Search

With vermireactors designed on the basis of the concept of high-rate vermicomposting recently introduced by S.A. Abbasi and co-workers, it has become possible to directly vermicompost phytomass, including pernicious weeds. It has also been shown that upon vermicomposting, even toxic and allelopathic weeds get transformed into highly plant-friendly and soil-friendly organic fertilizers. Pre-existing vemireactors were not able to achieve direct vermicomposting of weeds or other plant biomass, for reasons explained in the main text. But it is necessary to ascertain whether vermireactors can be operated indefinitely with problematic weeds and whether earthworms born in such vermireactors have adequate health and reproductive ability to sustain the vermireactors interminably. Hence the present work has been undertaken to assess the performance of three successive generations of four earthworm species in terms of their ability to vermicompost the highly ligninous aquatic weed salvinia and reproduce in the vermireactors solely fed by it. It was seen that in all cases the first generation of animals, which had been born and grown to adulthood in cow-dung fed vermiculture systems, took time to adapt to the weed-feed, but did so and remained healthy. The next generation which was born and raised in salvinia-fed vermireactor was significantly more efficient in vermicomposting salvinia while the third generation was still more efficient in comparison to the second generation. The trend of third generation being superior to the second and the second being superior to the first was manifest in the production of offspring (juveniles and cocoons) as well. All-in-all the findings, covering 16 months of uninterrupted vermireactor operation, reveal that earthworms tend to get acclimated to have salvinia as their exclusive feed and the successive generations of earthworms that are born and grown in the weed-feed reactors manifest not only greater vermicomposting efficiency but also superior reproductive ability than the earthworms which had been raised on animal manure.

In the context of the absence of any prior art on the vermicomposting of any xerophyte—presumably because xerophytes, in general, are structurally tough and have attributes which help them resist biodegradation—the present work has been undertaken. It has led to a procedure which makes even the highly toxic leaves of prosopis amenable to vermicomposting. Two years long and continuous operation of vermireactors with six different species of earthworms, has shown that the earthworms gradually adapted to prosopis as their exclusive feed, showing a consistently increasing rate of vermicast production while remaining healthy and displaying good fecundity throughout. The work provides an avenue of utilizing prosopis leaves which are generated in very large quantities across the tropical and sub-tropical world. At present no process exists which can make use of prosopis leaves even as the wood of its trees is utilizable. Besides valorizing an otherwise wasted phytomass the present work will also prevent falling of prosopis leaves on soil and their very slow biodegradation during which they toxify the soil with allelochemicals and emit global warming gases.

A novel machine, with the acronym HEVSTOW (high-efficiency vertically stacked vermicomposting system for treating organic waste), of which a patent has recently been granted, is described. It is capable of rapid, inexpensive, and emission-free processing of biorefinery waste and other forms of organic solid waste. The machine is based on the paradigm of high-rate vermicomposting earlier developed by the authors. It makes it possible to rapidly process biorefinery waste of plant origin, as also paper, which the conventional vermireactors are not able to handle without elaborate pre-treatment and/or augmentation of animal manure. The machine also makes it possible to simultaneously vermicompost different forms of biowaste as also use different species of earthworms in such a manner that each batch operates independently without one batch interfering with the other. The applicability of the machine has been demonstrated by its application in simultaneous yet independent processing of a biorefinery waste, and paper waste, each with two epigeic species of earthworms Eisenia andrei and Lumbricus rubellus.

Given that wetlands, especially man-made wetlands including paddy fields, are a major source of the greenhouse gases methane and nitrous oxide, a study of the present status of knowledge in this area was carried out with reference to India. Based on printed material, digital repositories, and personal correspondence an up-to-date assessment of all studies reported so far has been conducted. It is shown that despite India having 4.6% of its area covered by natural or man-made wetlands, being home to a very large number of wetlands, and being the second largest cultivator of paddy in the world, its wetlands—including paddy fields which are intermittently flooded as typical wetlands are—have been very poorly studied in terms of their GHG emissions. Even the reports that are available have been mostly confined to a few regions of India, and as many as seven of the most wetland-rich states—Bihar, Chhattisgarh, Jharkhand, Madhya Pradesh, Maharashtra, Himachal Pradesh, and Jammu & Kashmir—have not been studied in this respect at all. A major finding is that, contrary to a recent report published by authors based in USA, intermittently irrigated rice fields have not been found to emit exceptionally high quantities of nitrous oxide. The study brings out the urgent need for carrying out assessments of GHG emissions from wetlands throughout India with a view to finding strategies to minimize such emissions.

