Control of amphibious weed ipomoea (Ipomoea carnea) by utilizing it for the extraction of volatile fatty acids as energy precursors

Volatile fatty acids (VFAs), comprising mainly of acetic acid and lesser quantities of propionic and butyric acids, are generated when zoomass or phytomass is acted upon by acidogenic and acetogenic microorganisms. VFAs can be utilized by methanogens under anaerobic conditions to generate flammable methane–carbon dioxide mixtures known as ‘biogas’. Acting on the premise that this manner of VFA utilization for generating relatively clean energy can be easily accomplished in a controlled fashion in conventional biogas plants as well as higher-rate anaerobic digesters, we have carried out studies aimed to generate VFAs from the pernicious weed ipomoea (Ipomoea carnea). The VFA extraction was accomplished by a simple yet effective technology, appropriate for use even by laypersons. For this acid-phase reactors were set, to which measured quantities of ipomoea leaves were charged along with water inoculated with cow dung. The reactors were stirred intermittently. It was found that VFA production started within hours of the mixing of the reactants and peaked by the 10^th or 11^th day in all the reactors, effecting a conversion of over 10% of the biomass into VFAs. The reactor performance had good reproducibility and the process appeared easily controllable, frugal and robust.

A critical view on the eco-friendliness of small hydroelectric installations

Renewable energy sources are widely perceived as 'clean', 'green', and 'inexhaustible'. In recent years the spectre of global warming and ocean acidification, which has been primarily attributed to fossil fuel burning, has brought renewable energy at the forefront of most climate change mitigation strategies. There is strong advocacy for large-scale substitution of conventional energy sources with the renewables on the premise that such a move would substantially reduce environmental degradation and global warming. These sentiments are being echoed by scientists and policy makers as well as environmental activists all over the world. 'Small hydro', which generally represents hydroelectric power projects of capacities 25 MW or lower, is one of the renewable energy options which is believed to be clean and sustainable even as its bigger version, large hydro, is known to cause several strongly adverse environmental impacts. This paper brings out that the prevailing perception of 'eco-friendliness' of small hydro is mainly due to the fact that it has only been used to a very small extent so far. But once it is deployed at a scale comparable to fossil fuel use, the resulting impacts would be quite substantially adverse. The purpose is not to denegrade small hydro, less so to advocate use of fossil fuels. It, rather, is to bring home the point that a much more realistic and elaborate assessment of the likely direct as well as indirect impacts of extensive utilization of this energy source than has been done hitherto is necessary.

An eco-friendly method of synthesizing gold nanoparticles using an otherwise worthless weed pistia (Pistia stratiotes L.)

A biomimetic method of gold nanoparticles synthesis utilizing the highly invasive aquatic weed pistia (Pistia stratiotes) is presented. In an attempt to utilize the entire plant, the efficacy of the extracts of all its parts – aerial and submerged – was explored with different proportions of gold (III) solution in generating gold nanoparticles (GNPs). The progress of the synthesis, which occurred at ambient temperature and pressure and commenced soon after mixing the pistia extracts and gold (III) solutions, was tracked using UV–visible spectrophotometry. The electron micrographs of the synthesized GNPs revealed that, depending on the metal-extract concentrations used in the synthesis, GNPs of either monodispersed spherical shape were formed or there was anisotropy resulting in a mixture of triangular, hexagonal, pentagonal, and truncated triangular shaped GNPs. This phenomenon was witnessed with the extracts of aerial parts as well as submerged parts of pistia. The presence of gold atoms in the nanoparticles was confirmed from the EDAX and X-ray diffraction studies. The FT-IR spectral study indicated that the primary and secondary amines associated with the polypeptide biomolecules could have been responsible for the reduction of the gold (III) ions to GNPs and their subsequent stabilization.

