Search results for "Waste management"
showing 10 items of 1526 documents
Spoilage of oat bran by sporogenic microorganisms revived from soil buried 4000 years ago in Iranian archaeological site
2015
Abstract The Bronze Age archaeological site of Shahr-i Sokhta (30° 39′ N; 61° 24’ E), located today in southeastern Iran, Sistan region, is a special archaeological deposit in which the exceptional preservation of human, plant and animal remains, due to the dry climate of the region, can provide detailed information on one of the first complex proto-urban societies. In recent years, there has been growing interest in changes in local climate and environment as major reasons why the settlement was abandoned about 4000 years ago. Food shortage has been regarded as a direct effect of these changes. No attention has been paid to the potential health hazards associated with ancient urban/domesti…
Bacterial Bioconversion of Primary Aliphatic and Aromatic Alcohols into Acids: Effects of Molecular Structure and Physico-chemical Conditions
1997
The biotransformation of four alcohol substrates (butanol, 2-methylbutanol, 3-methylbutanol and 2-phenylethanol) into their acids was studied using a strain of Acetobacter aceti. Bioconversion yields depended on the molecular structure of the alcohol. Biotransformation of high concentrations of alcohols was possible until the precursor reached an inhibiting concentration (3.8 g dm -3 for butanol and 3-methylbutanol, 4.2 g dm -3 for 2-methylbutanol). In contrast, biotransformation of 2-phenylethanol decreased when alcohol concentration was higher than 0.3 g dm -3 . Dissolved oxygen concentrations and pH conditions of the medium were important factors in improving bioconversion. Transformatio…
Optimization of alkali pretreatment to enhance rice straw conversion to butanol
2021
Abstract The use of rice straw (RS) was enhanced to produce biobutanol as biofuel, for which the NaOH pretreatment was optimized by considering the butanol-biomass ratio that quantify the mass balance efficiency of the three sequential stages of the process: pretreatment, enzymatic hydrolysis and fermentation by Clostridium beijerinckii. The optimum point (solid loading of 5% w/v with 0.75% w/v NaOH at 134 °C for 20 min) of the best cost-wise option yielded an enhanced biomass use of 77.6 g kg RS−1. A maximum butanol titer of 10.1 g L−1 was reached after 72 h of fermentation with the complete uptake of glucose and nearly complete uptake of xylose. The NaOH concentration was the most influen…
Organics in soda-anthraquinone black liquors from hot-water-extracted non-wood feedstocks
2019
The chemical compositions of black liquors (BLs) obtained from the soda-anthraquinone (AQ) pulping of untreated and hot-water-extracted non-wood feedstocks (okra stalk, miscanthus stalk, and wheat straw) were determined. These under-utilized renewable and widely available feedstocks could provide a cheaper source for producing fiber and precursors for manufacturing green chemicals. These BLs were mainly characterized in terms of carbohydrate-derived volatile carboxylic acids (acetic and formic acids) and non-volatile carboxylic acids (hydroxy acids) as well as lignin. Additionally, in each case, the average molar mass and molar mass distribution of the dissolved lignin were measured. Result…
Detection and prevention of enhanced biological phosphorus removal deterioration caused by Zoogloea overabundance.
2008
A sequencing batch reactor was operated in the conventional anaerobic-aerobic mode for enhanced biological phosphorus removal using acetate as the sole substrate. Despite the nutrients concentrations in the influent being high enough to satisfy the biological requirements, Zoogloea ramigera managed to grow in the system until it had negative effects on the process performance. The excess of exocellular polymeric material produced by this microorganism contributed to a viscous bulking phenomenon and caused important settling problems. The examination of the sludge under the microscope was a valuable tool to diagnose the cause of the imbalance in the process. The strategy adopted to avoid the…
Economic and Environmental Assessment of Biomass Power Plants in Southern Italy
2022
In 2019, Europe adopted the New Green Deal as a strategic plan to become a competitive, resource-efficient, and driven economy by reducing its gas emissions and carbon footprint. Due the COVID-19 pandemic, this strategic plan was recently updated to expedite the green transition of European industries. Therefore, the present paper deals with the problem of deciding an appropriate size for a biomass plant that directly produces electric energy by means of two different conversion processes: combustion and gasification. After an initial estimation of the energy potential in western Sicily, GIS data of biomass growth were used to identify the appropriate size for the power plants under investi…
The socio-economic and communication challenges of spent nuclear fuel management in Finland
2010
Abstract One of the key factors behind the expansion of nuclear energy policy in Finland is nuclear waste management. As in many countries, nuclear waste management agencies are still struggling with the siting of intermediate and low level nuclear waste management facilities, in Finland Posiva, the nuclear waste company owned by the two nuclear power utilities Teollisuuden Voima (TVO) and Fortum Power and Heat (FPH), has been excavating a underground characterization facility since 2004 in the Olkiluoto site in the municipality of Eurajoki. The facility under construction is meant to be for a part of the final repository for disposal of spent nuclear fuel (SNF). The site selection process …
Occupational hygiene in a Finnish drum composting plant
2005
Bioaerosols (microbes, dust and endotoxins) and volatile organic compounds (VOCs) were determined in the working air of a drum composting plant treating source-separated catering waste. Different composting activities at the Oulu drum composting plant take place in their own units separated by modular design and constructions. Important implication of this is that the control room is a relatively clean working environment and the risk of exposure to harmful factors is low. However, the number of viable airborne microbes was high both in the biowaste receiving hall and in the drum composting hall. The concentration (geometric average) of total microbes was 21.8 million pcs/m3 in the biowaste…
Modeling of 137Cs migration in soils using an 80-year soil archive: role of fertilizers and agricultural amendments
2008
An 80-year soil archive, the 42-plot experimental design at the INRA in Versailles (France), is used here to study long-term contamination by 137Cs atmospheric deposition and the fate of this radioisotope when associated with various agricultural practices: fallow land, KCl, NH4(NO3), superphosphate fertilizers, horse manure and lime amendments. The pertinence of a simple box model, where radiocaesium is supposed to move downward by convectional mechanisms, is checked using samples from control plots which had been neither amended, nor cultivated since 1928. This simple model presents the advantage of depending on only two parameters: α, a proportional factor allowing the historical atmosph…
Carbohydrates as Chemical Constituents of Biowaste Composts and their Humic and Fulvic Acids
1995
The decomposition of organic matter of source-separated biowaste during composting was followed during 18 months. Compost samples were fractionated into three parts: (i) hot water soluble extract (HWE) (ii) bitumen fraction and (iii) humic substances (humic acids (HA) and fulvic acids (FA)). Original compost samples and the HA and FA fractions were hydrolyzed with sulfuric acid for hexoses and pentoses. Quantitative spectrophotometric and qualitative GC/MS analyses of monosaccharides as trimethylsilyl ethers of the corresponding alditols were carried out.During composting, the amount of HA in the organic matter of the compost increased, the amounts of HWE and bitumen decreased and the amoun…