Diffusion pollution from livestock and poultry rearing in the Yangtze Delta,China

BACKGROUND: The Yangtze Delta is one of the most developed regions in China and includes Shanghai, eight cities in Jiangsu province and eight cities in Zhejiang province. Meat consumption in this region has increased with economic growth, and most of the consumed meat is produced locally. The water quality of surface waters has deteriorated in recent years. An example was the huge blue-green algae bloom in Tai Lake in late May 2007, which affected millions of people's daily drinking water. However, animal husbandry is considered to be one of the main pollution sources. METHODS: Pollutants (NH3-N, total phosphorus (TP), and total nitrogen (TN)) excreted by livestock and poultry, and the resultant COD (chemical oxygen demand) and BOD (biochemical oxygen demand), were estimated using two different methods based on different data sets. RESULTS: The number of livestock and poultry has remained stable in the Yangtze Delta over the four years from 1999 to 2002, with the average number of pigs, cattle, sheep and poultry being 21.1 M, 0.4 M, 7.7 M and 597.6 M, respectively. Pollutants in livestock and poultry excreta estimated by Method I were: 0.12 Mt NH3-N, 0.11 Mt TP and 0.29 Mt TN, resulting in COD and BOD of 1.34 Mt and 1.30 Mt, respectively, while the estimations based on Method II were: 0.18 Mt NH3-N, 0.15 Mt TP and 0.40 Mt TN, resulting in COD and BOD of 1.95 Mt and 1.80 Mt, respectively. DISCUSSION: Pollutants excreted annually by livestock and poultry in the Yangtze Delta are estimated to be: 0.17 Mt NH3-N, 0.16 Mt TP and 0.42 Mt TN, giving rise to a COD of 1.86 Mt and a BOD of 1.72 Mt. Approximately 25% of this pollution was estimated to enter water bodies, which means that the annual pollutant load is 43,700 t NH3-N, 39,400 tTP, 104,600t TN with a COD of 465,000 tand a BOD of 430,100 t. Pollutants from animal husbandry were similar in magnitude to those from industrial wastewater. Pigs produced the most pollution, followed by poultry, cattle and sheep. The pollution load from animal husbandry in the Yangtze Delta is about twice the average level of the whole of China. CONCLUSIONS: Domestic wastewater was the main pollution source in the Yangtze Delta, followed by pollution from raising livestock and poultry and from industrial wastewater. The pollution load in Shanghai and Jiaxing were the greatest, followed by 7 cities of Jiangsu province (except Suzhou) and other cities of Zhejiang province and Suzhou. Pigs and poultry produced about 90% of the total pollutants from animal husbandry. RECOMMENDATIONS AND PERSPECTIVES: The local governments, especially in Shanghai and Jiaxing, should focus their attention on the pollution produced by livestock and poulrry. Controlling pollution from pigs and poultry will have the greatest impact in this region. Control of pollution will be facilitated by the development of large-scale livestock and poultry farming units and a shift away from small scale husbandry.     

液晶显示器液晶处理与铟回收技术

在实验室条件下,对液晶显示器回收的各个重要环节作了初步的探索,提出了一整套回收工艺.其中包括利用丙酮常温浸取去除偏光片、分离玻璃基板、溶解液晶,还包括利用硫酸溶液和二氧化锰联合浸取玻璃基板,铟的浸取率达89%.得到的铟的酸液经过萃取、置换和电解,可以得到铟的产品,为液晶显示器的资源化和无害化提供实验数据和技术支持.     

地震救灾过渡安置点避雷针的布设选点及安装要求

"5.12"汶川8级大地震波及范围很大,给陕西省部分地方造成了不小的损失.灾后,汉中、宝鸡的地震救灾过渡安置点由于缺乏防雷电保护,打雷时有遭受雷电灾害的可能,亟需要对其采取防雷电保护措施.对救灾过渡安置点采用独立避雷针进行防护,该措施安全可靠、简便易行,就成为首选,其布设选点要科学、规范,可使其效益最大化,避雷针的制作和安装应符合技术标准要求,做到牢固可靠,在施工中要因地制宜.综合考虑,始终把安全和牢靠放在首位.     

