Treatment Of Waste Streams Research Articles

Management of radioactive waste from molybdenum-99 production using low enriched uranium foil target and modified CINTICHEM process

Technetium-99m is the short-lived daughter product of the parent molybdenum-99, which is mainly produced by the fission of uranium-235. Management of radioactive waste is an integral part of fission 99Mo production and has high priority during the planning, design, construction and operational phase of a molybdenum-99 production facility. Within the licensing procedure the strategy of waste management, including the route for the spent targets and long lived fission products has to be described and approved by the responsible authorities. Waste will be generated as solids, liquids, and gases, and will include material in the low, intermediate and even highly radioactive categories. Initial treatment of waste streams is usually required at the production site, prior to short or long term storage. This technology is established and generally available in countries with an existing nuclear industry, such as Pakistan. In some instances storage facilities may need to be constructed. On site, treatment of gaseous waste will be carried out in the production facility while off-site treatment will be performed for solids and liquid radioactive waste.

Pilot production of activated carbon from cotton stalks using H 3PO 4

Cotton stalks, an agricultural waste, were chemically activated in a batch process using H 3PO 4 in a locally designed carbonizer at 420 °C in the absence of any purging gases. Mechanically cut short sticks were soaked in diluted H 3PO 4 for a short duration (Batch 1) and an extended period (Batch 2) prior to thermal treatment. The derived carbons contained both coarse and fine grains with acidic effect. Porosity was characterized by N 2 adsorption at −196 °C and the isotherms analyzed by the α-method to estimate total and microporous surface areas in addition to total and microporous volumes. The produced carbons exhibited well-developed porosity that was essentially microporous in composition. Several key performance parameters were altered considerably as a result of impregnation with H 3PO 4 and the extended chemical activation period (Batch 2). Most of the internal porosity of both carbons was accessible to adsorption of iodine, whereas the uptake of methylene blue dye was proportional to the average size of micropores which were larger for the batch with a longer acid soaking time. SEM and FTIR investigations revealed the presence of a developed honeycomb structure and different oxygen functionalities on surfaces of the activated products which are advantageous in liquid-phase applications. Preliminary laboratory-scale experiments with Pb(II) indicate that adsorption capacity of target heavy metals compares favorably with commercially available activated carbons. The raw material, pre-processing, and activation process prove feasible for the production of activated carbon on a large scale, thereby providing a sustainable strategy for treatment of toxic waste streams.

Assessment of the Integral Resource Consumption of Individual Chemical Production Processes in a Multipurpose Pharmaceutical Production Plant: A Complex Task

Up to now, process specific integral resource consumption is barely used as criterion for the selection and improvement of fine chemical and pharmaceutical production processes. Reasons are the complexity of the supply networks in multipurpose plants and the requirement of a detailed data inventory from the production plant itself and from facilities delivering supporting utilities and treating waste streams. In this paper, a methodology is presented to set up integral mass and energy balances of specific production processes in the pharmaceutical and fine chemical industry. This methodology is based on the principle that each chemical production process is a sequence of unit operations in which basic operations at individual equipment take place. These basic operations are considered as the building blocks for all production processes. If the resource consumption of each building block can be quantified, not only at the operation itself but also at the on-site and off-site upstream and downstream processes to sustain the operation, the integral resource requirement of a whole specific production process can be quantified by the summation of the resource requirements of all building blocks involved. This methodology allows the development of a calculation tool for the quantification of the integral resource consumption with minimized data inventory. This tool will enable the selection of the most resource efficient production process and will indicate points of improvement. In this way production processes in pharmaceutical and fine chemical industries can become economically and ecologically more sustainable.

