改性壳聚糖处理微生物浸矿废水

为解决采矿行业微生物浸矿酸性废水中和处理沉渣多、固液分离困难的问题,采用柠檬酸钠和环氧氯丙烷改性处理的壳聚糖在pH=2.2条件下吸附模拟废水中的Cu²⁺和Fe³⁺,用正交实验优化了壳聚糖改性工艺条件。实验结果表明,最适宜的工艺条件为：处理100 mL壳聚糖质量分数为2%的壳聚糖-冰醋酸溶液,柠檬酸钠缓冲溶液加入量200 mL,环氧氯丙烷加入量300 mL,反应时间6 h。改性壳聚糖对Fe³⁺的最大吸附容量为6.703 7 mg/g,对Cu²⁺的最大吸附容量为4.378 7 mg/g,Fe³⁺和Cu²⁺在改性壳聚糖上的吸附是单分子层形式。     

进口含锌物料的表征和鉴别

采用X射线荧光光谱(XRF)、X射线衍射光谱(XRD)等分析手段,对4种进口疑似固体废物的含锌物料进行了表征。通过分析含锌物料的主要元素组成、物相组成和常规理化特征,结合外观特征,与含锌矿物、含锌产品及相关文献资料等进行比对,推导出含锌物料的产生来源。然后,参照我国《进口废物管理目录》得出鉴别结论。结果表明:4种含锌物料分别为锌矿、湿法冶炼锌浸出渣、热镀锌灰和固定CO2产物;后3种属于我国目前禁止进口的固体废物。     

模拟实验研究煤矿酸性水中Co、Ni、Zn、Cd、Al、Cr、As、Pb可溶性金属迁移行为

通过模拟煤矿酸性水环境,对来自2个不同产地的煤系非均质黄铁矿样品进行了不同固液比的淋滤实验,对反应体系物理化学状态以及其中的Co、Ni、Zn、Cd、Al、Cr、As、Pb8种元素的释放行为进行了长达312h跟踪检测和对比.结果显示,在2种不同来源的煤系黄铁矿样品反应体系中,Co、Ni、Zn、Cd的释放行为均为持续升高,说明这些元素的释放受体系中物理化学状态的影响相对较小,在液相中具有较高的迁移行为;Al、Cr、As、Pb在不同样品体系中的释放行为差异较大,受到体系pH值、吸附及共沉淀作用等因素的影响,是相对不易迁移的元素.煤矿酸性水环境中元素释放和迁移行为主要受到黄铁矿的氧化还原反应速率、反应体系介质pH值和围岩矿物学性质3个宏观因素控制.     

杀虫双在土壤中的动态研究

本文参照OECD(经济合作与发展组织)的标准,以室内模拟条件,对杀虫双在土壤中的动态进行了淋溶试验。结果表明,杀虫双淋溶性极强,土壤中绝大部分杀虫双可被水淋溶,留在土壤中的也可随着水的不断加入而被淋溶出。土壤性质对淋溶影响很小,而流速、温度对淋溶影响较大。     

南方土壤酸沉降敏感性研究Ⅶ——盐基淋溶与缓冲机理

研究了模拟酸雨对我国南方主要土壤类型盐基离子淋溶的影响,结果表明,ＰＨ低于３．０或３．５时,盐基离子淋溶总量明显增加,但ＰＨ高于３．５时,则影响不明显。     

麦季施用不同尿素的氮排水和渗漏损失

在太湖地区乌栅土的稻麦轮作条件下,利用大型原状土柱渗漏液采集器(monolithlysimeter),比较不同尿素品种和施肥量(普通尿素150、300kg·hm-2和包膜尿素100、150kg·hm-2)处理对麦季土壤氮随径流和渗漏损失的影响。结果表明:施用的包膜尿素当季氮不易随排水流失,但可能增加下季氮流失的风险。两麦季排水溶解氮均以NO-3 N为主,达76.7%以上,NH+4 N比例很小;麦季排水氮输出量年际差异明显,降雨产生排水与施肥时间间隔的不同是造成排水氮输出量差异的关键因素;施肥后20d内发生排水易产生较多的氮排放。渗漏液硝态氮浓度(最高为8.12mg·L-1)均未超过饮用水NO-3 N含量标准,但均已超过水体富营养化标准;对照处理麦季渗漏液量显著高于施肥处理;在150kg·hm-2的施N量水平下,普通尿素或包膜尿素均未显著增加氮的渗漏,但过量施用普通尿素则加大氮渗漏的风险。     

卫生填埋场伊-灰复合土防渗层抗渗性能现场模拟试验研究

以伊（伊利土）－灰（粉煤灰）复合土和普通粘土作为对比进行了卫生填埋场防渗层抗渗性能现场模拟试验,防渗层密度１．８ｇ／ｃｍ＾３,模拟降水强度１．７－２．１ｍｍ／ｍｉｎ,试验结果表明：伊－灰复合土防渗层在抗渗性能上明显优于普通粘土防渗层;模拟降水发生后,卫生填埋场的渗滤液发生期可长达２５ｄ左右,８０５的渗滤液发生于前２／５时段。     

