Integrating photobiological hydrogen production with dye-metal bioremoval from simulated textile wastewater

Metal removal and recovery using bioelectrochemical technology: The major determinants and opportunities for synchronic wastewater treatment and energy production

Microbial fuel cell (MFC) technology has emerged as a new and attractive bioelectrochemical approach in the last one and a half decade that offers an alternative to conventional treatment methods to remove and recover heavy metals and organics from wastewaters with simultaneous energy production. This technique has advantage over the conventional wastewater treatment techniques, which are energy intensive, sludge producing and with little effectivity at high concentrations. Significant work has been done in the recent years on MFC principle, electrode configuration, biofilm composition, application of MFC in wastewater treatment, metal removal or recovery and energy production. Basically, metal in the cathode chamber acts as acceptor of the electrons released from the oxidation of organic matter in the anode chamber by electrogenic microbes. Literature shows that efficacy of MFCs in removal and recovery of metals and power production is significantly influenced by redox potential of the metal, initial concentration, mix metal systems, carbon source in substrate, pH, biocathode, biofilm composition, gaseous environment in cathode, electrode modification and external resistance, which have been critically reviewed for the first time in the present paper to understand the role of the determinant factors that may be explored for improvement of the MFC performance. The paper provides further insights into the techno-economic aspects of MFC technology and suggests research needs for enhanced performance and reduced costs to increase its feasibility for application at commercial level.

Green technology for sustainable biohydrogen production (waste to energy): A review

Perceiving and detecting a sustainable source of energy is very critical issue for current modern society. Hydrogen on combustion releases energy and water as a byproduct and has been considered as an environmental pollution free energy carrier. From the last decade, most of the researchers have recommended hydrogen as one of the cleanest fuels and its demand is rising ever since. Hydrogen having the highest energy density is more advantageous than any other fuel. Hydrogen obtained from the fossil fuels produces carbon dioxide as a byproduct and creates environment negative effect. Therefore, biohydrogen production from green algae and cyanobacteria is an attractive option that generates a benign renewable energy carrier. Microalgal feedstocks show a high potential for the generation of fuel such as biohydrogen, bioethanol and biodiesel. This article has reviewed the different methods of biohydrogen production while also trying to find out the most economical and ecofriendly method for its production. A thorough review process has been carried out to study the methods, enzymes involved, factors affecting the rate of hydrogen production, dual nature of algae, challenges and commercialization potential of algal biohydrogen.

Power generation in microbial fuel cell fed with post methanation distillery effluent as a function of pH microenvironment

The effect of anolyte and catholyte pH on power generation in an MFC using post methanation distillery effluent (PMDE) was studied in batch mode. Higher anodic pH (7-9) and low cathodic pH (2) were more favorable and at the optimal cathode:anode pH ratio of 2:8, power density attained was 0.457 W/m(3). An initial feed solution pH up to 10 was tolerated by the MFC. However, internal resistance increased 1.5 times and power density decreased by 60% at pH 10 as compared to that at pH 7, the normal anolyte pH. Internal resistance of the MFC was minimum (266 ohms) at cathodic pH 2, thus favoring better power generation. Under low cathodic and high anodic pH ratio of the MFC, a low internal resistance favored both high current density and power density.

Design and optimization of photo bioreactor for O2 regulation and control by system dynamics and computer simulation

In this paper, a valid kinetic model of photo bioreactor (PBR) used for highly-effective cultivation of blue algae, Spirulina platensis, was developed for fully describing the dynamic characteristics of O(2) concentration, then a closed-loop PBR with Linear-Quadratic Gaussian (LQG) servo controller was established and optimized via digital simulation and dynamic response optimization, and the effectiveness of the closed-loop PBR was further tested and accredited by real-time simulation. The result showed that the closed-loop PBR could regulate and control the O(2) concentration in its gas phase according to the reference with desired dynamic response performance, hence microalgae with unique characteristic could be selected as a powerful tool for O(2) regulation and control whenever O(2) concentration in Bioregenerative Life Support System (BLSS) deviates from the nominal level in emergencies, and greatly enhance safety and reliability of BLSS on space and ground missions.