Pharma-Ecology – The Occurrence and Fate of Pharmaceuticals and Personal Care Products in the Environment By Patrick K. Jjemba Hoboken, New Jersey:John Wiley & Sons, Inc., 2008. 314 pp. ISBN: 978-0-470-04630-2, $95

Vol. 117, No. 4 AnnouncementsOpen AccessPharma-Ecology – The Occurrence and Fate of Pharmaceuticals and Personal Care Products in the Environment Rolf U. Halden Rolf U. Halden Search for more papers by this author Published:1 April 2009https://doi.org/10.1289/ehp.117-a172aAboutSectionsPDF ToolsDownload CitationsTrack Citations ShareShare onFacebookTwitterLinked InRedditEmail Pharmaceuticals and personal care products (PPCPs) in the environment are a hot topic. Emitted from various sources, veterinary antibiotics, prescription drugs, and beauty products continuously enter the environment, where they have been detected at trace levels in reclaimed wastewater, surface and ground water, sludge-amended agricultural soils, aquatic and terrestrial biota, as well as in raw and finished drinking water. Fueled by media coverage, the general public has taken notice and is challenging the scientific and regulatory community to assess potential human health and ecological risks, and to take appropriate action where needed. Patrick K. Jjemba, a senior research analyst for innovation and technology with American Water, takes on the ambitious task of framing the complex issue of PPCPs in the environment.The first chapter introduces industrial agriculture, domestic waste-water treatment, and the land application of municipal sewage sludge (biosolids) as principal sources of PPCPs in the environment. For balance, usage rates of veterinary antibiotics are provided from both the agricultural industry and concerned scientists. Personal care products are categorized as fragrances and musks, detergents, and disinfectants. Human pharmaceuticals are discussed based on the ailment targeted. Jjemba suggests that the increase in the use of antidepressants is attributable at least partly to aggressive marketing. This treatise is comprehensive and well referenced.The next, key chapter deals with the detection and occurrence of PPCPs in the environment. The brief description of instrumentation contains minor technical inaccuracies. The challenge of accurately determining environmental concentrations in the parts-per-trillion (ppt) range is correctly portrayed, but readers receive no guidance on how to distinguish high-quality data from less rigorous monitoring information. A table presenting concentrations of individual compounds across different media to illustrate the wide range of environmental occurrences, from ppt levels in surface and drinking water to parts-per-million levels (ppm) in sludge-amended soils would have been useful. Although most information is presented adequately, readability is diminished by a missing figure caption, conflicting figure labels, environmental transport data from multiple independent studies that should not be interpreted as a single data set, a cited but unreferenced study, and some typos in reproduced equations.Ensuing chapters on ecopharmacokinetics, pharmacodynamics, and ecotoxicity are detailed and much more convincing. These important aspects make the book a worthwhile investment, and also help distinguish it from other PPCP compendia. A valuable chapter on technologies for wastewater and water treatment provides a good overview of conventional and advanced treatment technologies and their effectiveness in removing the trace contaminants of interest. Missing from this section are pollution prevention strategies, such as separation of urine and feces at the source followed by individual treatment of both waste streams, as well as alternatives to centralized sanitary sewer systems, such as no-flush composting toilets.The final pages are dedicated to future needs, including the development of better risk assessment approaches, a consideration of PPCPs as mixtures rather than single compounds, the potential of green chemistry in drug design, the utility of quantitative structure activity relationships in ecotoxicology, and the use of genomic approaches in bioassays. Jjemba closes with a call for a reexamination of the drug approval process and for tighter control of patient-directed advertising by the pharmaceutical industry.How is this book different from others on the topic? Jjemba is the sole author, providing comprehensive coverage of the various PPCP aspects in a logical order and in a consistent style of presentation. Edited compendia containting contributions form multiple authors can be more authoritative but also more disjointed. Jjemba acknowledges the risk that some readers may be “dissatisfied with the level of coverage of one aspect or another, particularly aspects that directly relate to their respective discipline.”Jjemba’s likely audience is newcomers seeking a general understanding of the subject and experts interested in broadening their perspectives. The more than 600 references provided will help readers pursue original sources.FiguresReferencesRelatedDetails Vol. 117, No. 4 April 2009Metrics About Article Metrics Publication History Originally published1 April 2009Published in print1 April 2009 Financial disclosures License information EHP is an open-access journal published with support from the National Institute of Environmental Health Sciences, National Institutes of Health. All content is public domain unless otherwise noted. Note to readers with disabilities EHP strives to ensure that all journal content is accessible to all readers. However, some figures and Supplemental Material published in EHP articles may not conform to 508 standards due to the complexity of the information being presented. If you need assistance accessing journal content, please contact [email protected]. Our staff will work with you to assess and meet your accessibility needs within 3 working days.

