Integrated emergy,energy and economic evaluation of rice and vegetable production systems in alluvial paddy fields: Implications for agricultural policy in China

China is the largest rice producing and consuming country in the world, but rice production has given way to the production of vegetables during the past twenty years. The government has been trying to stop this land-use conversion and increase the area in rice-vegetable rotation. Important questions that must be answered to determine what strategy is best for society are, “What is the reason behind this conversion?”; “Which system is more productive and which is more sustainable?”; and “How can economic policy be used to adjust the pattern of farmland use to attain sustainable development?” To answer these questions, a combined evaluation of these agricultural production systems was done using emergy, energy and economic methods. An economic analysis clearly showed that the reason for this conversion was simply that the economic output/input ratio and the benefit density of the vegetable production system were greater than that of rice. However, both energy and emergy evaluations showed that long-term rice was the best choice for sustainable development, followed by rotation systems. The current price of rice is lower than the em-value of rice produced from the long-term rice system, but higher than that of rice produced from the rotation system. Scenario analysis showed that if the government increases the price of rice to the em-value of rice produced from the long-term rice system, US$0.4/kg, and takes the value of soil organic matter into account, the economic output/input ratios of both the rice and rotation systems will be higher than that of the vegetable system. The three methods, energy, emergy and economics, are different but complementary, each revealing a different aspect of the same system. Their combined use shows not only the reasons behind a system’s current state or condition, but also the way to adjust these systems to move toward more sustainable states.     

中小型工业窑炉NOx废气的净化技术与应用

介绍了中小型工业窑炉生产过程中排放NOx的现状,并针对NOx的治理问题,从工程应用角度,简述了湿法和干法净化NOx的原理和化学反应过程。讨论了NOx排放特性和NOx废气中NO2/NOx比例的问题。提出了影响NOx治理的主要因素,包括吸收剂、吸附剂、催化剂和设备的部分应用参数,并结合工程实例指出工程需要注意的问题。介绍了多项采用湿法和干法净化NOx的工程应用项目,丰富了中小工业窑炉NOx废气的治理的实践经验,为中小工业窑炉排放NOx治理奠定了基础。     

Development Potentials and Policy Options of Biomass in China

Biomass, one of the most important renewable energies, is playing and will continue to play an important role in the future energy structure of the world. This article aims to analyze the position and role, assess the resource availability, discuss the geographic distribution, market scale and industry development, and present the policy options of biomass in China. The resource availability and geographical distribution of biomass byproducts are assessed in terms of crop residues, manure, forest and wood biomass byproducts, municipal waste and wastewater. The position of biomass use for power generation is just next to hydropower among types of renewable energy in China. The potential quantity of all biomass byproducts energy in 2004 is 3511 Mtce (Mtce is the abbreviation of million tons of coal equivalents and 1 Mtce is equal to10⁶ tce.), while the acquirable quantity is 460 Mtce. Biomass energy plays a critical role in rural regions of China. The geographical distribution and quantity of biomass byproducts resources depends mainly on the relationship between ecological zones and climate conditions. Our estimation shows that the total quantity of crop residues, manure, forest and wood biomass byproducts, municipal waste and wastewater resources are 728, 3926, 2175, 155 and 48240 Mt (million tons), respectively. Crop residues come mainly from the provinces of Henan, Shandong, Heilongjiang, Jilin and Sichuan. All manure is mainly located in the provinces of Henan, Shandong, Sichuan, Hebei and Hunan. Forest and wood biomass byproducts are mainly produced in the provinces or autonomous regions of Tibet, Sichuan, Yunnan, Heilongjiang and Inner Mongolia, while most of municipal waste mainly comes from Guangdong, Shandong, Heilongjiang, Hubei and Jiangsu. Most of wastewater is largely discharged from advanced provinces like Guangdong, Jiangsu, Zhejiang, Shandong and Henan. Biomass byproducts’ energy distribution also varies from province to province in China. Based on the analysis of the market scale and industry development, the article argues that China’s biomass energy industry is still at a very early stage of development and that Feed-in Tariffs (FIT) might be the best policy option for China to promote its development of biomass energy. A successful enforcement of FIT in China needs some policy combination of special capital subsidies, R&D funding, tax incentives and pricing.     

