Advanced Materials Research Vols. 573-574

Abstract: In this paper, nanometer titanium dioxide was synthesized by a simple reaction. The prepared adsorbent was characterized by surface area and porosimetry analyzer and it was used for the removal of heave metals in industrial wastewater. The main parameters affecting the adsorption of heavy metals including pH, adsorption condition and elution condition have been investigated in detail. Under the optimized operating conditions, most of the target heavy metals could be fast removed. The adsorbent could be simply regenerated by hydrochloric acid. Thus, the prepared nanometer titanium dioxide was an adsorbent which is suitable for the removal of heavy metals in industrial wastewater.

Abstract: L. hoffmeisteri was inoculated in reactor to investigate the effects on waste sludge and wastewater to reduce excess sludge and reduce the environmental risk of heavy metals in sludge and effluent in this study. The result showed a gravimetric sludge reduction of 53.8% and modification in the texture of the sludge. The residual form of heavy metals (As, Cd, Cr, Cu, Ni, Pb and Zn) was increased, which reduced the risk of the phytoaccumulation. An evident concentration of heavy metals in worm faece and a bioaccumulation of heavy metals in aquatic worms were also observed. Activated sludge is reduced significantly, sludge settleability is improved and the bioavailability of heavy metals in waste sludge is minimized, which are beneficial to wastewater treatment and safe disposal of waste sludge.

Abstract: The occurrence and removal of selected pharmaceuticals have been investigated in a municipal wastewater treatment plant (WWTP) of Shanghai in this study. Ibuprofen (IBP), naproxen (NPX), ketoprofen (KEP), diclofenac (DFC), and clofibric acid (CA) were selected as target compounds. Results showed that all of these pharmaceuticals were detected in the influent samples with IBP showing the highest concentrations (1380 ng/L). The partition coefficient (logKd) between the particulate and the dissolved phase calculated for KEP, NPX, CA, DFC, and IBP ranged from 1.2 to 2.2 in the raw sewage and the treated effluent suggesting the weak tendency of the target pharmaceuticals being absorbed onto particles. Different compounds were removed to different extent in the WWTP treatment processes. The highest removal efficiency was observed for IBP and the lowest for CA, 87.2% and 36.7%, respectively. The results indicated that municipal WWTP cannot remove these pharmaceuticals efficiently.

Abstract: Ozonation of clofibric acid (CA) in aqueous solution was carried out under continuous operation in a cascade bubble column. The influence of operation parameters including initial CA concentration, gas flow rate, liquid flow rate and pH on the removal of CA and TOC was investigated. The results indicated that ozonation could be used to effectively remove CA from water. Increasing the initial CA concentration resulted in a decrease of the CA and TOC removal efficiency. A comparison of CA removal efficiency and ozone utilization between cascade and conventional bubble column indicated that cascade bubble column was an effective way for increasing the solubility ozone in the reactor.

Abstract: According to the frequency distribution approach of Nutrition Criteria Technical Guidance Manual of U.S. EPA, we calculated eco-criteria of Tai Lake and Liao River in China by observing data. The results show that: ① Phytoplankton H is 2.81, phytoplankton D is 2.03, zooplankton H is 3.16 and zooplankton D is 7.70 in Tai Lake. ② Phytoplankton H is 3.04, phytoplankton D is 2.66, the zooplankton H is 3.46 and zooplankton D is 5.15 in Liao River. The results show that the eco-criteria by frequency distribution approach is feasible and correct.

Abstract: A simulation of the water quality was made in this paper with the help of QUAL2K model for CODCr 、NH3-N in the Le’An river .Based on the results ,The water environmental capacity about CODCr and NH3-N in every function river section of Le’An river was calculated by means of analytic method and section－beginning control mothod.