Methane capture from livestock manure

It has been estimated that livestock manure contributes about 240 million metric tons of carbon dioxide equivalent of methane to the atmosphere and represents one of the biggest anthropogenic sources of methane. Considering that methane is the second biggest contributor to global warming after carbon dioxide, it is imperative that ways and means are developed to capture as much of the anthropogenic methane as possible. There is a major associated advantage of methane capture: its use as a source of energy which is comparable in 'cleanness' to natural gas. The present review dwells upon the traditional ways of methane capture used in India, China, and other developing countries for providing energy to the rural poor. It then reviews the present status of methane capture from livestock manure in developed countries and touches upon the prevalent trends.

Modified Hodge test: A simple and effective test for detection of carbapenemase production

BACKGROUND AND OBJECTIVES

Resistance among bacterial isolates is the leading cause of increased mortality and morbidity worldwide. Carbapenems once thought to be effective are becoming ineffective mostly due to the emergence of carbapenemase. This study was designed to determine in vitro efficacy of Modified Hodge test for detection of carbapenemase production in Gram negative rods.

MATERIAL AND METHODS

The study was done in the Department of Microbiology, Armed Forces Institute of Pathology Rawalpindi Pakistan from January 2010 to December 2010. A total of 200 Gram negative rods from different clinical samples were taken. Those isolates which showed intermediate or susceptible zones i.e 16mm-21mm on disc diffusion were included in the study. These isolates were then subjected to Modified Hodge test.

RESULT

Out of 200 isolates, 138 (69%) were positive for carbapenemase production by Modified Hodge test. Out of 138 MHT positive organisms, the frequency of E. coli was 38%, followed by Pseudomonas aeruginosa (30%), Klebsiella pneumoniae (17%), Acinetobacter baumannii (12%), Citrobacter diversus (2%) and Enterobacter agglomerans (1.4%).

CONCLUSION

Modified Hodge test is a simple test which can be performed in the routine lab for detection of carbapenemases in isolates showing intermediate or sensitive zone diameter on disc diffusion.

Water quality indices based on bioassessment: the biotic indices

Water quality indices (WQIs), which translate numerical values of several water quality characteristics of a sample into a single value, play a very important role in the monitoring, comparison and control of water quality. The WQIs of modern and post-modern times have been almost exclusively based on physical and chemical characteristics, and have seldom included 'biological' characteristics other than biochemical oxygen demand (BOD) and faecal coliforms. During the last three decades of the 20th century, indices based on bioassessment have been increasingly used in some developed countries, besides South Africa and Serbia, to complement the conventional WQIs, but the rest of the world continues to base its WQIs predominantly on physical and chemical characteristics. The serious drawbacks of this approach have been elucidated in this paper and, against that background, the state-of-the-art of biotic indices has been summarized. The paper makes a strong case for greater reliance on bioassessment-based WQls, especially by developing countries, to strengthen the diagnostic value of the conventional WQls.

A new method for assessing domino effect in chemical process industry

A new methodology is presented with which the likely impact of accident in one process unit of an industry on other process units can be forecast and assessed. The methodology is based on Monte Carlo Simulation and overcomes the limitations of analytical methods, used hitherto, which were inherently limited in their ability to handle the uncertainty and the complexity associated with domino effect phenomena. The methodology has been validated and its applicability has been demonstrated with two case studies.

A scheme for the classification of explosions in the chemical process industry

All process industry accidents fall under three broad categories-fire, explosion, and toxic release. Of these fire is the most common, followed by explosions. Within these broad categories occur a large number of sub-categories, each depicting a specific sub-type of a fire/explosion/toxic release. But whereas clear and self-consistent sub-classifications exist for fires and toxic releases, the situation is not as clear vis a vis explosions. In this paper the inconsistencies and/or shortcomings associated with the classification of different types of explosions, which are seen even in otherwise highly authentic and useful reference books on process safety, are reviewed. In its context a new classification is attempted which may, hopefully, provide a frame-of-reference for the future.

