Rita Puig

Chromium recovery from tannery sludge with saponin and oxidative remediation

Two new methods for treatment of tannery sludge were studied to achieve cost-effective and environmentally acceptable remediation solutions for high chromium containing tannery sludge. Quillaja bark saponin, a plant derived biosurfactant, was applied to dewatered tannery sludge for chromium recovery and a comparative assessment with H(2)O(2) oxidative treatment method is presented. Tannery sludge samples were treated on a laboratory scale with saponin in the pH range 2-3. The effects of various factors like time, concentration of saponin, pH, and temperature on the extraction of chromium were studied. The treatment with saponin extracted 24% of Cr from tannery sludge at a pH around2, performing multiple wash of 6h, at 33 °C. On the other hand, the H(2)O(2) treatment, which include Cr(III) oxidation to Cr(VI) and extraction with sulfuric acid solution at pH 2, enabled to extract 70% of chromium within less than 4h at room temperature (21 °C). The results indicate that the extraction efficiency of saponin was strongly dependent on the organic matter content of the sample, which affects chromium mobility by its high adsorption capacity. On the other hand hydrogen peroxide treatment is effective and the duration of the process is short and requires cheap chemicals and moderate conditions.

From Life Cycle Assessment to Life Cycle Management

Life cycle assessment (LCA) is a widely accepted methodology to support decision‐making processes in which one compares alternatives, and that helps prevent shifting of environmental burdens along the value chain or among impact categories. According to regulation in the European Union (EU), the movement of waste needs to be reduced and, if unavoidable, the environmental gain from a specific waste treatment option requiring transport must be larger than the losses arising from transport. The EU explicitly recommends the use of LCA or life cycle thinking for the formulation of new waste management plans. In the last two revisions of the Industrial Waste Management Programme of Catalonia (PROGRIC), the use of a life cycle thinking approach to waste policy was mandated. In this article we explain the process developed to arrive at practical life cycle management (LCM) from what started as an LCA project. LCM principles we have labeled the “3/3” principle or the “good enough is best” principle were found to be essential to obtain simplified models that are easy to understand for legislators and industries, useful in waste management regulation, and, ultimately, feasible. In this article, we present the four models of options for the management of waste solvent to be addressed under Catalan industrial waste management regulation. All involved actors concluded that the models are sufficiently robust, are easy to apply, and accomplish the aim of limiting the transport of waste outside Catalonia, according to the principles of proximity and sufficiency.

Use of Life Cycle assessment in the procedure for the establishment of environmental criteria in the catalan ECO-label of leather

Life Cycle Assessment (LCA) has been used to detect the environmental ‘hot spots’ in the chrome-tanned bovine leather industry. We have studied those stages in the life cycle of leather, which occur ‘from cradle to gate’. The production chain studied starts with the agricultural products (fertiliser and pesticide production is also included) needed for cattle raising, it is followed by the slaughterhouse, and ends at the tanning industry gate. Main chemicals and waste flows in and out of this chain have also been included in the analysis. One of the main conclusions is that the tannery is an important stage in most of the impact categories, mainly due to the landfilling of the tannery wastes. Agriculture and — to a lesser extent — cattle raising also play a very important role in most of the impact categories; the former, due to the related energy consumption and use of fertilisers, and the latter due to the emissions associated with animal care. The Autonomous Government of Catalonia is using the results of this study to establish the environmental criteria that a leather product must fulfil in order to attain the Catalan eco-label.

Application of life cycle assessment to footwear

Life Cycle Assessment (LCA) has been applied in the leather footwear industry. Due to the fact that the goal of the study is to point those steps in the footwear cycle which contribute most to the total environmental impact, only a simplified semi-quantitative methodology is used. Background-data of all the inputs and outputs from the system have been inventoried. Impact assessment has been restricted to classification and characterisation. From the results of this LCA it has been concluded that energy consumption is an important impact generator phase, due to the characteristics of the electricity production in the studied area (Catalonia and the rest of Spain). A remarkable impact is generated in the solid waste management phase, also due to its characteristics in the studied area. Another significant impact source is the cattle raising phase where great values of Global Warming, Acidification and Eurrophication Potentials are estimated. At the tannery, a great value of water eutrophication potential is observed and this phase is also important for its non-renewable resource consumption.

