective of this study is to develop an efficient integrated treatment system that comprises of coagulation and advanced oxidation process (heterogeneous photocatalysis) to effectively remove suspended solids and to degrade recalcitrant organic pollutants found in PPME. The use of unmodified and natural Cassia obtusifolia (C. obtusifolia) seed gum as a natural coagulant in the treatment of raw PPME was studied as pre-treatment step (phase one) prior to photocatalysis (phase two) in the present study. Coagulation efficiency of C. obtusifolia was compared to conventional alum. Phase two comprises of the photocatalytic degradation of pre-treated PPME. Doped, co-doped and undoped TiO2 are synthesized via sonochemical method. The synthesized photocatalysts are used in the photodegradation of pre-treated PPME (from phase one) under visible and natural sunlight irradiation. The effect and interactions of various operating conditions are investigated for both coagulation and photocatalytic processes using response surface methodology. In addition, optimization and kinetic studies are also conducted in this research. The proposed treatment system is targeted to replace and/or adopt into the currently practiced PPME treatment methods in Malaysia and other countries. Lastly, the outcomes from this study are expected to serve as another milestone in (a) the use of natural coagulant in coagulation process; (b) synthesis of nano-structured materials via sonochemical method; (c) use of green technology in AOPs; (d) attaining a better understanding on the effects and relationship between operating conditions for coagulation and heterogeneous photocatalysis.

About the Speaker

Ms Wennie Subramonian graduated with Bachelor of Engineering (Chemical Engineering with Honours) from Monash University Sunway Campus in 2012. She joined Monash University in the same year for postgraduate studies under the supervision of Dr. Wu Ta Yeong and Dr. Chai Siang Piao. Her research focus is on integrated treatment process of pulp and paper mill effluent (PPME) using coagulation and heterogeneous photocatalysis.