Water quality management of rooftop rainwater harvesting systems

The ancient technique of harvesting rainwater falling on rooftops, which had been forgotten after the advent of large-scale centralized water resource systems like dam-based reservoirs, has staged a global comeback in the post-modern era. It is expected that in the near future all dwellings everywhere will be equipped to harvest and use rainwater. Such widespread use of rooftop rainwater harvesting makes it very important that the water quality aspects associated with it are clearly understood and managed. The present paper addresses the related issues. The pathways by which pollutants can enter in a rainwater harvest have been traced and the strategies to manage the water quality, at pre-harvest as well as post-harvest stages, have been discussed.

Vermicomposting of the leaf litter of acacia (Acacia auriculiformis): possible roles of reactor geometry, polyphenols, and lignin

Vermicomposting of the pre-composted leaf litter of acacia (Acacia auriculiformis) was studied in reactors of identical volume but with surface area: height ratios varying from 4 to 250. In separate sets of experiments with these reactors, epigeic earthworm species Eudrilus eugeniae and anecic earthworm species Lampito mauritii were employed at densities of 75 and 150 adult animals per litre of reactor volume. The results reveal that greater the surface area: volume ratio of the reactor, higher is the vermicast output in terms of vermicast output per animal; the more densely populated reactors were comparatively under-productive. Even as the vermicast production remained consistently high in all the reactors, there was significant earthworm mortality throughout the course of the experiments and the worms who survived, steadily lost weight with time. A detailed investigation of the possible causes revealed that, whereas the C:N ratio of acacia compost was comparable with that of other substrates; the polyphenols and lignin content were much higher. Studies by other authors on leaf litter consumption by earthworms in natural or man-made forests have indicated that leaf litter rich in polyphenols and lignin are not preferred by most species of earthworm. This may perhaps be the reason for the high rate of mortality and weight loss in earthworms forced to feed upon acacia in the experiments conducted by the authors.

Recovery of methane-rich gas from solid-feed anaerobic digestion of ipomoea (Ipomoea carnea)

Studies are presented on new types of anaerobic digesters in which chopped or dry crushed Ipomoea carnea was fed without any other pretreatment, in an attempt to develop commercially viable means of utilizing the otherwise very harmful plant. Two types of solid-feed anaerobic digesters (SFADs) were studied. The first type had a single vessel in which the bottom 35% portion was separated from the top portion by a perforated PVC disk. The weed was charged from the top and inoculated with anaerobically digested cowdung-water slurry. The fermentation of the weed in the reactor led to the formation of volatile fatty acids (VFAs) plus some biogas. The leachate, rich in the VFAs, was passed through the perforated PVC sheet and collected in the lower portion of the vessel. The other type of reactors had two vessels, the first one was fully charged with the weed and the second received the VFA leachate. With both types were attached upflow anaerobic filters (UAFs) which converted the leachate into combustible biogas consisting of approximately 70% methane. All SFADs developed very consistent performance in terms of biogas yield within 17 weeks of start. The two-compartment reactors yielded significantly more biogas than the single-compartment reactors of corresponding total volume, and the reactors with which anaerobic filters (AF) were attached yielded more biogas than the ones without AF. The best performing units generated 2.41m(3) of biogas per m(3) of digester volume, as compared to 0.1-0.2m(3) of biogas, m(-3)d(-1), obtainable with conventional digesters. This indicates the viability of this technology. The spent weed can be vermicomposted directly to obtain good soil-conditioner cum fertilizer; earthworm Eudrilus eugeniae produced 540mg vermicast per animal every day, achieving near total conversion of feed to vermicast in 20 days. The proposed systems, thus, makes it possible to accomplish total utilization of ipomoea.

Destructive deformation of the digits with auto-amputation: a review of pseudo-ainhum

Pseudo-ainhum is an auto-amputation of the digits. Although extremely rare, it is a traumatic and painful experience that can be alleviated with early recognition and intervention. The scientific literature is filled with reports of this interesting but unfortunate phenomenon. To date, a firm causative aetiology has not yet been established. Although reports on this phenomenon have attempted to further our understanding of pseudo-ainhum, a clear understanding has been complicated by the interchangeable use of terms describing this auto-amputation. In this review, we discuss the current understanding, diagnostic criteria, and management of pseudo-ainhum. Furthermore, the nomenclature of pseudo-ainhum is clarified. Ideally, this will allow for more efficient exploration of pseudo-ainhum, its causes, and therapeutic approaches.

