Enhanced biological phosphorus removal (EBPR) is a commonly used and sustainable method for phosphorus removal from wastewater.
Poly-β-hydroxybutyrate (PHB), polyphosphate, and glycogen are three kinds of intracellular storage polymers in phosphorus accumulation
organisms. The variation of these polymers under different conditions has an apparent influence on anaerobic phosphorus release,
which is very important for controlling the performance of EBPR. To obtain the mechanism and kinetic character of anaerobic
phosphorus release, a series of batch experiments were performed using the excessively aerated sludge from the aerobic unit
of the biological phosphorus removal system in this study. The results showed that the volatile suspended solid (VSS) had
an increasing trend, while the mixed liquid suspended sludge (MLSS) and ashes were reduced during the anaerobic phosphorus
release process. The interruption of anaerobic HAc-uptake and phosphorus-release occurs when the glycogen in the phosphorus-accumulating-organisms
is exhausted. Under the condition of lower initial HAc-COD, HAc became the limiting factor after some time for anaerobic HAc
uptake. Under the condition of higher initial HAc-COD, HAc uptake was stopped because of the depletion of glycogen in the
microorganisms. The mean ratio of ΔρP/ΔρPHB, ΔρGLY/ΔρPHB, ΔρP/ΔCOD, was 0.48, 0.50, 0.44, and 0.92, respectively, which was nearly the same as the theoretical value. The calibrated kinetic
parameters of the HAc-uptake and phosphorus-release model were evaluated as follows: QHAc,max was 164 mg/(g · h), QP,max was 69.9 mg/(g · h), Kgly was 0.005, and KCOD was 3 mg/L. An apparently linear correlation was observed between the ratio of ΔρP/ΔCOD and pH of the solution, and the equation between them was obtained in this study.
Translated from Acta Scientiae Circumstantiae, 2005, 25(9), 1164–1169 [译自: 环境科学学报] 相似文献
Air samples were collected using active samplers at various heights of 8, 15, 32, 47, 65, 80, 102, 120, 140, 160, 180, 200, 240, 280 and 320 m on a meteorological tower in an urban area of Beijing in two campaigns in winter 2006. Altitudinal distributions of polycyclic aromatic hydrocarbons (PAHs) in atmospheric boundary layer of Beijing in winter season were investigated. Meteorological conditions during the studied period were characterized by online measurements of four meteorological parameters as well as trajectory calculation. The mean total concentrations of 15 PAHs except naphthalene of gaseous and particulate phase were 667±450 and 331±144 ng m−3 in January and 61±19 and 29±6 ng m−3 in March, respectively. Domestic coal combustion and vehicle emission were the dominant PAH sources in winter. Although the composition profiles derived from the two campaigns were similar, the concentrations were different by one order of magnitude. The higher concentrations in January were partly caused by higher emission due to colder weather than March. Moreover, weak wind, passing through the city center before the sampling site, picked up more contaminants on the way and provided unfavorable dispersion condition in January. For both campaigns, PAH concentrations decreased with heights because of ground-level emission and unfavorable dispersion conditions in winter. The concentration ratio of PAHs in gas versus solid phases was temperature dependent and negatively correlated to their octanol–air partition coefficients. 相似文献
Environmental Science and Pollution Research - This study analyzed the determinants that impact innovation on offshore wind energy (OSW) for a select group of countries, applying mixed-method... 相似文献
In present study, an efficient ternary Ag/TiO2/mesoporous g-C3N4 (M-g-C3N4) photocatalyst was successfully synthesized through depositing Ag nanoparticles (NPs) on the surface of TiO2/M-g-C3N4 heterojunction. Ag/TiO2/M-g-C3N4 nanocomposite displayed the highest degradation efficiency for amoxicillin (AMX) compared to TiO2/M-g-C3N4 heterojunction, M-g-C3N4, and bulk-g-C3N4 (B-g-C3N4). The removal efficiency of AMX in real situation, surface water (SW), hospital wastewater (HW), and waste water treatment plant (WWTP) also were studied to illustrate the effectiveness of Ag/TiO2/M-g-C3N4 photocatalysts. The vulnerable atoms in AMX structure were revealed through DFT calculation. Additionally, the dominating active groups produced in time of the photocatalytic procedure were determined on account of free radical trapping experiments and ESR spectra. The mechanism of photocatalytic degradation was proposed and verified. The transfer of the electrons and the inhibition of the recombination of photogenerated electron-holes were enhanced effectively under the synergistic effect of the Ag NPs and TiO2. As a consequence, the catalytic activity of the composite was improved under visible light.
Pollutants always co-exist in the environment. Determining and characterizing the interaction among chemicals is an important
issue. Experimental designs (ED) play an important role in evaluating the interactions. The main aim of our study is to provide
the test and analysis of the toxicity interaction with a novel ED method. 相似文献