Advanced Materials Research Vols. 113-116

Abstract: The BCR-SEP method was used to determine the binding forms of heavy metals in Amuta Lake(AMT) in this paper. The chemical forms of heavy metals, namely extractable fractions or valid fractions, including exchangeable-carbonate fraction, Fe-Mn oxide fraction and Organic-sulfide fraction .The results of the partitioning study indicated that in the core AMT sediments, Cr, Fe and Ni are mainly associated with the residue fraction, Cu is mainly concentrated in the Fe–Mn oxide fractions and residue fraction, Mn is concentrated in the exchangeable-carbonate fraction and residue fraction. Zn is concentrated in organic-sulfide fraction and residue fraction.

Abstract: This paper introduced the design of gamma energy spectrometer by technology of LabVIEW and Bluetooth. The hardware of system included portable gamma energy spectrometer, Bluetooth module and PC. The software of system included the composed of acquisition system by the MCU and analysis system by PC.The design of acquisition system included the design of main program, liquid crystal display module, keyboard module, Bluetooth communication module and data acquisition module. The design of analysis system included the design of serial communication module, data storage module and data processing module. Practice shows that the energy spectrometer has a user-friendly, flexible, low cost, easy to expand and good performance.

Abstract: The strain Bacillus sp. WD23 exhibiting laccase activity was screened from forest soil. The M9 medium containing Cu2+ was used for enriching and isolating bacterial strains capable of oxidizing syringaldazine (SGZ). One isolated strain was identified as Bacillus subtilis WD23 based on the results of physiological and biochemical tests and 16S rDNA sequence analysis. The strain WD23 could grow at temperatures ranging from 20 to 55°C and showed optimum growth temperature and pH at 25°C and 7.0, respectively. The sporulation rate of the strain clearly correlated well with the laccase activity. The temperature half-life of the spore laccase was 2.5 h at 80°C and the pH half-life was 15 d at pH 9.0. Its spore laccase could decolorized 50~90% of Remazol brilliant blue R (RBBR), alizarin red, congo red, methyl orange and methyl violet, which suggests the potential application of spore laccase in dyestuff treatment.

Abstract: The reutilization of waste Printed Circuit Boards (PCB) is a focused topic in the field of environment protection and resource recycling, and the crushing is the crucial process for recycling waste PCB. A hamper impacting crusher was used to achieve metals crushing liberation from non-metals, the liberation mechanism of PCB can be explained by dispersion liberation accompanied disengaging liberation. The Rosin-Rammler distribution model of crushed PCB particle was put forward. The evaluation indexes show that Rosin-Rammler function can accurately describe size distribution of PCB particles because the convergence property R2 is 0.99694 and fitting error E is 4.80658. The selective crushing is appearance with metals concentrated in coarser fraction and non-metals in finer size during comminution processing. The impact crushing is an effective method to metals liberation of PCB particles.

Abstract: Chironomus kiiensis larvae which cannot be exterminated by conventional disinfection process propagates prolifically in eutrophic water body, and it therefore turns to be a potential problem encountered in drinking water quality. In this work, the quantitative experimental studies were carried out on removal of Chironomus kiiensis larvae in raw water by coagulation-sedimentation process. The coagulation jar test showed that the Chironomus kiiensis larvae could be partially removed from water by coagulation-sedimentation process. Based on it, removal effect of pre-oxidation combined with coagulation-sedimentation process on Chironomus kiiensis larvae was evaluated. The results showed that chlorine dioxide pre-oxidation possessed better removal performance than prechlorinion, and Chironomus kiiensis larvae in the raw water could be completely removed by chlorine dioxide pre-oxidation in combination with the coagulation-sedimentation process at chlorine dioxide dosage of 0.8mg/L. The pH in the range of 6-8 did not affect the inactivation efficiency of chlorine dioxide, whereas pH 10 resulted in around 10% decrease in removal rate. Meanwhile, the removal rate of Chironomus kiiensis larvae improved with the temperature increasing within the range investigated of 15-30°C. The removal rate was reduced by 6.7% when temperature reduced from 30°C to 15°C.