The boiling liquid expanding vapour explosion (BLEVE): mechanism, consequence assessment, management

Among the most devastating of accidents likely in chemical process industry is the boiling liquid expanding vapour explosion (BLEVE). It is accompanied by highly destructive blast waves and missiles. In most situations there is also a fireball or a toxic gas cloud. The damaging effect of BLEVEs is reflected in the fact that the 80-odd major BLEVEs that have occurred between 1940 and 2005 have claimed over a 1000 lives and have injured over 10,000 persons besides harming property worth billions of dollars. Release of toxic chemicals like chlorine and phosgene from BLEVEs have damaged large chunks of areas surrounding the BLEVE site. This paper presents an overview of the mechanism, the causes, the consequences, and the preventive strategies associated with BLEVEs.

Dust explosions-cases, causes, consequences, and control

Dust explosions pose the most serious and widespread of explosion hazards in the process industry alongside vapour cloud explosions (VCE) and boiling liquid expanding vapour explosions (BLEVE). Dust explosions almost always lead to serious financial losses in terms of damage to facilities and down time. They also often cause serious injuries to personnel, and fatalities. We present the gist of the dust explosion state-of-the-art. Illustrative case studies and past accident analyses reflect the high frequency, geographic spread, and damage potential of dust explosions across the world. The sources and triggers of dust explosions, and the measures with which different factors associated with dust explosions can be quantified are reviewed alongside dust explosion mechanism. The rest of the review is focused on the ways available to prevent dust explosion, and on cushioning the impact of a dust explosion by venting when the accident does take place.

Cellular automata-based forecasting of the impact of accidental fire and toxic dispersion in process industries

The strategies to prevent accidents from occurring in a process industry, or to minimize the harm if an accident does take place, always revolve around forecasting the likely accidents and their impacts. Based on the likely frequency and severity of the accidents, resources are committed towards preventing the accidents. Nearly all techniques of ranking hazardous units, be it the hazard and operability studies, fault tree analysis, hazard indice, etc.--qualitative as well as quantitative--depend essentially on the assessment of the likely frequency and the likely harm accidents in different units may cause. This fact makes it exceedingly important that the forecasting the accidents and their likely impact is done as accurately as possible. In the present study we introduce a new approach to accident forecasting based on the discrete modeling paradigm of cellular automata. In this treatment an accident is modeled as a self-evolving phenomena, the impact of which is strongly influenced by the size, nature, and position of the environmental components which lie in the vicinity of the accident site. The outward propagation of the mass, energy and momentum from the accident epicenter is modeled as a fast diffusion process occurring in discrete space-time coordinates. The quantum of energy and material that would flow into each discrete space element (cell) due to the accidental release is evaluated and the degree of vulnerability posed to the receptors if present in the cell is measured at the end of each time element. This approach is able to effectively take into account the modifications in the flux of energy and material which occur as a result of the heterogeneous environment prevailing between the accident epicenter and the receptor. Consequently, more realistic accident scenarios are generated than possible with the prevailing techniques. The efficacy of the approach has been illustrated with case studies.

Qualidex--a new software for generating water quality indices

Water quality indices are necessary for resolving lengthy, multi-parameter, water analysis reports into single digit scores. This, in turn, is essential for comparing the water quality of different sources and in monitoring the changes in the water quality of a given source as a function of time and other influencing factors. In this paper we present the computer-automated tool QUALIDEX (water QUALIty inDEX), which has been developed by us to generate and operate water quality indices. Several popular indices--such as the Oregon Water Quality Index developed in the 1970s by Oregon Department of Environmental Quality and later updated in 1995, the Aquatic Toxicity Index developed by Wepener and coworkers for protection of aquatic life at the Olifants river, Kruger National Park, South Africa, the water quality index developed by Dinius in 1987, the Overall Index of Pollution (of surface waters) developed at the National Environmental Engineering Research Institute (NEERI), and the water quality index of the Central Pollution Control Board (CPCB)--have also been added to QUALIDEX in modular form. There is also a New water quality index sub-module which enables the user to generate his or her own index and compare its performance with these well-known indices. The package is also capable of analyzing the variations in the water quality of different sites at different times. The software has been coded in Visual C++ and has been integrated with MS Access database.

