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Phosphorus Recycling from Wastes  [PDF]
Ketil Haarstad, John Bavor
Journal of Environmental Protection (JEP) , 2017, DOI: 10.4236/jep.2017.88052
Abstract: The plant phosphorus (P) uptake by Italian ryegrass using organic wastes such as sewage sludge, biochar, composted sewage sludge and spent wetland filters as fertilizer was investigated in pot experiments after manipulating the wastes pH by mixing with other wastes giving acidification by acetic acid and compost leachate, and liming by concrete waste and lime. Pots with no fertilizer and with mineral fertilizer served as control. Available P was measured both with passive diffuse gradient thin film (DGT) samplers and by P uptake in the grass. The pH in the treated waste was about 4 in the acid treatment, and more than 11 in the high pH treatment. The pH in the pot during the grass production was adjusted to normal levels. The P uptake increased up to 56% after pH treatment of the waste. The P uptake responded both to the high and low pH treatments, probably due to the prevalence of different P species. The more extreme pH treatments gave the highest uptake. The DGT uptake gave the same broad picture in the pots fertilized with biochar but not in pots with sludge, and, also, without the separation between high and low treatments. The passive samplers correlated relatively well with the measured grass uptake. A principal component (PCA) analysis showed that the P uptake as measured by the DGT correlated with P, potassium (K) and silicon (Si) concentrations, at to a lower degrade with iron (Fe) and lead (Pb), and was uncorrelated with nickel (Ni) and cupper (Cu). In summary we can say that the pH treatment of the different organic wastes increased the plant P availability. The smallest increase was in the wetland filter that also had the lowest P total uptake. Also the lupin treatment increased the plant P uptake.
The quality of the recovered matrix material as an element of assessment of effectiveness of the composite recycling process  [PDF]
D. Nagolska
Archives of Foundry Engineering , 2007,
Abstract: Metal composites are ever more readily used as structural materials, due to their properties. Therefore, in spite of their difficult processing, their use constantly grows (e.g. SGL Carbon Poland S.A.). In consequence, the amount of their wastes grows too. Since the social pressure aimed at improving the quality of environment has recently intensified and the significance of the technologies enabling recovery of secondary materials has increased, the interest in recycling of metal composites also grew, irrespective of all the difficulties related thereto.One of the groups of metal composites includes the composites with saturated reinforcement. They may be recycled only with the method of components separation. The simplest way for this consists in choosing an appropriate environment in which the recycling occurs so as to enable free outflow of melted matrix from capillaries of the porous reinforcing profile. As an effectiveness measure of the process not only the yield of the melted metal but also its quality should be considered. The paper presents results of the studies on recycling of a group of composite materials with saturated reinforcement of various structures and chemical compositions. The environments including salt mixtures chosen for the considered composites reinforced with pressed fibre profiles satisfy the first and the most important quantity criterion. i.e. allow for achieving the required metal yield. For the composite of the highest yield level the quality of melted metal was analyzed which showed that the environment selected this way meets also another criterion that enables obtaining high quality alloys, thus allowing for their direct use in the process of reinforcing the composite casts. On the other hand, in the case of the composites reinforced with sinters the first criterion has not been met and, therefore, the metal quality in this case has not been assessed.
Recycling of Ornamental Stones Hazardous Wastes  [PDF]
Abdel Monem Soltan, Zeinab Taman, Baher El-Kaliouby
Natural Resources (NR) , 2011, DOI: 10.4236/nr.2011.24031
Abstract: Sawing and polishing of the ornamental stones always generate large amount of solid and wet hazardous wastes, which pollute the environment. In Shak Al-Thoaban area, East Cairo, Egypt, huge amounts of these wastes were accumulated, during the last years, as rejects “Solid” and wet “Sahala” wastes, representing one of the main sources of environmental pollution. The aim of this work is to characterize and evaluate these wastes for recycling in quicklime production. Hence, samples of both wastes were investigated for their chemical and mineral composition applying XRF, XRD, DTA and TGA methods. Free lime content and reactivity (RDIN) of both samples were also determined after calcination for differnt soaking times (0.25 - 2.0 hrs) at 1000℃. The results were interpreted in relation to composition and microstructure of the fired samples as revealed by TLM and SEM methods. The RDIN reactivity of the resulted lime is changeable along soaking time at 1000℃because of the microfabric of its crystallites. The lime of the “Solid” sample is preserving the original limestone microstructure that contributes in its higher RDIN reactivity values at all soaking times. The relatively higher degree of grain growth of lime crystallites in the “Sahala” sample leads to its lower reactivity. The optimum soaking times for the highest lime reactivity are 0.25 and 1 hr. for the “Solid” and “Sahala” samples, respectively. On increasing soaking time up to 2 hrs, both samples show minimum RDIN values. The “Solid” sample also gives higher free lime content than the “Sahala” one at all soaking times. It is gradually increased in the former sample up to a maximum (96% - 97%) on increasing soaking time up to 1-2hrs. On the other side, a maximum free lime (~95%) is detected in “Sahala” sample at 0.25hr soaking time and gradually decreased to (87%) up to 2hrs.
