Zafar Adeel

Distribution of nonionic surfactant and phenanthrene in a sediment/aqueous system

A nonionic surfactant, Triton X-100, can act either to enhance or to inhibit phenanthrene sorption from bulk solution onto Lincoln fine sand, depending on the bulk solution surfactant concentration. The distribution of phenanthrene between the sand and the bulk solution is characterized by a partition coefficient that can range in value from less than 0.04 to nearly 10 times that in the absence of surfactant. Sorbed Triton X-100 acts to enhance phenanthrene sorption; not only does the sorbed surfactant directly increase the fractional organic carbon content of the sand but also, on a carbon-normalized basis, the sorbed surfactant is much more effective as a sorbent for phenanthrene than is humic matter.

Sorption and transport kinetics of a nonionic surfactant through an aquifer sediment

Sorption of nonionic surfactant onto aquifer sediment affects both surfactant transport and related surfactant solubilization properties as well as the potential for surfactant-aided mobilization of organic compounds in sediment-aqueous systems. Column experiments were conducted to evaluate the transport and sorption of a nonionic surfactant, Triton X-100, onto an aquifer sediment material, Lincoln fine sand. Unusual two-step breakthrough curves were observed in the column tests, suggesting the existence of two sorption regimes dependent on the sorbed surfactant concentration and molecular conformation. Elution of the sorbed surfactant exhibited considerable tailing. A simplified two-stage, sorption kinetic model is proposed as a first approximation toward characterizing the sorption phenomena, where sorption in each stage is governed by a specific kinetic parameter. The results from this study indicate the importance of kinetic phenomena to describe surfactant transport in sediments.

Modeling Transport of Multiple Organic Compounds: Segregated Transport‐Sorption/Solubilization Numerical Technique

The transport of multiple organic contaminants in the subsurface may be affected by their mutual interactions. Conventional modeling approaches cannot simulate the transport of multiple organic species whose sorption and/or solubilization is interdependent. This paper describes a numerical modeling approach for characterizing interactive solute sorption and solubilization reactions coupled with one-dimensional advective-dispersive transport in porous media. This numerical approach, referred to as segregated transport-sorption/solubilization (STSS), allows for interphase mass transfer at each time step after solute advection and dispersion have occurred. The overall capabilities of the STSS technique include modeling equilibrium or nonequilibrium transport of individual and multiple solutes with linear or nonlinear sorption isotherms. Application of this modeling approach is illustrated for the transport of a conservative tracer, a surfactant, a hydrophobic organic compound (HOC), and a polychlorinated biphenyl (PCB) mixture. The coupling of sorption modules for phenanthrene and surfactant is used to reasonably describe surfactant-enhanced flushing of sorbed phenanthrene from a sand column.

The disaster of arsenic poisoning of groundwater in South Asia—a focus on research needs and UNU's role

Overview of the Arsenic Crisis The pollution of groundwater – the primary source of drinking water – by arsenic in West Bengal (India), Nepal and Bangladesh has led to a crisis of unprecedented proportions. Some recent estimates show that more than 35 million people are potentially at risk from drinking arsenic-contaminated water (Smith et al., 2000) – this indeed brings the problem to a catastrophic scale. In comparison, the current estimate of people possibly infected by the HIV virus all over the world is around 34 million (UN AIDS, 2001). The sheer magnitude of this disaster means that we face new and unique challenges and tasks.

A renewed focus on water security within the 2030 agenda for sustainable development

Water security is integral to worldwide human and economic development objectives. Yet despite many successes, global forecasts show that achievement of universal water security remains elusive. The 2030 Agenda for Sustainable Development, because it is universal and comprehensive, offers an opportunity to renew the discourse on water security. It is argued that achievement of all water-related Sustainable Development Goals (SDGs) and underlying targets is crucial to the success of the entire suite of SDGs pertaining to universal health, food security, gender equality, sustainable consumption, resilient urbanization, and conservation of marine resources and terrestrial ecosystems. A comprehensive approach requires broad engagement of stakeholders, including civil society organizations, governments, private businesses and industries, researchers and scientists. National governments and international development community must help create an enabling environment for all these stakeholders.

