Metal and coal mining are essential for economic development. However, the metalliferous, acidic waters often emerging from these industrial sites, may also cause significant environmental damage. Multi-collector inductively-coupled plasma mass spectrometry (MC-ICP-MS) was developed in the early 1990s. MC-ICP-MS allows for the first time the simultaneous detection of many heavy stable isotopes of elevated ionization potential. Here, I outline the potential of this technique to improve our understanding on the mobilization and transport of metals and the remediation of metalliferous mine waters.

Biological diagnostic tools are becoming an increasingly important aspect of geoenvironmental problems. Modern geoenvironmental professionals must be able to both understand and exploit biological processes for a variety of applications, ranging from contaminant biodegradation and removal to evaluation and monitoring of environmental quality in and around landfills and landfill cover systems. Advancements in genetics and environmental measurement have yielded a wealth of sophisticated tools to evaluate biological processes in soils, sediments and groundwater. Successful use of these tools requires a keen understanding of the limitations and advantages offered by each. This paper provides an overview of the currently available biological diagnostic tools with an emphasis on their application in geoenvironmental engineering. Limitations and unresolved challenges in successful applications of these tools are also discussed.

This critical review emphasizes on the potential applications of low-cost lignocellulosic material in the field of heavy metal pollution remediation. It contains the information related to binding mechanism, relative uptake capacities, effect of modification on increment in uptake capacities, equilibrium, kinetic and thermodynamic modeling involved. This effort offers a good understanding about the role of functional groups in biosorption process. However, there exists a large barrier which inhibits the industry to switch on the biosorption process in place of conventional technologies. Future investigations on (1) assessment of low-cost lignocellulosic materials on multi-metal samples and real world samples, (2) low-cost methods of modification, (3) development of multifunctional lignocellulosic materials can help to decrease this barrier.

Kite power is a novel way of producing wind energy. One possible implementation uses the traction force of a fast-flying kite to drive a stationary generator on the ground. This concept aims at reducing the cost of energy produced by conventional wind turbines. There are however several technical challenges to overcome to develop kite power technology on a large scale. One of them arises from the light weight and flexible nature of the inflatable kite. This yields a tight coupling between the kite’s aero- and structural-dynamics, which is particularly critical when launching and retrieving the system. Computer models capable of predicting these interactions are at an early stage of development. This paper presents the grounds of an ongoing research project, which aims at computationally modelling fluid–structure interactions for kite power systems .

In the last 40 years, anaerobic sludge bed reactor technology evolved from localized lab-scale trials to worldwide successful implementations at a variety of industries. High-rate sludge bed reactors are characterized by a very small foot print and high applicable volumetric loading rates. Best performances are obtained when the sludge bed consists of highly active and well settleable granular sludge. Sludge granulation provides a rich microbial diversity, high biomass concentration, high solids retention time, good settling characteristics, reduction in both the operation costs and reactor volume, and high tolerance to inhibitors and temperature changes. However, sludge granulation cannot be guaranteed on every type of industrial wastewater. Especially in the last two decades, various types of high-rate anaerobic reactor configurations have been developed that are less dependent on the presence of granular sludge, and many of them are currently successfully applied for the treatment of various kinds of industrial wastewaters worldwide. This study discusses the evolution of anaerobic sludge bed technology for the treatment of industrial wastewaters in the last four decades, focusing on granular sludge bed systems.

High sulfide concentrations in biogas are a major problem associated with the anaerobic treatment of sulfate-rich substrates. It causes the corrosion of concrete and steel, compromises the functions of cogeneration units, produces the emissions of unpleasant odors, and is toxic to humans. Microaeration, i.e. the dosing of small amounts of air (oxygen) into an anaerobic digester, is a highly efficient, simple and economically feasible technique for hydrogen sulfide removal from biogas. Due to microaeration, sulfide is oxidized to elemental sulfur by the action of sulfide oxidizing bacteria. This process takes place directly in the digester. This paper reviews the most important aspects and recent developments of microaeration technology. It describes the basic principles (microbiology, chemistry) of microaeration and the key technological factors influencing microaeration. Other aspects such as process economy, mathematical modelling and control strategies are discussed as well. Besides its advantages, the limitations of microaeration such as partial oxidation of soluble substrate, clogging the walls and pipes with elemental sulfur or toxicity to methanogens are pointed out as well. An integrated mathematical model describing microaeration has not been developed so far and remains an important research gap.