保护地番茄养分利用及土壤氮素淋失

在施用不同复合肥料的条件下,对保护地蔬菜蕃茄对N、P、K养分的吸收利用及保护地条件下土壤的硝酸盐淋洗进行了研究,结果表明,复合肥的品种及施肥水平对番茄的产量影响不大,与CK相比番茄果实增产12．．7％－18．4％;复合肥N、P养分的当季利用率不足10％,而K素的当季利用率也不超出25％,传统的大水漫灌条件,蔬菜保护地土壤硝酸盐的淋洗状态相当严重,并有可能造成地下水的硝酸盐污染,长期过量施肥及大小漫灌等措施是造成土壤养分累积、硝酸盐淋洗严重、肥料利用率低的根本原因,图2表3参11     

Fractionation and mobility of phosphorus in a sandy forest soil amended with biosolids

Goal, Scope and Background Biosolids, i.e., treated sewage sludge, are commonly used as a fertilizer and amendment to improve soil productivity. Application of biosolids to meet the nitrogen (N) requirements of crops can lead to accumulation of phosphorus (P) in soils, which may result in P loss to water bodies. Since 1996, biosolids have been applied to a Pinus radiata D. Don plantation near Nelson City, New Zealand, in an N-deficient sandy soil. To investigate sustainability of the biosolids application programme, a long-term research trial was established in 1997, and biosolids were applied every three years, at three application rates, including control (no biosolids), standard and high treatments, based on total N loading. The objective of this study was to evaluate the effect of repeated application of biosolids on P mobility in the sandy soil. Materials and Methods Soil samples were collected in August 2004 from the trial site at depths of 0–10, 10–25, 25–50, 50–75, and 75–100 cm. The soil samples were analysed for total P (TP), plant-available P (Olsen P and Mehlich 3 P), and various P fractions (water-soluble, bioavailable, Fe and Al-bound, Ca-bound, and residual) using a sequential P fractionation procedure. Results and Discussion Soil TP and Olsen P in the high biosolids treatment (equivalent to 600 kg N ha⁻¹ applied every three years) had increased significantly (P<0.05) in both 0–10 cm and 10–25 cm layers. Mehlich 3 P in soil of the high treatment had increased significantly only at 0–10 cm. Olsen P appeared to be more sensitive than Mehlich 3 P as an indicator of P movement in a soil profile. Phosphorus fractionation revealed that inorganic P (Al/Fe-bound P and Ca-bound P) and residual P were the main P pools in soil, whereas water-soluble P accounted for approximately 70% of TP in biosolids. Little organic P was found in either the soil or biosolids. Concentrations of water-soluble P, bioavailable inorganic P (NaHCO₃ Pi) and potentially bioavailable inorganic P (NaOH Pi) in both 0–10 and 10–25 cm depths were significantly higher in the high biosolids treatment than in the control. Mass balance calculation indicated that most P applied with biosolids was retained by the top soil (0–25 cm). The standard biosolids treatment (equivalent to 300 kg N ha⁻¹ applied every three years) had no significant effect on concentrations of TP, Mehlich 3 P and Olsen P, and P fractions in soil. Conclusions The results indicate that the soil had the capacity to retain most biosolids-derived P, and there was a minimal risk of P losses via leaching in the medium term in the sandy forest soil because of the repeated biosolids application, particularly at the standard rate. Recommendations and Perspectives Application to low-fertility forest land can be used as an environmentally friendly option for biosolids management. When biosolids are applied at a rate to meet the N requirement of the tree crop, it can take a very long time before the forest soil is saturated with P. However, when a biosolids product contains high concentrations of P and is applied at a high rate, the forest ecosystem may not have the capacity to retain all P applied with biosolids in the long term. ESS-Submission Editor: Dr. Jean-Paul Schwitzguébel jean-paul.schwitzguebel@epfl.ch     

Modeling transport and fate of nitrogen from urea applied to a near-trench paddy field

A simple but comprehensive model is developed to quantify N losses from urea applied to a near-trench paddy field, considering all the N-transformations such as urea hydrolysis, volatilization, nitrification, denitrification, and all the important transportations like runoff, lateral seepage, vertical leaching and crop uptake. Seasonal average data of field observations for three crop seasons were used for model calibration and validation, which showed that ammonia volatilization accounted for 26.5-29.4% of the applied N and N uptake by crop occupied 38.2-44.8%, while N losses via surface runoff, vertical leaching and lateral seepage varied from 5.6-7.7%, 4.0-4.9% to 5.0-5.3% of the applied N, respectively. These observed results were well predicted by our model, indicating that the model performed effectively at quantifying N losses via individual processes in a wide range of urea application rates and benefit for developing water and fertilizer management strategies for near-trench paddy fields.