Quantification of Water, Salt and Nutrient Exchange Processes at the Mouth of A mediterranean Coastal Lagoon

Vassova lagoon is a typical Mediterranean (small, shallow, micro-tidal, well-mixed) coastal lagoon, receiving limited seasonal freshwater inflows from direct precipitation and underground seepage. An intensive study was carried out in order to quantify the mechanisms responsible for the intra-tidal and residual transport of water, salt, nutrients and chlorophyll at the mouth of this lagoon and to assess the lagoon's flushing behavior. Results indicated that although the system is micro-tidal, tidal effects appeared to be the dominant factor for the longitudinal distribution of physical and chemical parameters, while the associated residual flow is also important and serves as a baseline measure of overall circulation. However, analysis of the net longitudinal currents and fluxes of water, salt and nutrients revealed the importance of non-tidal effects (wind effect and precipitation incidents) in the mean tidal transport. It is shown that the Eulerian residual currents transported water and its properties inwards under southern winds, while a seaward transport was induced during precipitation incidents and northern winds. The Stokes drift effect was found an order of magnitude lower than the Eulerian current, directed towards the lagoon, proving the partially-progressive nature of the tide. Nutrients and chlorophyll-α loads are exported from the lagoon to the open sea during the ebb phase of the autumn and winter tidal cycles, associated with the inflow of nutrient-rich freshwater, seeped through the surrounding drainage canal. The reverse transport occurs in spring and early summer, when nutrients enter the lagoon during the flood tidal phase, from the nutrient-rich upper layer of the stratified adjacent sea. Application of a tidal prism model shows that Vassova lagoon has a mean flushing time of 7.5 days, ranging between 4 to 18 days, affected inversely by the tidal oscillation.     

Enhanced Desorption of Phenanthrene from Soils Using Hydroxypropyl‐β‐cyclodextrin: Experimental Results and Model Predictions

Objective of this study was to evaluate the effects of hydroxypropyl‐β‐cyclodextrin (HPCD) on the removal of phenanthrene from solid phase. Batch tests for the phenanthrene distribution between aqueous and solid phase were conducted in the presence of HPCD. Column tests and numerical simulations were conducted to evaluate the roles of HPCD cavities and interaction rates between water, HPCD, and solid phase in the enhanced removal of phenanthrene. Experimental results showed that HPCD was effective in removing sorbed phenanthrene from subsurface environment, primarily due to its negligible sorption to the solid phase and the partitioning of phenanthrene into HPCD cavities. From the numerical simulations, it was found that rate‐limited partitioning of phenanthrene into HPCD cavities was most influential factor in the enhanced elution of phenanthrene. Sorption and desorption rate of phenanthrene between aqueous and solid phase was very fast or near equilibrium state. Interaction rates of contaminant between water, HPCD, and solid phase could be affected by other factors such as soil types and organic matter contents. Results from this study implied that HPCD flushing could be effectively applied for the removal of hydrophobic organic pollutants existing in the soils as sorbed or NAPL state.     

循环水冲洗生态厕所及其污水处理方法

主要研究了循环水冲洗生态厕所对冲厕污水有机污染物和NH4 -N的去除效果.结果表明,在进水COD和NH4 -N负荷分别为1.2～1.4 kg COD/m3·d和0.1～0.11kg NH4 -N/m3·d时,循环水冲洗生态厕所出水COD和NH4 -N稳定维持在15 mg/L和5 mg/L,达到我国中水回用相关标准,满足了循环冲洗水水质要求,根本上实现了冲厕污水源头治理和资源化.     

氧化淋洗联合修复氰化物污染土壤技术及工程实践

以天津某氰化物污染场地污染土壤为研究对象,采用氧化淋洗联合使用的工艺方法,研究在不同氧化剂用量和淋洗次数条件下氰化物形态转变与修复效果之间的关系。利用氰化物的还原性和较高的溶解度,通过氧化分解和溶解作用实现对土壤中氰化物的去除。结果表明：在氧化条件下,随着氧化剂用量的增加,土壤中总氰化物呈现下降的趋势,土壤中氰化物的形态从络合态向易释放态转变,土壤浸提液中总氰化物的浓度呈现先升高后降低的趋势;当氧化剂用量为5%时,总氰化物浓度从51.2 mg·kg⁻¹降低至9.23 mg·kg⁻¹,满足总量的修复目标;而土壤浸提液浓度从初始的1.6 mg·L⁻¹降低至0.79 mg·L⁻¹,未能达到修复目标;在振荡淋洗条件下对土壤淋洗5次,随着淋洗次数的增加,土壤中总氰化物呈现下降的趋势,而氰化物易释放态逐渐减少,土壤浸提液中总氰化物浓度呈现快速下降的趋势;在淋洗3次时,土壤浸提液浓度从初始的1.6 mg·L⁻¹降低至0.04 mg·L⁻¹,达到修复目标,而土壤总氰化物含量从51.2 mg·kg⁻¹降低至10.2 mg·kg⁻¹,未能达到修复目标;氧化技术和淋洗技术联合使用时,在氧化剂用量为3%,淋洗1次条件下,工程实践表明土壤氰化物可以满足总量(9.86 mg·kg⁻¹)和浸出(0.1 mg·L⁻¹)的双重修复目标。本研究所提出的氧化淋洗联合修复技术应用于氰化物污染土壤修复是可行的。     