Dark fermentation, also known as acidogenesis, involves the transformation of a wide range of organic substrates into a mixture of products, e.g. acetic acid, butyric acid and hydrogen. This bioprocess occurs in the absence of oxygen and light. The ability to synthesize hydrogen, by dark fermentation, has raised its scientific attention. Hydrogen is a non-polluting energy carrier molecule. However, for energy generation, there is a variety of other sustainable alternatives to hydrogen energy, e.g. solar, wind, tide, hydroelectric, biomass incineration, or nuclear fission. Nevertheless, dark fermentation appears as an important sustainable process in another area: the synthesis of valuable chemicals, i.e. an alternative to petrochemical refinery. Currently, acetic acid, butyric acid and hydrogen are mostly produced by petrochemical reforming, and they serve as precursors of ubiquitous petrochemical derived products. Hence, the future of dark fermentation relies as a core bioprocess in the biorefinery concept. The present article aims to present and discuss the current and future status of dark fermentation in the biorefinery concept. The first half of the article presents the metabolic pathways, product yields and its technological importance, microorganisms responsible for mixed dark fermentation, and operational parameters, e.g. substrates, pH, temperature and head-space composition, which affect dark fermentation. The minimal selling price of dark fermentation products is also presented in this section. The second half discusses the perspectives and future of dark fermentation as a core bioprocess. The relationship of dark fermentation with other (bio)processes, e.g. liquid fuels and fine chemicals, algae cultivation, biomethane–biohythane–biosyngas production, and syngas fermentation, is then explored.

Wastewater originating from the textile industry is one of the major sources of pollution for surface and groundwater bodies in countries where textiles and other dye-products are produced. Along with dyes, textile wastewaters also contain varying amounts of metals/metalloids, salts and organic pollutants. Moreover, these wastewaters have high temperatures and varying pH. Various physico-chemical and biological strategies have been devised to remove dye contaminants from such wastewaters. However, biotechnological approaches have attracted worldwide attention for their relative cost-effectiveness and environmentally friendly nature. Most biotechnological approaches rely on the use of microbes that have the potential to enzymatically degrade and decolorize dye-containing textile effluents. During recent years, several microbial cultures as well as microbial enzymes have been characterized and used for removal of dyes from simulated wastewaters having defined chemical compositions. However, there are still many challenges in scaling up microbial and enzymatic technologies for decolorization of raw textile wastewater that contain metals/metalloids, salts and other toxic compounds. The present review article summarizes the findings of recent studies conducted on decolorization of raw textile wastewaters. To the best of our knowledge, this is the only review reporting the biodegradation of azo dyes in raw textile effluents.

Drinking water has been contaminated over decades with some very detrimental compounds such as fluoride. Exposure to fluoride through drinking water above the permissible limit (1.0–1.5 mg/L) causes severe dental and skeletal fluorosis. Adsorption technique which deals with adsorbents for fluoride removal from an aqueous solution is a highly efficient and selective process. This review paper provides insights on adsorbents used and developed by researchers for defluoridation of drinking water. It includes various categories of adsorbents used and parameters affecting the whole process. Adsorbents studied by researchers are enlisted with their adsorption capacity, optimum pH, temperature, equilibrium isotherm, kinetics, interfering ions, thermodynamic studies and regeneration procedure adapted. Efforts are needed to develop low cost reusable adsorbents with high adsorption capacity. Although, some adsorbents are reported to show remarkable capacity for fluoride removal; still there is an urgent need for development of more novel adsorbents holding both economic and technological benefits.

Biological treatment of wastewaters depends on microbial processes, usually carried out by mixed microbial communities. Environmental and operational factors can affect microorganisms and/or impact microbial community function, and this has repercussion in bioreactor performance. Novel high-throughput molecular methods (metagenomics, metatranscriptomics, metaproteomics, metabolomics) are providing detailed knowledge on the microorganisms governing wastewater treatment systems and on their metabolic capabilities. The genomes of uncultured microbes with key roles in wastewater treatment plants (WWTP), such as the polyphosphate-accumulating microorganism “Candidatus Accumulibacter phosphatis”, the nitrite oxidizer “Candidatus Nitrospira defluvii” or the anammox bacterium “Candidatus Kuenenia stuttgartiensis” are now available through metagenomic studies. Metagenomics allows to genetically characterize full-scale WWTP and provides information on the lifestyles and physiology of key microorganisms for wastewater treatment. Integrating metagenomic data of microorganisms with metatranscriptomic, metaproteomic and metabolomic information provides a better understanding of the microbial responses to perturbations or environmental variations. Data integration may allow the creation of predictive behavior models of wastewater ecosystems, which could help in an improved exploitation of microbial processes. This review discusses the impact of meta-omic approaches on the understanding of wastewater treatment processes, and the implications of these methods for the optimization and design of wastewater treatment bioreactors.