Modelling of moisture-dependent aerobic degradation of solid waste

In landfill, high temperature levels come from aerobic reactions inside the waste surface layer. They are known to make anaerobic processes more reliable, by partial removal of easily biodegradable substrates. Aerobic biodegradation of the main components of biodegradable matter (paper and cardboard waste, food and yard waste) is considered. In this paper, two models which take into account the effect of moisture on aerobic biodegradation kinetics are discussed. The first one (Model A) is a simple, first order, substrate-related model, which assumes that substrate hydrolysis is the limiting step of the process. The second one (Model B) is a biomass-dependant model, considering biological growth processes. Respirometric experiments were performed in order to evaluate the efficiency of each model. The biological oxygen demands of shredded paper and cardboard samples and of food and yard waste samples prepared at various initial water contents were measured. These experimental data were used to identify model parameters. Model A, which includes moisture dependency on the maximum amount of biodegraded matter, is relevant for paper and cardboard biodegradation. On the other hand, Model B, including moisture effect on the growth rate of biomass is suitable to describe food and yard waste biodegradation.     

Bipolar charged aerosol agglomeration and collection by a two-zone agglomerator

ＩｎｔｒｏｄｕｃｔｉｏｎＢｅｃａｕｓｅｏｆｔｈｅｌｏｗｅｆｆｉｃｉｅｎｃｙｏｆｔｈｅｅｌｅｃｔｒｏｓｔａｔｉｃｐｒｅｃｉｐｉｔａｔｏｒ (ＥＳＰ)ｆｏｒｃｏｌｌｅｃｔｉｎｇｔｈｅｓｕｂｍｉｃｒｏｎｐａｒｔｉｃｌｅｓ ,ｔｈｅｅｌｅｃｔｒｉｃａｌａｇｇｌｏｍｅｒａｔｉｏｎｍｅｔｈｏｄｈａｓｌｅｄｔｏａｎｉｎｃｒｅａｓｉｎｇｉｎｔｅｒｅｓｔｉｎｒｅｄｕｃｉｎｇｔｈｅｅｍｉｓｓｉｏｎｏｆｔｈｅｆｉｎｅｐａｒｔｉｃｌｅｓ .Ｍａｎｙａｕｔｈｏｒｓｈａｖｅｓｔｕｄｉｅｄｅｌｅｃｔｒｉｃａｌａｇｇｌｏｍｅｒａｔｉ…     

Analysis of microcystins in cyanobacteria blooms and surface water samples from Meiliang Bay,Taihu Lake,China

Taihu Lake is the third largest freshwater lake in China. In recent years, the water pollution of cyanobacteria blooms has become a severe problem in this area. Microcystins (MCs) are an important group of toxic compounds mainly produced by some cyanobacteria species and have both acute and chronic hepatotoxic effects on animals and humans. This paper presents the first data on the identification and detection of MCs in both natural occurring cyanobacteria blooms and surface water samples (0-0.5 m), collected from Meiliang Bay, Taihu Lake, China. A conventional method for extraction and isolation of MCs from cyanobacteria blooms was applied. High-performance liquid chromatography (HPLC) analysis showed that the main toxic component in the cyanobacteria materials was MC-LR. The monoclonal antibody (mAb) against MC-LR produced by hybridoma technique was employed for direct competitive ELISA to detect the concentrations of MCs in bloom and water samples collected in 2001. The results not only revealed the presence of MCs but also temporal variations of MCs levels of three sampling stations in Meiliang Bay in 1 year. It is obvious that the MC contents were relatively higher during warm months and related with the status of eutrophication. Our study indicates the threat associated with MCs in water body of Taihu Lake. To prevent the MCs potential hazard on public health in this area, some necessary measures of monitoring and control of growth of cyanobacteria are urgently needed.     

Identification of soil heavy metal sources from anthropogenic activities and pollution assessment of Fuyang County, China

Understanding regional variations of soil heavy metals and their anthropogenic influence are very important for environmental planning. In this study, 286 surface soil samples were collected in Fuyang county, and the 'total' metals for copper (Cu), zinc (Zn), lead (Pb), cadmium (Cd) and nickel (Ni) were measured in 2005. Statistic analysis showed that Cu, Zn, Pb and Cd had been added by exterior factors, and Ni was mainly controlled by natural factors. The combination of multivariate statistical and geostatistical analysis successfully grouped three groups (Cu, Zn and Pb; Cd; and Ni) of heavy metals from different sources. Through pollution evaluation, it was found that 15.76% of the study area for Cu, Zn and Pb, and 46.14% for Cd suffered from moderate or severe pollution. Further spatial analysis identified the limestone mining activities, paper mills, cement factory and metallurgic activities were the main sources for the concentration of Cu, Zn, Pb and Cd in soils, and soil Ni was mainly determined by the parent materials.     

