Electrolytic removal of algae was conducted in batch and continuous reactors to investigate operating factors affecting removal ef®ciency and to explore engineering relationships which could be useful for operation and scale-up. The system integrated both electro-¯occulation and electrootation mechanisms by using polyvalent metal anodes and inert metal cathodes. Batch reactor studies con®rmed that high electrical input power or higher electrical current achieved higher and faster removal ef®ciencies. Natural liquid circulation was observed during electrolytic operation and increased with higher electrical power. However, a small degree of external mixing may be useful at lower electrical power input. Electro-¯otation alone could not achieve complete algae removal (maximum ef®ciency 40±50%), and showed the importance of algal¯oc formation for the complete removal of algae. In continuous electrolysis experiments, the ratio of the volumetric current intensity (amperes dm À3) and the chlorophyll a loading (mg dm À3 h À1) was found to be a useful operating and scale-up factor to balance high algal removal ef®ciency with minimum release of excess aluminum. This ratio was eventually found to be just the charge dose or the amount of coulombs required to remove a unit mass of chlorophyll a. The optimum charge dose was determined and used to relate the operating current and electrolysis time of a continuous process.

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A good cysteine addition method that could increase the specific glutathione (GSH) production rate (Pc) was investigated and utilized to maximize total GSH production in fed-batch culture of Saccharomyce s cerevisiae. The single-shot addition of cysteine was a better method compared to a continuous method that maintained a constant cysteine concentration in the.. reactor. The shot method increased Pc about twofold compared to a culture without cysteine. The increase in Pc by the shot method can be achieved without growth inhibition if the cysteine dose is maintained at 0.7 mmol.g-1 cell or less. The positive effect on Pc (at every specific growth rate,/z) was saturated when the cysteine shot concentrations was 3 mM or more. A simple model was developed consisting of mass balance equations and the relationship between p and Pc, for the single cysteine shot addition method. From this model an optimal operating strategy was determined to maximize total GSH production in fed-batch culture. This optimal operation consisted of separating the process into phases of (1) cell growth and (2) GSH production, through a bang-bang profile control of/z, and a shot of cysteine just at the start of the GSH production phase. In other words, the cysteine shot time and the ~ switching time should be the same. For a total feeding time of 10 h, both the switching time of p and cysteine shot time were calculated to be about 6.4 h.

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Ozonation of distillery slop waste was done to evaluate the process in terms of organic matter removal and decolorization efficiencies. The chemical properties of melanoidins, which are known to harbor the chromophoric groups in the waste were also investigated. Ozone had primary effects on the decolorization of the slops and improvement in its biodegradability, compared to organic matter removal (as COD). A decolorization efficiency of 80% and a biodegradability improvement of 40% was obtained in 40 hours. Only 16% of the COD was removed. The melanoidins had a 10% decrease in molecular weight indicating slight depolymerization. UV spectral studies of melanoidins showed that olefinic linkages (which are said to be important in the structure of the chromophores) decreased.

In the long-run, microwave pyrolysis can be a simpler and low energy-requiring alternative to conventional pyrolysis for the thermochemical conversion of biomass to useful products. However, there are still research gaps in its mechanism. Thus, this study investigated the various factors affecting the biochar yield using a half resolution (2k-1) factorial design on the microwave pyrolysis of corn cob wastes. A viable biochar product was produced within minutes of the reaction; wherein, the statistical analysis confirmed the exposure time, microwave output power and their interaction as significant in the CCBc yield. The highest yield obtained was 52.87% when exposure time and output power were set to 5 min and 450W, respectively. A general decreasing effect on the yield was observed from increasing exposure time and output power. This was due to the rapid heating experienced by the corn cob wastes causing the hydrocarbons to react and transform into permanent gases at higher temperatures. To confirm the carbon content of the CCBc, elemental analysis showed an average of 67.11% C at low time-low power (LTLP) of 450 W for 5 min and 81.32% C for the samples operated at high time-high power (HTHP) of 700 W for 10 min.

Brine wastewater with a high ammonia content from an iodine processing plant (commonly called kansui in Japan) was treated by electrolysis. The system, which can be considered as an indirect electrolytic treatment process, generates chlorine at the anodes and initiates the formation of mixed oxidants like hypochlorous acid. The oxidants then act as agents for ammonia destruction. Laboratory-scale experiments showed that high ammonia concentrations (as much as 200 mg dm −3 ) could be completely removed within a few minutes, and could be considered a good alternative for efficient ammonia removal from saline wastewaters. From laboratory-scale experiments in the batch and continuous modes, the charge dose was analyzed and used as the operating and scale-up factor. The value of the charge dose was not severely affected by changes in operating conditions such as electrode spacing and temperature. The charge dose from batch and continuous runs was found to be in the range of 23 C (mg NH 4 -N removed) −1 to 29 C (mg NH 4 -N removed) −1 . Using the charge dose obtained from laboratory-scale continuous electrolysis experiments as the scale-up factor, a pilot-scale reactor was designed, and the operating conditions were calculated. In the pilot-scale reactor tests at different flow rates, the effluent ammonia concentrations were reasonably close to the calculated values predicted from the charge dose equation.

A fuzzy logic controller (FLC) for the control of ethanol concentration was developed and utilized to realize the maximum production of glutathione (GSH) in yeast fedbatch culture. A conventional fuzzy controller, which uses the control error and its rate of change in the premise part of the linguistic rules, worked well when the initial error of ethanol concentration was small. However, when the initial error was large, controller overreaction resulted in an overshoot.An improved fuzzy controller was obtained to avoid controller overreaction by diagnostic determination of "glucose emergency states" (i.e., glucose accumulation or deficiency), and then appropriate emergency control action was obtained by the use of weight coefficients and modification of linguistic rules to decrease the overreaction of the controller when the fermentation was in the emergency state. The improved fuzzy controller was able to control a constant ethanol concentration under conditions of large initial error.The improved fuzzy control system was used in the GSH production phase of the optimal operation to indirectly control the specific growth rate mu to its critical value micro(c). In the GSH production phase of the fed-batch culture, the optimal solution was to control micro to micro(c) in order to maintain a maximum specific GSH production rate. The value of micro(c) also coincided with the critical specific growth rate at which no ethanol formation occurs. Therefore, the control of micro to micro(c) could be done indirectly by maintaining a constant ethanol concentration, that is, zero net ethanol formation, through proper manipulation of the glucose feed rate. Maximum production of GSH was realized using the developed FLC; maximum production was a consequence of the substrate feeding strategy and cysteine addition, and the FLC was a simple way to realize the strategy.