Optimization of control parameters for petroleum waste composting

Composting is being widely employed in the treatment of petroleum waste. The purpose of this study was to find the optimum control parameters for petroleum waste in-vessel composting. Various physical and chemical parameters were monitored to evaluate their influence on the microbial communities present in composting. The CO2 evolution and the number of microorganisms were measured as the activity of composting. The results demonstrated that the optimum temperature, pH and moisture content were 56.5 - 59.5 degreesC, 7.0 - 8.5 and 55 % - 60%, respectively. Under the optimum conditions, the removal efficiency of petroleum hydrocarbon reached 83.29% after 30 days composting.

Heavy metal concentrations in edible bivalves and gastropods available in major markets of the Pearl River Delta

Molluscs are able to accumulate heavy metals and impose health hazard to consumers. The main objective of the present study is to investigate the heavy metal concentrations in edible bivalves and gastropods available in major markets of the Pearl River Delta. Fourteen species of edible molluscs were purchased from six markets in Hong Kong and Guangdong Province. The fresh of these biota were tested for their cadmium (Cd), copper (Cu), zinc (Zn), lead (Pb), nickel (Ni), chromium (Cr), antimony (Sb) and tin (Sn) concentrations (based on wet weight). The results indicated that amongst the 14 edible molluscs, only Cd, Pb, Ni, Cr, Sb and Sn concentrations in three species (Ruditapes philippinarum, Perna viridis and Hemifusus tuba) were within the local regulatory limits. Over 60% of bivalve species exceeded maximum permitted levels of Cd (2 mug/g) and Cr (1 mug/g), while over 40% of gastropod species exceeded the maximum levels of Sb (1 mug/g) and Cr (1 mug/g). Most of the samples collected from Hong Kong had significantly higher contents of Pb and Sb, but similar levels of Cd, Cu and Zn when compared with samples collected across the border ( p < 0.05; p 0.01; p < 0.001 respectively). In general, the molluscs purchased in Guangdong markets had higher metal contents than those purchased from the Hong Kong markets. When compared with the Provisional Tolerable Weekly Intake or Maximum Acceptable Daily Load recommended by FAO/WHO Expert Committee on Food Additives, Cd levels of five species (Anadara ferruginea, Pinna pectinata, Chlamys nobilis, Babylonia lutosa and Hemifusus terntanus) and Cr levels of seven species ( Anadara ferruginea, Paphia undulata, Pinna pectinata, Babylonia lutosa, Hemifusus terntanus, Cymbium melo and Cipangopaludina chinensis) were higher than both the human daily acceptable limits (for Cd and Cr respectively) and the local regulatory levels (for Cd and Cr respectively).

Assessing Agricultural Sustainable Development Based on the DPSIR Approach: Case Study in Jiangsu, China

According to the contemporary ecosystem approach, the linkages of human actions with their environment have to be assessed in an integrative manner. The Driver-Pressure-State-Impact-Response （DPSIR） model is applied to identify and describe processes and interactions in human-environmental systems. An example application from a research project dealing with the development of sustainable management strategies for the agriculture in Jiangsu, China, illustrates the potentials and limitations of its sustainable development. The concept and indicators of ecological integrity are used to assess the indicators in the dimensions of DPSIR between 2003 and 2006. The main drivers included population growth which caused increasing demand for food, growing environmental demands, and rapidly decreasing of land and other natural resources. The main environmental problem was water pollution. The results show that in the dimension of driver, total grain output and agricultural land productivity both increased. Labor intensive agriculture has been promoted to increase agricultural land productivity. In the dimension of pressure, on the positive side, infrastructure got greatly improved, the input level such as total power of machinery, and level of fertilizer use increased, and level of pesticides use decreased, but on the negative side, cultivated land per capita and irrigation rate decreased, natural resources keep decreased. Environmental pollution indicators such as industrial wastewater discharge and acid rain rate increased in Jiangsu Province. In the aspect of state, ecosystem state was improved, plant coverage index increased, biological abundance index increased, fertilizer productivity increased, eco-environmental quality index increased, but land degradation index also increased. In the aspect of impact, output level increased, output efficiency enhanced, farmer＇s social economic benefit improved. In the aspect of response, social support was greatly improved, input for environmental governance increased. To assess the effects of environmental governance, Jiangsu government was successful to increase compliance rate of sulfur dioxide emissions, but not so efficient in compliance rate of industrial wastewater discharge.

Integrating water use systems and soil and water conservation measures into a hydrological model of an Iranian Wadi system

Water resources are precious in arid and semi-arid areas such as the Wadis of Iran. To sustainably manage these limited water resources, the residents of the Iranian Wadis have been traditionally using several water use systems(WUSs) which affect natural hydrological processes. In this study, WUSs and soil and water conservation measures(SWCMs) were integrated in a hydrological model of the Halilrood Basin in Iran. The Soil and Water Assessment Tool(SWAT) model was used to simulate the hydrological processes between 1993 and 2009 at daily time scale. To assess the importance of WUSs and SWCMs, we compared a model setup without WUSs and SWCMs(Default model) with a model setup with WUSs and SWCMs(WUS-SWCM model). When compared to the observed daily stream flow, the number of acceptable calibration runs as defined by the performance thresholds(Nash-Sutcliffe efficiency(NSE)≥0.68, –25%≤percent bias(PBIAS)≤25% and ratio of standard deviation(RSR)≤0.56) is 177 for the Default model and 1945 for the WUS-SWCM model. Also, the average Kling–Gupta efficiency(KGE) of acceptable calibration runs for the WUS-SWCM model is higher in both calibration and validation periods. When WUSs and SWCMs are implemented, surface runoff(between 30% and 99%) and water yield(between 0 and 18%) decreased in all sub-basins. Moreover, SWCMs lead to a higher contribution of groundwater flow to the channel and compensate for the extracted water by WUSs from the shallow aquifer. In summary, implementing WUSs and SWCMs in the SWAT model enhances model plausibility significantly.

