Graphical strategies for design of evaporation crystallization networks for environmental wastewater applications

This paper introduces graphical strategies for the design of an evaporation/crystallization network for ternary wastewater environmental applications. Sources, sinks and other streams are located on a ternary composition diagram. While a source is any wastewater stream that has the potential to be recycled, a sink is any unit in the process that can accept sources. The proposed methodology is extremely simple to understand and implement, as it only requires basic solid-liquid phase equilibria data and uses lever arm principles to generate alternative process designs. Geometric constructions are carried out on the ternary composition diagram and the respective lever arms are used to determine intermediate flow rates in the evaporation/crystallization network. The relative locations and flow rates of the sources and sinks under consideration, as well as the unique shape of the solid-liquid equilibrium, drive the design of the separation (via evaporation/crystallization) network. Some generic structures are proposed for a typical evaporation and crystallization network. Once the general problem statement has been defined, special cases consisting of a single source-single sink, single source-two sinks and two sources-single sink are described. These special cases are representative of commonly occurring industrial wastewater design problems. Several graphical insights are listed that allow one to represent evaporation and crystallization operations on a ternary triangular composition diagram and avoid mathematical complexity. The possibility of bypassing a part of the initial feed streams is also considered. Certain feasible composition regions are identified on the ternary composition diagram for cases dealing with multiple sources and sinks. The methodology is useful in pre-screening and eliminating certain sources/sinks and is readily applicable to cases with lower number of sources and sinks. A case study involving the ammonium nitrate manufacturing process is included to demonstrate the broad applicability and value of the proposed approach.     

Genetic, morphological, and chemical divergence in the sponge genus Latrunculia (Porifera: Demospongiae) from New Zealand

We undertook a comprehensive study of Latrunculia in New Zealand to determine the relationship between taxonomic, environmental, and chemical variation within the genus. Sponges were collected from five locations around New Zealand: Three Kings Islands, Tutukaka, Wellington, Kaikoura, and Doubtful Sound. Allozyme electrophoresis at nine polymorphic loci indicated that sponges from each geographic location were genetically distinct, and that they displayed genetic differences of the magnitude usually associated with reproductively isolated species (Nei's D between locations =0.375-2.476). Additionally, the comparisons revealed that the green and brown colour morphs of Latrunculia that are sympatric at Three Kings Islands and Kaikoura are distinct from each other, and that there are two genetic groups within the green sponges in Doubtful Sound. On the basis of genetic data we conclude that there are at least eight species of Latrunculia in New Zealand waters, not one to four as had been previously thought. Morphological comparisons of the eight genetic species based on skeletal characters (i.e. skeletal organisation of the choanosome, spicule composition, size, and geometry) indicated that the eight Latrunculia species fell into only two morphological groups that could be easily diagnosed on the basis of discorhabd type. Within these two primary morphological groups, skeletal characteristics among the eight species largely overlap and are not diagnostic. These findings emphasise the limitations of traditional taxonomic methods based solely on skeletal characters for distinguishing species of Latrunculia. However, multivariate analysis (MANOVA and CDA) based on six measured skeletal variables did reveal significant morphological variation among the species (Pillai's Trace=3.28, F=6.90, P<0.0001), supporting the division of the genus into eight species. Comparisons of chemical extracts from Latrunculia also showed that the amounts of five different bioactive compounds (discorhabdins A, B, C, D, and J) varied predictably among the eight species. This finding suggests that discorhabdin variation within Latrunculia, previously thought to be associated with intra-specific environmental variability, is more likely to reflect differences among species rather than phenotypic plasticity. Our results also highlight the importance of thorough taxonomic studies associated with marine natural products research to understand fully the variation in bioactive properties among individuals. The potential processes underlying the unusually high speciation rates in New Zealand Latrunculia that are indicated in our study are discussed.     