When the otherwise toxic and allelopathic leaves of prosopis (Prosopis juliflora) are vermicomposted, the end product becomes a benign organic fertiliser. This paper describes extensive analytical ...

The efficacy of the well-known phytoremediation plant pistia (Pistia stratiotes), also called water lettuce or water cabbage, in treating sewage (greywater) was tested by its use as the main bioage...

The potential application of a novel continuous electrocoagulation (EC) reactor for simultaneous removal of color, chemical oxygen demand (COD), turbidity, and alkalinity from a real licorice processing wastewater was investigated. The individual and interactive effects of four key independent variables (electrolysis time, current density, NaCl concentration, and mixing intensity) was evaluated. The results suggested that color and COD removal enhances with increasing electrolysis time, current density, and mixing intensity and remains practically constant by adding higher concentrations of NaCl. The application of continuous EC process under optimal conditions, such as: electrolysis time (81.8 min), current density (350 A/m2), NaCl concentration (300 mg/L), mixing intensity (45 rpm) allows to achieve these promised removal efficiencies: 90.1 % color, 89.4 % COD, 82 % turbidity, and 73.3 % alkalinity.

As reported recently by the present authors, vermicomposting by the epigeic earthworm Eisenia fetida transforms the highly ligninous and allelopathic aquatic weed salvinia (Salvinia molesta) into a benign organic fertilizer. The present study was carried out with four other earthworm species, including three epigeic species of different sizes and phytophagic habits: Eisenia andrei, Lumbricus rubillus, and Perionyx sansibaricus. One anecic species, with geophytophagous habits, was also explored for comparison: Drawida willsi. The objective was to see whether the type of salvinia transformation caused by E. fetida is a general phenomenon or whether there are significant differences in the nature of biocomposts generated by different earthworm species. Accordingly, the characteristics of the biocomposts separately generated by each of the six species mentioned above were assessed with UV-visible spectrophotometry, Fourier-transform infrared spectrometry, differential scanning calorimetry, thermogravimetry, and scanning electron microscopy. The studies reveal that, with minor variations, the biocomposting by all four species was able to remove the intransigence of salvinia and impart plant/soil-friendly attributes to it in substantial measures. All the findings obtained with different techniques corroborated each other in arriving at this conclusion. Hence, it can be said that, in general, biocomposting by earthworms takes away the toxicity of pernicious weeds such as salvinia, converting them into plant-friendly and soil-friendly biofertilizers.

Earthworms are among the three classes of organisms which contribute more than any other class in tilling and fertilizing soil in nature—ants and termites being the other two. In nature, earthworms feed upon plant debris and animal dropping to produce vermicast which is an excellent organic fertilizer. But during rains and through small streams ‘vermiwash’ (VW) is also generated which is an extract of not only earthworm-worked biomass but also the earthworm body fluids. In recent years, procedures have been developed to generate VW under controlled conditions and its fertilizer value has been assessed. This chapter presents a state-of-the-art assessment of the virtues and the potential of VW.

The two free-floating aquatic weeds—salvinia (Salvinia molesta) and water hyacinth (Eichhornia crassipes) —feature among the world’s 100 most invasive plants and animals. Both occur widely in India as also in most other countries of the tropical and sub-tropical region. In this brief review the attributes of the two weeds, with special reference to their role in phytoremediation, are presented.

Recent studies by these authors have shown that the toxic and allalopathic weed ipomoea (Ipomoea carnea), gets transformed into benign organic fertilizer when subjected to vermicomposting. To deriv...

Vermicompost derived exclusively from ipomoea (Ipomoea carnea), a weed notorious for its toxic and allelopathic characteristics, was explored for its potential use as an organic fertilizer. Ipomoea vermicompost (IVC) at four levels (0, 2.5, 3.75, and 5 tonnes/ha) was explored for its effect on the germination, growth and fruition of ladies finger (Abelmoschus esculentus) in appropriately replicated experiments. It was seen that IVC encouraged the germination and growth of ladies finger at all levels of the IVC application, and best results were obtained in 5 t/ha treatments. The positive effect occurred at all stages of A.esculentus cultivation ─ from germination of its seeds to all the vegetative growth phases and the fruit yield. There was also improvement in the quality of fruits in terms of mineral, protein and carbohydrate contents, and reduction in the disease incidence and pest attacks, due to the IVC application. The studies reveal that vermicomposting enables ipomoea to acquire all the qualities of a good organic fertilizer with simultaneous loss of its toxicity and allelopathy. The findings raise hopes that the enormous quantities of ipomoea biomass that is generated across the world, and which presently goes to waste, may become utilizable in producing organic fertilizer. Keywords: Ipomoea, Toxicity, Allelopathy, Vermicomposting, Biofertilizer, Biopesticide