Inorganic nitrogen metabolism inUlva rigida illuminated with blue light

Inorganic nitrogen metabolism in blue light was studied for the green algaUlva rigida C. Agardh collected in the south of Spain (Punta Carnero, Algeciras) in the winter of 1987. NH₄ ⁺ has been reported to inhibit NO₃ ^- uptake; however,U. rigida showed a net NO₃ ^- uptake even when the NH₄ ⁺ concentration of the external medium was three or four times greater than the concentration of NO₃ ^-. NO₃ ^- uptake rates were similar in both darkness and in blue light of various photon fluence rates (PFR) ranging from 17 to 160 mol m^-2 s^-1. Since NO₃ ^- uptake is an active mechanism involving the consumption of ATP, respiratory metabolism can provide enough ATP to maintain the energetic requirement of NO₃ ^- transport even in darkness. In contrast, NO₃ ^- reduction inU. rigida was highly dependent on the net photosynthetic rate. After 7 h in blue light, intracellular NO₃ ^- concentrations ([NO₃ ^-] _i ) were higher in specimens exposed to intensities below the light compensation point (LCP) than in those incubated at a PFR above the LCP. When PFR is below the light compensation point, NO₃ ^- reduction is low, probably because all the NADH produced by the cells is oxidized in the respiratory chain in order to produce ATP to maintain a steady NO₃ ^- transport rate. The total nitrogen (TN) and carbon (TC) contents decreased from darkness to 33 mol m^-2 s^-1 in blue light. In this range, catabolic processes prevailed over anabolic ones. In contrast, increases in TN and TC contents were observed above the light compensation point. The C : N ratio increased with light intensity, reaching a stable value of 17 at 78 mol m^-2 s^-1 in blue light. Intracellular NO₃ ^- concentration and NO₃ ^- reduction appear to be directly controlled by light intensity. This external control of [NO₃ ^-]_i and the small capacity ofU. rigida to retain incorporated NO₃ ^-, NO₂ ^- and NH₄ ⁺ ions may explain its nitrophilic character.     

Carbon mitigation potential and costs of forestry options in Brazil,China, India,Indonesia, Mexico,the Philippines and Tanzania

This paper summarizes studies of carbon (C) mitigation potential and costs of about 40 forestry options in seven developing countries. Each study uses the same methodological approach – Comprehensive Mitigation Assessment Process (COMAP) – to estimate the above parameters between 2000 and 2030. The approach requires the projection of baseline and mitigation land-use scenarios. Coupled with data on a per ha basis on C sequestration or avoidance, and costs and benefits, it allows the estimation of monetary benefit per Mg C, and the total costs and carbon potential. The results show that about half (3.0 Pg C) the cumulative mitigation potential of 6.2 Petagram (Pg) C between 2000 and 2030 in the seven countries (about 200× 10⁶ Mg C yr^-1) could be achieved at a negative cost and the remainder at costs ranging up to $100 Mg C^-1. About 5 Pg C could be achieved, at a cost less than $20 per Mg C. Negative cost potential indicates that non-carbon revenue is sufficient to offset direct costs of these options. The achievable potential is likely to be smaller, however, due to market, institutional, and sociocultural barriers that can delay or prevent the implementation of the analyzed options.     

Chinese life cycle impact assessment factors

ＩｎｔｒｏｄｕｃｔｉｏｎＬｉｆｅｃｙｃｌｅａｓｓｅｓｓｍｅｎｔ(ＬＣＡ)ｉｓａｎｅｎｖｉｒｏｎｍｅｎｔａｌｍａｎａｇｅｍｅｎｔｔｏｏｌｔｈａｔｉｓｕｓｅｄｔｏｅｘａｍｉｎｅａｎｄｅｖａｌｕａｔｅｔｈｅｅｎｖｉｒｏｎｍｅｎｔａｌｉｍｐａｃｔｓａｓｓｏｃｉａｔｅｄｗｉｔｈｔｈｅｅｘｉｓｔｅｎｃｅｏｆｐｒｏｄｕｃｔｓ(Ｊｅｎｓｅｎ,1998;Ｗｅｉｄｅｍａ,1997;Ｗｅｎｚｅｌ,1997).ＴｈｅｆｏｃｕｓｏｆＬＣＡｉｓｏｎｔｈｅｅｎｔｉｒｅｌｉｆｅｃｙｃｌｅｏｆｔｈｅｐｒｏｄｕｃｔ,ｉ.ｅ.ｆｒｏｍｔｈｅｅｘｔｒａｃｔｉ…     

