Advanced Materials Research Vols. 183-185

Abstract: Struvite precipitation in sludge dewatering filtrate was achieved in a lab-scale sequencing batch reactor. The influence of the operational conditions on the struvite precipitation process has been studied. These operational conditions include stirring rate of the reactor, reaction time and sedimentation time. Experiments indicated that stirring rate of the reactor within 50 rpm to 250 rpm had no strong influence on the formation of struvite. As reaction time increased, there was a slight positive effect on the removal of Mg2+, NH4+ and PO43-. Suggested reaction time is 40-80 minutes based on our experiments. In order to obtain the lower turbidity and the lower PO43- concentration in the decanting filtrate of the batch reactor, the minimum sedimentation time should be more than 30 minutes.

Abstract: The effects of various extractants removing Cr from the soil of chromite ore processing residue (COPR) deposited sites were studied in order to select the optimal extractant agent. The effects of this agent on the removal of Cr(VI) and Cr(III) in the contaminated soil were also investigated. The results showed that organic complexing agents had higher removal efficiency than that of inorganic complexing agents due to the high content of Cr(III) in the soil(90.3%). The Cr removal of citric/sodium citrate (mole ratio: 1:1) was 35.95% in 24h. The reason why citric/sodium citrate removed more Cr than other agents is that citric can solubilize the mineral matrix, compete for the surfaces sites to desorb Cr(VI) and remove Cr(III) by its complexation. The concentration radio of Cr(VI) and Cr(III) in the initial soil was 0.11. Thus improving the removal of Cr(III)is the key point of improving the total Cr removal.

Abstract: Cyclodextrin played an important role in environmental protection in recent years.Application of cyclodextrins in enviroment science upon aspects;enrichment and removal of organic pollutants and heavy metals from soil,water,and atmosphere. β-cyclodextrin (β-CD) can be linked when it was sulfonation-modified.A convenient method of photocatalytic degradation of pesticide in lab by self-designed photocatalytic equipment was proposed based on analysis and comparison of different methods used to determine pesticide. The effects of illumination,reaction time,and pesticide concentration were analyzed. The results showed that the photodegradation of monocrotophes increased 2.08-2.86 times in the presence of 20g/L and 40g/L sulfonated β-cyclodextrin.In addition,the photodegradation of omethoate increased 1.8-2.2 times in the presence of 40g/L sulfonated β-cyclodextrin. The light activation were caused by the formaton of inclusion complexes of monocrotophes with sulfonated β-cyclodextrin. It was found that the method was simple and paid lower costs; and it could be used in lab for the photo-catalytic degradation of pesticide.

Abstract: In this study, we researched the removal effect of pesticides residues in vegetables after igition of scallop shells, and measured the effect of the concentration of natural cleaning agent, the washing time and temperature on the removal efficiency. In addition, the best experimental conditions for removal was determined.By analyzing infrared spectrum,scanning electronic microscope energy spectrum, the composition of scallop shells and the elements differences between before and after igition, the results could be attained that the main component of scallop shells was CaCO3, which was about 98%, and that the main component was changed into CaO when burned at 900°CWhat’s more, the best washing temperature for natural cleaning agent was room temperature(25°C) with the washing time of 5min, and the best concentration was 5%. Further, natural cleaning agent could remove 70% of pesticide residues in vegetables which was relatively stable, and the effect of natural cleaning agent was better than that of salty water and distilled water.

Abstract: There are many factor influences on adsorption-flotation results to Pb2+ among, in the solution. The effect of co-existing alkaline-earth metals ions was examined by using Bacillus mucilayinosus as the absorbent on the condition of different pH value, the coexistence ion amount used as well as in tri-, four-, five-, six-coexistent ion systems, to absorbed water solution in Pb2+ ion .The adsorption the biological surface zeta - the potential shift, indicated the Bacillus mucilayinosus to the Pb2+ adsorption process in, the electrostatic attraction occupies the leadership, but in the multi-dimensional coexistence adsorption system, has the competition adsorption and the ionic exchange.

