Reductive transformation of p-nitrotoluene by a new iron-fly ash packing

A new iron-fly ash packing was studied for reductive transformation of p-nitrotoluene. The packing was made of iron, fly ash and kaolin with the mass ratio of 36:7:2. A reactor was designed to investigate the long-term performance of the packing. The results showed that the reduction of p-nitrotoluene increased with decreasing pH, because the reduction potential of reaction increased with the concentration of H⁺. The pH was one of the key factors impacting the reductive transformation of p-nitrotoluene. Comparing iron-activated carbon packing with the new iron-fly ash packing, the reduction efficiencies were respectively 76.61% and 75.36% after 20 days. The reduction efficiency for both was around 50% at 40 days. It was evident that these two kinds of packing had no significant difference in their capability for p-nitrotoluene reductive transformation. Compared with iron-activated carbon, the new iron-fly ash packing had obvious advantages in terms of manufacturing costs and environmental pollution degradation. This study showed that the new iron-fly ash packing had good performance in reductive transformation of nitrotoluene compounds.     

二沉池污泥上浮的控制策略

河北大城县污水处理厂采用以氧化沟为主体的污水处理工艺,分析了二沉池污泥上浮产生的原因.认为硝化程度高、污泥在二沉池中停留时间过长是引起污泥上浮的主要原因.采取了减小氧化沟中的溶解氧以降低硝化反应的程度、合理调控二沉池的运行、加大污泥回流量和剩余污泥的排放量等措施后,污泥上浮现象得到有效控制,水厂运行逐渐恢复正常.     

Nutrient concentration variations during Oenanthe javanica growth and decay in the ecological floating bed system

The ecological floating bed system is a natural alternative to technical methods of wastewater treatment and involves complex processes induced by plants or microorganisms in the wastewater. This study aimed to identify nutrient concentration variations during Oenanthe javanica (Blume) DC growth and decay in the ecological floating bed system. Results showed that the third-order polynomial equation was suitable to describe pollutant concentration changes, showing that the effect of O. javanica ecological floating bed system on polluted water could be divided into the purification phase and decay phase. During the purification phase, nutrient concentrations rapidly decreased because O. javanica influenced water microbial communities and water physical parameters (i.e., dissolved oxygen, pH, and temperature), and had a direct uptake of nutrients. However, during the decay phase, nitrogen and phosphorus concentrations in the plant tissues decreased, and these lost nutrients ultimately transferred to water and led to water quality deterioration. Results also showed that the uptake and storage of O. javanica in nutrients were temporary and the plant served only as media of the nutrients removed from the water. Under these circumstances, harvesting was an appropriate intervention to improve the treatment efficiency of O. javanica ecological floating bed system.     

测定生产力中“叶绿素a”的方法探讨

对测定生产力中“叶绿素a”的方法进行了探讨与改进 ,并进行了方法的验证。本方法的精密度范围为 6 1 %～8 4% ,实验证明 ,本方法具有简单、快速、准确等特点。     

生物法处理丙烯腈废气的初步研究

在对生物膜填料塔处理丙烯腈废气的研究中,分别考察了气相浓度、填料层高度、营养物、停留时间等操作参数对净化性能的影响． 通过试验发现,生物膜填料塔对丙烯腈废气具有良好的净化效果,阻力降为２９．４～４９Ｐａ,在进口浓度小于２０００ｍ ｇ／ｍ³,停留时间小于９０ｓ,高度大于２００ｍ ｍ 的填料层上,去除率达到９０％ 以上．     

