Adsorption of phenol and its derivatives from water using synthetic resins and low-cost natural adsorbents: a review

In this article, the technical feasibility of the use of activated carbon, synthetic resins, and various low-cost natural adsorbents for the removal of phenol and its derivatives from contaminated water has been reviewed. Instead of using commercial activated carbon and synthetic resins, researchers have worked on inexpensive materials such as coal fly ash, sludge, biomass, zeolites, and other adsorbents, which have high adsorption capacity and are locally available. The comparison of their removal performance with that of activated carbon and synthetic resins is presented in this study. From our survey of about 100 papers, low-cost adsorbents have demonstrated outstanding removal capabilities for phenol and its derivatives compared to activated carbons. Adsorbents that stand out for high adsorption capacities are coal-reject, residual coal treated with H3PO4, dried activated sludge, red mud, and cetyltrimethylammonium bromide-modified montmorillonite. Of these synthetic resins, HiSiv 1000 and IRA-420 display high adsorption capacity of phenol and XAD-4 has good adsorption capability for 2-nitrophenol. These polymeric adsorbents are suitable for industrial effluents containing phenol and its derivatives as mentioned previously. It should be noted that the adsorption capacities of the adsorbents presented here vary significantly depending on the characteristics of the individual adsorbent, the extent of chemical modifications, and the concentrations of solutes.     

固态排渣煤粉炉NOx产生浓度影响因素偏相关分析

利用第一次全国污染源普查“火力发电行业产排污系数核算”工作中现场监测得到的数据,首次采用偏相关分析的方法,对固态排渣煤粉炉中机组规模、空气过剩系数、煤中挥发分和发电负荷率等因素对NOx产生浓度的影响进行定性分析,结论：NOx产生浓度与前三种因素存在显著的相关。而与发电负荷率的关系受锅炉是否采用低氮燃烧技术的影响。空气过剩系数越大,煤的挥发分越高,NOx产生浓度越低;采用低氮燃烧装置的锅炉中,机组规模越大,产生的NOx越少,且对于同一锅炉来说,NOx产生浓度随着发电负荷率的升高而增大;未采用燃烧控制的锅炉中,机组规模越大,NOx产生浓度越高,且与发电负荷率不相关。根据分析结果,提出了控制燃煤电厂固态排渣煤粉炉NOx排放的优化措施和建议。     

Effects of time-gap settings of adaptive cruise control (ACC) on driving performance and subjective acceptance in a bus driving simulator

A study was conducted to investigate the effects of time-gap settings and contents of secondary tasks on a fix-based bus driving simulator on drivers’ performance while reclaiming control from ACC in a car-following scenario of emergency brake by the lead vehicle. Thirty professional bus drivers drove on the simulator with the scenario of highway traffic flow under 12 random time-gap settings: from 0.64 s to 2.40 s with the interval of 0.16 s. As for the effects of secondary tasks, subjects were evenly divided into three conditions: no secondary task interference, simple secondary task, and complex task. The results demonstrated that different safety demarcations of time-gaps on subjective acceptance and driving performance can be found out. The integrated demarcations separated time-gaps into divisions that represented different levels of danger. It revealed that the safer time-gaps for different situations were: longer than 1.60 s for none-secondary task distraction and longer than 2.08 s for being continuously distracted by secondary tasks. The demand for simple tasks is relatively high, so a larger time-gap is needed for the driver to remain safe. This research has implications for the time-gap selection of ACC and effects of secondary task distraction on buses. A next logical step will focus on determining time-gaps for lead vehicles on curves or slopes, when multiple vehicles are present ahead, and modeling driver behavior and performance with ACC for cars, buses, and other types of vehicles.     