Recycling of poultry process wastewater by ultrafiltration

Poultry processing plants use relatively high amount of water with an average consumption of 26.5 L/bird during primary and secondary processing of live birds to meat. The used water contains proteins, fats, carbohydrates from meat, blood, skin and feathers, resulting in much higher biological oxygen demand (BOD) and chemical oxygen demand (COD). Hence the processors are required to remove majority of the soluble and particulate matter in the wastewater prior to discharge from the plant. Treatments for poultry wastewater include screening, diatomaceous earth filtration, ozonation, and chlorine dioxide. Food safety and inspection service regulations allow reconditioned water to replace potable water in prescribed ratios. Recycling of poultry wastewater by ultrafiltration improves the quality of recycled water and provides solution to water resource limitations. Ultrafiltration is basically a pressure-driven process that separates on the basis of molecular diameter. Membrane bioreactors (MBR) that integrate biological degradation of waste products with membrane filtration are also quite effective in removing organic and inorganic contaminants as well as biological entities from wastewater. Value added products like crude proteins could be separated through ultrafiltration from poultry wastewater, subsequently reducing the chemical oxygen demand. Ongoing research in membrane separation techniques involves exploration of new membrane materials and of new module design configurations to address issues of membrane fouling and treatment of waste streams containing high suspended solids or viscous wastes. Poultry processing plants use large volumes of water at different stages of the process due to set policies regarding the pathogen reduction requirements in the broiler meat. Recovery of process wastewater benefits the plant by reducing fresh water demand, wastewater volume and energy consumption. Microbial safety is the primary concern in reconditioning of process wastewater. Proteins and fats which come from carcass debris and the blood are the major pollutants in the wastewater. These materials are of high nutritional value and should be recovered. The proteins and fats are difficult to harvest by conventional procedures. From an environmental and economic point of view, ultrafiltration is an efficient technique to recondition wastewater and to recover proteins and fats from it. Importantly, this technology addressed the water quantity and quality issues that have been raised in this industry by reducing primary water use and electrical energy. Though the capital costs of ultrafiltration are higher, their life cycle costs are comparable with conventional treatments. Further, foot print of ultrafiltration could be 30–50% of conventional filters with less consumption of chemicals. Hence this paper focuses upon the potential for the use of ultrafiltration membrane processing for recycling poultry process wastewater and recovery of value added products.

Performance Comparison of Tin Oxide Anodes to Commercially Available Dimensionally Stable Anodes

Dimensionally stable anodes (DSAs) demonstrate potential for the electrochemical treatment of industrial waste streams and disinfection of effluent. Oxidation by laboratory-prepared tin oxide DSAs was compared with that of commercially available ruthenium oxide, iridium oxide, and mixed metal oxide DSAs, using hexanol as a probe molecule. The performance of the four anodes was similar in two-chamber reactors, in which the anode cell was separated from the cathode cell by a Nafion membrane, which allows transmission of current between the chambers, but not passage of chemical constituents. The anodes were then evaluated in single-cell reactors, which are more representative of potential treatment and disinfection applications. However, in the single-cell reactors, the tin oxide anodes were significantly more effective at oxidation and generated higher quality cyclic voltammograms than the other DSAs. These results suggest that tin oxide anodes have greater potential than the three commercially available DSAs tested for industrial waste stream treatment and effluent disinfection.