Vermicompost (VC) of different substrates, especially of animal manures, is known to be highly potent organic fertilizer but it is not known how beneficial VC is in paddy cultivation. Considering that rice is the world’s third most cultivated and consumed grain, it is important to assess the effect of VC on its productivity. Equally important is to see whether vermicompost application leads to higher or lower greenhouse gas (GHG) emissions compared to synthetic chemical fertilizers (SFs). The present mini-review has aimed to assess and summarize this state-of-the-art. It is seen that only 27 studies have been reported on this subject so far, and in 18 of them, it is possible to compare the performance of VC with SF and other organic fertilizers. Half of these studies reveal the VC to be superior to all the other fertilizers tested while 39% of the studies show VC to be the second best. With the exception of three papers—two from Bangladesh and one from Iran—all other publications have been from India, representing 89% of all work reported in this field. In respect of types of VC studied, 25 (93%) of all studies have been on VC derived from cow-dung. For the remaining two studies, the VC was obtained from the dung of other cattle and distillation waste respectively. As for GHG emissions occurring from VC-fertilized rice fields, only five reports are available. In four of these reports, no statistically significant difference has been reported in the GHG emissions from the VC and the SF-fertilized rice fields. Hence, the available information is too scanty to enable any generalization.

More often than not, major fires and explosions occur in chemical process industries as also in public places, due to accidental spills of flammable substances. This makes it important to study the dynamics of flammable liquids spilled onto the ground, so that strategies to contain and quench such spills can be devised. Moreover, the risk posed by a liquid spilling over an inclined plane is much greater than the risk posed by a spill over a flat surface because in the former case there is an increased rate of evaporation due to an enhanced spread rate, thereby enhancing the possibility of the formation of highly flammable/explosive vapor clouds. Such vapor clouds are known to drift to other units and damage them, often escalating a mere spill into a major catastrophe. But even though a large number of accidents have occurred where the flammable liquid had spilled over inclined planes, little work has been done toward understanding the dynamics of such spills which may help in the development of models to forecast the pattern and impact of such spills. The present work is an attempt to fill the knowledge gap and is arguably the first-ever study of its kind. In this work, the dynamics of spill of three different fuels—petrol, kerosene and ethanol—on two types of substrates of different roughness—vinyl and plastered concrete—have been studied. The angle of inclinations over which the spill dynamics have been studied is 0°, 5°, 10°, 15° and 20° to the horizontal. Further, for the first time, the application of artificial neural networks to predict the spill velocity has been demonstrated.

Majority of the accidents occurring in chemical process industry begin with the accidental spill of one or the other liquid fuel. This makes it important to forecast the areas likely to be covered by the spill of a given fuel on a given surface of a given inclination, and to devise accident prevention strategies on its basis. This work reviews all the reported models for forecasting the area attained by a liquid spill at equilibrium. It then evaluates the efficacy of these models by testing them with available data. It was possible to run four of the six reported models as data was not adequate to operate the remaining two. It is seen that three of the four models thus tested under-predicted the spill area for some liquid―surface combinations and over-predicted it for some others the percentage error covering large ranges. Only one model consistently under-predicted the area and did so in a much narrower error range. After a ‘weight’ or a ‘correction factor’ was attached to that model it was able to forecast spill area with adequate accuracy.

A large number of highly flammable and/or toxic substances are stored in huge quantities in chemical process industries throughout the world. In the past, when such hazardous facilities have met with a major accident, the resulting explosions/fires or toxic releases have led to massive losses of lives and of property worth billions of rupees. This has, in turn, given rise to risk perception vis a vis the probability of the likely accidents and extents of their impacts that may occur in similar installations. If this risk can be quantified and ways found to reduce the risk, it can help in reducing the occurrence such an accidents as also tell us the measures needed to cushion the impact when a major accident does take place. This paper identifies the risks associated with facilities storing hazardous substances and provides a template for conducting quantitative risk assessment of such facilities.

