Applied Mechanics and Materials Vols. 522-524

Abstract: Under laboratory conditions, by determining the appropriate proportion added to sludge, composting experiments were carried out to achieve the best results in cold climates. Aerobic sludge composting reactors adopted positive forced aeration for static pile. Additives and sludge were mixed at the volume ratios of 2:1 and 3:1 respectively. By investigating the change laws of temperature, moisture, organic matter, pH, total phosphorus and ammonium, the maturity of sludge composting was evaluated. During the composting at the volume ratio of 2:1, the temperature could rise quickly, the moisture and organic matter declined apparently, and the total phosphorus content increased significantly. Besides, the rest of the indicators all met the maturity standards. Under the condition, sewage sludge could be converted to organic fertilizer in favor of the growth of crops through composting process.

Abstract: The new technology of thin film evaporation - molecular distillation was introduced to the regeneration process of waste heavy oil. According to the results, this method was proved to be effective to the narrow separation of the material of waste engine oil from engine maintenance workshop, and also be suitable to a large-scale production. The properties of the distillation products from molecular distillation were found to be comparable with those of the typical standards of MVI250 and MVI350 respectively. The overall yield of 90% was got in the process. The recommended conditions of the pabs was 5-80 pa, heat transfer oils was 200-240oC, circulating water temperature is 25-28oC. The resulted product can meet the standards of MVI250, MVI 350.The practice shown in this paper suggested a good method to get high yield of good base oils. The molecular distillation will show excellent prospects in the field of waste oil regeneration.

Abstract: In this paper, the influence of RAP content on pavement performance of hot plant recycling asphalt mixture is experimentally studied. The pavement performances contain high temperature stability, low temperature stability, water stability and fatigue resistance. Recovered asphalt was firstly extracted from RAP, and the properties of recovered asphalt was then tested and compared to normal 70# pavement asphalt. The gradation of recovered aggregate and new aggregate was then tested, and the mine material mixture gradation was determined. Marshall Test was adopted to determine the optimal asphalt content. The pavement performances show that the dynamic stability increases with RAP content increasing. The blending strain and fatigue life decreases while the stiffness modulus increases with the RAP content increasing. However, the residual stability and TSR show no obviously change with RAP content increasing.

Abstract: In order to attain a simple and reliable process in the salt recycle in industrial waste water, non-filler evaporating tower is proposed. Based on the heat and mass transfer theory, the saline wastewater recycle process is proposed, and the sensitivity of water evaporating rate to the tower height and the inlet salt water temperature is analyzed. The numerical simulation is developed, which establishes optimal parameters of the process.

Abstract: In order to test the feasibility of co-composting for surplus sludge and garbage RD thermal decompositing nutrient soil, the mid-temperature composting experiments for the optimized conditions such as bacteria inoculating mode, initial moisture and pH were carried. The results showed that:(1) K-bacteria isolated from soil had a ability of decompositing insoluble mineral potassium to soluble forms at a rate of 9.20 μgK/200ml.h, and a decomposing ratio of 7.83% for potassium feldspar in liquid batch culturing. Moreover, after liquid enlargement culturing for 32h, the quantity of bacteria spores reached its climax, which ensured the high survival rate of K-bacteria. (2) The pre-compost inoculating mode (M₁) was superior to post-compost (5^th d M₂) based on available nutrient or K-bacteria quantity increasing;(3) Through optimizing experiments, the best initial moisture of 50-60% and pH of 6.5 were determined with an ideal available nutrients and K-bacteria quantity in compost; (4) The inoculating of K-bacteria could increase the microbial quantity and activity, which may increase the heavy metal activity in compost, so the further researches on heavy metal passivation should be considered.

Abstract: According the high energy consumption and pollution in foundry industry, the reason of high energy consumption and the source of the pollution were analyzed. Based on the analysis, for the sustainable development of foundry industry, some effective measures were suggested: defining the responsibility of all referred parties (governor and enterpriser); trying to save energy and protect environment from the source; reusing the waste scientifically.

Abstract: Wetland wastewater treatment commonly used in farming, but aquaculture wastewater often contains large amounts of antibiotics, making the wetland system there is uncertainty on the removal of contaminants. To this end, this paper four antibiotics (Ampicillin, Oxytetracycline, Bacitracin, Colistin sulfate) composite vertical flow constructed wetland wastewater treatment on the effects of mariculture. The results showed that for the next four kinds of antibiotics interfere IVCW with TOCNH₃-NNO₃^--N removal rate decreased; But after some time, TE for TOC removal and CS for NO₃^--N removal was without interference. In addition, wetland microbial resistance to antibiotics will be gradually formed, the lower the formation of drug-resistant and high resistant faster than the upper level, and prolonged use of broad-spectrum antibiotics are more prone to tolerance.

Abstract: The growth performance of duckweed (Spirodela polyrrhiza) and its removal rate of nitrate and phosphorus in sewages taken from sewage treatment plant with different processes were studied. The experiments were conducted in an environmentally controlled growth chamber. Three kinds of sewages were taken from a grit chamber, a sedimentation tank, and the anoxic pond in a sewage treatment plant, respectively. The fourth kind of sewage was mixed using the sedimentation tank sewage and the anoxic pond sewage in a volumetric ratio 1:1. The weight of duckweed biomass were determined with a balance. Wastewater samples taken from the media were analyzed for total nitrogen (TN), ammonium nitrogen (NH₄N), total phosphorus (TP), phosphatephosphorus (PO₄P) using AA3 Continous Flow Analyzer. The results showed that Spirodela polyrrhiza grew well in sewages taken from grit chamber and sedimentation tank of a sewage treatment plant, whereas a lot of duckweed fronds were dead in the sewage taken from the anoxic pond due to the high TP (higher than 7.9 mg/L) and TN (higher than 51.6 mg/L). The suitable TN concentration for Spirodela polyrrhiza growth should not be higher than 45 mg/L. Compared with the treatments without duckweed, the NH₄N concentrations were reduced more than 60% in ST and GC sewages with duckweed due to the NH₄N uptake by duckweed. Spirodela polyrrhiza could remove TN efficiently in sewages with relative low concentration TN (less than 20 mg/L), while duckweed could not remove TN effectively in sewages with high concentration TN (higher than 20 mg/L). The TN concentration in GC sewage decreased greatly in the first four days, which probably brought about anaerobic condition, thus P uptake switched to net release of P, which caused the increase of the TP concentration in the GC sewage without duckweed in the last six days. O₂ or oxidant should be provided for sewage treatment system using duckweed to ensure that efficient removal of TN and TP meanwhile. The TP and PO₄P concentrations in the mixed sewage with duckweed increased far more than those for no-duckweed treatments, which could be related that the dead duckweed released P into the sewage.

Abstract: This paper concludes that emergency has a derivative nature On the basis of outlining its situation over the past two years in Beijing. The derivativity is expressed in the field of emergency, economics, politics and social insurance. The paper then analyzes the causes of the derivative nature: uncertainty of emergency, the limits of research and covert ideological struggles.

Abstract: The emergency rescue can be implemented rapidly after the breakout of the public health emergency, greatly benefited from the emergency media science communication that develops to a great extend. This article analyzes the current situation and existing problems of media science communication modal that media develops after an outbreak of public health emergency and puts forward the countermeasures and suggestions on the innovative modal of media science communication.