Adsorption mechanisms of Cr(VI) on the modified bauxite tailings

The main waste product generated during the bauxite flotation in China is the aluminosilicate tailings. It is desirable to develop an application of these aluminosilicate tailings for the treatment of waste streams containing dissolved heavy metals. The Cr(VI) adsorption capacity and mechanisms of the bauxite tailings modified by FeCl 3 · 6H 2O are investigated in the present study. A maximum removal rate of Cr(VI) by the modified bauxite flotation tailings is obtained at 99.3% in batch experiments. The IEPs of the unmodified and modified bauxite tailings are 3.6 and 5.0, respectively. The IEP of the modified bauxite tailings shifts to lower pH value in the presence of Cr(VI), which indicates that an adsorption of anionic species happens on the modified bauxite tailings. A new band of Cr 2 O 7 2 - appears in the FTIR determination of the modified bauxite tailings, which shows that Cr(VI) adsorbs on the modified bauxite tailings in the form of chemical adsorption. Furthermore, the adsorption data of Cr(VI) on the modified bauxite tailings are well described by both Langmuir and Freundlich models. The pseudo-second-order kinetic model also fits experimental data for the adsorption of Cr(VI).

Pyrolysis/gasification of biomass for synthetic fuel production using a hybrid gas–water stabilized plasma torch

An experimental plasma-chemical reactor equipped with a novel hybrid gas–water stabilized torch is available at IPP Prague for the innovative and environmentally friendly plasma treatment of waste streams with a view to their sustainable energetic and chemical valorization and to a reduction of the emission of greenhouse gases. Gasification/pyrolysis of biomass was experimentally studied using crushed wood as a model substance. The experimental results demonstrate homogeneous heating of the reactor volume and proper mixing of plasma with treated material in spite of the low plasma mass flow rate and constricted plasma jet. The conditions within the reactor ensure complete destruction of the tested substance. The economical viability, environmental performance and safety of biofuels/hydrogen produced from syngas resulting from the plasma-thermochemical gasification of a very broad range of second generation biomass feedstock will be investigated. The performance of several types of plasma torches and of possible combinations of torches will be compared. The final biofuels will be tested in the existing Internal Combustion Engine (ICE) test stands.

Simultaneous degradation of nitroaromatic compounds TNT, RDX, atrazine, and simazine by Pseudomonas putida HK‐6 in bench‐scale bioreactors

AbstractBACKGROUND: Environmental contamination by nitroaromatic compounds such as 2,4,6‐trinitrotoluene (TNT), hexahydro‐1,3,5‐trinitro‐1,3,5‐s‐triazine (RDX), atrazine, and/or simazine (TRAS) generated as waste from military and agricultural activities is a serious worldwide problem. Microbiological treatment of these compounds is an attractive method because many explosives and herbicides are biodegradable and the process can be made cost‐effective. We explored the feasibility of using cultures of Pseudomonas putida HK‐6 for simultaneous degradation of TRAS with the aim of microbial application in wastewater treatment in bench‐scale bioreactors.RESULTS: Experiments were conducted to study the effects of supplemental carbons, nitrogens, and Tween‐80 on the degradation of Ps. putida HK‐6 in media containing TRAS as target substrate(s). The most effective TRAS degradation was shown in the presence of molasses. Addition of nitrogen sources produced a delayed effect for the target substrate(s). Tween‐80 enhanced the degradation of target substrate(s). Simultaneous degradation of these compounds proceeded to completion within the given period.CONCLUSIONS: Ps. putida HK‐6 was capable of growth with TRAS, and the effects of supplements on TRAS degradation and simultaneous TRAS degradation were evaluated in bench‐scale bioreactors. The results of this study have practical applications in the processes of industrial waste stream treatment where the disposal of TRAS may be problematic. Copyright © 2008 Society of Chemical Industry