Efficacy of all the existing transient models for forecasting the area attained by accidentally spilled liquid fuels has been sought to be assessed on the basis of experimental data available in prior art. Of the two models for which required inputs are available in the prior art, the model of Huppert (1982) is able to forecast spill area with much greater precision than the model of Raj and Kalelkar (1974). Both the models give better predictions when the spill volume is higher and the spill duration is lower but neither model yields a correlation between the accuracy of the spill area forecast and the nature of the spilled liquid or the receiving surface.

Chemical process industries often handle, store and transport chemicals which are flammable and/or toxic. Also, often, processes are employed which are carried out at high temperatures of pressures. These happenings constitute major hazards which carry the risk of serious accidents. The bigger the hazard, the greater is the risk associated with its existence. Despite the best intentions of the industries not to allow any accident to occur, major accidents keep occurring all over the world. This makes it necessary to develop newer methods with which the likelihood of accidents can be forecast and steps taken to prevent those accidents from occurring. This paper presents an overview of the already developed, and still evolving, methods for assessing risk of accidents in chemical process industries.

A circular (close-loop) biorefinery, which integrates wastewater treatment with the generation of an energy precursor and organic fertilizer, tested at the level of a pilot plant treating 54,000 L per day (LPD) of sewage, is described. In the biorefinery’s first stage, sewage was treated in a novel SHEFROL® (sheet-flow-root-level) bioreactor at a very rapid rate, indicated by a hydraulic retention time of a mere 6 h, to a level that met the prevailing national standards for the discharge of treated sewage. The main bioagent of the reactor—water hyacinth—was then processed for the generation of energy precursors. For this, volatile fatty acids (VFA) were extracted in a simple batch reactor operating at ambient temperature and pressure. The ‘spent’ weeds were then converted into organic fertilizer, also at ambient temperature and pressure, by the high-rate vermicomposting process earlier reported by the authors. In this manner, wastewater treatment, energy production, and the generation of a fertilizer were achieved rapidly and efficiently, creating a circular close-loop system that required very little energy and materials and generated almost zero net waste.

In a first-ever report on this subject, it is shown that a common amphibious plant joyweed (Alternanthera sessilis) can be used in rapid and efficient treatment of biodegradable wastewaters, typifi...

In separate treatments rice (Oryza sativa) of the Chinna Ponni variety was grown either with the application of synthetic fertilizer (SF) containing 120 kg/ha, 60 kg/ha, and 60 kg/ha of nitrogen, phosphorous, and potassium, respectively, or vermicompost (4 t/ha) with equivalent nitrogen content. The objective was to see whether vermicompost performs as well, or better, than the SF in terms of grain length, unit mass, and overall yield of rice. The relative contribution of the two fertilizer applications on the emission of the global warming gas methane was also studied. Direct sowing method was applied for the rice cultivation which spanned 140 days during which intermittent flooding of the plots was done. The average grain yield (2300 kg/ha), grain weight (21 mg), and grain length (6.3 mm) of the vermicompost-fertilized rice were all marginally higher than the corresponding values: 2060 kg/ha, 18 mg, and 6.1 mm, respectively, of the SF-fertilized rice. The overall hourly methane flux in vermicompost-fertilized plots was 111.3 ± 58.3 µg/m2 h in comparison with 71.0 ± 81.0 µg/m2 h emitted by the SF-fertilized plots, but the difference was not statistically significant.

The authors wish to make the following corrections to this paper [...]

Licorice processing industry produces a characteristic wastewater with a high chemical oxygen demand (COD), high turbidity, and intense color. Direct disposal of untreated licorice processing wastewater into water bodies can pose a serious risk to the human health and environment. The main objective of this study is to evaluate the performance of a novel laboratory scale continuous electrocoagulation (EC) reactor using iron (Fe) rod electrodes (anode and cathode) for treating a real licorice processing wastewater. Response surface methodology (RSM) was employed to investigate the effects of important parameters such as: current density (CD), electrolysis time, mixing intensity, and NaCl concentration for Fe rod electrodes on the removal efficiency of color, soluble COD (sCOD), and turbidity. In order to evaluate the effect of reactor design on the overall process performance, the results were compared with our previous study in which Fe plate electrodes were employed in an identical system. The process exhibited better performance in terms of turbidity removal for Fe rod electrodes with an average value of 59.35% in contrast to Fe plate electrodes (47.88%). Color and sCOD removal efficiencies of 94.6% and 90.1% were achieved, respectively for the EC system using Fe rod electrodes under optimum conditions: electrolysis time (71.8 min), CD (28 mA/cm2), mixing intensity (45 rpm). While in the EC reactor using Fe plate electrodes, the optimum (electrolysis time of 81.8 min, current density of 35 A/cm2, and mixing intensity of 45 rpm) color and sCOD removal were obtained 90.1% and 89.4%, respectively. Analysis and comparison of the data revealed that Fe rod electrodes delivered a better treatment performance than Fe plate electrodes, taking into account that the optimum electrolysis time and applied current density were considerably lower for the Fe rod electrodes. Overall, these results confirmed that the novel EC reactor using Fe rod electrodes can reduce the operating cost and be proposed as a pragmatic approach to remove high amount of color, COD, and suspended solids from licorice processing wastewater.