Socioeconomic and Enviromental Sustainability Through Recycling of Chemical Wastes
Oloruntegbe Kunle Oke
Research Journal of Applied Sciences , 2012, DOI: 10.3923/rjasci.2010.13.19
Abstract: This study examines the process of achieving socioeconomic and environmental sustainability through recycling of chemical wastes. The chemistry principle that matter is not lost or gained but remains constant is applied in here. Atom never wears out. What one laboratory or industry has no need of could be found useful in another. The recycling of chemical waste can serve as a means of providing solutions to many environmental and economic problems such as high cost of waste disposal and depletion of natural resources. The state of the art in the field of chemical recycling of polymers, textile waste and carpet, Cement Kiln Dust (CKD), Old Newspapers (ONP), domestic and municipal organic waste is reviewed in this study. The benefits and problems of this exercise are also highlighted. The conclusion drawn is that the recycling of waste is of immense benefits especially in solving the numerous environmental problems and boosting the nation s economy but that not much is done, in developing nations for example, to sensitize the schools and the general public on the importance of recycling of chemical waste.
Recycling of Different Available Organic Wastes through Vermicomposting
S. Karmakar,K. Brahmachari,A. Gangopadhyay,S. R. Choudhury
Journal of Chemistry , 2012, DOI: 10.1155/2012/945762
Abstract: Generation of organic wastes has been increased in an unprecedented rate in India with rapid population expansion, leading to disposal problems. These organic wastes can be converted into valuable wealth by applying vermicomposting technology. Vermicompost which provides macro and micro nutrients to the plants, also reduces pollution by providing a valuable substitute for chemical fertilizers. Present paper deals with vermicomposting of organic wastes from seven different sources and evaluation of nutrient in those vermicomposts following chemical analyses. These seven sources include coconut coir, water hyacinth, mixed materials, cabbage, banana pseudostem, cow dung, and rice husk. Three composting species of earthworms e.g. Eisenia. fetida, Eudrilus. eugeniae, and Perionyx excavatus were chosen for the experiment. Chemical analysis of vermicomposts under study clearly showed that the vermicompost from water hyacinth contained maximum amount of organic C, total N, and total K though the phosphorous content was maximum in vermicompost from mixed materials. Lowest nutrient content was observed in vermicompost of coconut coir. Vermicomposts from mixed materials, cabbage, banana pseudostem were at per in their chemical properties. It can be concluded that among the seven sources, vermicompost from water hyacinth is best for its nutrient value.
Recycling and Disposal Methods for Polyurethane Wastes: A Review  [PDF]
Ravindra V. Gadhave, Shrray Srivastava, Prakash A. Mahanwar, Pradeep T. Gadekar
Open Journal of Polymer Chemistry (OJPChem) , 2019, DOI: 10.4236/ojpchem.2019.92004
Abstract: Polyurethanes (PU) are a general class of polymers prepared by the polyaddition of isocyanates and hydroxyl group containing compounds. PU foams are formed via the reaction of poly-isocyanate and multi-functional hydroxyl compounds resulting in urethane linkages. The foams are formed in wide range of densities and maybe flexible, semi-flexible or rigid in structure. To control the foam structure, blowing agents are employed. These agents are introduced during foam formation through volatilization of low-boiling liquids or through the formation of gas due to chemical reaction. Additionally, surfactants, catalysts, etc. are used during the manufacturing of foams. PU, including PU foams, is one of the most important groups of materials today and hence, their recycling has been of great interest. Many methods of recycling PU are available and many more are being studied further. However, no method has seen large scale commercialization or is brought into regular practice. The objective of this review is to bring to light the various technologies available and their current status of development as well as newer upcoming methods that may be available in the future.
Recycling of glass cullet as aggregate for clays used to produce roof tiles
Costa, F.B.;Teixeira, S.R.;Souza, A.E.;Santos, G.T.A.;
Matéria (Rio de Janeiro) , 2009, DOI: 10.1590/S1517-70762009000400007
Abstract: numerous silicates based wastes have been produced and considered for recycling and reuse. among them, glass cullet is one of the most common silicate wastes and has considerable volume in the cities wastes. a big amount of this waste is recycled by the glass industry but another part is dumped in the cities garbage deposits. in the last few decades there has been considerable research on the reuse of glass waste as aggregate to produce glass-ceramic, for mortars, ceramics and for cement and concrete. this work is concerned to study the reuse of one way glass bottles as aggregate to produce roof tiles (red ceramic). two kinds of glass powder were prepared by sieving: alpha (0.088 to 0.125 mm) and beta (0.037 to 0.088 mm). prismatic ceramic bodies (cb) were pressed (60 x 20 x ~5 mm) using a ceramic mass with 0, 5, 8 and 10 % of glass cullet powder added and fired at five different temperatures (800 to 1200 oc). the results of the technological tests (flexural strength, water absorption, dimensional changes, density and porosity apparent) show that shrinkage increases with the glass content and all other properties above are improved. these changes are more exhibited at temperatures higher than 900°c and in the higher powder glass concentrations (8 e 10%).