Impact of degradation products of sulfamethoxazole on mammalian cultured cells

Sulfamethoxazole (SMX) is a widely used antibiotic which has been detected in surface water samples in the ng/L range and also detected in drinking water samples. To limit the environmental impact, ozonation treatment of waste streams has been proposed. However, the degradation products created by ozonation as well as their toxicity have not been reported. In this study, we investigated the degradation products of SMX formed during ozonation and the effects of these products on mammalian cultured cells. In addition to alcohols and nitrates, sulfanilamide was identified as the larger molecular weight compound of the degradation products detected. Cells exposed to the degradation products of SMX maintained their polyhedral geometry longer than the control cells. Proliferation of the cells exposed to the degradation products was not negatively affected when compared with the control cells. The results of this study show that bioactive degradation products can be formed by ozonation of SMX.

Palladium-catalyzed hydrodehalogenation of 1,2,4,5-tetrachlorobenzene in water–ethanol mixtures

Palladium-catalyzed hydrodehalogenation (HDH) was applied for destroying 1,2,4,5-tetrachlorobenzene (TeCB) in mixtures of water and ethanol. This investigation was performed as a critical step in the development of a new technology for clean-up of soil contaminated by halogenated hydrophobic organic contaminants. The main goals of the investigation were to demonstrate the feasibility of the technology, to determine the effect of the solvent composition (water:ethanol ratio), and to develop a model for the kinetics of the dehalogenation process. All experiments were conducted in a batch reactor at ambient temperature under mild hydrogen pressure. The experimental results are all consistent with a Langmuir–Hinshelwood model for heterogeneous catalysis. Major findings that can be interpreted within the Langmuir–Hinshelwood framework include: (1) the rate of hydrodehalogenation depends strongly on the solvent composition, increasing as the water fraction of the solvent increases; (2) the HDH rate increases as the catalyst concentration in the reactor increases; (3) when enough catalyst is present, the HDH reaction appears to follow first-order kinetics, but the kinetics appear to be zero-order at low catalyst concentrations. TeCB is converted rapidly and quantitatively to benzene, with only trace concentrations of 1,2,4-trichlorobenzene appearing as a reactive intermediate. The results obtained here have important implications for the further development of the proposed soil remediation technology, and may also be important for the treatment of other hazardous waste streams.

Optimization of Ti/SnO2–Sb2O5 anode preparation for electrochemical oxidation of organic contaminants in water and wastewater

The preparation of antimony-doped tin oxide anodes on a titanium substrate (Ti/SnO2–Sb2O5 anodes) by dipping in a solution of tin chloride and antimony chloride and annealing at high temperatures was optimized for the potential applications of drinking water disinfection, wastewater effluent disinfection, and industrial waste stream treatment. The effectiveness of Ti/SnO2–Sb2O5 anodes prepared under different conditions was evaluated by using hexanol as a probe molecule to measure the extent of oxidative reactions, and anode performance was monitored by cyclic voltammetry. A large factorial matrix consisting of tin chloride concentration × antimony chloride concentration × annealing temperature was first evaluated, and the optimum conditions were found to be 20% tin chloride and 1% antimony chloride in the dip solution and an annealing temperature of 500°C. Further investigation showed that the rate of withdrawal from the dip solution, the number of coatings of the dip solution, and the addition of oxygen during annealing did not significantly affect anode performance. Under optimum preparation conditions, Ti/SnO2–Sb2O5 anodes showed no loss of performance over 1,280 cycles of cyclic voltammetry, suggesting that their performance can be sustained over long periods of use. The result of this research is a simple preparation method for effective and long-lived Ti/SnO2–Sb2O5 anodes; this method could be easily adopted by a utility for pilot- or full-scale disinfection of water and wastewater and the treatment of industrial waste streams.