The Water, Energy, and Food Security Nexus in the Arab Region

This book investigates the need for a more open and interdisciplinary dialogue on the nexus of food, water and energy security in the Arab region. It argues that achieving sustainable economic development is irretrievably tied to the security of the water–energy–food nexus, which is in turn essential for bringing about sustained peace. Further, it discusses various approaches to achieving these lofty objectives, and offers the following take-away messages: The Arab region is currently under considerable water stress, and the situation will continue to get worse with a number of global changes – most notably those related to climate and regional water distribution. Viable solutions are available in the Arab region and can be implemented through innovative policies, judicious use of new technologies, and stimulating public opinion. Integration across water, energy, and food sectors is obviously needed but achieving it in practice is extremely challenging. There are some gaps in the scientific understanding but at the same time there is a wealth of data and synthesized information that can guide decision-making.

Societal Vulnerability to Desertification and Policy Response Options

Desertification – land degradation and loss of productivity in drylands resulting from human and climatic factors – is one of the greatest global challenges of our times, and correlates directly to poverty, food insecurity and degradation of human well-being. Desertification directly results in biodiversity changes and a decline in soil fertility, water availability and plant cover, which indirectly affect the livelihoods of dryland populations. Conservative figures estimate the extent of the desertified area ranging from 10 to 20 per cent of all drylands, while a much larger area remains at risk.1 Measurement of a persistent reduction in the capacity of ecosystems to supply services provides a robust and operational way to quantify land degradation, and thus desertification. Such a quantification approach is robust because these services can be monitored, and some of them are monitored routinely.

Solubilization and methanogenesis of a particulate industrial waste: Impact of solids loading and temperature

Abstract Effective anaerobic treatment of particulate wastes requires solubilization and acid formation prior to methanogenesis. In this case study of a particulate waste from a corn-processing industry, the influence of solids loading in solubilization, acid formation and methanogenesis was studied under mesophilic (35°C) and thermophilic (60°C) conditions. The waste was concentrated by centrifugation to initial suspended solids concentrations (TSS i ) of 150 to 350 g/L (15% to 35%). Anaerobic batch tests were conducted for 20 days, and significant solubilization of the particulate organic matter occurred in all cases. The thermophilic systems were more effective than the mesophilic systems with respect to solubilization of particulates, volatile solids destruction, acetic acid uptake, and methane generation. Methanogenesis appreared to be a rate-limiting step at higher TSS i values, indicated by accumulation of volatile organic acids in the batch systems. Slower rates of methane production led to identification of the limiting solids loading for both temperature regimes. The results of this study can be used to evaluate the limitations of a single stage system for anaerobic treatment of organic particulate industrial wastes.

Summarizing the Story

This volume investigates the need for a more open and inter-disciplinary dialogue on the nexus of food security, water security, and energy security in the Arab Region. The water security challenges of the Arab Region are well known and well documented, including by some of the authors in this volume. The water security concerns link directly with the achievement of food and energy security but more importantly, also to broader regional security and peace. It has been argued in a number of chapters that achieving sustainable economic development is tied to the security of the water-energy-food nexus, which is in turn essential for achieving sustained peace. Achieving these lofty objectives is much more challenging and a discussion of various approaches is provided throughout the volume; this chapter intends to provide a broader overview.

Managing Water, Energy, and Food for Long-Term Regional Security

This chapter presents a contemporary and robust definition of regional security that encompasses flow of resources, sustainable economic development, poverty reduction, and peaceful co-existence. Regional integration and political stability are key ingredients for achieving regional security. A great level of diversity in human security, quantified by using the Human Development Index as a surrogate, persists in the region. The chapter focuses on the role played by water, food, and energy in regional security; it presents some inter-related drivers of change that impinge on regional security: the burgeoning population with a significant ‘youth bulge’ and accompanying widespread youth unemployment; the economic impacts as a result of globalization, particularly in food and energy sectors; the rise in extremist ideologies and their intersection with efforts to enhance democratic processes; and, geopolitical tussles that are often aimed at greater control of the region’s various resources. A major factor in the regional insecurity is the lack of adequate environmental management, resulting from poor environmental governance; the environmental management gaps are also tied to capacity gaps in human, technological, and institutional resources. The pros and cons are discussed for a number of approaches for sustaining regional water, energy, and food security; these include agricultural land acquisition in Africa, increasing focus on smallholder rain-fed agriculture, mastering the water-energy-food nexus including renewable energy sources, and enabling a favorable policy environment. It is concluded that in order to convince policymakers and governments in the Arab Region that the Water-Energy-Food Nexus (WEF Nexus) is central to regional security, supporting arguments must be presented in quantifiable economic and social terms.