Landscape Application of Ground Covers in Beijing Highway

Ground cover is a necessary component of highway green space, and as a background color of landscape, it enriches landscape hierarchy, reflects regional characteristics, and reduces maintenance cost. By analyzing application of ground covers in some sections of 6 highways in Beijing, China, selection standards, application species, and planting designs of ground covers in highway green spaces of Beijing were explored, so as to enrich the application species, optimize landscape designs, and enhance the application of under-bridge ground covers.

Partial Nitrification from Domestic Wastewater by Aeration Control at Ambient Temperature

The objective of this paper was to examine the feasibility of partial nitrification from raw domestic wastewater at ambient temperature by aeration control only. Airflow rate was selected as the sole operational parameter. A 14L sequencing batch reactor was operated at 23℃ for 8 months, with an input of domestic wastewater. There was a prolgrammed decrease of the airflow rate to 28L·h^-1, the corresponding average dissolved oxygen （DO） was 0.32mg·h^-1, and the average nitrite accumulation rate increased to 92.4% in 3 weeks. Subsequently, further increase in the airflow rate to 48L·h^-1 did not destroy the partial nitrification to nitrite, with average DO of 0.60mg·h^-1 and nitrite accumulating rate of 95.6%. The results showed that limited airflow rate to cause oxygen deficiency in the reactor would eventually induce only nitrification to nitrite and not further to nitrate and that this system showed relatively stability at higher airflow rate independent of pH and temperature. About 50% of influent total nitrogen was eliminated coupling with partial nitrification, taking the advantage of low DO during the reaction.

Comparison of Two Water Treatment Processes with Activated Aluminum Oxide

We focused on the need for the phosphorus removal in water plant process. As for surface water plant, the enhancement of phosphorus removal in purification process can raise the biological stability of effluent potable water. This study conducted the effect of two water treatment processes for phosphorus removal, including the PAC + AAL (the treatment process using poly aluminum chloride and activated aluminum oxide) and PFS + AAL (the treatment process using poly ferric sulfate and activated aluminum oxide). The aim is to use the adsorption capacity of activated aluminum oxide to increase the removal of phosphorus in filtration process. The result showed that the two processes both can remove the phosphorus concentration to reach below 10 μg/L, and the PAC + AAL is the better process.

Degradation and detoxification of microcystin-LR in drinking water by sequential use of UV and ozone

Microcystins （MCs） produced by cyanobacteria are strong hepatotoxins and classified as possible carcinogens. MCs pose a considerable threat to human health through tainted drinking and surface waters. Herein filtrated water from a waterworks in Harbin, China, was spiked with microcysfin-LR （MC-LR） extracted from a toxic scum of microcystis aeruginosa, and the spiked sample waters were treated using UV irradiation with consequent ozonation process （UV/O3）, compared with ozonation at a dose range commonly applied in water treatment plants, UV irradiation at 254 nm and UV irradiation combined with ozonation （UV＋O3）, respectively. The remaining of toxins were analyzed using high-performance liquid chromatography and also determined using a protein phosphatase type 2A inhibition assay, which was utilized to evaluate the reduction in toxicity. Results indicated that in comparison to other three processes （O3, UV, and UV＋O3）, UV/O3 process could effectively decrease both the concentration and toxicity of MC-LR at 100 μg/L level after 5 min UV irradiation with consequent 5 min ozonation at 0.2 mg/L （below 1 μg/L ）, while 0.5 mg/L ozone dose was required for the level below 0.1 μg/L. The addition of an UV treatment step to the existing treatment train may induce significant transformation of micropollutants and breaks down the natural organic matters into moieties unfavorable for ozone decomposition, stabilizing the ozone residual. These findings suggested that sequential use of UV and ozone may be a suitable method for the removal of these potentially hazardous microcystins from drinking water.

Effect of Magnetic Carrier NiFe2O4 Nanoparticles on Physicochemical and Catalytic Properties of Magnetically Separable Photocatalyst TiO2/NiFe2O4

A series of magnetically separable photocatalyst TiO2/NiFe2O4（TN） with different mass ratios of NiFe204 to TiO2 was prepared by sol-gel method. The X-ray diffraction（XRD）, X-ray photoelectron spectroscopy（XPS）, transmission electron microscopy（TEM）, ultraviolet-visible spectroscopy（UV-Vis）, Brunauer-Emmett-Teller（BET） surface analysis and photoluminescence spectroscopy（PL） were used to characterize the photocatalyst TN. The XRD patterns of TN indicate that adulterating a smidgen of NiFe204 into TiOR（about 0.1%, mass ratio） can promote the phase transformation of TiO2, however, when the doped amount of NiFe2O4 surpasses 1%, the introduction of NiFe2O4 can inhibit the growth of YiO2 crystal grain and reduce the size of TiO2 crystal grain. The XPS results of TN indicate that some Fe3＋ replace Ti4＋ of the TiO2 lattice forming Fe--O--Ti bonds. The PL analysis of TN shows that the NiFezO4 nanoparticles in photocatalyst TN play the role of the effective recombination centre of the photogenerated electrons and holes, leading to the decrease in photocatalytic activity.