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81.
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In this laboratory study different combinations of bed (sand, pebble gravel [gravel], and a mix of sand and gravel) and flow (typical and overtopping) were experimented with to investigate the impact of porous deflectors in flow diversity, water quality, and fish performance in prismatic open channels. Deflectors changed the gradually varied flow to a rapidly varied flow, as a sudden change in the water depth was observed at the deflectors, and this change was large for smooth beds. With the presence of gravel, the scouring near the downstream deflector was almost twice that of the sand bed, and with the scouring at its own upstream deflector, irrespective of whether the flow was typical or overtopping. This behavior was a result of sand mobilization due to shear stress and sand mobilization aided gravel transport. The mixed bed showed less gravel movement compared to the gravel-only bed. The percentage of sediment washed out was minor for all bed scenarios, indicating that sediment transport was local. Relative to the sand bed without deflectors (representing a typical urban canal), deflectors resulted in reduced and improved water quality (in terms of sediment load) for sand, and mixed bed, respectively. The fishes found refuge and were comfortable in the pool areas created by deflectors unlike in channels without deflectors where they showed exhaustion. 相似文献
84.
Gabriel N. de O. Teixeira Arthur M. S. da Cruz Gisella R. L. Samanamud Alexandre B. França Luzia L. R. Naves Diego Melo 《Journal of environmental science and health. Part. B》2020,55(1):19-29
AbstractThe main objective of this study is the degradation of a synthetic solution of atrazine by a modified vermiculite catalyzed ozonation, in a rotating packed bed (RPB) reactor. A 0.5?L RPB reactor was used to perform the experiments, using a Central Composite Design (CCD) response surface to construct the quadratic model based on the factors: pH, catalyst concentration and reactor rotation frequency. The response variable was the removal of the organic load measured in terms of Chemical Oxygen Demand (COD). After the complete quadratic model was constructed through the response surface, the COD degradation process had an optimal removal of 41% under the following conditions: pH 8.0, rotation of 1150?rpm and catalyst concentration 0.66?g L?1. 相似文献
85.
天然沸石床处理受污染景观水体的试验 总被引:2,自引:0,他引:2
采用天然沸石滤床对富营养化景观湖水进行净化试验,结果表明,天然沸石滤床能有效地净化受污染的湖水,CODCr、氨氮、总磷和浊度的去除率分别为35.8%、95.0%、66.7%和78.0%,沸石能有效地去除水中的氨氮,其作用机理包括离子交换和生物硝化两种作用。 相似文献
86.
复极性固定床电解槽内电极电位的分布 总被引:25,自引:1,他引:25
本文通过设计独特的测量和检验实验装置,对复极性固定床电解槽内的电极电位进行了测试。发现了槽内反应的动力就是槽内粒子与溶液的电位之差,可通过调节它的变化来控制反应的进行。 相似文献
87.
88.
186菌生物流化床处理甲醇废水 总被引:7,自引:0,他引:7
用三相生物流化床工艺处理甲醇废水COD_(cr)容积负荷达4.24~12.32kg/m~3·d,去除率达82.7%~93.1%;甲醇容积负荷达1.8~3.9kg/m~3·d,去除率达81.4%~98.1%。加186菌种后,甲醇的容积负荷可提高到3.02~3.36kg/m~3·d,COD_(cr)去除率可达到89.3~96.7%。 相似文献
89.
Trace metal emissions from co-combustion of refuse derived and packaging derived fuels in a circulating fluidized bed boiler 总被引:3,自引:0,他引:3
Helena Manninen Annikki Perkiö Juha Palonena Karl Peltola Juhanl Ruuskanen 《Chemosphere》1996,32(12):2457-2469
Energy recovery from refuse derived fuels (RDF) and packaging derived fuels (PDF) is one option in integrated waste management. Nine RDF and PDF co-combustion tests with peat and coal in a circulating fluidized bed boiler were carried out in this work. Heavy metal emissions in flue gas and fly ash were measured. Multivariate data analyses were used to find out the most important parameters affecting metal emissions in the flue gas.
The results showed that total heavy metal emissions were low. Although RDF and PDF had more heavy metals than peat and coal, the multivariate data analysis showed that an increase of the RDF or PDF share in the fuel mixture up to 20% did not correlate directly with the metal emissions in the flue gas. Distribution of Cd, Cu, Zn and Sn between flue gas and fly ash correlated with each other. Injection of limestone to bind sulphur and chlorine did not have a significant effect on heavy metal emissions in the flue gas. Heavy metals concentrated on the fly ash, but all fly ashes passed the EPA-TCLP tests. 相似文献
90.
研究了操作参数对活性炭固定床处理有机废气的影响。温度升高,吸附容量下降。湿度的存在会减少活性炭对有机物的吸附容量。适当的操作气速为0.1-0.5m/s,在此范围内,气速与压降在对数坐标上呈线性关系。 相似文献