Hypotermes obscuriceps is the most abundant of termite species found in North-eastern Puducherry. It has been seen to assimilate ligninous waste kept for degradation in the termireactors designed earlier by the authors by the process of termigradation. Termigradation is a termite-based biodegradation process and involves attracting termites towards the ligninous waste in specially designed reactors. Such reactors are kept in pits or aboveground near termite mounds. In order to increase the number of termites that will move towards the feed kept in such termireactors, 2-Phenoxyethanol (2-PE) was explored in the laboratory for making trails that may attract H. obscuriceps. Five different concentrations of 2-PE, ranging from 0.1 to 0.0005% were explored and in controlled experiments, the numbers of termites that followed the trails made by these levels of 2-PE as a function of time were determined. It was seen that all the trails that contained 2-PE attracted H. obscuriceps and none was toxic to termites for the first 60 minutes.

The paper presents a method for the biomimetic extracellular synthesis of gold nanoparticles (AuNPs) by using the aqueous extracts of all the main parts (leaves, stem and roots) of the highly invasive terrestrial weed mimosa (Mimosa pudica). Aqueous extracts of each of these parts served as reducing as well as stabilizing agents. The effects of key variables that influenced the shape and/or size of the AuNPs – mainly metal-extract stoichiometry, temperature and pH – were studied with the help of ultraviolet–visible spectrophotometry, X-ray diffraction, energy-dispersive X-ray spectroscopy, electron microscopy and Fourier transform infrared spectroscopy. The efficacy of the AuNPs in free radical scavenging and as catalyst was witnessed. The studies thus provide a template for scaling up AuNP synthesis and utilizing it. Given the fact that M. pudica is freely available in large quantities, with no other recognized use, the present method opens up a possibility for its large-scale utilization in synthesizing AuNPs of tunable shapes and sizes in a rapid, non-polluting, energy-frugal and inexpensive manner.

Twentyeight accidents involving major fires and/or explosions, which have occurred across the world in tank farms storing flammable liquids, have been studied. The focus has been on determining, a) what were the distances between the tank which failed and the tank(s) which were damaged or could have been damaged due to fire/explosion in the former; b) what were the distances prescribed as safe by prevailing codes/standards/models between the concerned tanks, and c) whether the tanks were relocated in a safer way by the concerned industry after the accident. The study also identifies some of the codes, standards, and models which appear to provide more realistic safe distances for the given tank types/sizes.

Background Any manner of development can be sustainable only if the waste generated by it is not allowed to accumulate but is fully reused/recycled/recovered. Among the strategies to attain this goal have been the attempts to recover energy from municipal solid waste (MSW). About 60% of MSW is carbonaceous, consisting of materials which can either be biodegraded into fuels like methane or incinerated, thereby generating utilizable energy. MSW also contains several components—like metallic scrap and glass pieces—which can be reused or recycled, thereby achieving energy conservation. Given these attributes, MSW appears to be a potential source of energy and resources. Indeed, this belief that MSW is usable if only we try sincerely enough to do so prompts most of us to keep generating much more MSW than is warranted. But how realizable really is the energy potential of MSW? What perils loom into view when we actually set out to utilize MSW as an energy source? The present study addresses these crucially important questions. Methods The work is based on a critical content analysis of the prior art. Results The generation of MSW has consistently outpaced the world’s efforts to dispose of it cleanly, and the energy (and material) recovery from MSW is easier said than done. In most instances, what is technically feasible is economically unfeasible. And what is economically feasible—such as setting the waste on fire as is often done in developing countries—is exceedingly harmful to the environment and the human health. Measures such as sanitary landfilling and incineration create as many new problems as the old ones they solve. Moreover, despite the use of these less-than-adequate technologies, a major portion of MSW generated in the world lies untreated. Conclusions As the MSW output is expected to double by 2025, this situation is only set to become worse. Rising tides of E-waste would compound the problem even further. Hence, enormous stress should be put on the reduction of MSW generation by controlling wanton consumerism and wastage, rather than continuing with it in the false hope that technology will soon provide a magical solution and eliminate the problem.

