Fly ash from municipal solid waste incinerators (MSWI) is classified as hazardous in the European Waste Catalogue. Proper stabilization processes should be required before any management option is put into practice. Due to the inorganic nature of MSWI fly ash, cementitious stabilization processes are worthy of consideration. However, the effectiveness of such processes can be severely compromised by the high content of soluble chlorides and sulphates. In this paper, a preliminary washing treatment has been optimized to remove as much as possible soluble salts by employing as little as possible water. Two different operating conditions (single-step and two-step) have been developed to this scope. Furthermore, it has been demonstrated that stabilized systems containing 20% of binder are suitable for safer disposal as well as for material recovery in the field of road basement (cement bound granular material layer). Three commercially available cements (pozzolanic, limestone and slag) have been employed as binders.

http://dx.doi.org/10.1016/j.wasman.2011.12.013

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1. Material and energy recovery in integrated waste management systems. An evaluation based on life cycle assessment
2. Use of Incinerator Bottom Ash for Frit Production

Greenhouse and field experiments were conducted to evaluate the response of okra to different levels of human urine (0, 10,000, 15,000 and 20,000 L/ha) and 400 kg/ha NPK 15:15:15 inorganic fertilizer in five riverine communities of Cross River State, Nigeria. The soils of the communities are generally acid with low organic matter, total nitrogen, exchangeable cations, but were rated medium in available P. The pH of the urine was alkaline with moderate amount of nutrients. There was a significant (P < 0.05) increase in nutrient uptake with application of either urine or inorganic fertilizer compared with the control. Application level of 20,000 L urine/ha significantly increased the growth and yield attributes of okra plants relative to NPK fertilizer, while 15,000 L urine/ha had a similar effect on okra plant as the inorganic fertilizer. The inert potentials of human urine as a good source of organic fertilizer are discussed.

http://dx.doi.org/10.1016/j.resconrec.2012.02.003

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1. Stored Human Urine Supplemented with Wood Ash as Fertilizer in Tomato (Solanum lycopersicum) Cultivation and Its Impacts on Fruit Yield and Quality
2. Comprehensive quality assessment of municipal organic waste composts produced by different preparation methods

We present a solid-acid catalyzed one-pot method for the selective conversion of solid hemicellulose without its separation from other lignocellulosic components, such as cellulose and lignin. The reactions were carried out in aqueous and biphasic media to yield xylose, arabinose, and furfural. To overcome the drawbacks posed by mineral acid methods in converting hemicelllulose, we used heterogeneous catalysts that work at neutral pH. In a batch reactor, these heterogeneous catalysts, such as solid acids (zeolites, clays, metal oxides etc.), resulted in >90 % conversion of hemicellulose. It has been shown that the selectivity for the products can be tuned by changing the reaction conditions, for example, a reaction carried out in water at 170 °C for 1 h with HBeta (Si/Al=19) and HUSY (Si/Al=15) catalysts gave yields of 62 and 56 % for xylose and arabinose, respectively. With increased reaction time (6 h) and in presence of only water, HUSY resulted in yields of 30 % xylose + arabinose and 18 % furfural. However, in a biphasic reaction system (water + p-xylene, 170 °C, 6 h) yields of 56 % furfural with 17 % xylose+arabinose could be achieved. It was shown that with the addition of organic solvent the furfural yield could be increased from 18 to 56 %. Under optimized reaction conditions, >90 % carbon balance was observed. The study revealed that catalysts were recyclable with a 20 % drop in activity for each subsequent run. It was observed that temperature, pressure, reaction time, substrate to catalyst ratio, solvent, and so forth had an effect on product formation. The catalysts were characterized by means of X-ray diffraction, temperature-programmed desorption of NH3, inductively coupled plasma spectroscopy, elemental analysis, and solid-state NMR (29Si, 27Al) spectroscopy techniques.

DOI: http://dx.doi.org/10.1002/cssc.201100448

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1. Production of jet and diesel fuel range alkanes from waste hemicellulose-derived aqueous solutions
2. Chemical recycling of post-consumer polymer waste over fluidizing cracking catalysts for producing chemicals and hydrocarbon fuels

Presently, appropriate waste management is one of the main requisites for sustainable development; this task is tackled by the material construction industry. The work described herein is focused on the valorization of granite waste through incorporation, as a filler-functional admixture, into cement-based mortar formulations. The main components of the waste are SiO2 (62.1 %), Al2O3 (13.2 %), Fe2O3 (10.1 %), and CaO (4.6 %). The presence of iron oxides is used to develop the photocatalytic properties of the waste. Following heating at 700 °C, α-Fe2O3 forms in the waste. The inclusion of the heated sample as a filler admixture in a cement-based mortar is possible. Moreover, this sample exhibits a moderate ability in the photodegradation of organic dye solutions. Also, the plastering mortars, in which the heated samples have been used, show self-cleaning properties. The preparation of sustainable building materials is demonstrated through the adequate reuse of the granite waste.

DOI: http://dx.doi.org/10.1002/cssc.201100552

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1. Use of Olive Biomass Fly Ash in the Preparation of Environmentally Friendly Mortars
2. Use of waste brick as a partial replacement of cement in mortar

Nitrogen recovery through NH3 stripping is energy intensive and requires large amounts of chemicals. Therefore, a microbial fuel cell was developed to simultaneously produce energy and recover ammonium. The applied microbial fuel cell used a gas diffusion cathode. The ammonium transport to the cathode occurred due to migration of ammonium and diffusion of ammonia. In the cathode chamber ionic ammonium was converted to volatile ammonia due to the high pH. Ammonia was recovered from the liquid–gas boundary via volatilization and subsequent absorption into an acid solution. An ammonium recovery rate of 3.29 gN d−1 m−2 (vs. membrane surface area) was achieved at a current density of 0.50 A m−2 (vs. membrane surface area). The energy balance showed a surplus of energy 3.46 kJ gN−1, which means more energy was produced than needed for the ammonium recovery. Hence, ammonium recovery and simultaneous energy production from urine was proven possible by this novel approach.

http://dx.doi.org/10.1016/j.watres.2012.02.025

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1. Life Cycle Assessment of High-Rate Anaerobic Treatment, Microbial Fuel Cells, and Microbial Electrolysis Cells
2. Microbial Fuel Cell as Wastewater Treatment and Desalination Technology

The possible role of ammonia in a future energy infrastructure is discussed. The review is focused on the catalytic decomposition of ammonia as a key step. Other aspects, such as the catalytic removal of ammonia from gasification product gas or direct ammonia fuel cells, are highlighted as well. The more general question of the integration of ammonia in an infrastructure is also covered.

DOI: http://dx.doi.org/10.1039/C2EE02865D

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