用革新技术改善水处理厂运行性能

由于60％以上的城市饮用水源受到不同程度的污染,采用常规处理工艺的水厂在处理受污染原水时,效果不显著,效率低,尤其对于重度污染的原水只有采用深度处理工艺,如臭氧化、生物活性炭和膜分离等技术才能有效地处理、然而,多年的研究、探索和工程实践证明,在处理轻度污染原水时,由传统工艺的改善和革新形成的革新技术,比传统处理工艺更为高效,比深度处理技术投资更经济和合理．在对微涡旋絮凝池以及小间距斜板强化沉淀池同传统处理工艺作了比较后发现,传统絮凝池和沉淀池的水力负荷为 7m³（m²·h）,絮凝和沉淀时间分别为 20～25min和 60～80min,出水浊度为7～15NTU,色度为 15～25PtCU;而革新絮凝池和沉淀池,在水力负荷为 12～13m³/（m²·h）时,絮凝和沉淀时间分别为12～15min和40～50min,出水水质优于传统工艺,浊度为1～4NTU,色度为3～8TtCU．     

不同浪高条件下生态浮岛稳定性模拟分析

以辽河干流实际水文资料为依据,在沈阳农业大学水利综合实验基地实验池,通过模拟不同浪高条件,研究不同固定方式生态浮岛的稳定性差异,确定适合于辽河生态浮岛建设的合适类型。结果表明,各位移指标经方差分析和多重比较及均值比较分析,立桩式浮岛稳定性最优,索道式浮岛次之,沉坠式浮岛稳定性较差;绳索张力和沉坠位移指标经比较分析,索道式浮岛较立桩式浮岛稳定,沉坠式浮岛稳定性较差。综合考虑各项分析结果,本研究选择索道式和立桩式作为辽河生态浮岛野外段建设预实验的固定方式,经河流实际水文及其他条件检验后,选择一种最优的固定方式,指导大规模建设。     

新型立体浮床处理河道微污染源水的挂膜特性

立体浮床是一种新型的生物预处理方法。采用了"曝气充氧+新型立体浮床"强化处理方法治理微污染河水,对立体浮床挂膜期间底部填料上的生物膜特性及微污染河水处理效果进行了实验研究。结果表明,在河道水温为15.2～23.6℃,pH在7.0～7.8,溶解氧浓度为4.0～5.9 mg/L时,经40 d左右时填料挂膜成熟。通过对水质和微生物指标分析,填料挂膜分为4阶段:物理吸附阶段—物理吸附-生物繁殖阶段—生物强化吸附降解阶段—挂膜成熟阶段。填料挂膜成熟后,污染物去除效果良好,浊度、COD和NH3-N的去除率分别达到了20.1%、17.5%和18.3%。     

漂浮植物塘处理农村分散生活污水的应用

通过现场实验评价了漂浮植物塘配合化粪池处理农村分散生活污水的效果。实验结果表明,漂浮植物有效地抑制了污染水体中藻类的生长;在平均水力停留时间为36 d,COD、TN、TP平均污染负荷分别为3.1、0.86和0.056 g/(m2.d)的条件下,大薸塘对COD、TN、TP的平均去除率分别为68.5%、89.9%和85.2%,出水COD、TN和TP平均浓度分别为47、4.15和0.40 mg/L,达到GB18918-2002中的一级A标准。在水乡地区利用漂浮植物与农村宅河构造漂浮植物处理系统,是一种深度处理化粪池出水、控制农村生活污水对河道造成污染的有效措施。     

悬浮生物填料床处理微污染原水硝化试验研究

对采用新型悬浮填料床处理微污染原水硝化过程进行了探讨分析了自然挂膜条件下的工艺启动过程，研究了不同工况条件下，悬浮填料床硝化效果。通过春、夏、秋和冬季的中试运行效果表明：在温度适宜、停留时间60min、填料填充率50％条件下，氨氮平均去除效率达到77．60％，定义了氨氮填料表面负荷指数判断氨氮去除效果，水温对硝化的影响较大，在低于20℃时，氨氮填料表面负荷随温度呈指数增长，高于该温度时则增长缓慢，但能维持较高水平；浊度对本工艺硝化影响较小；实验表明原水中氨氮浓度较低，硝化反应符合一级反应，其反应速率常数为0.75h^-1。