江苏沿海风能资源禀赋与开发利用研究

江苏沿海地区拥有丰富的风能资源,开发前景十分广阔,尤其是中部、南部地区拥有广阔的沿海滩涂和辐射沙洲,建设沿海风电场的条件优越,是打造江苏"海上三峡"新能源基地的希望所在。阐述了江苏沿海风能资源开发的重要意义,分析了沿海风能资源的禀赋与时空分布特点,指出江苏沿海岸区风能资源丰富,且沿海滩涂宽广,是建立大型风力发电场的理想之地,在此基础上提出发展江苏沿海绿色能源基地的构想。     

Occurrence,distribution, and multi-phase partitioning of triclocarban and triclosan in an urban river receiving wastewater treatment plants effluent in China

Occurrence, distribution, spatial and seasonal variations, and partitioning between aqueous phase and suspended particulate matters (SPM) of triclocarban (TCC) and triclosan (TCS) in Xiaoqing River, which receives wastewater treatment plant (WWTP) effluents, were studied. The distribution of the total TCC and TCS levels in surface water and sediments along the river were discussed. The highest TCC and TCS concentrations were both found near the discharge port of WWTPs, and the TCC and TCS levels decreased downstream of the WWTPs as a result of their distances from the source of WWTP discharges. The mean values of TCC and TCS in low-flow season were 1.62 and 1.80 times, respectively, as much as in high-flow season in surface water. The study on partitioning of TCC and TCS between aqueous phase and SPM shown the mean level of dissolved TCC accounted for about 10 % of the total level in surface water, whereas the TCS level was about 30 %. The TCC concentrations detected in the surface sediment samples (0 to 5 cm) ranged from 226 to 1,956 ng/g, with a mean value of 733 ng/g. The TCS levels were between 85 and 705 ng/g, with a mean value of 255 ng/g. The distribution and variations of TCC and TCS in sediments along the river were highly consistent with those in the water phase. The TCC and TCS levels in deep sediments (5 to 10 cm) were significantly lower than those in surface sediments. The mean TCC level in surface sediments was about 2.4 times as much as in deep sediments, and the TCS level in surface sediments was 3.1 times as much as in deep sediments.     

Co-composting of livestock manure with rice straw: Characterization and establishment of maturity evaluation system

Composting is considered to be a primary treatment method for livestock manure and rice straw, and high degree of maturity is a prerequisite for safe land application of the composting products. In this study pilot-scale experiments were carried out to characterize the co-composting process of livestock manure with rice straw, as well as to establish a maturity evaluation index system for the composts obtained. Two pilot composting piles with different feedstocks were conducted for 3 months: (1) swine manure and rice straw (SM–RS); and (2) dairy manure and rice straw (DM–RS). During the composting process, parameters including temperature, moisture, pH, total organic carbon (TOC), organic matter (OM), different forms of nitrogen (total, ammonia and nitrate), and humification index (humic acid and fulvic acid) were monitored in addition to germination index (GI), plant growth index (PGI) and Solvita maturity index. OM loss followed the first-order kinetic model in both piles, and a slightly faster OM mineralization was achieved in the SM–RS pile. Also, the SM–RS pile exhibited slightly better performance than the DM–RS according to the evolutions of temperature, OM degradation, GI and PGI. The C/N ratio, GI and PGI could be included in the maturity evaluation index system in which GI > 120% and PGI > 1.00 signal mature co-composts.     

