Keynote Speaker

Dr.,Retired Prof.Shyam S. Nandwani,
Universidad Nacional, Heredia, Costa Rica

Due to necessity, en February 1979, author designed, constructed and used simple hot box solar oven just for warming lunch. Looking into the success, since then various more models of solar cookers, like Conventional Hot box oven, Cooker cum water heater, cooker cum Dryer, Two compartments cooker for research, hybrid Sun- AC Electric, hybrid Sun DC Electric and Multipurpose hybrid  cookers have been designed, constructed and studied.  In addition to a popular book on Solar Cooking with recipes, editing three world conferences on solar cooking, more than 20 articles have been published in technical journals, national and international conferences.
Also these have been promoted through lectures in communities, educational and cultural centres, TV, Radio, newspapers, workshops and seminars in Costa Rica and many other countries. For one of the simple model of Solar oven, patent was issued in 1984 in Costa Rica.
In the present work different models, economical and environmental advantages, some promotional activities especially at educational institutes to warm the lunch for the students will be mentioned. Massive uses of Solar Cookers can definitely reduce some Global warming, specially in places where coal or fire wood is used for cooking.  

Prof.Chih-Huang Weng, Dept. of Civil and Ecological Engineering, I-Shou University, Taiwan

Title: Biotite activated persulfate oxidation for decolorization of real textile wastewater
The high Fe2+ content of biotite, iron mica, has potential of activating a persulfate reaction. However, information pertaining to using biotite as an activator in persulfate oxidation process is currently unavailable. In this study, persulfate (PS) activated by powdered biotite was evaluated the effectiveness in treating real textile wastewater. Findings revealed that decolorization efficienty was significantly enhanced by PS/biotite combined with ultrasound (US) (PS/biotite/US) or heat (PS/biotite/55°C). A suitable oxidation condition for removal true color was biotite 3.0 g/L, PS 4×10-3 M, 55°C, US 106 W/cm2 (20 min sonication at 20 kHz), and initial pH 3.0 which could reduce ADMI from 950 to 71 (far less than effluent criteria of ADMI 550) after 50 min tresatment period. Nonetheless, under this condition, the COD was only reduced from 264 to 216 mg/L. When powder activated carbon was added to the oxidation process, the COD was further reduced to 84 mg/L and completely ADMI removal achieved within 10 min. Findings revealed that oxidation condition under higher biotite and persulfate dosages with longer sonication is beneficial for generation of sulfate radicals, consequently, promoting the oxidation performance of PS/biotite. Based on the observed pseudo-1st-order decolorization rate constants, an Arrhenius activation energy for the PS process activated with biotite was estimated as 2.84 kcal/mol, implying that higher temperature is beneficial for the ADMI decolorization. Results clearly indicated that natural Fe-mineral, biotite, can be directly used to activate persulfate for effective decolorization of real textile wastewater to meet stringent effluent criteria.