Applied Mechanics and Materials Vols. 448-453

Abstract: promoting the effective use of construction waste is the basic way to carry out construction waste comprehensive control; this paper introduces the current situation of the construction waste, and taking the construction waste of Beijing for example, by using linear regression model analysis. At last, according to the construction waste recycle, we put forward economy mode and reuse of the solution.

Abstract: This paper confirmed the best compost process and parameter of pharmaceutical sludge by forced aerated compost experiment. The volume ratio between sludge and straw is 2:1. The first fermentation is 0-14 days and the primary ventilation quantity is 6m³/h·m³. The second fermentation is 15-35 days. 35 days later, the sludge will be moved from compost tank to space for the post-processing period. 50 days later, composting sludge is completely decomposed. The application effect of sludge fertilizer was analyzed on the lawn and desert land. Rotten sludge fertilizer can raise soil fertility, promote the growth of grass, and be applied in urban greening, and then this can avoid the heavy metals and harmful material entering the food chain. That the sludge fertilizer exploited in desert soil can improve the sand soil nutrient effectively and amend the poor physical and chemical properties of desert soil. Therefore, the entire achievement can be used to strengthen wind prevention and sand fixation and treat ecosystem recession of desert land.

Abstract: overmuch heavy metal is one major restrictive factor for land application of sewage sludge. The environmental behavior of heavy metals depends strongly on their specific chemical fraction or binding state in sludge. The present paper gives an overview of recent researches about the chemical speciation of heavy metals in sludge. A detailed discussion was also made on the various problems associated with the distribution of chemical fractions of heavy metals in sewage sludge, which need to be addressed while exploring more efficient treatment of removing heavy metal.

Abstract: A novel three-dimensional MnO₂ catalyst have been successfully prepared by a facile hydrothermal route. They were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). In addition, they showed excellent catalytic activity over the aqueous degradation of methylene blue (MB).

Abstract: Due to long test cycle, high cost and the complex factors, the long-term deformation properties (such as creep and shrinkage) of recycled aggregate concrete (short for RAC) are rarely reported so far. However this property is essential to fully understanding and widely applying the RAC. Base on investigation on plenty of research results of the long-term deformation of RAC, this paper systematically analyzed the effect of recycled coarse aggregate (C-RA) and recycled fine aggregate (F-RA) on creep and shrinkage performance of concrete. The analysis shows that not only the replacement proportion but also the quality level of recycle aggregate (RA) affect the shrinkage and creep properties of RAC. This outcome could serve as a basis for further research.

Abstract: NH₃ and H₂S emissions not only reduced the nutrient content of compost, and caused odor pollution during organic waste composting_. In this study, composting kitchen waste, agricultural waste and co-composting kitchen waste and agricultural waste were conducted. The temperature, oxygen content and the typical odors emission were analyzed in all treatments. The results indicated that Co-composting kitchen waste and agricultural wastes significantly improve the pile temperature and shorten the mesophilic stage. Poor O₂ transfer and pile temperature were the main reason for H₂S production during waste composting. H₂S release occurred mainly within 15 days in this study for all treatments. The highest concentration of H₂S was observed in the treatment of T2. The productions of H₂S were reduced by 24.8%, 42.3% and 55.1% for T1, T3 and T4 that compared to T2, respectively. The NH₃ had a similar trend to that of H₂S. About 66.4%-72.0% of the total NH₃ released in the high temperature stage for all treatments. The highest concentration of NH₃ was observed in the treatment of T4.The productions of NH₃ were reduced by 36.5%, 19.8% and 21.3% for T1, T2 and T3 that compared to T4, respectively. In terms of H₂S control, it is suitable to co-composting of kitchen waste and agricultural waste. In terms of NH₃ control, it is better to compost kitchen waste and agricultural waste independently.

Abstract: The paper elaborates on the operating principle and technical features of thermo-compression drying process, the kinetics involved in the dewatering process, and the technological process system and equipment used. It is demonstrated by the case of the treatment of Ti-Gypsum using the thermo-compression drying process that the moisture of the products can reach 30%.

Abstract: Electrolytic manganese residues containing a substantial amount of manganese are a potential pollution. Removing water-soluble manganese ions from electrolytic manganese residues by hydrometallurgical process was discussed. In the work, the basic property of the electrolytic manganese residues was analyzed. Based on it, we proposed the suitable method to remove Mn²⁺ from the slag by pollution-free oxidation in alkaline solution. The results shown that the best conditions to remove Mn²⁺ were pH 10.5, temperature 55 °C, the flow rate of hydrogen peroxide 0.50 mL·L^-1·min^-1 and agitation speed 250 r/min. At the optimum condition, the removal ratio of water-soluble Mn²⁺ exceeded 99.9% and the concentration of Mn²⁺ in the final solutions was about 3 mg/L.

Abstract: Sewage sludge treatment and disposal has become a hot issue of current environmental concern, not only its effect will cause secondary pollution to the environment, more importantly, a large quantity of sludge is produced and growth rapidly, acceptable urban area is limited. So its become an important issue need to be solved by us urgently. This article present the current domestic sewage sludge treatment and disposal methods respectively, elaborate the ways for utility, explain the practical advantages and disadvantages of each of these approaches and analyze the existing problems. At the same time, a number of resource utilization of new technologies was prospected.

Abstract: Banana peel is the main by-product in banana processing.A lot of banana waste are not disposeed in China every year.Used for degradation of cellulose on a banana peel and converted into fermentable sugars research. Efficiency of hydrolysis of cellulose to investigate the effect of factors: substrate concentration, reaction temperature, reaction time, enzyme dosage, pH. A single factor experiments the results: substrate concentration is 25%; the reaction time of 6h; reaction temperature of 50°C; the pH is 4.8;the amount of enzyme is 1%. Experimental results show that the application of enzymatic degradation of cellulose can be prepared banana fermentable sugar residue is feasible.