The design and testing of a novel vermicomposting system, acronymed FLUVTS ─ FLippable Units Vermireactor Train System ─ is presented. It enables rapid vermicomposting of paper waste without the need of pre-composting and requires animal manure supplementation to the extent of only 10:1 paper: manure mass ratio in contrast to reported systems which must have 50% or more of the feed mass as animal manure. Moreover, the system enables the vermicomposting to be accomplished at a high rate, achieving near-total convertion of feed to vermicast at solid retention times of just 30 days in comparison to conventional systems which take 90–120 days for the same process. Uninterrupted vermireactor operation for 6 months, during which the feed was put in and its vermicompost harvested once in 30 days, demonstrates the robustness and the consistency of the system. The suitability of the paper-waste vermicompost as an organic fertilizer was then tested in terms of it's effect on seed germination and early growth of four food plants chilly (Capsicum annuum), ladies finger, (Abelmoschus esculentus), cucumber (Cucumis sativus), and tomato (Lycopersicon esculentum). In general, the paper waste vermicompost when applied at levels

Very large quantities of flammable substances are produced, transported, and refilled across the world. Of these some, like gasoline and diesel, are liquids at normal temperature and pressure while some others – like liquid petroleum gas (LPG – are pressure liquefied gases. Ever so often accidental spills of these chemicals occur. While some spills are contained before they could do much damage, many others catch fire and often also lead to massive explosions. Indeed, accidental spills have been the initiators of the majority of industrial disasters the world has seen. Given the exceptional importance associated with the containing and controlling of accidental spills, it is essential to understand the factors which effect the spill dynamics so that ways to reduce the risk posed by such spills can be devised. But even as a great deal of work has been done on the dynamics of spills occurring on flat surfaces, little past effort is on record pertaining to the study of spills occurring on inclined surfaces. This is surprising because the spillways actually provided in the industries for large storage tanks invariably have downward slope to enable quick drainage of the flammable liquid away from the storage tank in the event of an accidental leak. The present work is an attempt to make some contribution towards the understanding of the dynamics of spillage of flammable liquids on inclined surfaces. When accidental spills occur in the open – during transportation by road, railroad, or pipeline – the receiving surfaces can be porous and the liquid can percolate down, making environmental contamination that much difficult to remediate. To incorporate this aspect in the present study we have chosen porous surfaces and studied the dynamics of the spill of three different flammable liquids on them at angles of inclination varying from zero to 20°.

A pool or a pile of a flammable substance catching fire—which is termed a ‘pool fire’—is among the most common of fire-related accidents. In chemical process industries (CPI) in particular, pool fires are the most frequent of all possible types of accidents. Pool fires are also, more often than not, the triggers of larger fires, explosions and/or toxic releases in CPI. As demonstrated in this paper, most of the catastrophic accidents that have occurred in CPI have begun with a pool fire, which has then led to other fires and/or explosions, compounding the initial accident many times over. In day-to-day life also, as also in forest fires, major fire accidents begin with a small pool fire. Due to these reasons an understanding of factors which influence pool fires, and the associated mechanisms, is essential for devising strategies to control and mitigate pool fires. This review, which is specific to pool fires occurring in CPI, recounts illustrative case studies of some major pool fire accidents, performs a past accident analysis and describes pool fire mechanism, modeling and control.

The existing methods for calculating overpressure resulting from a vapour cloud explosion (VCE) were tested for their ability to predict overpressures from unconfined hydrogen explosions. For it, data collated from five reported experimental investigations on open air hydrogen explosions covering 1.4–300 m3 volume of hydrogen-air mixtures and concentrations ranging 20–57% were employed. It was found that the existing VCE models are grossly inadequate for predicting the overpressure generated by unconfined hydrogen explosions. A new method was then developed for assessing overpressures from hydrogen explosions for a given concentration and volume of release based on Sach's scaling laws. The new model has much greater ability to fit the experimental data, hence much stronger ability to forecast the severity and consequences of hydrogen-based VCEs compared to the existing models.