In vitro and in vivo study of neutrophil functions after acute methanol intoxication in albino rats

Toxicity from methanol (MeOH), a potentially significant problem due to occupational, accidental, or intentional, as well as daily ingestion of small amounts of the agent, only receives considerable attention after severe signs of intoxication have set in or death is imminent. While accidental and intentional exposures usually involve very high doses, the occupational and ingestion forms more often reflect small daily intakes. Still, even at the low levels, little is known about the potential immunotoxic implications (and less so in regard to mechanisms) from these ongoing exposures. This study has been attempted to focus the effects of acute methanol exposure on blood neutrophil functions in both in vitro and in vivo conditions at 30 and 60?min time intervals. Innate immunity of the host defense relies mostly on neutrophils. The blood MeOH levels were determined upon exposing the experimental animals to ¼ of LD₅₀ MeOH. No significant change in the blood methanol level was observed at 30 and 60?min of methanol exposure. The in vitro results showed a decrease in the neutrophil functions of adherence and phagocytic index without affecting the avidity index, followed by an increased nitroblue tetrazolium (NBT) reduction. The in vivo exposures of MeOH showed a decline in neutrophil adherence. However, the other neutrophil functions were found to be significantly increased, which indicates that in vivo results are different from that of the in vitro studies. The present study concludes that MeOH exposure can reconstitute the innate immune status by altering the neutrophil functions. Moreover, the in vivo effects are much pronounced compared to the in vitro effects, which may be due to the formation of the metabolites under in vivo conditions.     

The potential impacts of sea level rise along the coastal zone of Kanyakumari District in Tamilnadu,India

Climate change associated with sea level rise (SLR) is one of the major environmental concerns of today. This paper presents an assessment of the impacts of sea level rise on the coastal zone of Kanyakumari District in Tamilnadu, India. Digital Elevation Model (DEM) combined with overlay techniques in GIS are used in determining the inundation zones along the coastal region. The analysis evaluated the impact on coastal fishing villages, landuse, tourist spots and sensitive areas under threat. The vulnerability of the coastal areas in Kanyakumari to inundation was quantified, based on the projected sea level rise scenarios of 0.5 and 1 m. Our findings reveal that approximately 13 km² of the land area of Kanyakumari would be permanently inundated due to SLR. This would result in loss of land, alteration of the coastal zone and affects coastal ecosystem. From the study, the mitigation measures (engineering measures) and Coastal Zone Management practices that can be taken to protect human life and property from sea level rise are suggested.     

Modeling watershed-scale effectiveness of agricultural best management practices to reduce phosphorus loading

Planners advocate best management practices (BMPs) to reduce loss of sediment and nutrients in agricultural areas. However, the scientific community lacks tools that use readily available data to investigate the relationships between BMPs and their spatial locations and water quality. In rural, humid regions where runoff is associated with saturation-excess processes from variable source areas (VSAs), BMPs are potentially most effective when they are located in areas that produce the majority of the runoff. Thus, two critical elements necessary to predict the water quality impact of BMPs include correct identification of VSAs and accurate predictions of nutrient reduction due to particular BMPs. The objective of this research was to determine the effectiveness of BMPs using the Variable Source Loading Function (VSLF) model, which captures the spatial and temporal evolutions of VSAs in the landscape. Data from a long-term monitoring campaign on a 164-ha farm in the New York City source watersheds in the Catskills Mountains of New York state were used to evaluate the effectiveness of a range of BMPs. The data spanned an 11-year period over which a suite of BMPs, including a nutrient management plan, riparian buffers, filter strips and fencing, was installed to reduce phosphorus (P) loading. Despite its simplicity, VSLF predicted the spatial distribution of runoff producing areas well. Dissolved P reductions were simulated well by using calibrated reduction factors for various BMPs in the VSLF model. Total P losses decreased only after cattle crossings were installed in the creek. The results demonstrated that BMPs, when sited with respect to VSAs, reduce P loss from agricultural watersheds, providing useful information for targeted water quality management.     

Organochlorine and organophosphorous pesticide residues in ground water and surface waters of Kanpur, Uttar Pradesh, India

A survey undertaken in Kanpur, northern India, has shown the presence of high concentrations of both organochlorine and organophosphorous pesticides in the surface and ground water samples. Liquid-liquid extraction followed by GC-ECD was used for the determination of these compounds. Among the various pesticides analyzed, high concentrations of gamma-HCH (0.259 microg/l) and malathion (2.618 microg/l) were detected in the surface water samples collected from the River Ganges in Kanpur. In the ground water samples collected from the various hand pumps located in agricultural and industrial areas, apart from gamma-HCH and malathion, dieldrin was also detected. The maximum concentration values of gamma-HCH, malathion and dieldrin were 0.900, 29.835 and 16.227 microg/l, respectively. Especially, the concentration of malathion was found to be much higher than the EC water quality standards in the ground water samples from industrial area posing a high risk to the common people. Pesticides like DDE, DDT, aldrin, ethion, methyl parathion and endosulfan were not detected in both the surface and ground water samples.     

