Development of a Simple Phosphorus Model for a Large Urban Watershed: A Case Study

Often, the initiation of a total maximum daily load (TMDL) program is delayed until intensive monitoring data can be collected—even in watersheds where large historical data sets exist. This paper provides a case study of a modeling effort that utilizes available historical data to fulfill an intermediate goal of a TMDL program for the Passaic River Basin. The subject model is developed to simulate total phosphorus concentrations (and loads) within the basin’s effluent-dominated streams. The model is based on the assumption that the primary process controlling in-stream total phosphorus concentrations is the dilution of the cumulative upstream effluent load—which was computed on a continuous (daily) basis. Model comparisons indicate a generally good fit to long-term river-monitoring data at several key sites. Model results, and data analyses, suggest that secondary processes have a relatively minor impact on total phosphorus (TP) concentrations in this relatively large, urbanized system. This finding is consistent with a previous QUAL2E model study of the system, and consistent with the relatively conservative behavior of TP reported in many medium-to-large river systems throughout the United States. Model results are used to facilitate TMDL planning efforts for a major water supply reservoir in the basin.     

水稻土中硅磷元素的存在形态及其相互影响研究

采用室内培养试验研究不同施硅和施磷处理对水稻土中硅、磷不同存在形态的影响。结果表明 ,硅磷具有相互促进肥效的关系。施硅影响土壤无机磷的形态 ,硅的施用增加了土壤中Ca2 -P、Al-P和O -P的含量 ,Ca8-P、Ca10 -P变化不明显 ,Fe -P的含量显著降低。其中原因可能是Fe -P在水稻土中活性较高。硅酸钠与硅酸钙相比 ,前者的作用更为明显。施磷影响土壤硅的不同形态 ,磷的施用增加了土壤中水溶性硅和活性硅的含量 ,降低了无定形硅的含量 ,这可能与磷的存在改变了土壤 pH有关     

镍磷合金镀层中高含量磷的测定

本文研究了应用钒钼黄光度法测定镍磷合金镀层中高含量磷的条件及方法，研究结果表明该方法能快速、准确测定镀层中的磷含量。     

高炉锰铁液固态的锰磷成分差异

用数理统计方法对大量生产记录数据进行了分析核对,确认高炉锰铁在液、固两种状态时,锰、磷成分存在着差异这一事实。并确定了固态锰铁含锰量降低、含磷量增加的成分劣化区间为:锰的平均降低值在-0.275％和 0.022％之间,磷的平均升高值在-0.0015％和 0.0171％之间。按GB7730.1-7730.4-87规定与允许化验误差比较分析,也有一定超差比例存在。     

攀钢钒钛回收新进展

详细介绍了攀钢钒渣，五氧化二钒，钒铁，钛精矿，钛白等主要钒钛产品的生产工艺，产品质量和生产能力。概述了现有生产工艺采用的一些新技术和钒钛回收方面取得的最新进展。预测了攀钢未来钒钛发展的趋势。     

Silicon doping by nuclear transmutation

This paper describes, from the view of nuclear physics and radiochemistry, the mode of operation in doping semiconductor silicon with phosphorus by neutron irradiation. In addition to precise control of the irradiation fluence, this includes control of neutron-flux distribution, self-shielding and radioactive products from the silicon matrix and the surface impurities. The accuracy of the resistivity values achieved by this method is better than ± 5% at the predicated value. The good homogeneity of the dopant distribution is shown by the results of location-resolving resistivity measurements as well as by the breakdown radiation emitted by diodes. Neutron-bombarded homogeneously doped silicon (NBH-silicon) is used for routine manufacture of multi-diode vidicons and power devices.     

