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571.
A/O脱氮工艺实时控制对策的试验研究 总被引:2,自引:0,他引:2
以人工合成废水为研究对象,系统研究了提高A/O(anoxic/oxic)工艺氨氮和硝酸氮去除效率的实时控制对策.氨氮控制的本质是通过控制DO设定值和好氧区体积大小使出水氨氮浓度达标排放.硝酸氮控制的本质在于高效利用缺氧区反硝化潜力,为此建立了以调节内循环回流量或(和)外碳源投加量维持缺氧区末端硝酸氮浓度处于设定值的实时控制对策.系统控制采用两级结构,高水平监控层用来选择低水平执行层的设定值,而低水平执行层对DO值、好氧区体积、内循环回流量和外碳源投加量进行直接控制,试验表明上述控制对策可以显著提高系统脱氮效率,降低出水氨氮和硝酸氮浓度,并最大程度节约运行费用. 相似文献
572.
论述了关于重庆钢铁股份有限公司炼钢厂LF炉除尘工艺的现状和系统的不足,并且就相关技术问题进行了分析与研讨,提出了相应的处理方案。 相似文献
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575.
In this paper, a study was conducted on the effect of polyhydroxyalkanoates (PHA) and glycogen transformations on biologic nitrogen and phosphorus removal in low dissolved oxygen (DO) systems. Two laboratory-scale sequencing batch reactors (SBR1 and SBR2) were operating with anaerobic/aerobic (low DO, 0.15–0.45 mg·L-1) configurations, which cultured a propionic to acetic acid ratio (molar carbon ratio) of 1.0 and 2.0, respectively. Fewer poly-3-hydroxybutyrate (PHB), total PHA, and glycogen transformations were observed with the increase of propionic/acetic acid, along with more poly-3-hydroxyvalerate (PHV) and poly-3-hydroxy-2-methyvalerate (PH2MV) shifts. The total nitrogen (TN) removal efficiency was 68% and 82% in SBR1 and SBR2, respectively. In the two SBRs, the soluble ortho-phosphate (SOP) removal efficiency was 94% and 99%, and the average sludge polyphosphate (poly-P) content (g·g-MLVSS-1) was 8.3% and 10.2%, respectively. Thus, the propionic to acetic acid ratio of the influent greatly influenced the PHA form and quantity, glycogen transformation, and poly-P contained in activated sludge and further determined TN and SOP removal efficiency. Moreover, significant correlations between the SOP removal rate and the (PHV+ PH2MV)/PHA ratio were observed (R 2>0.99). Accordingly, PHA and glycogen transformations should be taken into account as key components for optimizing anaerobic/aerobic (low DO) biologic nitrogen and phosphorus removal systems. 相似文献
576.
Rongchang WANG Xinmin ZHAN Yalei ZHANG Jianfu ZHAO 《Frontiers of Environmental Science & Engineering》2011,5(1):48-56
Nitrogen removal performance and nitrifying population dynamics were investigated in a redox stratified membrane biofilm reactor (RSMBR) under oxygen limited condition to treat ammonium-rich wastewater. When the N H 4 + - N loading rate increased from 11.1±1.0 to 37.2 ± 3.2 g N H 4 + - N · m - 2 · d - 1 , the nitrogen removal in the RSMBR system increased from 18.0±9.6 mgN·d-1 to 128.9±61.7 mgN·d-1. Shortcut nitrogen removal was achieved with nitrite accumulation of about 22.3 ± 5.3 m g N O 2 - - N · L - 1 . Confocal micrographs showed the stratified distributions of nitrifiers and denitrifiers in the membrane aerated biofilms (MABs) at day 120, i.e., ammonia and nitrite oxidizing bacteria (AOB and NOB) were dominant in the region adjacent to the membrane, while heterotrophic bacteria propagated at the top of the biofilm. Real-time qPCR results showed that the abundance of amoA gene was two orders of magnitude higher than the abundance of nxrA gene in the MABs. However, the nxrA gene was always detected during the operation time, which indicates the difficulty of complete washout of NOB in MABs. The growth of heterotrophic bacteria compromised the dominance of nitrifiers in biofilm communities, but it enhanced the denitrification performance of the RSMBR system. Applying a high ammonia loading together with oxygen limitation was found to be an effective way to start nitrite accumulation in MABs, but other approaches were needed to sustain or improve the extent of nitritation in nitrogen conversion in MABs. 相似文献
577.
