Search results for "WASTE"
showing 10 items of 2580 documents
The influence of preservation method and time on theδ13C value of dissolved inorganic carbon in water samples
2009
The precise delta(13)C value of dissolved inorganic carbon (DIC) is important for various types of ecological studies. Without a preservation agent, microbial degradation of organic compounds continues in water samples and the delta(13)C value of DIC will become more depleted with time. HgCl(2) or acidification is often used to prevent microbial activity in water samples collected for carbon isotope ratio analyses of DIC. Mercury compounds are toxic and result in waste disposal problems. Other inhibiting agents or preservation methods are therefore needed. Two possible solutions are to use copper sulphate (CuSO(4)) as a preservative agent or to acidify water samples with phosphoric acid (H(…
Methane production from orange peel pressing liquid: A kinetic study
1992
Abstract This paper studies the anaerobic fermentation of orange peel pressing liquid (OPPL), in semi‐continuous digesters under thermophilic conditions (50, 55 and 60°C), using rabbit manure as inoculum which has been previously conditioned to substrate and temperature. Experimental data have been fitted, at each temperature, to the Chen and Hashimoto model. Kinetic parameters governing the process have been obtained. It can be observed that both μm and K decrease when temperature increases, within the studied range, whereas the calculated minimum hydraulic retention time, θm, increases with temperature, as tested experimentally.
How to reduce energy and water consumption in the preparation of raw materials for ceramic tile manufacturing: Dry versus wet route
2017
Abstract Dry and wet routes in the ceramic tile manufacturing process refer to two different technologies for preparing the raw materials for the forming stage. Both result in a granulated solid ready for use in the pressing stage, but with different characteristics. The dry route was the first to be developed. As quality standards and tile sizes increased, the wet route was developed and introduced successfully into the manufacturing process. Since 1990, the wet route has been the most used around the world to prepare ceramic tile body raw materials. The powder produced by the wet route has finer particles and higher flowability, which has allowed the production of higher quality ceramic t…
Control of VOC emissions from a flexographic printing facility using an industrial biotrickling filter.
2011
The study of an industrial unit of biotrickling filter for the treatment of the exhaust gases of a flexographic facility was investigated over a 2-year period with the objective to meet the volatile organic compound (VOC) regulatory emission limits. Increasing the water flow rate from 2 to 40 m3 h−1 improved the performance of the process, meeting the VOC regulation when 40 m3 h−1 were used. An empty bed residence time (EBRT) of 36 s was used when the inlet air temperature was 18.7 °C, and an EBRT as low as 26 s was set when the inlet temperature was 26.8 °C. During this long-term operation, the pressure drop over the column of the bioreactor was completely controlled avoiding clogging prob…
Modelling of an activated primary settling tank including the fermentation process and VFA elutriation
2002
A complete model of a primary settler including both sedimentation and biological processes is presented. It is a one-dimensional model based on the solids flux concept and the conservation of mass that uses the Takács model for the settling velocity, which is corrected by a compression function in the lower layers. The biological model is based on the ASM2 and enlarged with the fermentation model proposed by this research group. The settler was split in ten layers and the flux terms in the mass balance for each layer is obtained by means of the settling model. A pilot plant has been operated to study the primary sludge fermentation and volatile fatty acids (VFA) elutriation in a primary se…
Biological nitrogen and phosphorus removal in membrane bioreactors: model development and parameter estimation
2012
Membrane bioreactors (MBR) are being increasingly used for wastewater treatment. Mathematical modeling of MBR systems plays a key role in order to better explain their characteristics. Several MBR models have been presented in the literature focusing on different aspects: biological models, models which include soluble microbial products (SMP), physical models able to describe the membrane fouling and integrated models which couple the SMP models with the physical models. However, only a few integrated models have been developed which take into account the relationships between membrane fouling and biological processes. With respect to biological phosphorus removal in MBR systems, due to th…
From inequitable to sustainable e-waste processing for reduction of impact on human health and the environment
2021
Recycling of electric and electronic waste products (e-waste) which amounted to more than 50 million metric tonnes per year worldwide is a massive and global operation. Unfortunately, an estimated 70 & ndash;80% of this waste has not been properly managed because the waste went from developed to low-income countries to be dumped into landfills or informally recycled. Such recycling has been carried out either directly on landfill sites or in small, often family-run recycling shops without much regulations or oversights. The process traditionally involved manual dismantling, cleaning with hazardous solvents, burning and melting on open fires, etc., which would generate a variety of toxic sub…
Halloysite based geopolymers filled with wax microparticles as sustainable building materials with enhanced thermo-mechanical performances
2022
This work proposes a novel protocol for the fabrication of halloysite based geopolymers filled with beeswax microparticles obtained from Pickering emulsions. The actual filling of the microwax into the geopolymers has been demonstrated by using several techniques, including thermal analyses, spectroscopies, microscopies and contact angle experiments. According to the morphological and structural investigations, microwax spherical particles (diameter ranging between ca. 3 and 5 μm) have been homogeneously dispersed within the geopolymeric network conferring excellent properties to the hybrid geopolymers in terms of mechanical performances and heat storage capacity although their low content …
Overcoming managers’ myopic decisions in a waste collection company
2019
Purpose The purpose of this paper is to show how the changing interrelationships between fleet management, human resources and outsourcer capacity areas are likely to counterbalance managerial policies, thereby generating a performance decay. The use of system dynamics modelling in a waste collection company offered an effective contribution to support decision makers to overcoming myopic decisions. Design/methodology/approach Literature review and a case study analysis (including interviews with company actors and data gathering) offered the basis to build a system dynamics model. The model built was then used to run simulations sessions to assess alternative investments decisions. Findin…
THE INTEGRATION OF GREEN-BUILDING TASKS AND PROJECT-DESIGN PROCESSO - CASE STUDY
2018
The development of a green-building project following a specific reference standard such as LEED, brings new conditions and restrains for all subjects involved in the process. Such changes affect technicians, owners, bureaucracy and also the management tasks either during design or construction phases. Within this scope, the management of sustainabilityrelated activities plays a key role for the optimization of the design-project development. This research analyzes the design process of two different case-study projects undergoing the same green-building certification from the project management perspective. In both project sustainability-related activities were performed throughout the de…