Enzymatic Synthesis and Chemical Recycling of Novel Polyester-Type Thermoplastic Elastomers  [PDF]
Tsukuru Yagihara,Shuichi Matsumura
Polymers , 2012, DOI: 10.3390/polym4021259
Abstract: Novel polyester-type thermoplastic elastomers based on poly(alkylene succinate)s were synthesized by the lipase-catalyzed copolymerization of cyclic diol/succinate oligomer and cyclic diol/alkylthiosuccinate oligomer. These copolymers exhibited biodegradabilities by activated sludge and a wide range of thermal and mechanical properties that were dependent on the molecular structure and the content of side alkylthio groups. The degree of crystallinity of the copolymer decreased with increasing content of alkylthio groups, which were introduced into the polymer chain as a soft segment. Furthermore, lipase-catalyzed depolymerization of these copolymers into cyclic oligomers and repolymerization of the oligomers was carried out. A repolymerized copolymer having the same M w and monomer composition as the initial copolymer was obtained, indicating the chemical recyclability of the copolymer.
Survey of Knowledge, Attitude and Practice of Yazd University of Medical Sciences Students about Solid Wastes Disposal and Recycling  [PDF]
MH Ehrampoush , MH Baghiani Moghadam
Iranian Journal of Environmental Health Science & Engineering , 2005,
Abstract: The risk of unhealthy disposal of solid waste is one of the important problems in many societies, and recycling is considered as a solution for managing solid wastes. Environmental knowledge and attitude of young people (like students) appears to be crucial as their point of view ultimately plays an important role in providing solution to future environmental problems. In this study the knowledge, attitude and practice of Yazd University of Medical Sciences students in respect of disposal of solid wastes and the important factors were studied. Two hundred thirty seven students were included in this cross-sectional study, selected from 5 schools of this university. Data collected by a self administered questionnaire containing four sections, were analyzed using SPSS for Windows. The mean grade of knowledge of men and women was 13.53 and 12.38, of 20, respectively. The difference between the knowledge of males and females was significant (P< 0.016). On the whole the knowledge of the students was not appropriate. About 66% of students did not have any action in segregation and recycling of solid wastes. It is concluded that all students must take part in formal and informal education classes to promote their knowledge in this regard.
Ecotoxicological e ects of mixed pollutants resulted from e-wastes recycling and bioaccumulation of polybrominated diphenyl ethers in Chinese loach (Misgurnus anguillicaudatus)
Ecotoxicological effects of mixed pollutants resulted from e-wastes recycling and bioaccumulation of polybrominated diphenyl ethers in Chinese loach (Misgurnus anguiUicaudatus)

QIN Xiaofei,XIA Xijuan,LI Yan,ZHAO Yaxian,YANG Zhongzhi,FU Shan,TIAN Mi,ZHAO Xingru,QIN Zhanfen,XU Xiaobai,YANG Yongjian,
QIN Xiaofei
,XIA Xijuan,LI Yan,ZHAO Yaxian,YANG Zhongzhi,FU Shan,TIAN Mi,ZHAO Xingru,QIN Zhanfen,XU Xiaobai,YANG Yongjian

环境科学学报(英文版) , 2009,
Abstract: To understand potential ecotoxicological e ects of electrical and electronic equipment waste (e-waste) recycling and polybrominated diphenyl ethers (PBDEs) bioaccumulation in loaches, a semi-field experiment using Chinese loach (Misgurnus anguillicaudatus) as experimental fish was performed. Larval loaches were kept in net-cage for three months in an e-wastes recycling site and a reference site in Southeastern China. There was significant di erence of the survival rate between the loaches from the e-wastes recycling site (27%, 19/70) and from reference site (70%, 49/70). Histopathological responses were also found in all the livers examined in loaches from the e-wastes recycling site. These results showed that mixed pollutants resulted from e-wastes recycling led to ecotoxicological e ects on loaches. The bioaccumulation of polybrominated diphenyl ethers (PBDEs), the main pollutants in e-waste, in loaches was also studied, the mean concentration of total PBDEs in sediment was 6726.17 ng/g wet weight and in water samples was 4.08 ng/L (dissolved phase). BDE 209 was the dominant congener in sediment and with relatively high concentration in water. Relatively low concentration of BDE 209 (less than 0.01% of total PBDEs) and high concentration of BDE47 (up to 39.34% of total PBDEs) were detected in loaches.
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