RESUMEN
Solid blasting waste generated from coating removal during ship repair and maintenance poses environmental challenges. This paper presents a review of the generation, characterization, and treatment of blasting waste in the ship repair industry. The quantities, properties, and environmental impacts of the generated blasting waste are summarized and analyzed, and the results indicate that blasting waste has a high generation rate and/or high toxicity. As alternatives to landfill, available blasting waste treatment methods include hydrometallurgical leaching, physical/physicochemical separation, thermal treatment, and direct utilization in the production of building materials. The advantages and disadvantages of these treatments are reviewed and compared. The production of building materials from blasting waste is currently attractive owning to its economic benefits and technical simplicity, whereas recycling blasting waste for high-value applications is gradually gaining research interest. The high dependence of the choice and performance of treatment methods on the waste type and characteristics is highlighted. The results emphasize the interest in conducting more research on physiochemical and thermal properties and the environmental effects of blasting waste. This review suggests that future research should focus more on paint waste management because of the restricted application of dry abrasive blasting and the development of nonabrasive blasting methods in the ship repair industry.
Asunto(s)
Navíos , Administración de Residuos , Conservación de los Recursos Naturales , Materiales de Construcción , Pintura , Reciclaje , Residuos SólidosRESUMEN
In this study, Prosopis juliflora biomass was co-liquefied with hydrocarbons rich paint waste for next generation fuel (bio-oil) production. Co-liquefaction (HTL) was performed at varying biomass to paint waste ratios (1:0, 0:1, 1:1, 2:1 and 1:2) at different temperatures from 340 to 440⯰C for a holding time of 60â¯min. Bentonite catalyst was added from 1 to 5% wt. to the HTL reactor. Gas Chromatography-Mass Spectroscopy (GC-MS) and Fourier Transform Infrared Spectroscopy (FTIR) analysis were carried out for bio-oil and HTL aqueous phase. Maximum bio-oil yield was around 49.26% wt. at 420⯰C, 2:1 blend and 4% wt. of bentonite catalyst. Energy and carbon recovery of bio-oil was around 70% and 96% respectively. Additionally, HTL aqueous phase was analysed and it showed presence of acids molecules in it. The gas from HTL process contained Carbon dioxide (46.25%), Carbon monoxide (6.38%), Methane (9.35%) and hydrogen (24.53%).
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Biomasa , Hidrocarburos/metabolismo , Pintura , Prosopis/metabolismo , Aguas del Alcantarillado , Catálisis , Cromatografía de Gases y Espectrometría de Masas , Calor , Aceites de Plantas/metabolismo , Polifenoles/metabolismo , Espectroscopía Infrarroja por Transformada de FourierRESUMEN
Between 1950 and 1980, lead and chromium along with other metals have been used in paint coatings to protect bridges from corrosion. In New York State with 4500 bridges in 11 Regions 2385 of the bridges have been rehabilitated and subsequently repainted after 1989 when commercial use of lead based paint was prohibited. The purpose of this research was to address the concentration and distribution of trace metals in the paint waste generated during bridge rehabilitation. Using hypothesis testing and stratified sampling theory, a representative sample size of 24 bridges from across the state was selected that resulted in 117 paint waste samples. Field portable X-ray fluorescence (FP-XRF) analysis revealed metal concentrations ranged from 5 to 168,090 mg kg(-1) for Pb, 49,367 to 799,210 mg kg(-1) for Fe, and 27 to 425,510 mg kg(-1) for Zn. Eighty percent of the samples exhibited lead concentrations greater than 5000 mg kg(-1). The elevated iron concentrations may be attributed to the application of steel grit as an abrasive blasting material routinely used by state Departments of Transportation in the paint removal process. Other metals including Ba and Cr were observed in the paint waste as well. As a result of the paint formulation, metals were found to be associated in the paint waste (Pb correlated with Cr (r=0.85)). The elevated metal concentrations observed raises concern over the potential impact of leaching from this waste stream.
Asunto(s)
Monitoreo del Ambiente , Metales/análisis , Pintura/análisis , Contaminantes Químicos del Agua/análisis , Industria de la Construcción , New YorkRESUMEN
The disposal of paint waste from bridge rehabilitation is a significant issue because of the potential release of contaminants and the consequent impact to human health and the environment. In this study, leaching behavior of paint waste was evaluated for 24 bridges in New York State. Although elevated Pb (5-168,090 mg kg(-1)) and other metal concentrations were observed in the paint samples, leaching experiments that included the toxicity characteristic leaching procedure (TCLP) and the multiple extraction procedure (MEP) revealed toxicity characteristic (TC) limits were not exceeded. The relatively low concentrations observed are attributed to the use of iron-based abrasives (steel grit) in the paint removal process. In this research, trace metals are hypothesized to be sequestered through interactions with iron oxide coatings formed on the steel grit surface resulting in reduced leachable concentrations. Through sequential extraction iron oxides were observed at 11.03% by wt and X-ray diffraction (XRD) further corroborated the presence of iron oxide coatings on the steel grit surface. Sequential extraction demonstrated that less than 6.8% of Pb, Cr, and Ba were associated with the exchangeable and carbonate forms, while greater contributions were found with iron oxides. The largest fraction, however, greater than 80%, was associated with the residual phase comprised of minerals in the paint including SiO2 and TiO2.
Asunto(s)
Compuestos Férricos/química , Metales Pesados/química , Pintura , Acero , New York , Dióxido de Silicio/química , Titanio/química , Difracción de Rayos XRESUMEN
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.