Waste Management Technology Offers Page 3

University of Vigo posted this:

Many industries, such as those belonging to the textile, wine, and paper industry, consume huge volumes of water and, as a result, generate a large amount of contaminated water containing persistent colour pollutant compounds. These compounds represent an environmental and health threat due to their well-known associated problems, such as carcinogenicity, toxicity and mutagenicity. Furthermore, they entail a great environmental impact when discharged in aquatic environments, perceptible at very low concentrations, creating an undesirable visual impact, which, in many cases, does not meet the degree of conformity under the current directives on the wastewater treatment for industrial effluents (Directive 91/271 / EEC). The solution proposed by the research group Chemical Engineering at the University of Vigo, is the use as adsorbent of peat, or a similar lignocellulosic material, immobilized in calcium alginate beads. This process is efficient, cheap and environmentally friendly, unlike other processes and technologies. In fact, the utilization of peat instead of activated carbon as industrial adsorbent has the advantage that peat requires no activation, unlike activated carbon, reducing operating costs. In addition, the low cost of the adsorbent would be translated into significant economic benefits. Moreover, depending on the contaminant removed from the waste effluent, the exhausted adsorbent may be used as soil fertilizer at its end of life.

Universidad de Cádiz posted this:

Currently, considerable quantities of lingo-cellulosic residues are generated continuously in many sectors of the agro-food industry. If these can be suitably processed, they are of great commercial interest to industry as potential raw materials for the production of biofuels and a variety of other high value-added products. The residual biomass of the agro-food industry typically has a high content in lipids, carbohydrates, proteins and other compounds of industrial interest. The only limitations to its use as a precursor of biofuel are the economic viability of the process for obtaining these precursors and their quality. One of the byproducts of special interest for this application is spent beer grain, also known as bagasse; given the existing lack of commercial value, this bagasse is widely available as a low-cost raw material. Currently, the principal application of bagasse is as feedstuff for livestock. In general, bagasse does not represent a source of income for breweries, and the reason why it is sold is to minimize the associated problems of waste management and disposal. The UCA research group on "Allelopathy in Higher Plants and Microorganisms" (FQM- 286) has developed an acid hydrolysis procedure whereby precursor materials for biofuels and other high -value-added products are obtained from beer bagasse. Its content in lipids and food fibre (equal to or more than 5% and 20%, dry weight, respectively), make it an ideal material for this application. This would represent a more attractive commercial outlet for many of the residues resulting from operations of the agro-food industry, and in particular, for beer bagasse. The object of the process is to obtain two different products. The first is an oil consisting mainly of the fats contained in the bagasse; the second is a substance rich in sugars or molasses. The oil is of interest as raw material for the production of biodiesel by the process of transesterification; the molasses can be employed as raw material for the production of bio-ethanol by means of fermentation. Molasses can also be formulated as sugar, after a crystallization process. The oil would be particularly useful for correcting the viscosity of biodiesel, thus achieving the optimum parameters for its use as biofuel. In outline, the process developed by the research group consists of a principal line, in which a series of operations take place for the conditioning of the bagasse, such as milling, extraction of lipids and the separation of the resulting solids. Downstream, this line divides into two secondary lines: in one line, for production of oils, the solvents from the prior extraction stage are separated out; in the other secondary line, for the production of molasses, an acid hydrolysis of the sugars is carried out. Another significant feature is that the optimum operating mode of the process is continuous operation, although batch loading is also accepted.

Centre Technology Transfer CITTRU posted this:

Due to the rising emission of methane and its extensive contribution to the greenhouse effect, the reduction of CH4 emissions from low-caloric anthropogenic sources is currently a vital importance. The main sources of the methane emission are: exploitation of oil pools, coal mining, pas power stations, landfills, agriculture and biomass. The most popular method of the reduction of methane is its catalytic combustion. Unfortunately, this method has few limitations associated mainly with hard activation of the C-H bond in CH4 and low concentrations of methane in the emitted gases. The catalytic oxidation of methane is limited also by the very large airflows (of order 105 m3/min), passing through the catalyst bed during the process. There is still a lack on the market of a technological solution based on total catalytic combustion of CH4 in the economically reasonable low-temperature window, i.e. below 400 °C. The most popular method among the methods limiting the emission of methane to the atmosphere is the one based on its catalytic combustion. However, this procedure has disadvantages, mainly due to the high activation energy of methane molecules and also because of the low concentration of methane emitted from anthropogenic sources. There is no technology allowing effectively combusting of methane with the concentration of 1-2 % and in the economically justified temperatures, i.e. lower than 400 °C. The fundamental advantages of offered solutions are: - method for preparing catalysts that ensures the repeatability of the parameters and high efficiency in the reactions of methane combustion, - increased both the activity and the thermal stability of the catalysts in comparison with other systems described in the literature, - possibility of using the catalysts in the total oxidation of methane emitted from the low-caloric sources at temperatures below 400 °C.