Reduced-glutathione concentrations in Boleophthalmus pectinirostris tissues exposed to benzo(a)pyrene

ＩｎｔｒｏｄｕｃｔｉｏｎＢｅｉｎｇａｔｙｐｉｃａｌｐｏｌｙｃｙｃｌｉｃａｒｏｍａｔｉｃｈｙｄｒｏｃａｒｂｏｎｓ(ＰＡＨｓ) ,ｂｅｎｚｏ[ａ]ｐｙｒｅｎｅ(ＢａＰ)ｄｅｓｅｒｖｅｓｓｅｒｉｏｕｓｓｔｕｄｙｂｅｃａｕｓｅＰＡＨｓａｒｅｎｏｗｒｅｃｏｇｎｉｚｅｄａｓｍａｊｏｒｅｎｖｉｒｏｎｍｅｎｔａｌｐｏｌｌｕｔａｎｔｓ .ＥｘｐｏｓｕｒｅｔｏＰａＨｓｉｓｖｉｒｔｕａｌｌｙｕｎａｖｏｉｄａｂｌｅａｎｄｉｓｓｔｒｏｎｇｌｙｓｕｓｐｅｎｄｅｄｏｆｂｅｉｎｇａｃａｕｓａｔｉｖｅｆａｃｔｏｒｉｎｃｅｒｔａｉｎｔｕｍｏ…     

Effects of cultivation on N2O emission and seasonal quantitative variations of related microbes in a temperate grassland soil

ＩｎｔｒｏｄｕｃｔｉｏｎＡｔｍｏｓｐｈｅｒｉｃｎｉｔｒｏｕｓｏｘｉｄｅ (Ｎ2 Ｏ)ｉｓａｖｅｒｙｒａｄｉｏａｃｔｉｖｅｌｙａｃｔｉｖｅｇｒｅｅｎｈｏｕｓｅｇａｓ,ａｌｓｏｃｏｎｔｒｉｂｕｔｉｎｇｔｏｔｈｅｄｅｐｌｅｔｉｏｎｏｆｏｚｏｎｅｌａｙｅｒｏｆｓｔｒａｔｏｓｐｈｅｒｅ .ＡｔｍｏｓｐｈｅｒｉｃＮ2 Ｏｍａｉｎｌｙｏｒｉｇｉｎａｔｅｄｆｒｏｍｎｉｔｒｉｆｉｃａｔｉｏｎａｎｄｄｅｎｉｔｒｉｆｉｃａｔｉｏｎｉｎｔｅｒｒｅｓｔｒｉａｌｅｃｏｓｙｓｔｅｍｓ.Ｇｒａｓｓｌａｎｄｅｃｏｓｙｓｔｅｍ ,ａｃｃｏｕｎ…     

Identifying water resources management strategies in adaptation to climate change under uncertainty

In this study, an integrated simulation-based allocation modeling system (ISAMS) is developed for identifying water resources management strategies in response to climate change. The ISAMS incorporates global climate models (GCMs), a semi-distributed land use-based runoff process (SLURP) model, and a multistage interval-stochastic programming (MISP) approach within a general framework. The ISAMS can not only handle uncertainties expressed as probability distributions and interval values but also reveal climate change impacts on water resources allocation under different projections of GCMs. The ISAMS is then applied to the Kaidu-kongque watershed with cold arid characteristics in the Tarim River Basin (the largest inland watershed basin in China) for demonstrating its efficiency. Results reveal that different climate change models corresponding to various projections (e.g., precipitation and temperature) would lead to changed water resources allocation patterns. Variations in water availability and demand due to uncertainties could result in different water allocation targets and shortages. A variety of decision alternatives about water allocations adaptive to climate change are generated under combinations of different global climate models and ecological water release plans. These findings indicate that understanding the uncertainties in water resources system, building adaptive methods for generating sustainable water allocation patterns, and taking actions for mitigating water shortage problems are key adaptation strategies responding to climate change.