Chemical tracers as indicator of human fecal coliforms at storm water outfalls

Indicators to distinguish between fecal coliforms of human and animal origin were investigated in water from storm sewer outfalls to a coastal lake during wet and dry weather. The ratio of fecal coliform relative to fecal streptococci count was used as the microbiological indicator. Concentrations of human-activities originated caffeine, anionic surfactant, fluoride, and fluorescence whitening agent (FWA) were used as chemical indicators. The ratio of fecal coliform to fecal streptococci ranged from 0.2 to 3.0, during wet weather making it difficult to interpret the origin of fecal pollution. However, concentrations of caffeine, anionic surfactant, fluoride, and FWA in storm water outflow during wet weather were much higher than those in the lake water during dry weather, indicating the presence of human waste at storm water outfall. Strong correlation between fecal coliform counts and chemical parameter values further indicated the human contribution to the fecal coliform count. In addition, a strong correlation among the chemical parameters suggested that only one of them is needed as chemical tracer to detect the presence of human input.     

Spatio-temporal classification and prediction of land use and land cover change for the Vembanad Lake system,Kerala: a machine learning approach

Environmental Science and Pollution Research - Land use and land cover (LULC) change has become a critical issue for decision planners and conservationists due to inappropriate growth and its...     

Effect of mycosynthesized silver nanoparticles from filtrate of Trichoderma harzianum against larvae and pupa of dengue vector Aedes aegypti L

Mosquitoes transmit dreadful diseases, causing millions of deaths every year. Therefore, screening for larvicidal and pupicidal activity of microbial extracts attributes could lead to development of new and improved mosquito control methods that are economical and safe for nontarget organisms and are ecofriendly. Synthetic chemical insecticides occupy predominant position in control strategies. These hazardous chemicals exert unwarranted toxicity and lethal effects on nontarget organisms, develop physiological resistance in target, and cause adverse environmental effect. For vector control, fungal-mediated natural products have been a priority in this area at present. In the current study, effective larvicidal and pupicidal effect of mycosynthesized silver nanoparticles (Ag NPs) using an entomopathogenic fungi Trichoderma harzianum against developmental stages of the dengue vector Aedes aegypti was investigated. An attractive possibility of green nanotechnology is to use microorganisms in the synthesis of nanosilver especially Ag NPs. The mycosynthesized Ag NPs were characterized to find their unique properties through UV-visible spectrophotometer, X-ray diffraction analysis, Fourier transform infrared, and surface characteristics by scanning electron microscopy. To analyze the bioefficacy, different test concentrations for extracellular filtrate (0.2, 0.4, 0.6, 0.8, and 1.0 %) and Ag NPs (0.05, 0.10, 0.15, 0.20, and 0.25 %) were prepared to a final volume of 200 mL using deionized water; 20 larvae of each instars (I–IV) and pupa were exposed to each test concentration separately which included a set of control (distilled water) group with five replicates. Characterization of the synthesized Ag NPs were about 10–20 nm without aggregation. Susceptibility of larval instars to synthesized Ag NPs was higher than the extracellular filtrate of T. harzianum alone after 24-h exposure, where the highest mortality was recorded as 92 and 96 % for first and second instars and 100 % for third, fourth instars, and pupa. Lethal concentration 50 values of 0.079, 0.084, 0.087, 0.068, and 0.026 % were recorded for I–IV instars and pupa, respectively, when exposed to Ag NPs at 0.25 % concentration. Toxicity was exhibited against first (1.076 %), second (0.912 %), third (0.770 %), fourth (0.914 %) instars larvae, and pupa (0.387 %) with extracellular filtrate at a concentration of 1 % that was three- to fourfold higher compared to Ag NPs; no mortality was observed in the control. The present study is the first report on effective larvicidal and pupicidal activity of Ag NPs synthesized from an entomopathogenic fungi T. harzianum extracellular filtrate and could be an ideal ecofriendly, single-step, and inexpensive approach for the control of A. aegypti.