All

Unicellular microalgal culture represents a new opportunity for producing significant biofuel quantities in the future along with other specialty products, due to several major advantages microalgae species present when compared to conventional crops, including much faster growth rates, cultivation in a variety of environments and photobioreactor systems, and almost 100% recycling of nutrients. In the current research, the scaling-up of the cultivation of Chlorella vulgaris microalgae to a 4 m3 pilot-plant photobioreactor is examined, compared to the performance of a 25 L automated laboratory bioreactor. Beyond the size and configuration, the main differences of the two bioreactors are the mode of operation, the illumination nature and depth, the temperature, and pH. Specifically, temperature and illumination are naturally varying from day to day and season to season into the pilot-plant photobioreactor that is set inside a greenhouse. The specific growth factor appears to be higher for microalgal cultivation in the laboratory bioreactor. It is also found that the growth kinetics is severely slowed down during the winter months. This is primarily due to the low temperatures and the poor illumination observed during winter.

The urge of environmental friendly techniques in textile processing is gaining much attention due to high risks of effluent load causing eco-imbalance. For the present study, the cotton fabric and Reactive Violet H3R dye solution were treated with microwave radiation for 2, 4, 6, 8 & 10 min. at different powers (low, medium & high). Dyeing was performed using un-irradiated (NRC) and irradiated cotton (RC) with un-irradiated (NRS) and irradiated dye solution (RS). Different dyeing parameters were optimized and ISO standard methods for color fastness were employed to rate the color change before and after irradiation. It is found that microwave irradiation for 8 min. at high power has given good colour strength. When 60 mL irradiated dye solution of 7.5pH containing 8g/L of salt as exhausting agent is used to dye irradiated fabric at 60^oC for 55 min. ISO standards for colorfastness employed at various shades have shown that microwave irradiation has improved the rating of fastness properties. It is concluded that microwave irradiation has a promising potential to improve the color strength and dyeing properties under mild conditions.

The commercial imidacloprid (IMD) insecticide [1-(6-chloro-3-pyridinyl) methyl-4,5-dihydro-N-nitro-1H-imidazole-2-amine] is widely used for the enhancement of crop production, but the intensive use of this insecticide has caused serious environmental problems. This work presents an electrochemical process for the removal of this insecticide using galvanostatic electrolysis at modified tantalum surface by lead dioxide film anode (Ta(PbO2)) anode. The electrolytic process was monitored by chemical oxygen demand (COD). The influence of operating parameters, such as current density, initial concentration of IMD, temperature and initial pH value was investigated. The COD decay follows a pseudo first-order kinetic and the process was under mass transport control. COD removal reach 97% when using an apparent current density of 100 mA cm−2, initial COD of 953 mg L−1 and at 25 °C after 4.5 h electrolysis time.

The Membrane Bio-Reactor (MBR) technology offers a series of environmentally-friendly advantages, such as high quality effluent, pathogens removal capacity and avoided use of chemicals for disinfection, allowing it to be regarded as an environmentally friendly technology, when applied for wastewater treatment. However, membrane fouling still remains a major drawback, preventing its widespread application for municipal or industrial wastewater treatment. The use of additives (i.e. adsorbents, bio-carriers etc.) is considered to be among the major strategies implemented for membrane fouling control over the last few years. The present work examines the influence of bio-carriers addition, as well as of zeolite powder on the reversible and irreversible membrane fouling of a lab-scale MBR. High-strength synthetic municipal wastewater (with BOD5 around 1000 mg/L) was fed as the substrate for the activated sludge process and a flat-sheet microfiltration membrane was operated for solids (biomass) - liquid separation at the flux of 17 L/m2h. The obtained results showed that the addition of zeolite contributed mainly to the alleviation of irreversible fouling, leaving the reversible fouling practically unaffected, while the addition of bio-carriers had quite the opposite effect. In addition, it was shown that the lab-scale MBR system operated successfully, treating a high-strength synthetic municipal wastewater, as high removals were observed in terms of both organics and especially of ammonium removal (over 98%).