Advanced Materials Research Vols. 518-523

Abstract: Effects of temperature (conventional (25°С) vs. mesophilic (35°С) vs. thermophilic (55°С)) on activated sludge properties (production and composition of EPS and interaction potential) and their roles in bioflocculation and settling were studied using well-controlled sequencing batch reactors fed with a synthetic wastewater comprised of glucose and inorganic nutrients. The results show that thermophilic sludge had a poorer bioflocculation ability and settleability than that of conventional and mesophilic sludge. Analysis of extracellular polymeric substances (EPS) indicates that thermophilic sludge had a higher level of loosely bound EPS (LB-EPS) content than that of conventional and mesophilic sludge. The LB-EPS content of thermophilic sludge was ten times more than TB-EPS content of it, which coincided with higher supernatant turbidity. Therefore, the worse bioflocculation and settling ability of thermophilic sludge could be explained from the perspective of LB-EPS. Calculating the interaction energy of three kinds of sludge, the interaction barrier of thermophilic sludge disappeared which meant the attractive potential was dominant in the system. Thus, it should have led to a better flocculation, which did not agree with the actual performance. It indicates that the worse bioflocculation and settling ability of thermophilic sludge could be explained from the perspective of interaction energy.

Abstract: Phosphorus is one of the prime cause of eutrophication,the research of phosphorus removal technology catches the most attention all the time.This paper is focusing on introducing the application and development of the solutions for the phosphorus removal, such as new type of coagulant, new coagulation craft and new flocculation reactor.It points out the core problems in restricting the development of the methods of enhanced coagulation in phosphorus removal ，and gives a clear direction for the research of the methods of enhanced coagulation in phosphorus removal.The enhanced coagulation technology at lower cost and less energy is worth deeply researching.

Abstract: Lop Nur salt Lake is the largest potassium brine deposits discovered in China. Its brine is a kind of magnesium sulfate sub-type brine and can be used to produce potassium sulfate fertilizer. In this paper, response to the feature of various potassium salts in brine evaporation and crystallization product and the great variety with evaporation temperature, the potassium sulfate production process was studied in detail. The mixed salts were pre-conversed and post-floated to form schoenite with the desirable potassium grade. In view of the natural conditions of severe water shortage in Lop Nur, carnallite from post-stage of brine evaporation was decomposed creatively by low-magnesium saturated brine to produce coarse potassium chloride. Eventually, conversion experiment was carried out to produce potassium sulfate by adding water into schoenite and coarse potassium chloride. Raw material ratio, water volume, conversion time, conversion temperature, stirring intensity and other conditions was tested and determined. Optimized product of superior quality for agricultural use, with 57.54% conversion rate and 43.27% potassium sulfate, was achieved.

Abstract: Particle pollution inevitably happens in most engineering environment and in the workplaces. In current studies on polluted particles, the information of particle dynamics with respect to its size distribution can be obtained from The Scanning Mobility Particle Sizer (SMPS) technique. However, the measured data usually can’t be directly used to account for sourced particle because the measured position and the sourced position are always not the same. Without flow transport, in theory, the difference between the measured data and the real sourced data should attribute to the coagulation mechanism which leads to the aerosol instability in thermodynamics. By introducing coagulation mechanism in the particle general dynamic equation and then introducing Taylor-expansion moment method proposed by Yu et al. (Aerosol Sci. Technol., 42:705-713, 2008), a novel method is proposed in this work which has an ability to estimate the emission rate of the source based on the measured data.

Abstract: Trying to carry out environmental risk assessment for the chemical synthestic pharmaceutical wastewater quantificational, the investigation for the fauna of aquatic protozoa, co-relationship analysis among different concentrations of wastewater and survival rates of primarily selected protozoa, and fitting function analysis were performed. At last the euglena, the representative bio-indicator, was selected according to the principles of being dominant species, high co-relationship and high coefficient of fitting function. The optimal culture time was set as 60 mins empirically, that at this point the survival rates of euglena were influenced by the concentrations of wastewater mainly with the biggest difference spectrum of 0.183 and highly significant negative co-relationship (r=-0.9988, P=0.022). The equation of fitting function was: y=-0.69x+0.82; the risk levels were set according to the fitting function: survival rate≥0.82, no risk; 0.41

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