Two bench-scale hybrid processes, anaerobic/anoxic/oxic (A2O) reactor and sequencing batch reactor (SBR), each followed by the microfiltration (MF) system, were simultaneously operated to compare their performances on the removal of organics and phosphorus from both synthetic and real wastewater to further explore the potential for effluent reuse. The effects of different influent chemical oxygen demand (COD) to total phosphorus (TP) ratios (27, 50, 80, and 200) were investigated. For both processes, when the influent COD/TP ratio was 200, the effluent quality was satisfactory for some reuse potential. The MF membrane system showed an evident further removal of COD (20–89%) and color (18–60%), especially the removal of suspended solids (SS) and turbidity with the final effluent SS <1?mg/L and turbidity <0.1 NTU. When real wastewater was tested, the effluent quality was adequate and met the standard goals for regional reuse purposes.

The mechanisms and pseudo-kinetics of the electrochemical oxidation for wastewater treatment and the synergistic effect of combining algal biological treatment were investigated. NaCl, Na2SO4 and HCl were applied to compare the effect of electrolyte species on nutrients removal. NaCl was proved to be more efficient in removing ammonia (), total phosphorus (TP), total organic carbon (TOC) and inorganic carbon (IC). oxidation by using Ti/Pt–IrO2 electrodes was modelled, which indicates that the removal followed the zero-order kinetic with sufficient Cl− and the first-order kinetic with insufficient Cl−, respectively. The feasibility of combining electrochemical oxidation with microalgae cultivation for wastewater treatment was also determined. A 2?h electrochemical pretreatment reduced 57% , 76% TP, 72% TOC and 77% IC from the digested effluent, which is applied as feedstock for algae cultivation, and resulted in increasing both the biomass production and pollutants removal efficiencies of the algal biological process.

The current global energy situation has demonstrated an urgent need for the development of alternative fuel sources to the continually diminishing fossil fuel reserves. Much research to address this issue focuses on the development of financially viable technologies for the production of biofuels. The current market for biofuels, defined as fuel products obtained from organic substrates, is dominated by bioethanol, biodiesel, biobutanol and biogas, relying on the use of substrates such as sugars, starch and oil crops, agricultural and animal wastes, and lignocellulosic biomass. This conversion from biomass to biofuel through microbial catalysis has gained much momentum as biotechnology has evolved to its current status. Extremophiles are a robust group of organisms producing stable enzymes, which are often capable of tolerating changes in environmental conditions such as pH and temperature. The potential application of such organisms and their enzymes in biotechnology is enormous, and a particular application is in biofuel production. In this review an overview of the different biofuels is given, covering those already produced commercially as well as those under development. The past and present trends in biofuel production are discussed, and future prospects for the industry are highlighted. The focus is on the current and future application of extremophilic organisms and enzymes in technologies to develop and improve the biotechnological production of biofuels.

Biogas production in agriculture is processed mostly continuously at mesophilic temperatures in completely stirred tank reactors. Therefore, reactor performance data were studied in long‐term semi‐continuous laboratory‐scale experiments with maize silage, whole‐crop rye silage and fodder beet silage as mono‐substrate and cattle slurry at mesophilic temperatures. For calculation of biogas yield as function of the organic loading rate, a hyperbolic equation was developed on the base of a first‐order reaction rate for substrate degradation. The biogas yield depends also on the maximum biogas yield, the concentration of volatile solids of the input, the density of the effluent, the density of the biogas and the reaction rate constant, which are all substrate‐ or process‐specific. Values of the theoretical maximum biogas yield and the reaction rate constant were observed in the range 0.61–0.93 m3 per kg volatile solids and 0.032 – 0.316 d−1, respectively. By means of the hyperbolic equation, the proportion of the biogas yield from the maximum can be calculated for the first and a second reactor which also depends on the volume of each reactor.

This study aimed to compare the performance of an internal combustion engine fed with blends of biodiesel produced from soybean and diesel, and blends of biodiesel produced from beef tallow and diesel. Performance was evaluated in terms of power generated at low loading conditions (0.5, 1.0 and 1.5?kW) and emission of organic and inorganic pollutants. In order to analyse inorganic gases (CO, SO2 and NOx), an automatic analyser was used and the organic emissions (benzene, toluene, ethylbenzene and xylene – BTEX) were carried out using a gas chromatograph. The results indicate that the introduction of the two biodiesels in the fuel caused a reduction in CO, SO2 and BTEX emissions. In addition, the reduction was proportional to the increase in loading regime. Beef tallow biodiesels presented better results regarding emission than soybean biodiesels. The use of pure biodiesels also presented a net reduction in pollutant gas emissions without hindering the engine generator performance.