Studies on Indigenous Ion Exchange Resins I: Alkali Metal Ion-Hydrogen Ion Exchange Equilibria

Ion exchange characteristics of gel-type, macroporous and nuclear grade strongly acidic cation exchange resins from three Indian manufacturers were evaluated for their efficacy to remove Sr ion from aqueous solution, which has relevance to the treatment of Low level Liquid Waste (LLW) streams. In order to achieve this goal in proper perceptive, the alkaline earth metal ion- hydrogen ion exchange equilibria were studied by batch technique at a total ionic strength of 0.1 mol dm-3. The rational equilibrium constants were determined after incorporating activity coefficient corrections. The log Kc vs NM (equivalent fraction in the resin phase) plots indicated the heterogeneity in the resin phase and formation of clusters. All the resins showed unusually high selectivity for Ca2+ rather than Ba2+. This could be due to the fact that all the resins are tailor made for the demineralisation process, which requires the removal of chiefly Ca ions.

Environmental Biotech

Environmental Biotech

Waste-Solvent Management as an Element of Green Chemistry: A Comprehensive Study on the Swiss Chemical Industry

The treatment of organic waste solvents is an important issue in the chemical industry as large amounts accrue annually. As all treatment options are associated with specific environmental impacts, a sound management of waste solvents can therefore lead to large ecological benefits. The goal of this work was therefore to identify opportunities and requirements for an environmentally sound waste-solvent management. To this end, a survey was carried out together with the Swiss chemical industry. The results show that only a few technologies are used on a grand scale, such as incineration and distillation for solvent recovery. But waste-solvent management is strongly influenced by boundary conditions such as costs, logistics, legislation and guidelines, storage capacity, safety considerations, and the existing technologies on the production site. Thus, we identified that the best opportunity to optimize waste-solvent management would be in an early stage of process design, for instance, before scale-up for the launching of the production or when production campaigns change. Two actual case studies from the chemical industry show how environmentally sound waste-solvent management can be integrated in the planning of a chemical company and lead to ecological benefits. In the first case study a company investigates different routes of waste-solvent treatment for waste streams which are treated outside the plant by third parties. In the second case study different options for the treatment of a dimethoxy ethane mixture are assessed, taking into account environmental impacts by a life-cycle perspective.

A Decade of Research on the Environmental Impacts of Pulp and Paper Mill Effluents in Canada: Development and Application of Fish Bioassays

Laboratory tests have been used to assess the regulatory and research questions related to the effects of pulp mill effluents on aquatic biota. Acute, short-term laboratory tests have clearly shown the improvement in final effluent quality following installation of secondary treatment at Canadian pulp mills. In an effort to predict and investigate impacts on wild fish, laboratory bioassays were developed to examine sublethal endpoints: induction of hepatic mixed function oxygenase activity and reduction of sex steroid concentrations. These laboratory assays have been used to assess whole effluents, specific chemicals, and components of pulp mill processes, and to discriminate between historical and present-day effluent discharges. These tests have shown that induction of mixed-function oxygenase activity and reduction of sex steroid concentrations are produced by effluents from a variety of mill types, with and without chlorine bleaching, in hardwood and softwood pulping facilities, and before and after effluent treatment. These short-term bioassays have enabled reductions in sex steroid concentrations to be linked to mill process streams, and have provided information on effective waste stream treatment. Longer term, life-cycle fish bioassays have shown that chronic exposure to pulp mill effluents commonly results in growth enhancement, liver enlargement, and decreases in gonad size, secondary sex characteristics, and fecundity. These long-term laboratory exposures are able to mimic the most commonly observed alterations of wild fish exposed to pulp mill effluents: increases in condition factors, increases in liver-somatic indices, and decreases in gonadosomatic indices. This pattern of response is a combination of nutrient enrichment with metabolic disruption. The most sensitive and biologically meaningful endpoint is decreased reproduction in fish life-cycle exposures. As the laboratory tests move forward into the next decade, attention will focus on the reproductive endpoints and on the possibility of shortening the fish bioassays while still maintaining sensitivity and biological relevance.

