Fate of coliforms and pathogenic parasite in four full-scale sewage treatment systems in India

Global positioning systems (GPS) are increasingly being used for habitat mapping because they provide spatially referenced data that can be used to characterize habitat structure across the landscape and document habitat change over time. We evaluated the accuracy of using a GPS for determining the size and location of habitat patches in a riverine environment. We simulated error attributable to a mapping-grade GPS receiver capable of achieving sub-meter accuracy onto discrete macrophyte bed and wood habitat patches (2 to 177 m(2)) that were digitized from an aerial photograph of the Laramie River, Wyoming, USA in a way that emulated field mapping. Patches with simulated error were compared to the original digitized patches. The accuracy in measuring habitat patches was affected most by patch size and less by patch shape and complexity. Perimeter length was consistently overestimated but was less biased for large, elongate patches with complex shapes. Patch area was slightly overestimated for small patches but was unbiased for large patches. Precision of area estimates was highest for large (>100 m(2)), elongate patches. Percent spatial overlap, a measure of the spatial accuracy of patch location, was low and variable for the smallest patches (2 to 5 m(2)). Mean percent spatial overlap was not related to patch shape but the precision of overlap was lower for small, elongate, and complex patches. Mapping habitat patches with a mapping-grade GPS can yield useful data, but research objectives will determine the acceptable amount of error and the smallest habitats that can be reliably measured.     

Source evaluation of physicochemically contaminated groundwater of Dera Ismail Khan area, Pakistan

Groundwater samples collected from Dera Ismail Khan, Pakistan, in 15 different stations were analyzed to determine the status of concentration of different physicochemical parameters. The samples were collected around a sugar mill in the study area. Sample location was selected on the basis of the flow of sugar mill effluents and groundwater. The samples were collected at random intervals in different villages. The physicochemical parameters such as pH, electrical conductivity (EC), total dissolved salts (TDS), TH, HCO₃, NO₃, SO₄, PO₄, Na, K, Ca, Mg, Fe, F, and Pb have been analyzed. The results showed that values of the tested parameters for EC, TDS, TH, HCO₃, SO₄, and Na near the sugar mill were very high, which indicate the descent of standard norms of quality and protection procedures for the groundwater around this area.     

Composite use of numerical groundwater flow modeling and geoinformatics techniques for monitoring Indus Basin aquifer, Pakistan

The integration of the Geographic Information System (GIS) with groundwater modeling and satellite remote sensing capabilities has provided an efficient way of analyzing and monitoring groundwater behavior and its associated land conditions. A 3-dimensional finite element model (Feflow) has been used for regional groundwater flow modeling of Upper Chaj Doab in Indus Basin, Pakistan. The approach of using GIS techniques that partially fulfill the data requirements and define the parameters of existing hydrologic models was adopted. The numerical groundwater flow model is developed to configure the groundwater equipotential surface, hydraulic head gradient, and estimation of the groundwater budget of the aquifer. GIS is used for spatial database development, integration with a remote sensing, and numerical groundwater flow modeling capabilities. The thematic layers of soils, land use, hydrology, infrastructure, and climate were developed using GIS. The Arcview GIS software is used as additive tool to develop supportive data for numerical groundwater flow modeling and integration and presentation of image processing and modeling results. The groundwater flow model was calibrated to simulate future changes in piezometric heads from the period 2006 to 2020. Different scenarios were developed to study the impact of extreme climatic conditions (drought/flood) and variable groundwater abstraction on the regional groundwater system. The model results indicated a significant response in watertable due to external influential factors. The developed model provides an effective tool for evaluating better management options for monitoring future groundwater development in the study area.     

Effect of Nutrient Management Planning on Crop Yield, Nitrate Leaching and Sediment Loading in Thomas Brook Watershed

Government priorities on provincial Nutrient Management Planning (NMP) programs include improving the program effectiveness for environmental quality protection, and promoting more widespread adoption. Understanding the effect of NMP on both crop yield and key water-quality parameters in agricultural watersheds requires a comprehensive evaluation that takes into consideration important NMP attributes and location-specific farming conditions. This study applied the Soil and Water Assessment Tool (SWAT) to investigate the effects of crop and rotation sequence, tillage type, and nutrient N application rate on crop yield and the associated groundwater ${\text{NO}_{3}}^{ - } {\text{-N }}$ leaching and sediment loss. The SWAT model was applied to the Thomas Brook Watershed, located in the most intensively managed agricultural region of Nova Scotia, Canada. Cropping systems evaluated included seven fertilizer application rates and two tillage systems (i.e., conventional tillage and no-till). The analysis reflected cropping systems commonly managed by farmers in the Annapolis Valley region, including grain corn-based and potato-based cropping systems, and a vegetable-horticulture system. ANOVA models were developed and used to assess the effects of crop management choices on crop yield and two water-quality parameters (i.e., ${\text{NO}_{3}}^{ - } {\text{-N }}$ leaching and sediment loading). Results suggest that existing recommended N-fertilizer rate can be reduced by 10–25 %, for grain crop production, to significantly lower ${\text{NO}_{3}}^{ - } {\text{-N }}$ leaching (P > 0.05) while optimizing the crop yield. The analysis identified the nutrient N rates in combination with specific crops and rotation systems that can be used to manage ${\text{NO}_{3}}^{ - } {\text{-N }}$ leaching while balancing impacts on crop yields within the watershed.     