Catalytic hydrolysis of urea from wastewater using different aluminas by a fixed bed reactor

In order to find an effective method for treating urea wastewater, the experiments on the hydrolysis of urea in wastewater were conducted in a fixed bed reactor with different aluminas (α-Al₂O₃, γ-Al₂O₃, and η-Al₂O₃) as catalysts respectively in contrast with inert ceramic particle. The results indicate that the three alumina catalysts show obvious catalytic activity for urea hydrolysis at 125 °C. The order of activity is η-Al₂O₃?>?γ-Al₂O₃?>?α-Al₂O₃, and the activity difference increases with increasing temperature. According to the characterization results, surface acidity has little impact on the activity of catalyst. However, it was found that surface basicity of alumina catalyst plays an important role in catalytic hydrolysis of urea, and the activity of catalyst may be also influenced by the basic strength. With η-Al₂O₃ as catalyst, the urea concentration in wastewater is reduced to 4.96 mg/L at a temperature of 165 °C. Moreover, the η-Al₂O₃ shows a good stability for urea hydrolysis. The hydrolysis of urea over η-Al₂O₃ catalyst can evidently reduce the reaction temperature and is promising to replace industrial thermal hydrolysis process.     

Characterization of Particulates from Power Plants

The emphasis on participate control from industrial processes has been shifted recently towards fine particulates, having diameters less than 3 microns. There exists an urgent need for more scientific information of fine particle characterization.^1,2 Coal and oil fired power plants are among the largest anthropogenic point sources of particulate matter.³ Limited knowledge is available on particle size distribution and trace metal composition in power plant emissions.^4-7 The morphological properties of particle emissions have been largely neglected. In this report we present some information on particle characteristics for an oil-fired and coal-fired power plant.     

Comprehensive Assessment and Promotion Policy of Producer Services’ Competitiveness in Beijing City:A Comparative Analysis among Beijing,Tianjin,Shanghai,Guangzhou and Shenzhen

The five central cities-Beijing,Tianjin,Shanghai,Guangzhou and Shenzhen-of the three most important strategic regions in China,namely Beijing-Tianjin-Hebei metropolitan region,the Yangtze River Delta and the Pearl River Delta,are taken as a comparative analysis on urban producer services’ competitiveness,especially focusing on the comparative advantages and disadvantages of producer services in Beijing.Firstly,based on an integrated indicator system including one objective hierarchy,four standard hierarchies and 35 indicator hierarchies,the study applies factor analysis model and analytic hierarchy process model reformed by entropy technology to measure the comprehensive competitiveness of producer services in the above five cities.Secondly,Beijing has comparative advantages of capital resource,industrial base,scientific research resource and market scale,since it takes the first place of the five cities in the comprehensive competitiveness of producer services,the competitiveness of industrial development,business environment and living environment,only inferior to Shanghai in the competitiveness of talent capital.Thirdly,Beijing has comparative disadvantages in the level of producer services development,urban innovation capability and living environment.Finally,five proposals are put forth to enhance the competitiveness of producer services in Beijing,namely perfecting the system of laws and statutes,supporting the development of industry association,implementing scientific development planning,introducing preferential fiscal and taxation policies and strengthening human capital reserve.     

Quantifying air pollution attenuation within urban parks: an experimental approach in Shanghai, China

Parks with various types of vegetations played an important role in ameliorating air quality in urban areas. However, the attenuation effect of urban vegetation on levels of air pollution was rarely been experimentally estimated. This study, using seasonal monitoring data of total suspended particles (TSP), sulfur dioxide (SO(2)) and nitrogen dioxide (NO(2)) from six parks in Pudong District, Shanghai, China, demonstrated vegetations in parks can remove large amount of airborne pollutants. In addition, crown volume coverage (CVC) was introduced to characterize vegetation conditions in parks and a mixed-effects model indicated that CVC and the pollution diffusion distance were key predictors influencing pollutants removal rate. Therefore, it could be estimated by regression analysis that in summer, urban vegetations in Pudong District could contribute to 9.1% of TSP removal, 5.3% of SO(2) and 2.6% of NO(2). The results could be considered for a better park planning and improving air quality.