Biodegradation of paclobutrazol by a microbial consortium isolated from industrially contaminated sediment 总被引:1,自引:0,他引:1
Biodegradability of the plant growth retardant paclobutrazol by a microbial consortium in which Pseudomonas was the predominant strain was investigated in batch culture. The consortium which had been isolated from an industrially contaminated sediment was proven to be useful for the treatment of effluents containing paclobutrazol. Paclobutrazol was degraded by the pure isolated strain of Pseudomonas sp. as well as the microbial consortium. Paclobutrazol was utilized as the sole source of carbon and energy. Sixty percent of the paclobutrazol was degraded by the microbial consortium from an initial concentration of 54 mg L?1 within 48 h and more than 98% of an initial concentration of 3.4 mg L?1 was degraded within 36 h. The optimum temperature and pH were determined to be 30°C and 7.0, respectively. A pure strain of a bacterium, isolated from the enrichment culture was identified as Pseudomonas sp. The microbial consortium was tolerant of high pH and could degrade paclobutrazol faster than the pure strain. The degradation rate of this plant growth regulator in an aerobic environment was greater than that under anaerobic conditions. 相似文献
578.
Removal of Mo(VI) from aqueous solutions was investigated using cinder modified by sulfuric acid. Various parameters such as pH, agitation time, Mo(VI) concentration, and temperature have been studied. The maximum adsorption of Mo(VI) occurred at pH between 4.0 and 6.0. Kinetic studies showed that the adsorption generally obeyed a pseudo second-order model. The activation energy was 31.4?kJ?mol?1, indicating that the adsorption process was governed mainly by interactions of physical nature. Furthermore, application of Langmuir and Freundlich isotherm models to the adsorption equilibrium data showed that the adsorption behavior obeyed the Langmuir model. The adsorption capacity was found to be 10.8?g Mo(VI)?kg?1 adsorbent. Finally, thermodynamic parameters such as ΔH 0, ΔS 0, and ΔG 0 were also evaluated, which showed that the adsorption of Mo(VI) on the treated cinder was endothermic, entropy increasing, and spontaneous. In conclusion, the sulfuric acid-modified cinder was shown to be an inexpensive, effective, and simple adsorbent for the removal of Mo(VI) from water. 相似文献
579.
Eutrophication control programs are based on phosphorus management which, in turn, requires a detailed quantification of the watershed phosphorus budget. This involves an assessment of non‐point sources of phosphorus, a key element of which is determining the fraction of soil‐P and sediment‐P available to support algal growth. This paper presents a review of the state‐of‐the‐art of estimating algal available‐P from non‐point sources, and an analysis of pertinent data. The need to employ multi‐interval algal bioassays in developing phosphorus management systems is stressed. 相似文献
580.
Removal of pesticides from water samples by adsorption with fatty acids supported on barium sulphate
Oleic or linoleic acid supported on barium sulphate was used to remove atrazine and terbuthylazine in the range of 0.1–2.0 μg/L using spiked water samples. The sorption of atrazine depends on the stirring time and the best value is 150 min. Terbuthylazine is removed well with a stirring time of 60 min and its adsorption is about 90%. Detection of the residual pesticide in treated waters, after solid phase extraction (SPE), was carried out by GC‐MS operating in selected ion monitoring (SIM) using a calibration curve by direct injection of standard solutions of herbicide. 相似文献