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Sewage sludge is regarded as a potential source for soil fertilizer However, the direct utilization of sewage sludge in agricultural land is restricted since it also contains heavy metals, pathogens, and toxic compounds. Pyrolysis of the sewage sludge destroys the organic pollutants and partly volatilizes the heavy metals. In this study, pyrolysis of sewage sludge was carried out in order to determine the optimum residence time and temperature to recover the phosphorous and remove heavy metals from the resultant sewage sludge char (SSC). Pyrolysis was conducted on dried sewage sludge (DSS) by means of thermogravimetric analysis (TGA) and high-temperature oven with an N2-atmosphere. Microwave Plasma-Atomic Emission Spectroscopy (MP-AES) was used to determine the concentration of P and trace elements in the resulting solid char fraction. A combination of chemical fractionation (step-by-step leaching) of the DSS and thermodynamic equilibrium calculations were utilized to estimate the availability of phosphorous and removal of heavy metals in the SSC fraction at different temperatures. The results from the thermodynamics calculation were in line with the measured chemical composition of the SSC. Furthermore, the energy contents of the SSC obtained at different temperatures were measured. The pyrolysis evaluation results indicate that phosphorous was enriched in the char, while lead, zinc, and cadmium were significantly removed.

A catalyst for tar cracking has been prepared successfully from natural zeolites using ion exchange with NH4NO3, and acid leaching with HNO3 solution for removing impurities and increasing pore volume. The activity of the modified zeolite was tested using toluene as a tar model compound. Tar conversion of about 54% was achieved in catalytic steam reforming at a temperature of 750C using 2 gram of catalyst and the gas hourly space velocity about 5040 h-1.

In an era characterized by a move towards a “knowledge society”, universities are central in fostering “knowledgeability”, that is the reflexive understanding of knowledge in knowledge societies. The objective of “knowledgeability” can be met through creating a stronger link between education and research. Furthermore, overall student performance, for example in critical thinking and problem solving, can be improved if research-related activities are incorporated into the curriculum. The aim of this paper is to use international examples to discuss the research- education nexus from four different perspectives, namely context, policy, implementation and quality, with case studies from higher education institutions in Singapore and Sweden. We suggest that different integrative technologies can be used to enhance the links, but it will be essential to consider the inputs of training, service and support in using new technology. Interestingly, the act of evaluating the link between education and research will increase awareness of this linkage by stakeholders involved in both education and research. In turn the link can be strengthened, contributing to increased quality in both education and research., Published even in Preprints 2019

A new model for predicting the specific chemical exergy of municipal solid waste (MSW) is presented, the model is based on the content of carbon, hydrogen, oxygen, nitrogen, sulfur, and chlorine on a dry ash-free basis (daf). The proposed model was obtained from estimations of the higher heating value (HHV) and standard entropy of MSW using statistical analysis. The ultimate analysis of 56 different parts of MSW was used for the derivation of the HHV expression. In addition, 30 extra parts were used for validation. One hundred and seventeen relevant organic substances that represented the main constituents in MSW were used for derivation of the standard entropy of solid waste. The substances were divided into different waste fractions, and the standard entropies of each waste fraction and for the complete mixture were calculated. The specific chemical exergy of inorganic matter in the waste was also investigated by considering the inorganic compounds in the ash. However, as a result of the extremely low value calculated, the exergy of inorganic matter was ignored. The results obtained from the HHV model show a good correlation with the measured values and are comparable with other recent and previous models. The correlation of the standard entropy of the complete waste mixture is less accurate than the correlations of each individual waste fraction. However, the correlations give similar results for the specific chemical exergy, indicating that HHV has a greater impact when estimating the specific exergy of solid waste than entropy.