麻石除尘器的技术改造

详细介绍了山西焦化股份有限公司针对锅炉除尘系统运行中存在的问题进行的多项技术改造，改造后其除尘效率得以提高，烟尘排放质量浓度达到国家一级标准。     

旅客列车真空集便器便盆冲洗排空影响因素及相关技术研究

旅客列车真空集便器便盆污物冲洗排空效果受诸多因素影响,各影响因素间相互作用.为实现以较低冲洗水量达到良好冲洗排空效果、提高系统洁净性能,对便盆曲面、冲洗流型进行分析设计,对旋流和扇面2种不同冲洗流型特点进行比较,分析不同设计参数及安装位置对冲洗排空效果的影响,最终通过试验研究验证冲洗喷嘴的安装位置、旋流喷嘴的射流方向等...     

土壤、地下水中有机污染物的就地处置

有机化合物对土壤、地下水的污染已引起世界各国的普遍关注.地层介质中的有机物主要以自由态、挥发态、溶解态和固态4种形态存在.有机污染物的自然降解能力较差,如不进行人工清除,在自然环境中它们可能存留长达几十年之久,对土壤、地下水资源构成长期的威胁.传统的开挖处理技术不仅费用昂贵,而且当贮油设施的地表被利用时则无法进行开挖处理(如有建筑物等).近年来,以地下冲洗法、土壤抽水法和地下水曝气法为代表的有机污染物就地处置技术得到了迅速的发展.本文对这3种技术进行概要的介绍,总结指出决定这些技术可能性的主要因素是地层介质的通透能力,有机物的挥发、溶解能力及其可生物降解能力,并列出目前的主要有机污染物挥发、溶解及生物降解能力的相对强弱作为制定具体处置技术的参考指标.     

THE DILUTION/FLUSHING TECHNIQUE IN LAKE RESTORATION1

ABSTRACT: Dilution/flushing has been documented as an effective restoration technique to restore eutrophic Moses and Green Lakes in Washington State. The dilution water added to both lakes was low in nitrogen and phosphorus content relative to the lake or normal input water. Consequently, lake nutrient content dropped predictably. Dilution or flushing rates were about ten times normal during the spring-summer periods in Moses Lake and three times normal on an annual basis in Green Lake. Improvement in quality (nutrients, algae, and transparency) was on the order of 50 percent in Moses Lake and even greater in Green Lake. The facilities for supplying dilution water were largely in place for the cited lakes; thus, costs for water transport were minimal. Available facilities, and therefore, costs, for water transport would usually vary greatly, however. Achieving maximum benefit from the technique may be more limited by availability of low nutrient water rather than facilities costs. Quality improvement may occur from physical effects of algal cell washout and water column instability if only high nutrient water is available.     

气水比回流比及冲击负荷对BAF的影响

研究气水比、回流比及冲击负荷对BAF前置反硝化工艺的影响。研究结果表明BAF前置反硝化工艺最佳气水比为 3∶1 ,最佳回流比为 2 0 0 %。该工艺具有较强的抗冲击负荷能力 ,COD的最佳去除负荷可达 7.70 4kg/ (m3·d) ,NH3-N的最大去除负荷为 1 .2 85kg/ (m3·d) ;水力负荷对COD的去除影响较小 ,对NH3-N、TN的去除影响较大 ,宜将水力负荷控制在 2 .39m/h以下     

穿层水力冲孔措施在低透煤层中有效影响半径效果考察

为研究水力冲孔措施下煤层瓦斯高效抽采钻孔合理布置参数,提高煤层瓦斯抽采效率,以平煤十三矿己15-17-13051工作面为例,对水力冲孔有效影响半径进行效果考察。通过布置多组试验钻孔,分别对水力冲孔措施前后钻孔瓦斯浓度、瓦斯流量数据进行综合考察,结果表明:水力冲孔措施增大了煤层透气性系数,高效提升了煤层瓦斯抽采率,执行冲孔措施后瓦斯浓度最低可提高至2.05倍、瓦斯纯流量增至2.56倍以上,采用瓦斯流量法确定了己15-17煤层水力冲孔措施实际有效影响半径为4.8~5.9 m,对于指导煤层瓦斯抽采钻孔合理布置具有指导性意义。