The ornamental plant Alternanthera ficoidea (also named A. tenella), which is common and widespread throughout the tropics and is being increasingly regarded as an invasive, problematic weed, has been explored as a bioagent in greywater treatment. In the recently developed SHEFROL® bioreactor, it was seen to treat greywater of varying strengths (250–1,300 mg/L chemical oxygen demand, COD) quickly and substantially to the extent of 75–77%. Biological oxygen demand (BOD), nitrogen, phosphorus, suspended solids, and heavy metals copper, nickel, manganese, and zinc were also removed to the extents of 83.5, 94.9, 33.1, 27.0, 44.8, 27.5, 38.2, and 43.2%, respectively. As all this was achieved in a single pot, single step, and in a simple reactor operation, at hydraulic retention times of a mere 6 h, it shows the process to be several times more efficient as well as potentially less expensive than the conventional treatment systems which utilize macrophytes in tanks or constructed wetlands.

Most accidents in chemical process industry, as well as a large number of fires in general, are triggered by accidental spilling of flammable liquids. Such spills either get auto-ignited or are set on fire by one or the other ignition source. If other flammable material happens to catch fire before the initial fire is extinguished, the accident gets escalated. In many situations, the escalation is catastrophic, resulting in very large fires, with or without explosions. This paper assesses the transient models developed so far to predict the areas covered by accidental fuel spills.

A new method, RIsk and DIstance Minimization in Process Units Siting (RIDIMPUS), is presented with which hazardous units can be sited in a chemical process facility in a manner that the risk of accidents involving the hazardous units as also the cost of spacing the units is minimized. To achieve this, safety and cost factors were modeled using various governing parameters and then expressions were designed to integrate the safety and the economic concerns to form model equations, inequalities and disjunctions. The resulting nonlinear programming model is solvable by using algorithms and solvers on any common desktop computer, thereby providing an optimal and prompt solution.

Utilization of Salvinia molesta, an aquatic weed which is notorious for its allelopathy and invasiveness, has been explored by its vermicomposting. Fourier transform infrared spectroscopy (FT-IR) and plant bioassay tests were conducted to analyze the composition and fertilizer value of S .molesta vermicompost. Germination and seedling growth tests were performed in soil supplemented with vermicompost at levels ranging from 0.75 to 40% by weight of the soil on three common food plants, ladies finger (Abelmoschus esculentus), cucumber (Cucumis sativus), and green gram (Vigna radiata). The influence of S. molesta's vermicompost on some of the physicochemical and biological attributes of the soil was also studied. FT-IR analysis revealed that S. molesta loses its allelopathy, as the chemical compounds that are responsible for it are largely destroyed, in the course of its vermicomposting. There is also an indication that a portion of lignin content of S. molesta is degraded. Vermicompost enhanced the germination success and promoted the morphological growth and biochemical content of the plant species studied. It also bestowed plant friendly physicochemical and biological attributes to the soil. The findings raise the prospect that billions of tons of S. molesta biomass-which not only goes to waste at present but is also a cause of serious harm to the environment-may become utilizable in organic agriculture.

Purpose In a novel attempt, vermicompost derived from an intransigent and noxious weed salvinia was assessed for its fertilizer value and pest repellent properties. Methods In outdoor experiments which simulated the way vegetables are cultivated by farmers, ladies finger (Abelmoschus esculentus) seeds were germinated and grown in soil supplemented with salvinia vermicompost at four levels: 0 (V0), 2.5 (V1), 3.75 (V2) and 5 (V3) t/ha. Besides assessing germination success and subsequent growth, yield, and biochemical content of the plants, the impact of pest attacks on them was also studied. Results Salvinia vermicompost significantly enhanced germination success, growth, and yield of the plants. Maximum growth in terms of shoot length (96.2 cm), root length (48.2 cm), shoot and root dry weight (23.31, 7.96 g), stem diameter (14.04 mm), and number of leaves and branches (26.8, 4.8) was recorded in V4 (5t/ha). Likewise, the mineral and biochemical content in vermicompost-treated plants was significantly higher than in the controls. The vermicompost also induced resistance in plants against pests and disease. Compared to the controls, vermicompost had reduced the fruit borer infection by 65, 78 and 82% in V1, V2 and V3, respectively. Conclusion The toxicity of salvinia is largely eliminated when it is vermicomposted, and the product acquires the qualities of a good organic fertilizer. The present work can potentially lead to the development of an inexpensive, sustainable and eco-friendly method of utilizing billions of tons of phytomass that is generated annually by salvinia, and which presently goes to waste.