Environmental optimization of chromium recovery from tannery sludge using a life cycle assessment approach

Life cycle assessment (LCA) was used to evaluate the environmental impact of an oxidative chromium recovery method from tannery sludge, in comparison with the usual landfilling process. Three improvement options (water reduction, byproduct use and anaerobic sludge digestion) were considered. The results showed that the proposed chromium recovery process would be better environmentally than conventional landfilling in all the evaluated impact categories if the amount of chromium recovered was 43 kg per ton of sludge. This amount could be recovered if the chromium concentration was about 20 times higher than that considered in this study. Alternatively, a lower chromium concentration would produce a better result if the recovery method was optimized and implemented at industrial rather than laboratory scale, and if more accurate data were provided on environmental credits for avoiding the chromium production process. Thus, the recovery method is environmentally beneficial when tannery sludge contains a chromium concentration of about 100,000 ppm. According to the literature, such concentrations are not unusual. The results could serve as the basis for further environmental improvements in chromium recovery and tannery sludge management and should be used in decision-making processes, especially for end-of-pipe treatments.

A cumulative energy demand indicator (CED), life cycle based, for industrial waste management decision making.

Life cycle thinking is a good approach to be used for environmental decision-support, although the complexity of the Life Cycle Assessment (LCA) studies sometimes prevents their wide use. The purpose of this paper is to show how LCA methodology can be simplified to be more useful for certain applications. In order to improve waste management in Catalonia (Spain), a Cumulative Energy Demand indicator (LCA-based) has been used to obtain four mathematical models to help the government in the decision of preventing or allowing a specific waste from going out of the borders. The conceptual equations and all the subsequent developments and assumptions made to obtain the simplified models are presented. One of the four models is discussed in detail, presenting the final simplified equation to be subsequently used by the government in decision making. The resulting model has been found to be scientifically robust, simple to implement and, above all, fulfilling its purpose: the limitation of waste transport out of Catalonia unless the waste recovery operations are significantly better and justify this transport.

Proposal of a new model to improve the collection of small WEEE: a pilot project for the recovery and recycling of toys

A new collection model was designed and tested in Catalonia (Spain) to foster the separate collection and recycling of electrical and electronic toys, with the participation of selected primary and secondary schools, as well as waste collection points and municipalities. This project approach is very original and important because small household WEEE has low rates of collection (16–21% WEEE within the EU or 5–7% WEEE in Spain) and no research on new approaches to enhance the collection of small WEEE is found in the literature. The project was successful in achieving enhanced toys collection and recycling rates, which went up from the national Spanish average of 0.5% toys before the project to 1.9 and 6% toys during the two project years, respectively. The environmental benefits of the campaign were calculated through a life-cycle approach, accounting for the avoided impact afforded by the reuse of the toys and the recycling of the valuable materials contained therein (such as metals, batteries and circuit boards) and subtracting the additional environmental burdens associated with the establishment of the collection campaign.

Measuring the environmental footprint of leather processing technologies

The selection of materials and manufacturing processes determines most of the environmental impact that a product will have during its life cycle. In directing consumption towards products with the ...

Use of Rapeseed Straight Vegetable Oil as Fuel Produced in Small-Scale Exploitations

This chapter presents a method to produce rapeseed and process it to obtain rapeseed oil and rapeseed cake meal from a small-scale point of view. It also shows how rapeseed oil can be used as fuel in diesel engines for agriculture self-consumption. A production, processing and use-as-fuel model for rapeseed oil is also presented, analysing environmentally and economically the use of rapeseed oil as fuel compared to other agricultural production alternatives. The results are evaluated for dry Mediterranean area conditions

Are functional fillers improving environmental behavior of plastics? A review on LCA studies

The use of functional fillers can be advantageous in terms of cost reduction and improved properties in plastics. There are many types of fillers used in industry, organic and inorganic, with a wide application area. As a response to the growing concerns about environmental damage that plastics cause, recently fillers have started to be considered as a way to reduce it by decreasing the need for petrochemical resources. Life cycle assessment (LCA) is identified as a proper tool to evaluate potential environmental impacts of products or systems. Therefore, in this study, the literature regarding LCA of plastics with functional fillers was reviewed in order to see if the use of fillers in plastics could be environmentally helpful. It was interesting to find out that environmental impacts of functional fillers in plastics had not been studied too often, especially in the case of inorganic fillers. Therefore, a gap in the literature was identified for the future works. Results of the study showed that, although there were not many and some differences exist among the LCA studies, the use of fillers in plastics industry may help to reduce environmental emissions. In addition, how LCA methodology was applied to these materials was also investigated.