Bioreactor systems for thermophilic fermentative hydrogen production: evaluation and comparison of appropriate systems

Numerous different bioreactor systems are applied for hydrogen production by dark fermentation. Thermophilic fermentations are gaining an increased interest due to the high hydrogen yields associated with them. In order to reach the best thermophilic fermentation system, 2 types of bioreactors, a trickling bed and a fluidized bed system, were constructed and operated under similar conditions. Both systems were designed to meet the requirements of thermophilic fermentations, such as reduction of hydrogen partial pressure, system immanence as its best as well as increasing cell densities. For comparing the 2 systems, the extreme thermophilic organism Caldicellulosiruptor owensensis OL^T and a glucose-containing medium were employed. Parameters like hydraulic retention time, glucose concentration and stripping gas amount were varied. Each bioreactor system exhibited certain advantages; the trickling bed system enabled yields close to 3 mol-H₂ (mol-glucose)^?1 and productivities of 0.2 L L^?1 h^?1, but the application of stripping gas seemed to be obligatory. The fermentations in the fluidized bed system were characterized by slightly higher productivities (0.25 L L^?1 h^?1), but generally lower yields. However, operation of this system without stripping gas was possible.     

An equal sex ratio followed by differential sex mortality causes overestimation of females in gall midges: no evidence for sex ratio regulation

Monogeny, the production of unisexual broods by individual females, has been recognized for nearly 80?years. The genetic nature of gall midges' sex determination predicts an equal numbers of male-producing and female-producing females in the populations such that the overall sex ratio is expected to be nearly 1:1. However, observations of some strictly monogenous populations with biased sex ratio, mainly toward females, have raised the question of whether gall midges are able to adjust their offspring sex ratio in response to changes in environmental conditions, and some authors have even considered sex ratio regulation as a strong force in the course of the evolution of monogeny. In this paper, first, by studying the sex ratio variations of the predatory gall midge, Aphidoletes aphidimyza within a generation, we showed that adult males emerge up to 1?day earlier and have shorter life span than females (less than 4?days and up to 6?days, respectively). Although, the sex ratio of A. aphidimyza at the time of emergence was nearly 1:1 (52.41?% males), a simple population simulation indicated that the differential mortality of sexes can lead to a female-biased sex ratio estimation (57.88?% females) under random sampling in the natural environments. Our results imply that the primary sex ratio of monogenous gall midges is nearly 1:1 and that the arrhenogenic/thelygenic gall midges are not able to alter the number of their male/female progenies in response to changes in environmental conditions.     

Stand-alone PV-hydrogen energy system in Taleghan-Iran using HOMER software: optimization and techno-economic analysis

One of the most attractive features of hydrogen as an energy carrier is that it can be produced from water. Hydrogen has the highest energy content per unit mass as compared to chemical fuel and can be substituted. Its burning process is non-polluting, and it can be used in the fuel cells to produce both electricity and useful heat. Photovoltaic arrays can be used in supplying the water electrolysis systems by their energy requirements. During the daylight hours, the sunlight on the photovoltaic array converts into electrical energy which can be used for electrolyzer. The hydrogen produced by the electrolyzer is compressed and stored in hydrogen vessel and provides energy for the fuel cell to meet the load when the solar energy is insufficient. This study investigates a stand-alone power system that consists of PV array as power supply and electrolyzer. They have been integrated and worked at the Taleghan renewable energies’ site in Iran. The National Renewable Energy Laboratory’s Hybrid Optimization Model for Electric Renewables simulation software has been used to carry out the optimal design and techno-economic viability of the energy system. The simulation results demonstrate that energy system is composed of 10-kW PV array, 3.5-kW electrolyzer, 0.4-kW proton exchange membrane fuel cell, 2.5-kW inverter, and 60 batteries (100 Ah and 12 V). The total initial capital cost, net present cost, and cost of electricity produced from this energy system are 193,563 US$, 237,509 US$, and 3.35 US$/kWh, respectively.     

Identifying impact of international trade and renewable energy consumption on environmental quality improvement and their role in global warming

There is a lack of proper research that highlights the impact of institutional quality (IQ) and renewable energy consumption (REC) on the carbon emission (CE). The significance of IQ and REC in the achievement of zero CE is highlighted in this research. The current research reports the effects of these important factors on the consumption-based carbon emissions in the G-7 countries from 1995 to 2018. Based on the outcome of the cointegration test, the long-run connection is recognized between IQ, REC, GDP, exports, imports, and consumption-based CE. The findings also validated that there exist significant decrease and increase in the CE in both the short and long run; for instance, IQ, REC, and exports decrease the CE, while imports and GDP increase the CE. The estimates of causality test showed that policies aimed at improving IQ, REC, GDP, exports, and imports have a significant impact on the CE. Consequently, based on these results, policymakers in the G-7 must prioritize IQ and REC to enhance environmental quality and attain carbon neutrality.