A systematic survey of termite species in Northeastern Puducherry which is part of peninsular India, was carried out. As there is no pre-existing report on the richness or diversity of termifauna in this region, the present work aims to fill this major knowledge gap. The findings are discussed in the context of the quantitative studies on termifauna carried out across the world, as also in terms of the defining traits of the species identified in the survey vis a vis their possible use in biodegrading ligninous biowaste. The latter aspect is particularly relevant to the controlled use of termites by the process named ‘termigradation’, which denotes termite-based biodegradation of waste. Key words: Termites, termigradation, indices, India, Puducherry.

When two or more pool fires burn in close enough proximity to influence one another, the resultant combination is termed ‘multiple pool fire’ (MPF). Even though MPFs occur fairly often in chemical process industries, with highly destructive consequences, much lesser work has been done towards simulation, modeling, and control of MPFs than on stand-alone pool fires. Among the factors which strongly influence the interaction among the MPFs, and the consequent damage MPFs may cause, the most important is the type of fuel contained in the individual pools. This aspect affects the temperatures of the interacting flames, their soot production, and the resultant radiation load. However, studies to dynamically model this aspect have not been carried out so far. In this paper an attempt has been made, arguably the first of its kind, to explore the efficacy of computational fluid dynamics (CFD) in simulating the effect of fuel types on MPF clusters. A fair agreement has been found between the CFD simulation and the experimental findings reported by Vincent and Gollahalli (1995). The agreement between the experimental data and CFD simulation results is good considering the fact that the soot production has not been accounted by us.

The composition and the fertilizer value of vermicompost derived solely from ipomoea, a weed known for its toxicity and allelopathy, has been studied employing Fourier transform Infrared Spectroscopy (FT-IR) and plant bioassay (germination and seedling growth). The impact of ipomoea’s vermicompost on the physicochemical and biological characteristics of the soil was also studied. FT-IR analysis revealed that chemical compounds that are responsible for the deleterious effect of ipomoea are largely destroyed in the course of ipomoea’s vermicomposting. The ipomoea vermicompost was seen to be a good organic fertilizer as it significantly enhanced germination success, promoted growth of the seedlings and induced plant friendly physicochemical and biological features to the soil. The studies raise the possibility that very large quantities of biomass that are generated by ipomoea across the world can be utilized in producing organic fertilizer through vermicomposting. This may also provide a means of checking the seemingly unstoppable spread of ipomoea and cushioning its adverse impacts.

In this work, we report for the first time a new bio-inspired method for platinum nanoparticle (PtNP) synthesis utilizing a highly invasive terrestrial weed coral vine (Antigonon leptopus) as the main bioagent. Extracts of all three basic components of the plant – leaves, stem and root – were explored and were found to be suitable in effecting the PtNP synthesis. The electron micrographs of the synthesized PtNPs revealed the presence of particles of monodispersed spherical and polydispersed shapes in sizes ranging from 5 to 190 nm. The presence of Pt atoms was confirmed from the energy dispersive X-ray (EDAX) and X-ray diffraction (XRD) studies. The FTIR spectral study indicated that the polysaccharides and proteins in the plant extract could have been responsible for the reduction of Pt ions to PtNPs and the latter’s stabilization.

Understanding the link between termites' impact on ecosystem functioning and their ecological needs remains a key question in ecology. This study focused on the influence of the fungus-growing termite species, Hypotermes obscuriceps, on soil properties in Southern India. This species produces soil sheetings and mounds on the ground. In contrast to other termite species, such as those belonging to the Macrotermes and Odontotermes genera, which produce mounds to live in, H. obscuriceps excavates soil above ground for constructing its chambers below ground. Using a captive colony of H. obscuriceps growing up in control conditions, we measured the soil properties (carbon content, particle size distribution, pH, electrical conductivity and concentration in soluble anions and cations) of its mound and of the sheetings it produced over the leaves of Acacia auriculiformis and on the branches of Ipomoea carnea and Lantana camara. The physical and chemical properties of H. obscuriceps mounds were very similar to those of the surrounding soil and even if rain erodes these mounds in the field, it is likely to have only a small effect on the resulting run-off water quality. In contrast, sheetings have higher clay and C contents than the surrounding soil. Their degradation by rain is likely to be associated with soil detachment and F-, Cl- and K+ export in water runoff and/or leachate. In conclusion, this study shows that this species impacts soil properties more through the construction of sheetings than mounds. This difference is explained by the ecological needs of termites. While H. obscuriceps is not dependent on soil mound properties for survival, soil sheetings' properties are essential for providing them a protective cover.