NOPR Collection:

Bioremediation concepts for treatment of dye containing wastewater: A review

Mon, 01 Sep 2003 00:00:00 GMT

Title: Bioremediation concepts for treatment of dye containing wastewater: A review Authors: Keharia, Haresh; Madamwar, Datta Abstract: Synthetic dyes are extensively used in wide range of industries amongst which textile processing industries are the major consumers. Large amounts of dyes are lost in wastewaters of these industries during dyeing and subsequent washing steps of textiles. These dyes are resistant to degradation by conventional wastewater treatment plants and are released into environment untreated thus causing pollution of surface and ground waters in the areas of the world harboring such industries. Presence of color in wastewaters has become major environmental concern and stringent discharge standards are being enforced on release of colored wastewater in environment. The seriousness of the problem is apparent from the magnitude of the research done in this field in last decade. Increasing number of microorganisms are being described for their ability to decolorize and degrade artificial dyes and novel bioremediation approaches for treatment dye bearing wastewaters are being worked out. In this review we have investigated potential microbial processes for developing feasible remediation technology to combat environmental pollution due to dye bearing wastewaters. Page(s): 1068-1075

Microbiologically influenced corrosion in petroleum product pipelines - A review

Mon, 01 Sep 2003 00:00:00 GMT

Title: Microbiologically influenced corrosion in petroleum product pipelines - A review Authors: Muthukumar, N; Rajasekar, A; Ponmariappan, S; Mohanan, S; Maruthamuthu, S; Muralidharan, S; Subramanian, P; Palaniswamy, N; Raghavan, M Abstract: Microbiologically influenced corrosion is responsible for most of the internal corrosion problems in oil transportation pipelines and storage tanks. One problematic area in treating gas lines is the occurrence of the stratification of water in the line. Under these conditions, corrosion inhibitors do not come into contact properly and oil and inhibitors undergo degradation. The role of bacteria on oil degradation, the consequences of oil degradation in fuel systems and its influence on corrosion have been explained in detail. Besides, factors influencing on degradation of oil and corrosion inhibitors have also been discussed. Mechanism of microbiologically influenced corrosion in oil pipeline has been explained. Many of the misapplication of biocides/inhibitors occur mainly because the characteristics of biocides/inhibitors are not considered before use in pipe line industry. List of biocides and monitoring programme have been collected from literature and presented. Page(s): 1012-1022

Biorecovery of gold

Mon, 01 Sep 2003 00:00:00 GMT

Title: Biorecovery of gold Authors: Eisler, Ronald Abstract: Recovery of ionic and metallic gold (Au) from a wide variety of solutions by selected species of bacteria, yeasts, fungi,algae, and higher plants is documented. Gold accumulations were up to 7.0 g/kg dry weight (DW) in various species of bacteria, 25.0 g/kg DW in freshwater algae, 84.0 g/kg DW in peat, and 100.0 g/kg DW in dried fungus mixed with keratinous material. Mechanisms of accumulation include oxidation, dissolution, reduction,leaching, and sorption. Uptake patterns are significantly modified by the physicochemical milieu. Crab exoskeletons accumulate up to 4.9 g Au/kg DW;however, gold accumulations in various tissues of living teleosts, decapod crustaceans, and bivalve molluscs are negligible. Page(s): 967-971

Separation and recovery of radioactive and non-radioactive toxic trace elements from aqueous industrial effluents

Mon, 01 Sep 2003 00:00:00 GMT

Title: Separation and recovery of radioactive and non-radioactive toxic trace elements from aqueous industrial effluents Authors: Iyer, R H Abstract: An update is presented on liquid membrane - based processes as viable and relevant alternatives to conventional approaches such as precipitation. solvent extraction, ion exchange processes and electrochemical techniques for the removal and recovery of some toxic and/or valuable trace metal ions including some actinides and fission products e.g. U, Am, Y etc and As, Cd, Co, Cr, Cu, Hg, Ni, Pb, Zn etc from radioactive as well as non-radioactive aqueous waste solutions respectively. In particular, results of experiments aimed at developing supported liquid membrane(SLM)- based process using commercially available porous membranes and indigenously prepared track - etch membranes (TEMs) have been critically examined in laboratory studies to generate basic data needed to evaluate their utility for continuous operation without regeneration . These include effect of pore size, porosity, optimum pore size and the reusability. It is clearly demonstrated that indigenously prepared 10μm thick T EMs with a porosity in the range of 2-5% give comparable transport rates for metal ions-matching with that of commercial membranes of much higher thick ness (160 μm) and higher porosity of 60-85%. The smaller thickness of TEMs more than compensates for their lower porosity. It is shown that because of the ir well defined pore charactcristics TEMs could serve as model supports in SLM studies. By comparing the values of permeability coefficient (P) for TEM and polytetraflouroethylene (PTFE) supports for the transport of Pb²⁺ chosen as a typical divalent metal ion. and using di-2 ethyl hexyl phosphoric acid (D2 EHPA) as the carrier, it is unambiguously proved that diffusion of the metal complex across the membrane is the rate controlling step in metal ion transport in SLM-based processes. An overview of the experimental findings along with future outlook and suggestions for further work are presented in this paper. Page(s): 1002-1011