搞好煤矿安全生产工作的建议

煤矿作为高危行业,安全始终是天字号的头等大事。从全国范围内发生的重特大事故来看,也主要集中在煤炭领域。泰安市是煤炭主要产区,因此,抓好煤矿安全生产工作,不仅能有效遏制和减少重特大安全事故的发生,也充分体现了代表最广大人民群众的根本利益,执政为民的具体要求。     

Status and habitat preferences for endemic inhabitants of fiddler crab Uca formosensis in Hsiang-Shan wetland, Taiwan

This article reports on soil samples collected from Hsiang-Shan wetland, Taiwan. Canonical discriminant analysis (CDA) was applied to identify an existing habitat type's scheme by identifying the physico-chemical properties of sediment in Hsiang-Shan wetland. The three constructed discriminant functions (CDFs) showed a marked contribution by most of the discriminant variables, and the recognition capacities in these three CDFs were 49.5, 32.8 and 17.7%. Our study revealed that the most important latent factors in Hsiang-Shan wetland are soil texture-caused factor, ocean current-caused factor, nutrient-caused factor, and the redox reaction-caused factor. And the most sensitivity parameters in this habitat followed the descending order: OBD, EC, Eh, sand, TN, porosity, STP, silt, VCP and pH. And the inhabited sediment properties for U. formosensis in terms of soil texture are sand, silt, and clay (34.05, 29.72, and 32.35%, respectively): that is clay loam soil. We also found that U. formosensis preferred to inhabit the upper intertidal zone, spending 8.41% of the time submerged. Vegetation coverage on the ground was less than 2.20%, showing that it preferred to live in a bare intertidal habitat. Concerning nest choosing, excavating burrows is more difficult when a high soil penetration force is required, and in this study the soil penetration force for 20 cm was found to be is 45.98 N/cm(2). The results will be helpful in developing a methodology for use by the government in refining its management programs.     

Temporal and spatial variations of nutrients in the Ten Mile Creek of South Florida, USA and effects on phytoplankton biomass

Water quality throughout south Florida has been a major concern for many years. Nutrient enrichment in the Indian River Lagoon (IRL) is a major surface water issue and is suggested as a possible cause of symptoms of ecological degradation. In 2005-06, water samples were collected weekly from seven sites along Ten Mile Creek (TMC), which drains into the Indian River Lagoon, to investigate and analyze spatial and temporal fluctuations of nutrients nitrogen (N) and phosphorus (P). The objective of this study was to understand the relationships among chlorophyll a concentration, nutrient enrichment and hydrological parameters in the surface water body.High median concentrations of total P (TP, 0.272 mg L(-1)), PO4-P (0.122 mg L(-1)), and dissolved total P (DTP, 0.179 mg L(-1)); and total N (TN, 0.988 mg L(-1)), NO3(-)-N (0.104 mg L(-1)), NH4+-N (0.103 mg L(-1)), and total Kjeldahl N (TKN, 0.829 mg L(-1)), were measured in TMC. The concentrations of TP, PO4-P, DTP, TN, NO3(-)-N, NH4+-N, and TKN were higher in summer and fall than in winter and spring. However, chlorophyll a and pheophytin concentrations during this period in TMC varied in the range of 0.000-60.7 and 0.000-17.4 microg L(-1), with their median values of 3.54 and 3.02 microg L(-1), respectively. The greatest mean chlorophyll a (10.3 microg L(-1)) and pheophytin (5.71 microg L(-1)) concentrations occurred in spring, while the lowest chlorophyll a (1.49 microg L(-1)) and pheophytin (1.97 mug L(-1)) in fall. High concentrations of PO4-P (>0.16 mg L(-1)), DTP (>0.24 mg L(-1)), NO3(-)-N (>0.15 mg L(-1)), NH4+-N (>0.12 mg L(-1)), and TKN (>0.96 mg L(-1)), occurred in the upstream of TMC, while high concentrations of chlorophyll a (>6.8 mug L(-l)) and pheophytin (>3.9 microg L(-l)) were detected in the downstream of TMC. The highest chlorophyll a (11.8 mug L(-l)) and pheophytin (6.06 microg L(-l)) concentrations, however, were associated with static and open water conditions. Hydrological parameters (total dissolved solid, electrical conductivity, salinity, pH, and water temperature) were positively correlated with chlorophyll a and pheophytin concentrations (P < 0.01) and these factors overshadowed the relationships between N and P concentrations and chlorophyll a under field conditions. Principal component analysis and the ratios of DIN/DP and TN/TP in the water suggest that N is the limiting nutrient factor for phytoplankton growth in the TMC and elevated N relative to P is beneficial to the growth of phytoplankton, which is supported by laboratory culture experiments under controlled conditions.     