Drip-feed bioreactor for the treatment of concentrated wastes with minimal dilution

Avoiding substrate inhibition is a significant challenge in designing biological treatment systems for concentrated or toxic wastes. Substrate inhibition is commonly avoided by diluting the waste before treatment, however, dilution of a waste before treatment is not always feasible. In the case of radioactive mixed wastes and chemical warfare materiel (CWM), dilution presents regulatory and safety concerns. In this study, we investigated a “drip-feed” reactor configuration as an alternative approach for the biological treatment of concentrated waste streams with minimal dilution and complete containment. In the drip-feed reactor undiluted waste is slowly fed to biomass in a reactor at a rate sufficient to maintain activity, but at a low enough rate so that bacterial degradation maintains the reactor concentration below the toxic threshold. The reactor has no effluent, but rather fills as the undiluted waste is fed to the reactor, which has the advantage of preventing the release of hazardous material into the environment during treatment. Volatile releases are prevented with the use of condensers. The drip-feed bioreactor configuration was tested under aerobic conditions, at 25 °C, using a 10% acetonitrile feed solution. The treatment of acetonitrile to less than 0.1 mg l −1 was achieved with a dilution factor of only 3.4. The acetonitrile degradation reaction was pH sensitive, where the optimal pH range for the biodegradation process was approximately between 6.5 and 7.1 and the biodegradation rate declined precipitously above pH 7.2. The applicability of the drip-feed reactor configuration to the treatment of mixed wastes and CWM is discussed.

Characterization of fuel gas products from the treatment of solid waste streams with a plasma arc torch

This work addresses the plasma treatment of two solid waste streams and production of fuel gases from the process. In this study, carpet waste and simulated solid wastes generated by a United States Air Force Basic Expeditionary Airfield Resources Base deployment were used. Waste was treated in a furnace fitted with a 100 kW plasma arc torch. The off gas was analyzed to determine its composition. The product gas was composed primarily of carbon monoxide and hydrogen, with small amounts of methane, benzene and toluene also detected. These experiments demonstrate the feasibility of producing fuel gases by plasma treatment of the solid waste streams. While the thermal energy value of the fuel gas produced in these experiments was less than the energy input, a higher waste-to-fuel gas conversion efficiency is expected in full-scale application.

Degradation of 1-butanol by solvent-tolerant Enterobacter sp. VKGH12

Abstract Biodegradation of solution-phase 1-butanol by solvent-tolerant Enterobacter sp. VKGH12 (NCIM 5221), which utilizes 1-butanol as its sole source of carbon and energy, was investigated. At an initial loading of 0.4% and 0.8% (v/v) 1-butanol, freely suspended cells degraded 76% and 26%, whereas calcium alginate-immobilized cells degraded 96% and 92% 1-butanol, respectively, in batch cultures. At these loadings, alginate-immobilized cells could be reused for 10 and 7 cycles, respectively, without significant loss in degradation efficiency. A packed-bed reactor containing immobilized cells efficiently degraded 1-butanol at a flow rate of 25–75 ml h −1 at an initial loading of 0.4% (v/v), and could be continuously operated for 10 days at an influent concentration of 0.4% (v/v) 1-butanol without a loss in degradation efficiency. The results suggest the application of immobilized solvent-tolerant bacterium in treatment of solvent waste streams.

Pyrolysis of waste using a hybrid argon–water stabilized torch

An experimental plasmachemical reactor equipped with the novel IPP-ASCR hybrid gas–water stabilized DC torch (160 kW) has recently been started at IPP Prague for the innovative and environmentally friendly plasma treatment of waste streams with a view to their sustainable energetic and chemical valorization and to a reduction of the emission of greenhouse gases. Since the process energy is provided by direct heat transfer from plasma, gases of widely varying chemical composition may be used. The use of electrical energy also reduces the gas flows and requirements for exhaust-gas treatment, and offers control over the chemistry. Pyrolysis of biomass was experimentally studied using wood chips as a model substance. Syngas with a high content of hydrogen and CO was produced. The influence of adding CO 2 for increase of oxygen content in the reactor was investigated.