Abstract: Dry methane fermentation is an innovative anaerobic digestion technique to treat solid bio-wastes without dilution for potential energy recovery with nutrient rich fertilizer and sustainable waste management. Although dry anaerobic fermentation offers great advantages like utilization of wastes in its produced form, high organic loading rate, no liquid effluent and comparable amount of biogas production with wet fermentation, commercial dry anaerobic digestion is scarcely used so far. In order to develop feasible dry fermentation process, it is important to review the optimization techniques and suggested possible areas where improvements could be made, including the reactor configuration, mixing, feed stocks, co-digestion, pretreatment and environmental conditions within the digester.

Abstract: Chironomus kiiensis larvae which cannot be exterminated by conventional disinfection process propagates prolifically in eutrophic water body, and it therefore turns to be a potential problem encountered in drinking water quality. In order to tackle this problem, a pilot-scale study of removal effect on Chironomus kiiensis larvae with chlorine dioxide in a waterworks is performed. The experiment results showed that Chironomus kiiensis larvae can be effectively removed from water by 0.55 mg/L chlorine dioxide pre-oxidation combined with the conventional drinking water treatment process. Higher oxidizability and molecular state of chlorine dioxide in water is the key to the inactivation of Chironomus kiiensis larvae. The chlorite, disinfection by-products (DBPs) of chlorine dioxide, is stable at 0.217 mg/L, which is lower than that critical value of the WHO. Ames test revealed that the mutagenicity was reduced by chlorine dioxide with respect to prechlorine. The propagation of Chironomus kiiensis larvae can be inactivated effectively and safely by chlorine dioxide pre-oxidation.

Abstract: To solve the obscure and vague problem in present agricultural circular economy evaluation, in this paper we from the perspective of ecological restoration adopt PPC model directly driven by sample data to make the objective evaluation. We choose 17 evaluation indicators in 3 types to compute the affecting factors of agricultural circular economy in 31 provinces and cities in 2007 and make sorting and classification for optimal projection direction and optimal projection value . The research result can provide differentiated agricultural circular economy strategy with theoretical base and supply the integrated evaluation of agricultural circular economy with new method and has practical promotion value.

Abstract: Zeolite is a kind of normal adsorber. Unfortunately the adsorption capacity of natural zeolite is low, it must be activated on behalf of reaching a higher adsorption capacity. On this condition, removal of phosphorus through modifying zeolite has been studied in lab scale through using a mechanically stirred batch system. The results showed that the adsorption isotherm of modified zeolite conformed to Freundlich model and the rate of adsorption conformed to Banerm equation.

Abstract: Mulching is considered as a simplest utilization of water hyacinth. In this study, a field experiment using the litterbag method was conducted on the decomposition of the water hyacinth mulch under vegetable plot conditions. Mulch mass losses and changes in nutrient and C/N ratio were measured over 100 days to determine the effects of mulch characteristics on decomposition and nutrient concentration in the remaining mulches. The remaining mass after 100 days decomposed on the vegetable plot was 45.4%, 9.4% and 0.0% to the initial mass of the root, stem and leaf, respectively. Water hyacinth leaf recorded the highest decomposition rate 0.1538 day-1 7 times greater than stem, with stem 0.0217 day-1 but significantly greater than root 0.0072 day-1. The time taken for 95% mass loss varied with mulches. Root took 403 days, stem took 130 days and leaf took 36 days, respectively. The remaining N of leaf mulch decreased with decomposition time. On the other hand, the remaining N of root and stem showed three phases: decreased (reaching 42.0% and 26.2%), increased (reaching 44.8% and 26.5%) and decreased again (reaching 32.5% and 8.0% of the initial N content of the root and stem). The remaining P of stem and leaf declined continuously from the beginning to the end of the study. The dynamic of the P of root can be divided into two phases. In the end of the experiment the C/N ratio was 25.5, 24.7 and 19.4 of the root, stem and leaf, respectively. The results demonstrated that the leaf decay first and the root can last for more than 1 year during the water hyacinth mulch decomposition, this may be good for the soil nutrient cycling and moisture conserving under vegetable plot.