Abstract: Bio-ferric membrane bioreactor(MBR) was made through adding ferric hydroxide to traditional MBR and forming bio-ferric sludge. Through analyzing treatment efficiency of dyeing and printing wastewater in bio-ferric MBR and traditional MBR respectively, the results showed: COD removal efficiency in bio-ferric MBR was more better than that in traditional MBR which increased 10% or so, but the influence of HRT on COD removal efficiency wasn’t evident; Via changing SRT, it was obtained: bio-ferric MBR could operate in longer SRT while treatment effect couldn’t be impacted that could discharge less sludge than traditional MBR which coule get sludge minimization; bio-ferric sludge flocs could provide better survival environment for nitrobacteria that made NH3-N removal efficiency stable. The experiment illuminated: the biochemical and physical function of bio-ferric sludge could strengthen the holistic stability of the system.

Abstract: Somatic embryogenesis was obtained by using immature zygotic embryos of S. pohuashanesis as explants and emblings were obtained. For induction of somatic embryos, immature zygotic embryos which 30 days old after pollination were cultured on solid MS medium with 1.0 mg•L^-1 NAA, 0.1 mg•L^-1 6-BA, 500 mg•L^-1casein hydrolysate (CH) and 40 g•L^-1 sucrose . Inducted somatic embryos were cultured in solid MS medium containing 500 mg•L^-1CH and 40 g•L^-1 sucrose. After 30 days of culture, many normal cotyledonary embryos were produced. Plantlets were regenerated when somatic embryos were transferred to MS medium with 30 g•L^-1 sucrose. The somatic embryos germinated at a germination frequency of approximately 80%, but rate of the plantlets that successfully acclimated and continued growing was 40% in the greenhouse.

Abstract: A new rapid detection the number of spores method had been developed in raw milk through analyzing dipicolinic acid. The method was based on the concentration of DPA in raw milk which was converted into endospore numbers using endospore forming pure cultures as standards. To increase the detection limit the extraction of DPA from endospores in raw milk was optimized. The results showed adding 0.5 mL of the 0.1 mol L^-1 DTT solutions into centrifuged raw milk (4 mL containing spores) and incubating at 25°C for 30 min, then adding 2 mol L^-1 HCl at boiling water for 30 min, the concentration of DPA was highest. The relationship between the absorbency (expressed in DPA) and the counts of spores was established. And the regression equation was obtained that is y = 0.1087 x － 0.3182, R2 = 0.7842. Thus, the methods of detection spores were ascertained in skim milk. The detection limits were 1.46×103 CFU mL^-1.

Abstract: Biogas fermentation is always limited or affected at low temperature conditions, one of key factors may be physiological adaption of methanogenic communities to low temperature. Howerer, biogas process could be stimulated and enhanced with addition of enriched consortia. Here, six psychroactive methanogenic consortiums were enriched as additives, and consortium E-1 was found to be most effective at 150C. The total biogas production addition with E-1 improved 39.3 % and 17.0% from pig manure and cow manure, respectively, when decreasing from 210C to 150C, which is a potential microbial addition for biogas fermentation at low temperature.

Abstract: The metabolic activity of sludge samples taken from two pilot scale activated sludge reactor was studied. The two reactors were of the same size and structure. One was operated according to the reversed A2/O process (R-reactor) and another was operated according to conventional A2/O process (C-reactor). The activities of dehydrogenase (DHA) and electron transport system (ETS) and the specific oxygen uptake rate (SOUR) of sludge taken from R-reactor were 34.98%, 22.44% and 12.70% higher than those of the sludge taken from C-reactor. As for the R-reactor, the sludge undergoes aerobic condition right after anaerobic experience. Compared to entering aerobic stage from anoxic stage (C-reactor), entering aerobic stage from anaerobic stage can significantly enhance the activity of microbes, accelerate the decomposition of organics and improve the SOUR of the sludge.