地震台站体应变观测资料处理系统简介

介绍了新近研制的地震台站体应变观测资料的日常处理系统 ;简要地介绍了该系统及其数据库的结构以及各功能模块的作用。     

Modeling in-situ uranium(VI) bioreduction by sulfate-reducing bacteria

We present a travel-time based reactive transport model to simulate an in-situ bioremediation experiment for demonstrating enhanced bioreduction of uranium(VI). The model considers aquatic equilibrium chemistry of uranium and other groundwater constituents, uranium sorption and precipitation, and the microbial reduction of nitrate, sulfate and U(VI). Kinetic sorption/desorption of U(VI) is characterized by mass transfer between stagnant micro-pores and mobile flow zones. The model describes the succession of terminal electron accepting processes and the growth and decay of sulfate-reducing bacteria, concurrent with the enzymatic reduction of aqueous U(VI) species. The effective U(VI) reduction rate and sorption site distributions are determined by fitting the model simulation to an in-situ experiment at Oak Ridge, TN. Results show that (1) the presence of nitrate inhibits U(VI) reduction at the site; (2) the fitted effective rate of in-situ U(VI) reduction is much smaller than the values reported for laboratory experiments; (3) U(VI) sorption/desorption, which affects U(VI) bioavailability at the site, is strongly controlled by kinetics; (4) both pH and bicarbonate concentration significantly influence the sorption/desorption of U(VI), which therefore cannot be characterized by empirical isotherms; and (5) calcium-uranyl-carbonate complexes significantly influence the model performance of U(VI) reduction.     

对环境评价中替代方案编写的几点看法

阐述了环境影响评价中有关替代方案应当包括的内容 ,并对替代方案编写的原则和方法做了说明 ,最后 ,列举厂址选择的替代方案的编写实例。     

垃圾填埋场稳定化及其研究现状

文章对直埋场稳定化过程进行了初步描述,并从填埋气、渗滤液、垃圾组成和沉降等４个方面总结了填埋场稳定化的研究现状。     

Effects of Compounded Curing Agents on Properties and Performance of Urea Formaldehyde Resin

The effects of three compounded curing agents on the properties and performance of the urea-formaldehyde (UF) resin were investigated in this study. The compounded curing agents were prepared by mixing ammonium chloride with hexamethylenetetramine, citric acid, and oxalic acid respectively at a ratio of 1:1, named N-H, N–CA, and N–OA, respectively. The curing process, crystallinity, and physical properties were measured, and the three-ply plywood was fabricated to measure its prepress strength, wet shear strength, and formaldehyde emission. Results showed that the compounded curing agents N–CA and N–OA enhanced the initial viscosity, crosslinking density and thermal stability of UF resin. Additionally, the prepress strength of the plywood bonded by UF resin with N–CA and N–OA increased by 82 and 111% respectively compared to the UF resin with NH₄Cl, and the wet shear strength increased by 14 and 16%, the formaldehyde emission decreased by 19 and 42% respectively. However, owing to the short pot-life of these curing agent limited their storage time, the curing agents N–CA and N–OA should be applied to fabricate plywood in winter for obtaining a better bond strength and a lower formaldehyde emission. While the UF resin with N–HT showed a suitable pot-life, so it could be applied to fabricate plywood in summer for long time storage and avoiding procuring problem.     

Sb release characteristics of the solid waste produced in antimony mining smelting process

Sb release characteristics of blast furnace slag, mining waste rock and tailing sand were investigated in static immersion and dynamic leaching test. These three kinds of waste samples were collected from the antimony mine in Lengshuijiang, China, produced in mining smelting process. Effects of solid/liquid ratio, sample size and pH of leaching solution on Sb release characteristics were inspected based on the analysis of scanning electron microscope, pH and EC of leachate. The optimal parameters for Sb leaching of each sample were analyzed. For blast furnace slag and mining waste rock, Sb release contents increased along with the decline of solid/liquid ratio. The maximum accumulative release contents were 42.13, 34.26 mg/kg at the solid/liquid ratio of 1:20. While Sb release content for tailing sand decreased first and then increased with the reduction of solid/liquid ratio. When the solid/liquid ratio was 1:5, the accumulative Sb release content reached the most (24.30 mg/kg). Sb release content of mining waste rock increased with the drop of leaching solution pH, with the highest accumulative release content of 26.01 mg/kg at pH 2.0. Sb release contents of blast furnace slag and tailing sand showed positive correlation with the variation of leaching solution pH. The maximum accumulative release contents of these two samples were 215.91 and 147.83 mg/kg, respectively, when leaching solution pH was 7.0. In summary, Sb release capacity of the three samples in descending order was tailing sand, blast furnace slag and mining waste rock. pH and EC of the leachate in dynamic test varied independently with the initial pH of leaching solution while showing close relationship with mineral hydrolysis in the waste.