Composting-vermicomposting of leaf litter ensuing from the trees of mango (Mangifera indica)

Litter of the mango (Mangifera indica) tree leaves was composted and then converted into vermicast by the action of the earthworm Eudrilus eugeniae Kinberg. After over nine months of continuous operation the vermireactors with 62.5 animals l(-1) generated approximately 13.6g vermicast per litre of reactor volume (l) per day (d) whereas the reactors with 75 animals l(-1) produced approximately 14.9 g vermicast l(-1) d(-1). This difference in performance of the reactors operating in duplicate at the two different earthworm densities was statistically significant (> or = 90% confidence level) for most of the nine-month span. The animals grew well in all reactors, increasing their zoomass by approximately 103% and producing approximately 157 offspring. Not a single of the 1100 animals died during the first four months. In the subsequent five months a total of 122 worms died, representing a loss of approximately 2% per month. We attribute this to the normal process of ageing. The ability of the earthworms to survive, grow and breed in the vermireactors fed with composted mango tree leaves, and a rising trend in vermicast output inspite of the death of a few worms after four months of reactor operation, indicate the sustainability of this type of vermireactors. The studies also indicate that even better vermireactor efficiency may be possible by modifying the reactor geometry. Studies on changes in C:N ratio during composting and vermicomposting revealed that whereas composting helped in lowering the ratio due to loss of carbon in bacterial metabolism, vermicomposting had no such effect on the ratio.

Vermiconversion of paper waste by earthworm born and grown in the waste-fed reactors compared to the pioneers raised to adulthood on cowdung feed

The performance of four species of earthworm--Eudrilus eugeniae, Kinberg, Drawida willsi Michaelsen, Lampito mauritii, Kinberg and Perionyx excavatus, Perrier--born and grown in vermireactors fed with paper waste was studied over six months, in terms of vermicast output per unit feed, production of offspring, and increase in worm zoomass. These were compared with the performance of the previous generation which had been raised to adulthood on cowdung as principal feed before shifting them to vermireactors operating on cowdung-spiked paper waste. The results indicated that except with D. willsi of which the second generation performed only a shade better than the first, there was significant improvement in vermicast output, animal growth, and reproduction in the second generation compared to the first. The results indicated that cowdung-spiked paper waste can be an adequate food for successive generations of earthworms and that reactors can be operated indefinitely on this feed. The results also indicated that the earthworm generations born and raised in vermireactors operated on this feed become better vermiconverters of this feed than the parent earthworms.

Feasibility studies on the treatment of dairy wastewaters with upflow anaerobic sludge blanket reactors

The feasibility of using upflow anaerobic sludge blanket (UASB) reactors for the treatment of dairy wastewaters was explored. Two types of UASBs were used--one operating on anaerobic sludge granules developed by us from digested cowdung slurry (DCDS) and the other on the granules obtained from the reactors of M/s EID Parry treating sugar industry wastewaters. The reactors were operated at HRT of 3 and 12 h and on COD loading rates ranging from 2.4 kg per m3 of digester volume, per day to 13.5 kg m(-3) d(-1). At the 3 h HRT, the maximum COD reduction in the DCDS-seeded and the industrial sludge-seeded reactors was 95.6% and 96.3%, respectively, better than at 12 h HRT (90% and 92%, respectively). In both the reactors, the maximum, the second best, and the third best COD reduction occurred at the loading rates of 10.8, 8.6 and 7.2 kg m3 d(-1), respectively. At loading rates higher than 10.8 kg, the reactor performance dropped precipitously. Whereas in the first few months the reactors operating on sludge from EID Parry achieved better biodegradation of the waste, compared to the reactors operated on DCDS, the performance of the latter gradually improved and matched with the performance of the former.