Lake sedimentary evidence of phosphorus,iron and manganese mobilisation from intensively fertilised soils

A study of historical P inputs to Friary Lough, Co. Tyrone, Northern Ireland used a multi-sediment core approach. One of the sediment cores taken from the littoral zone at 2.5m water depth showed exceptionally high P, Fe and Mn concentrations below 20 cm sediment depth. Concentrations increased to 14 mg Pg(-1), 238 mg Feg(-1) and 35 mg Mng(-1) in the sediment profile and compared with deep basin maxima of 7 mg Pg(-1), 70 mg Feg(-1) and 2 mg Mng(-1) in surface sediments at 8.5m water depth. It is proposed that the high concentrations in the littoral zone core are due to post-depositional intrusion of chemical-rich local groundwater from soils in adjacent fields that are excessively fertilised with organic slurry. Soil analyses showed Olsen-P concentrations in these fields up to 125 mgkg(-1) at the soil surface (0-7.5 cm) and 39 mgkg(-1) in the sub-soil at 20 cm depth. We suggest that the mobilisation of P, Fe and Mn is due to leaching following P saturation and/or the loss of P absorbing chemicals due to prolonged reduction and complexing in wet soils. Further work will explore this relationship and the nature of the hydrological pathways through soil.     

Annual variation of fresh water quality in the Gachang Dam reservoir

This paper investigated the relationship between the annual variation of the algae population and the physicochemical properties of the water reservoired in the Gachang Dam in the hopes of serving as a guideline in the production of a clean water supply to regions of the city of Taegu. Summer thermal stratification was formed in the freshwater reservoired in the Gachang Dam and thus dissolved oxygen (DO) decreased according to the depth of the water. The pH of epilimnion was much higher than that of hypolimnion in summer because of the difference in the photosynthesis rate of algae. In July, at the beginning of the rainy season, the amount of total nitrogen (T-N) in the freshwater reached a maximum of 1.92 mg/L without an increase in the amount of total phosphorus (T-P). In August, the concentration of T-P in the freshwater increased steeply and reached 0.12 mg/L.Aulacoseira spp. (diatoms) were predominantly distributed in the freshwater throughout the year andSynedra andAsterionella (diatoms) predominantly populated in the spring. However,Anabaena andMicrocystis (blue-green algae), which caused malodor and a bad taste, flourished predominantly in epilimnion in August when the temperature of the water at the surface region increased to the maximum and the concentration of T-P was sufficiently high.     

Kinetics of Phosphorus Release and Uptake in a Membrane-Assisted Biological Phosphorus Removal Process

A long-term comparative study on the kinetics of enhanced biological phosphorus removal (EBPR) was carried out in pilot scale membrane-assisted and conventional biological phosphorus removal processes, by monitoring system performance, phosphorus mass balances, and maximum specific rates in off-line batch tests. The two systems exhibited similar performance in the removal of soluble phosphorus (P) from the influent wastewater, in the specific P release observed in the anaerobic zone, and in the maximum specific P release and volatile fatty acid (VFA) uptake rates. However, when the VFA in the influent was limiting, the conventional EBPR (CEBPR) process performed significantly better than the membrane (MEBPR) counterpart, and this behavior was also reflected in the kinetics of P release. Denitrifying dephosphatation was observed to be significant in both processes during periods of satisfactory P removal. When the aerobic recycle ratio was reduced to a minimum level, the anoxic P uptake activity in the CEBPR sludge was lower than that of the MEBPR sludge. Finally, the biomass decay rates of the two sludge types were estimated to be comparable, with significant reduction of the decay under unaerated conditions.     

HZSM-5催化下N2O5对氯苯的选择性硝化研究

工业传统混酸硝化法严重腐蚀设备和污染环境,同时对硝基氯苯选择性较低,针对这个问题,研究了在HZSM-5分子筛催化下,五氧化二氮对氯苯的硝化反应。由于HZSM-5优异的择形性,对硝基氯苯在硝化产物中的比例从原先的42%提高到81%。实验考察了反应温度、反应时间、催化剂用量及Si/Al等因素对反应结果的影响。研究表明,在温度为50℃,时间为1h,5gSi/Al质量比为260的催化剂HZSM-5作用下,反应条件最佳,此时氯苯硝化反应得率达到50%,对位选择性为85%。