Entropy, as an outcome of the second law of thermodynamics, measures the level of irreversibility associated with any process. The identification and reduction of irreversibility in the energy conversion process helps to improve the efficiency of the system. The entropy of pure substances known as absolute entropy is determined at an absolute reference point and is useful in the thermodynamic analysis of chemical reactions; however, municipal solid waste (MSW) is a structurally complicated material with unknown absolute entropy. In this work, an empirical model to calculate the absolute entropy of MSW based on the content of carbon, hydrogen, oxygen, nitrogen, sulphur, and chlorine on a dry ash free basis (daf) is presented. The proposed model was derived from 117 relevant organic substances which represent the main constituents in MSW with known standard entropies using statistical analysis. The substances were divided into different waste fractions; namely, food, wood/paper, textiles/rubber and plastics waste and the standard entropies of each waste fraction and for the complete mixture were calculated. The correlation of the standard entropy of the complete waste mixture derived was found to be somsw= 0.0101C + 0.0630H + 0.0106O + 0.0108N + 0.0155S + 0.0084Cl (kJ.K-1.kg) and the present correlation can be used for estimating the absolute entropy of MSW by using the elemental compositions of the fuel within the range of 10.3% ≤ C ≤ 95.1%, 0.0% ≤ H ≤ 14.3%, 0.0% ≤ O ≤ 71.1%, 0.0 ≤ N ≤ 66.7%, 0.0% ≤ S ≤ 42.1%, 0.0% ≤ Cl ≤ 89.7%. The model is also applicable for the efficient modelling of a combustion system in a waste-to-energy plant., {"references":["K. S. Woon, and I. M. C. Lo, \"Greenhouse gas accounting of the proposed landfill extension and advanced incineration facility for municipal solid waste management in Hong Kong,\" Science of the Total Environment, vol. 458-460, pp. 499-507, 2013.","A. Fazeli, F. Bakhtvar, L. Jahanshaloo, N. A. Che Sidik, and A. E. Bayat, \"Malaysia's stand on municipal solid waste conversion to energy: A review,\" Renewable and Sustainable Energy Reviews, vol. 58, pp. 1007-1016, 2016.","T. Solheimslid, H. K. Harneshaug, and N. Lümmen, \"Calculation of first-law and second-law-efficiency of a Norwegian combined heat and power facility driven by municipal waste incineration-A case study,\" Energy Conversion and Management, vol. 95, pp. 149-159, 2015.","V. S. Stepanov, \"Chemical energies and exergies of fuels,\" Energy, vol. 20, no. 3, pp. 235-242, 1995.","W. Eisermann, P. Johnson, and W. L. Conger, \"Estimating thermodynamic properties of coal, char, tar and ash,\" Fuel Processing Technology, vol. 3, no. 1, pp. 39-53, 1980.","J. H. Shieh, and L. T. Fan, \"Estimation of energy (enthalpy) and exergy (availability) contents in structurally complicated materials,\" Energy Sources, vol. 6, no. 1-2, pp. 1-46, 1982.","S. Ikumi, C. D. Luo, and C. Y. Wen, \"METHOD OF ESTIMATING ENTROPIES OF COALS AND COAL LIQUIDS,\" CAN J CHEM ENG, vol. V 60, no. N 4, pp. 551-555, 1982.","G. Song, L. Shen, and J. Xiao, \"Estimating specific chemical exergy of biomass from basic analysis data,\" Industrial and Engineering Chemistry Research, vol. 50, no. 16, pp. 9758-9766, 2011.","G. Song, J. Xiao, H. Zhao, and L. Shen, \"A unified correlation for estimating specific chemical exergy of solid and liquid fuels,\" Energy, vol. 40, no. 1, pp. 164-173, 2012.\n[10]\tE. S. Domalski, and E. D. Hearing, \"Heat Capacities and Entropies of Organic Compounds in the Condensed Phase. Volume III,\" Journal of Physical and Chemical Reference Data, vol. 25, no. 1, pp. 1-525, 1996.\n[11]\tK. K. Pandey, \"A Study of Chemical Structure of Soft and Hardwood and Wood Polymers by FTIR Spectroscopy,\" Journal of Applied Polymer Science, vol. 71, no. 12, pp. 1969-1975, 1999.\n[12]\tF. Dietrich, and W. Gerd, \"Wood: Chemistry, Ultrastructure, Reactions,\" De Gruyter, Berlin, pp. 66-181, 1983.\n[13]\tA. K. Bledzki, V. E. Sperber and O. Faruk. \"Natural Wood and Fibre Reinforcement in Polymers,\" Smithers Rapra, Shropshire, United Kingdom. pp. 4-18, 2002.\n[14]\tJ. F. Fundo, M. A. C. Quintas, and C. L. M. Silva, \"Molecular Dynamics and Structure in Physical Properties and Stability of Food Systems,\" Food Engineering Reviews, vol. 7, no. 4, pp. 384-392, 2015.\n[15]\tR. E. Wrolstad, \"Food Carbohydrate Chemistry,\" Wiley-Blackwell, West Sussex, United Kingdom. 2011.\n[16]\tT. P. Coultate, \"Food: the chemistry of its components,\" Royal Society of Chemistry, Cambridge, United Kingdom, pp. 7-408, 2002.\n[17]\tJ. A. Brydson, \"Plastics Materials (Seventh Edition),\" Butterworth-Heinemann, Oxford, United Kingdom. pp. 205-813, 1999.\n[18]\tQ. Fan, \"Chemical Testing of Textiles (First Edition),\" Woodhead Publishing, Cambridge, England. 2005.\n[19]\tS. Gordon and Y. L. Hsieh, \"Cotton: Science and Technology,\" Woodhead Publishing, Cambridge, England. 2007.\n[20]\tR. B. Simpson, \"Rubber Basics,\" Smithers Rapra, United Kingdom. 2002.\n[21]\tC. Sheng, and J. L. T. Azevedo, \"Estimating the higher heating value of\nbiomass fuels from basic analysis data,\" Biomass and Bioenergy, vol.\n28, no. 5, pp. 499-507, 2005.\n[22]\tS. A. Channiwala, and P. P. Parikh, \"A unified correlation for estimating HHV of solid, liquid and gaseous fuels,\" Fuel, vol. 81, no. 8, pp.1051-1063, 2002.\n[23]\tStandard thermodynamic properties of chemical substances, CRC Press.\nAvailable at http://www.update.uu.se/~jolkkonen/pdf/CRC_TD.pdf\n(accessed 3 July 2015), 2000."]}

Resurser och hållbarhet är nära förknippade. Hållbarhet innebär att hushålla med resurser - materiella, miljömässiga och mänskliga. Och hushållning är per definition kärnan i ekonomi. Man börjar alltmer se framväxten av en hel arsenal av verktyg och förhållnings- och angreppssätt för att bygga hållbarhet. Detta förenas av ett synsätt att det som hitintills setts om avfall och värdelöst, och rent utav besvärligt att ta hand om, nu blir en värdefull resurs. Det glömda och gömda kommer åter. Faktum är att många ord och begrepp kring detta börjar på just åter- eller re- . Internationellt talar man om Redesign, Recycling, Remake, Recycle, Recraft, Reuse, Recreate, Reclaim, Reduce, Repair, Refashion. Vad är då allt detta? Ja, vill man dra det långt, är det inte mindre än framväxten av ett nyvunnet sätt att tänka, ja av en ny samhällssektor, en bransch och en industri, sammanbundet av filosofin att återanvändningen, spillminskningen, vidarebruket, efterlivet anses som viktiga faktorer för ett miljömedvetet samhälle. Re: blir paraplytermen för detta. I denna antologi av forskare från skilda discipliner vid Högskolan i Borås lyfts ett antal av dessa begrepp inom Re: fram.