Neem leaves as a source of fertilizer-cum-pesticide vermicompost

Vermicomposting of neem (Azadirachta indica A. Juss) was accomplished in "high-rate" reactors operated at the earthworm (Eudrilus eugeniae) densities of 62.5 and 75 animals per litre of reactor volume. Contrary to the fears that neem--a powerful nematicide--might not be palatable to the annelids, the earthworms fed voraciously on the neem compost, converting upto 7% of the feed into vermicompost per day. Indeed the worms grew faster and reproduced more rapidly in the neem-fed vermireactors than in the reactors fed with mango leaf litter earlier studied by the authors (Gajalakshmi et al., 2003). Another set of experiments on the growth, flowering, and fruition of brinjal (Solanum melongena) plants with and without fertilization with vermicompost, revealed that the vermicompost had a significantly beneficial impact.

Growth hormone responses to low-dose physostigmine administration: functional sex differences (sexual diergism) between major depressives and matched controls

BACKGROUND

Considerable endocrine and non-endocrine evidence supports the hypothesis of increased cholinergic activity relative to noradrenergic activity in major depression. We previously reported functional sex differences (sexual diergism) in hypothalamo-pituitary-adrenal cortical (HPA) hormone responses to the administration of low-dose physostigmine (PHYSO), a cholinesterase inhibitor, in 12 female and eight male unipolar major depressives and 12 female and eight male individually matched control subjects. Because growth hormone (GH) secretion also is influenced by cholinergic mechanisms, we measured GH in the samples from this study.

METHOD

Subjects underwent four test sessions 5-7 days apart: PHYSO (8 microg/kg i.v.), arginine vasopressin (AVP) (0.08 U/kg i.m.), PHYSO + AVP and saline control. The AVP was administered as a second stimulus to HPA axis hormone secretion. PHYSO and AVP produced no side-effects in about half the subjects and predominantly mild side-effects in the other half, with no significant patient-control differences. Point biserial correlations between side-effects (absent or present) after PHYSO and the corresponding GH responses were non-significant in all groups.

RESULTS

Afternoon baseline GH was significantly higher in the women than in the men, but it was not significantly different between the female or the male patients and their respective matched controls. AVP administration had no effect on GH. PHYSO administration acutely stimulated GH secretion, to a similar degree in the women and men. The depressed patients as a group had a significantly greater average post-PHYSO GH response than did their controls, with a trend toward a significant sex x diagnosis interaction: The female depressives had a significantly greater GH response than their female controls, whereas the male depressives had a similar GH response as their male controls.

CONCLUSIONS

These findings suggest sexual diergism (functional sex differences) in baseline and cholinergically stimulated plasma GH measures between major depressives and matched normal controls.

Effect of the application of water hyacinth compost/vermicompost on the growth and flowering of Crossandra undulaefolia, and on several vegetables

The impact of the application of compost/vermicompost obtained from water hyacinth (Eichhornia crassipes, Mart. Solms) on plants was assessed in terms of growth and flowering of the angiosperm crossandra (Crossandra undulaefolia). Overall nine morphological, size, and yield attributes were studied in crossandra saplings raised on water hyacinth compost or vermicompost as compared to the untreated saplings. Application of vermicompost led to statistically significant improvement in the growth and flowering of crossandra compared to the untreated plants. The impact of compost was also beneficial but a little less distinct than the positive impact of vermicompost. Qualitative studies were simultaneously conducted in five kitchen gardens owned by farmers near Pondicherry. In three of these locations water hyacinth vermicompost was applied-and no other fertilizer-for months to different species of vegetables. Water hyacinth compost was similarly applied in another two locations. In all the locations no adverse effect on any of the plant species was observed. We believe these studies would help in dispelling the apprehension of farmers that compost/vermicompost obtained form a pernicious weed like water hyacinth may have deleterious effect on other plants.