Tasneem Abbasi

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.

Sources of Pollution in Rooftop Rainwater Harvesting Systems and Their Control

Contrary to the popular perception that rainwater harvested from rooftops is nearly as clean as pure water, a number of contaminants can be present in such a water—this is borne out by numerous studies reviewed by the authors. Once this fact is acknowledged, it is possible to control the water quality and to bring it within acceptable levels with simple and inexpensive devices. The authors address these issues. Besides reviewing the status of the quality of harvested rainwater, they trace the pathways by which pollutants can enter in a rainwater harvest. In this backdrop the authors discuss the strategies to manage the water quality at preharvest as well as postharvest stages.

The Generation, Impact, and Management of E-Waste: State of the Art

Even as the world has been unsuccessfully trying to dispose off the rising quantities of its municipal solid waste (MSW) and hazardous waste (HW) in a clean manner, it has been confronted with an even more complex problem—of e-waste. Only a few countries in the developed world are able to scientifically recycle or dispose the e-waste they generate. In other developed countries only a fraction of the e-waste is properly recycled, the rest is either incinerated or sent to landfills—which are solutions that cause serious secondary problems. Worse still, a sizeable portion of the e-waste generated in the developed world is exported to developing countries where it is recycled or dumped without any concern for the gross pollution that is being caused. It can be said that if the situation vis-à-vis e-waste is posing a challenge in most developed counties, it is alarmingly bad in the developing world. In an attempt to contain the e-waste problem most of the developed world and several countries in the developing world have enacted legislation to curb illegal trafficking and unlicensed recycling of e-waste. These legislations invoke the extended producer responsibility concept based on life-cycle considerations in the hope that it will provide prevention as well as cure. Innumerable non-governmental organizations and citizens groups have also been trying to help out. So far, all these measures together have achieved only a modicum of success—that, too, only in a few regions of the developed world—but if viewed on the global scale ever bigger streams of e-waste are threatening to join the rising tides of MSW and HW in engulfing the world. The present paper assesses the state-of-the-art, bringing out how and why the e-waste problem has been defying all attempts to contain it. The paper also brings out that—much the same way as has happened with MSW and HW—the size and the complexity of the e-waste problem is increasing at much faster rate than the efficacy of our strategies to contain it. This trend is not likely to reverse soon and the only viable means to solve the problem is to drastically reduce generation of waste.

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.

Vermicomposting eliminates the toxicity of Lantana (Lantana camara) and turns it into a plant friendly organic fertilizer

In evidently the first study of its kind, vermicompost derived solely from a weed known to possess plant and animal toxicity was used to assess its impact on the germination and early growth of several plant species. No pre-composting or supplementation of animal manure was done to generate the vermicompost in order to ensure that the impact is clearly attributable to the weed. Whereas the weed used in this study, Lantana (Lantana camara), is known to possess strong negative allelopathy, besides plant/animal toxicity in other forms, its vermicompost was seen to be a good organic fertilizer as it increased germination success and encouraged growth of all the three botanical species explored by the authors - green gram (Vigna radiata), ladies finger (Abelmoschus esculentus) and cucumber (Cucumis sativus). In terms of several physical, chemical and biochemical attributes that were studied, the vermicompost appeared plant-friendly, giving best results in general when employed at concentrations of 1.5% in soil (w/w). Fourier transform infrared spectrometry revealed that the phenols and the sesquiterpene lactones that are responsible for the allelopathic impact of Lantana were largely destroyed in the course of vermicomposting. There is also an indication that lignin content of Lantana was reduced during its vermicomposting. The findings open up the possibility that the billions of tons of phytomass that is generated annually by Lantana and other invasives can be gainfully utilized in generating organic fertilizer via vermicomposting.

Is the Use of Renewable Energy Sources an Answer to the Problems of Global Warming and Pollution

It has always been a widely prevalent belief that renewable energy sources are clean and green in contrast to nonrenewable fossil fuels. The oil price shocks of 1973 and 1979, alongside increasing global awareness towards environmental pollution had stimulated great interest in the development of renewable energy sources during the early 1980s. But as the oil prices came down and few breakthroughs were achieved in that period for making the cost of renewable energy comparable or lesser to fossil fuel energy, the enthusiasm of the early 1980s began to wane. In more recent years the spectres of global warming and ocean acidification, which have been primarily attributed to fossil fuel burning, has caused a resurgence of interest in renewable energy sources. As illustrated in this article, scientists from all over the world are strongly advocating large-scale substitution of conventional energy sources with renewable alternatives on the premise that such a move would substantially reduce environmental degradation and global warming. These sentiments are being echoed by policy makers as well as environmental activists. The authors examine the scenarios when different renewable energy technologies may be pressed into service to either produce power in large-scale centralized systems or be used widely in small-scale and dispersed fashion (instead of the rarely large-scale and mostly sporadic manner of their use at present). They discuss that there are likely to be impacts as strongly adverse as global warming and others experienced with fossil fuel use. The purpose of this exercise is not to make a case against renewable resources, but rather to report on a much more realistic and elaborate assessment of the direct and indirect impacts of extensive utilization of renewable energy technologies than has been done hitherto, which will help the cause of renewable resources in the long run. It would help us in preventing most of the likely problems from taking root. In addition, it will spare the world from the type of disillusionment it faces vis a vis large hydel power projects, which were—before their widespread use—perceived as the epitome of virtue.

Ocean Acidification: The Newest Threat to the Global Environment

Ocean acidification is the newest global environmental threat confronting the earth. It is the consequence of the same anthropogenic excess that is responsible for global warming—release of much more CO2 at much faster rates, minute after minute, than the earths capability to assimilate. Considering that oceans cover almost 70% of the earths surface, any upset in the balance of forces in the oceans due to anthropogenic CO2 emissions has, potentially, much more massive consequences than the impacts scientists are witnessing on the rest 30% of the earth. Ocean acidification is the name given to the lowering of ocean pH that is beginning to occur because the oceans are being forced to absorb CO2 at a much faster rate during the last few decades than it has been over the previous thousands of years. The term does not imply that the oceans have actually become acidic, or will become acidic in the near future; it signifies a shift of ocean pH toward less alkaline levels. This shift has already threatened coral reefs and calcifying organisms. The latest forecast based on the most sophisticated models and the most authentic field data indicate that the adverse impact may become precipitous in the much more immediate future than was forecast previously. Ocean acidification has also come to be called the other CO2 problem. Oceans are also absorbing large quantities of two more acid-forming gases being released at unprecedented rates into atmosphere—SOx and NOx. Thus far, on a global scale, their impact has been relatively minor; less than 3% of the impact of CO2, but is expected to grow in magnitude as the emissions continue to increase. Moreover, the impact is likely to be much stronger in coastal regions, with serious portents for humankind.

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.

A Brief History of Anaerobic Digestion and “Biogas”

This chapter briefly traces the history of anaerobic digestion from the time the existence of this phenomenon was first recorded four centuries ago to its rapidly increasing popularity at present. The extent of adaptation of biogas technology across the world is also briefly reviewed. Whereas China and India lead the initiative from among developing countries, the thrust of the developed world is mainly coming from Western Europe.

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 10th or 11th 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.