Enzymatic treatment for controlling irreversible membrane fouling in cross-flow humic acid-fed ultrafiltration.

Exploring reasonable ways to remove foulant is of great importance in order to allow sustainable operation of ultrafiltration (UF) membranes in water/wastewater treatment technology. Compounds of organic and inorganic origin largely contribute to irreversible fouling. This study attempted to remove problem of UF membrane fouling by using four different enzymes including alpha-amylase, lipase, cellulase and protease. This investigation showed that none of the above mentioned enzymes was found to be effective for the removal of foulant when used alone. However, when these enzymes were used in combination with NaOH and citric acid, about 90% cleaning was achieved. The addition of non-ionic surfactant to the enzymatic solution appears to increase the efficiency of flux recovery by reducing the adhesion of foulant species to the membrane surface through the decrease of contact angle. Field emission gun scanning electron microscopy, Fourier transform infrared spectroscopy and atomic force microscopy (AFM) techniques were employed to qualitatively illustrate the foulant characteristics. The surface roughness through AFM was used to explain the potential mechanism for the enzymatic cleaning.

Effects of TiO2 dosage, pH and temperature on decolorization of C.I. Reactive Red 2 in a UV/US/TiO2 system.

This study elucidates the decolorization of C.I. Reactive Red 2 (RR2) in ultrasound (US), US/TiO(2), ultraviolet (UV)/TiO(2) and UV/US/TiO(2) systems. The effects of TiO(2) dosage, pH and temperature on RR2 decolorization were determined in a UV/US/TiO(2) system. The pseudo-first-order decolorization rate constants of 0.5, 1 and 2g/l TiO(2) in the UV/US/TiO(2) system were 0.45, 0.57 and 0.94 h(-1), respectively. In the UV/US/TiO(2) system, the decolorization rate of RR2 declines as pH increases, and increases as temperature increasing. At pH 7, the decolorization rates followed the order of UV/US/TiO(2) (0.94 h(-1))>UV/TiO(2) (0.85h(-1))>US/TiO(2) (0.25 h(-1))>US. The activation energy of the UV/US/TiO(2) system at pHs of 4, 7 and 10 was 6.58, 11.62 and 21.32kJ/mol, respectively. Experimental results suggest that the RR2 decolorization in the UV/US/TiO(2) system was a diffusion-controlled reaction.

Development of a dynamic strategy planning theory and system for sustainable river basin land use management.

Land use management is central to government planning for sustainable development. The main purpose of this study is to develop a novel strategy planning theory and system to assist responsible authorities in obtaining alternatives of sustainable top river basin land use management. The concepts and theory of system analysis, driving force-state-response (DSR) framework, and system dynamics are used to establish the DSR dynamic strategy planning procedure in this work. The integrated management of the land, water, and air resources of a river basin system is considered in the procedure. Two modified land use management procedures combined with the DSR dynamic strategy planning procedure are developed in this work. Based on the DSR dynamic strategy planning procedure, the sustainable river basin land use management DSR dynamic decision support system (SRBLUM-DSRD-DSS) is developed by using the Vensim, MS Excel, ArcView, and Visual Basic software. The concepts of object-orientation are used to develop the system dynamic optimization and simulation models of SRBLUM-DSRD-DSS. Based on the modified land use management procedures, SRBLUM-DSRD-DSS is used to assist decision makers in generating the land use plans of the Nankan river basin in Taoyuan County of Taiwan. Since the decisions of land, water and air resources management are still made at different agencies, the land use management system should be modified based on the innovational procedure to implement the management strategy developed in this work. The results show that the modified land use management procedures can be a guidance for the governments in modifying the systems and regulation of urban and regional plans in Taiwan.