Evolutionary Mode of Metallothioneins Inferred from Cd-MT Genes of Tetrahymena

From Tetrahymena thermophila （strain BF5）, the coding region of Cd-MT gene was cloned and sequenced. and identified as MTT1 isoform. A serial duplicate structure is discovered in its amino acid sequence, which separates the coding region into three parts （Part 1：7-61; Part 2：64-118; Part 3：122-162）. The alignments among them and comparison with the corresponding parts of MT1 isoform suggest that MT1 and MTT1 isoforms both come from the same ancient gene that is homologous to Part 1, and Cd-MTs of Tetrahymena are aroused by such ancient gene duplication. The prediction of secondary structures and the analysis of the disulfide-bonding state of cysteine show that there are a lot of differences between MT1 and MTT1 isoforms, which maybe relate to their function mechanism.

Identifying the most important spatially distributed variables for explaining land use patterns in a rural lowland catchment in Germany

Land use patterns arise from interactive processes between the physical environment and anthropogenic activities. While land use patterns and the associated explanatory variables have often been analyzed on the large scale, this study aims to determine the most important variables for explaining land use patterns in the 50 km2 catchment of the Kielstau, Germany, which is dominated by agricultural land use. A set of spatially distributed variables including topography, soil properties, socioeconomic variables, and landscape indices are exploited to set up logistic regression models for the land use map of 2017 with detailed agricultural classes. Spatial validation indicates a reasonable performance as the relative operating characteristic (ROC) ranges between 0.73 and 0.97 for all land use classes except for corn (ROC = 0.68). The robustness of the models in time is confirmed by the temporal validation for which the ROC values are on the same level (maximum deviation 0.1). Non-agricultural land use is generally better explained than agricultural land use. The most important variables are the share of drained area, distance to protected areas, population density, and patch fractal dimension. These variables can either be linked to agriculture or the river course of the Kielstau.

Wind farm potential is higher in prime habitat for uncommon soil crust lichens

Introduction:Biotic soil crust communities contribute valuable ecosystem services and biodiversity in steppe ecosystems.The uncommon crust lichens Acarospora schleicheri,Fuscopannaria cyanolepra,Rhizocarpon diploschistidina,and Texosporium sancti-jacobi are associated with fine-textured soils along rivers of the Columbia Basin.A.schleicheri and R.diploschistidina indicate late-successional habitat and may serve as indicators for other rare or cryptic species associated with similar habitats.Much of the most favorable habitat for these species has been lost to urban and agricultural development.We sought to overlay favorable habitats with wind farm development potential to assess whether these species are likely to be affected by renewable energy development.Methods:We overlaid habitat models for four lichen species on land use and wind farm potential maps.Using a sample of 5,000 points,we determined whether there were differences in probability of occurrence among wind farm potential classes within developed and natural lands using Multi-Response Permutation Procedures.Sites with modeled probability of occurrence greater than 60%were considered“favorable”habitats;for these,aχ2 test allowed us to determine whether favorable habitats were associated with wind farm potential categories.Results:Sites that are developed for agriculture or have higher wind farm potential coincide with more favorable habitats for uncommon soil crust lichens.Of the favorable habitats for the four focal lichens,28–42%are already affected by development or agriculture;5–14%of favorable habitats remain in natural vegetation and are considered sites with fair or good potential for wind farms.Conclusions:Development of wind energy has the potential to negatively impact uncommon soil crust lichen species because favorable sites coincide with especially good habitat for these species.However,as these renewable energy resources are developed,we have the opportunity to ensure that valuable soil crust functions and diversity are maintained by surveying before construction and planning new facilities such that disturbance to existing habitat is minimized.

Enrichment of hydrogen in product gas from a pilot-scale rice husk updraft gasification system

An updraft gasifier was employed to treat 3 kg of dried rice husk per batch with different types of gasifying agents such as air,steam/air,and air with dolomite catalyst addition at various operating conditions.The H2 content,low heating value,and H2/CO ratio in syngas were compared to determine the most effective solution to enhance the H2 production from rice husk gasification.The presence of dolomite in air gasification produced the highest H2 content in the product gas,up to 15.4 mol%,followed by 7.08 and 3.6 mol%when steam/air and air standalone were used as gasifying agents,respectively.The higher low heating value of syngas 5.1 MJ/Nm3 was observed in catalytic air gasification compared to 3.6 MJ/Nm3 when steam was added.The optimal operation condition was reported at an airflow rate of 3 m3/h and a catalyst mixing ratio of 15%.