Environmental Progress 

About: Environmental Progress is an academic journal. The journal publishes majorly in the area(s): Adsorption & Wastewater. It has an ISSN identifier of 0278-4491. Over the lifetime, 3636 publications have been published receiving 51975 citations.

The glycerin glut: Options for the value‐added conversion of crude glycerol resulting from biodiesel production

Abstract: Dramatic increases in the price of crude oil, and consequently, transportation fuels, coupled with increased environmental concerns have resulted in rapid growth in biodiesel production, both in the United States and worldwide. As biodiesel production increases, so does production of the primary coproduct, glycerol. Since the existing glycerol supply and demand market was tight, recent increases in glycerol production from biodiesel refining has created a glut in the glycerol market. As a result, the price of glycerol has fallen significantly and biodiesel refiners are faced with limited options for managing the glycerol by-product, which in the biodiesel industry, has essentially become a waste stream. This article is a review of promising options for both the catalytic and biological conversion of glycerol into various value-added products, many of which are bio-based alternatives to petroleum-derived chemicals. © 2007 American Institute of Chemical Engineers Environ Prog, 26: 338–348, 2007

A review of pressure‐driven membrane processes in wastewater treatment and drinking water production

Abstract: In pressure-driven membrane processes (reverse osmosis, nanofiltration, ultrafiltration, and microfiltration) a pressure exerted on the solution at one side of the membrane serves as a driving force to separate it into a permeate and a retentate. The permeate is usually pure water, whereas the retentate is a concentrated solution that must be disposed of or treated by other methods. Membranes may be polymeric, organo-mineral, ceramic, or metallic, and filtration techniques differ in pore size, from dense (no pores) to porous membranes. Depending on the type of technique, salts, small organic molecules, macromolecules, or particles can be retained, and the applied pressure will differ. This paper reviews the principles behind the different techniques, the types of membranes used, rejection mechanisms, and process modeling. Applications of pressure-driven membrane processes are also considered, including reverse osmosis and nanofiltration for the treatment of wastewater from landfills and composting plants, nanofiltration in the textile industry, and ultrafiltration and microfiltration in drinking water production and wastewater treatment. Lastly, the paper discusses recent developments, including techniques to prevent membrane fouling by modifications affecting surface roughness or hydrophilicity/hydrophobicity, or by cleaning the membranes, and methods for treating or disposing of the retentate.

Characterization of biochar from fast pyrolysis and gasification systems

Abstract: Thermochemical processing of biomass produces a solid product containing char (mostly carbon) and ash. This char can be combusted for heat and power, gasified, activated for adsorption applications, or applied to soils as a soil amendment and carbon sequestration agent. The most advantageous use of a given char depends on its physical and chemical characteristics, although the relationship of char properties to these applications is not well understood. Chars from fast pyrolysis and gasification of switchgrass and corn stover were characterized by proximate analysis, CHNS elemental analysis, Brunauer-Emmet-Teller (BET) surface area, particle density, higher heating value (HHV), scanning electron microscopy, X-ray fluorescence ash content analysis, Fourier transform infrared spectroscopy using a photo-acoustic detector (FTIR-PAS), and quantitative 13C nuclear magnetic resonance spectroscopy (NMR) using direct polarization and magic angle spinning. Chars from the same feedstocks produced under slow pyrolysis conditions, and a commercial hardwood charcoal, were also characterized. Switchgrass and corn stover chars were found to have high ash content (32–55 wt %), much of which was silica. BET surface areas were low (7–50 m2/g) and HHVs ranged from 13 to 21 kJ/kg. The aromaticities from NMR, ranging between 81 and 94%, appeared to increase with reaction time. A pronounced decrease in aromatic CH functionality between slow pyrolysis and gasification chars was observed in NMR and FTIR-PAS spectra. NMR estimates of fused aromatic ring cluster size showed fast and slow pyrolysis chars to be similar (∼7–8 rings per cluster), while higher-temperature gasification char was much more condensed (∼17 rings per cluster). © 2009 American Institute of Chemical Engineers Environ Prog, 2009

Integration of chemical and biological oxidation processes for water treatment: Review and recommendations

Abstract: The literature of studies which used a combination of chemical and biological degradation (usually oxidative) of organic contaminants in water is reviewed. Beneficial effects of such two-step treatments are commonly reported; these results, primarily from laboratory studies, suggest potential advantages for water treatment via process integration rather than single technology processing. Four wastewater contaminant types are identified which can benefit from combined processes: 1.) recalcitrant compounds 2.) biodegradable wastes with small amounts of recalcitrant compounds 3.) inhibitory compounds and 4.) intermediate dead-end products. The design key for such two-step systems lies in choosing processes that complement each other and lead to a synergistic effect. Predicting this performance outcome requires knowledge of the physical, chemical and biological properties of the major reaction intermediates and their susceptibility to degradation by each process. Economic, physical and technological limitations of the individual processes should be recognized for design of more effective and economical integrated processes. The ultimate treatment goal, whether specific pollutant removal or reduction of a global parameter such as TOC, must be known so that appropriate and complementary processes can be utilized. More work is needed concerning the degradation kinetics within the combined process, from initial attack of the primary compound through dynamics of intermediates and on to total mineralization.

Thermal pretreatment of lignocellulosic biomass

Abstract: Torrefaction is a process to convert diverse lignocellulosic biomass feedstocks into an energy dense homogeneous solid, a pretreatment for subsequent thermochemical conversion. Loblolly pine was treated by wet torrefaction (hot compressed water, 200–260°C) and dry torrefaction (nitrogen, 250–300°C), with mass yield of solid product ranging between 57 and 89%, and energy densification to 108–136% of the original feedstock. The solid product has been characterized, including proximate analysis, fiber analysis, ultimate analysis, and equilibrium moisture. In both dry and wet torrefaction, increasing temperature results in decreased mass yield and increased energy densification, and results in a solid with increased carbon content, decreased oxygen content, and decreased volatiles. The biomass is transformed into a fuel similar to a low-rank coal. Generally, the wet torrefaction process produces a solid with greater energy density than dry torrefaction, with the same mass yield. The fiber analysis indicates that hemicellulose is quickly removed during wet torrefaction, and the solid product contains substantial quantities of aqueous soluble compounds. The equilibrium moisture content of solids produced by both processes is somewhat decreased from that of the biomass feedstock, indicating a hydrophobic solid suitable for storage and transportation. © 2009 American Institute of Chemical Engineers Environ Prog, 2009