Abstract: It is crucial to understand the nitrogen output loads in leaching water of soils in different lands controlling non-point source pollution. Leaching water collecting devices were installed in soils of 7 kinds of typical land use types in a representative watershed to collect water samples and evaluate output loads of TN, nitrate nitrogen, and ammonium nitrogen under the conditions of natural rains. Results showed that concentration of TN, nitrate nitrogen, and ammonium nitrogen in leaching water from vegetable fields and slope croplands were significantly higher than those from other lands. The concentration of these three indexes in leaching water from rice fields was lowest during the whole growing period except for seedling establishment and tillering stages among slope croplands, terraced fields and paddy fields. With the growth of crops and increasing depth of soils, different-typed nitrogen concentration in leaching water from different lands gradually decreased. Slope croplands, terraced lands and secondary evergreen broadleaf forests generated high output loads of nitrogen pollutants but rice fields and vegetable fields not due to less leaching water and open forests and sugiki forests not due to low nitrogen concentration in leaching waters. On the average, the output loads of TN, nitrate nitrogen, and ammonium nitrogen were 179.764 kg•ha-1，103.645 kg•ha-1 and 7.431kg• ha-1 in the watershed. The study revealed the intensity of nitrogen pollution from different land uses in typical watershed of Yun-Gui plateau.

Abstract: Coal fly ash at 10 and 35% (m/m) was mixed with dewatered sewage sludge (on fresh weight basis) and then the ash-sludge mixture was mixed separately with 1 and 2% (m/m) calcium oxide to kill the entrained pathogens and to suppress the availability of heavy metals enriched in sludge. A sequential extraction method was used to determine chemical forms of Cu, Zn, Ni and Cd in the sludge and fly ash and CaO stabilized sludge. A loamy acid soil amended with sludge and stabilized sludge was used to grow corn under greenhouse conditions. The results showed that sewage sludge amended with coal fly ash and CaO could reduce the availability of Cu, Zn, Ni and Cd in the sludge. Increasing fly ash and CaO amendment rate significantly increased pH and reduced DTPA extractable Cu, Zn, Ni, Cd contents and EC of the sludge. Fly ash and CaO addition significantly reduced the Zn and Cd concentration in exchangeable and total fraction. But add CaO significantly increase the Cu concentration in exchangeable fraction. Majority of Cu was associated with organic form, but Zn and Ni were associated with Fe-Mn oxide and residual forms. Fly ash and CaO addition significantly increase the percentage of Zn and Ni in residual fraction. Addition of 10% fly ash amended sludge and 10% fly ash then 1% CaO amended sludge significantly increased the dry weight yield and decreased the concentrations of Zn, Cu and Cd in shoot of corn. The results demonstrate the beneficial effects of fly ash and CaO addition on suppress the availability of heavy metals enriched in the sludge.

Abstract: Fe/MnO2 was prepared from hydrothermal procedure, and its properties for removal of arsenic from aqueous solution were investigated. The samples were characterized with XRD, SEM and FTIR. SEM images revealed the Fe/MnO2 was dispersing flower-like sphere with the diameter of 500-800 nm and the width of petal was of 20-30 nm. Sorption of the arsenic to Fe/MnO2 reached equilibrium in less than 180 s, which was the much faster than that of pure MnO2 and amorphous iron manganese binary oxide. The adsorption isotherm was agreed well to the Freundlich adsorption model with maximum adsorption capacities of 26.5 mg/g. The Fe/MnO2 was able to remove 100% of arsenic in water at pH 4.0, and this adsorbent was stable in solution with low pH. The Fe/MnO2 nano-flowers are a potential high efficient nanomaterial for removal of arsenic from water.

Abstract: At present, Nansi Lake restoration is maily focused on reducing extraneous pollution, however, it is unclear about the endogenous pollution. In this study, twelve intact sediment cores were collected from four sub-lakes (Nanyang Lake, Dushan Lake, Zhaoyang Lake and Weishan Lake) in Nansi Lake, and the fluxes of NH4+-N, PO43--P, NO3--N, TN and TP at sediment-water interface were calculated based on static incubation of sediment cores with a laboratory-scale benthic chamber. The incubation results showed fluxes of PO43--P, NO3--N, TN and TP in Nanyang Lake were the highest and as follows: 2.73, 7.55, 44.43 and 3.06 mg/m2.d, respectivly, and the flux of NH4+-N in Nanyang Lake, Dushan Lake and Zhaoyang Lake had little difference ranged from 8.99 to 10.19 mg/m2.d. This study indicated that during the sampling period sediment acted as a source of nitrogen as well as phosphorus to the overlying water body in Nansi Lake.