Performance evaluation of a full-scale natural treatment system for nonpoint source and point source pollution removal

This study presents a full-scale performance of a natural treatment system (NTS) facility in Taiwan with nearly 2 years of observations. The study site, composed of several treatment ponds in series, was designed primarily to reduce polluted stormwater runoff from tea gardens and partially to untreated domestic wastewater from nearby villages. Thus, both nonpoint source and point source pollution are treated in this system. From 28 field samplings in 2006-2007, the NTS site shows satisfactory treatment performance and the effluent water quality is significantly improved. Seven of the 28 sampling events are storm events (nonpoint source pollution) and the remainder are from regular monitoring (point source pollution). The average volume of influent and effluent is 533 CMD and 196 CMD, respectively. In order to determine the removal efficiency, several assessment measures are employed in an attempt to obtain unbiased conclusions. They are removal rate (RR), efficiency rate (ER), summation of loads (SOL), flux rate (FR), and effluent probability method (EPM). The average percent removal efficiency of NH(3)-N is 53.5-75.2% and of TP is 59.0-84.7%, in which the highest result is calculated by SOL method and the lowest rate is obtained from RR. In FR evaluation, larger treatment capacity for NH(3)-N than for TP is provided in the site and the average FR is respectively 0.230 g/m(2) day and 0.017 g/m(2) day. Of the methods examined, EPM is the only method capable of illustrating data distribution. Finally, recommendations on the usefulness of these measures are summarized to facilitate the understandings of NTS performance evaluations.     

Vegetation recovery patterns assessment at landslides caused by catastrophic earthquake: A case study in central Taiwan

The catastrophic earthquake, 7.3 on the Richter scale, occurred on September 21, 1999 in Central Taiwan. Much of standing vegetation on slopes was eliminated and massive, scattered landslides were induced at the Jou-Jou Mountain area of the Wu-Chi basin in Nantou County. We evaluated three methods for assessing landslide hazard and vegetation recovery conditions. (1) Self-organizing map (SOM) neural network coupled with fuzzy technique was used to quickly extract the landslide. (2) The NDVI-based vegetation recovery index derived from multi-temporal SPOT satellite images was used to evaluate vegetation recovery rate in the denudation sites. (3) The spatial distribution index (SDI) based on land-cover topographic location was employed to analyze vegetation recovery patterns, including the invading, surviving and mixed patterns at the Jou-Jou Mountain area. On September 27, 1999, there were 849.20 ha of landslide area extracted using the self-organizing map and fuzzy technique combined model. After six years of natural vegetation succession, the landslide has gradually restored, and vegetation recovery rate reached up to 86%. On-site observation shows that many native pioneer plants have invaded onto the denudation sites even if disturbed by several typhoons. Two native surviving plants, Arundo formosana Hack and Pinus taiwanensis Hayata, play a vital role in natural vegetation succession in this area, especially for the sites on ridgeline and steep slopes.     

冬、春季大气PM_(10)重污染的监测与预警——以江苏省典型城市为例

时2007年3月与2008年1月城市大气PM10重污染过程进行监测.结果表明,江苏省冬、春季城市PM10小时值总体呈正态分布,严重污染的发生与大气物理条件密切相关.PM<,10>重污染预报准确性仍有待改进,以完善省级大气环境监测预警体系.     

A storm event-based approach to TMDL development

It is vitally important to define the critical condition for a receiving water body in the total maximum daily load (TMDL) development process. One of the major disadvantages of using a continuous simulation approach is that there is no guarantee that the most critical condition will be covered within the subjectively selected representative hydrologic period, which is usually several years depending on the availability of data. Another limitation of the continuous simulation approach, compared to a design storm approach, is the lack of an estimate of the risk involved. Because of the above limitations, a storm event-based critical flow-storm (CFS) approach was previously developed to explicitly address the critical condition as a combination of a prescribed stream flow and a storm event of certain magnitude, both having a certain frequency of occurrence and when combined, would create a critical condition. The CFS approach was tested successfully in a TMDL study for Muddy Creek in Virginia. The present paper reports results of a comparative study on the applicability of the CFS approach in Taiwan. The Dy-yu creek watershed in northern Taiwan differs significantly from Muddy Creek in terms of climate, hydrology, terrain, and other characteristics. Results show that the critical condition for different watersheds might be also different, and that the CFS approach could clearly define that critical condition and should be considered as an alternative method for TMDL development to a continuous simulation approach.