聚乳酸/淀粉固体缓释碳源生物反硝化研究

以被硝酸盐氮污染的地下水为研究对象,利用共混/熔融聚合技术将聚乳酸和淀粉混合,制备成兼具碳源和生物载体的缓释碳.并考察不同质量比(聚乳酸∶淀粉为8∶2、7∶3、6∶4、5∶5)的缓释碳在反硝化间歇试验中硝氮、亚硝氮和COD的去除效果,结果表明,当聚乳酸/淀粉质量比为5∶5的缓释碳,其反硝化效果最佳,硝氮去除率达99%;以该比例的缓释碳进行反硝化填充柱连续动态试验时,反应器中反硝化效果显著,出水硝氮浓度在2 mg·L-1以下,为开发环境友好的可控性缓释碳源提供了科学依据.     

Sources of nitrous and nitric oxides in paddy soils：Nitrification and denitrification

Rice-paddies are regarded as one of the main agricultural sources of N 2O and NO emissions. To date, however, specific N2O and NO production pathways are poorly understood in paddy soils. ^15N-tracing experiments were carded out to investigate the processes responsible for N2O and NO production in two paddy soils with substantially different soil properties. Laboratory incubation experiments were carried out under aerobic conditions at moisture contents corresponding to 60% of water holding capacity. The relative importance of nitrification and denitrification to the flux of NaO was quantified by periodically measuring and comparing the enrichments of the N2O, NH~-N and NO3-N pools. The results showed that both N2O and NO emission rates in an alkaline paddy soil with clayey texture were substantially higher than those in a neutral paddy soil with silty loamy texture. In accordance with most published results, the ammonium N pool was the main source of N2O emission across the soil profiles of the two paddy soils, being responsible for 59.7% to 97.7% of total N2O emissions. The NO3-N pool of N2O emission was relatively less important under the given aerobic conditions. The rates of N2O emission from nitrification （N2On） among different soil layers were significantly different, which could be attributed to both the differences in gross N nitrification rates and to the ratios of nitrified N emitted as NzO among soil layers. Furthermore, NO fluxes were positively correlated with the changes in gross nitrification rates and the ratios of NO/N2O in the two paddy soils were always greater than one （from 1.26 to 6.47）. We therefore deduce that, similar to N2O, nitrification was also the dominant source of NO in the tested paddy soils at water contents below 60% water holding capacity.     

人工湿地氮转化与氧关系研究

应用N转化迁移模型分析廊道式人工湿地氮转化与氧供应的关系,验证目前湿地全程硝化反硝化脱氮机制的有效性.对各个廊道进出水NH₄⁺-N、NO₃^--N、TN、B₅、DO进行了测定和分析.在水力负荷5cm/d条件下,各廊道湿地有机氮矿化率为0.01～0.28g·(m²·d)^-1、氨氮硝化率0.50～1.54 g·(m²·d)^-1,反硝化率0.41～1.13 g·(m²·d)^-1(占总氮损失的3.4%～35.4%)、植物净吸收氮0.07～0.26 g·(m²·d)^-1(占总氮损失的7%～33%).硝化反硝化与有机质降解同时进行,在进水端最明显,这与传统认识相悖.按照全程硝化化学计量学得到的硝化需氧量(NOD)高于实际的表面复氧和植物根系放氧.最后对在高浓度有机质存在条件下,能减少对氧需求的2种新型脱氮机制进行了讨论.     

净水厂滤池反冲洗水回用的贾第鞭毛虫和隐孢子虫的泄漏问题研究

采用美国EPA1623方法,研究滤池反冲洗水回用的贾第鞭毛虫和隐孢子虫泄漏问题.通过检测某水厂原水、出厂水和滤池反冲洗水中贾第鞭毛虫和隐孢子虫数量,表明该厂水源未受到贾第鞭毛虫和隐孢子虫的污染,但输送过程易造成水质的污染.滤池反冲洗水中只检出贾第鞭毛虫,出厂水中未检出贾第鞭毛虫和隐孢子虫,说明该厂滤池反冲洗水直接回用未造成"两虫"泄漏问题.     

污水厂提标改造中的反硝化滤池工程设计与调试

随着国家对污水厂处理厂排放标准的提高,现有污水处理厂的提标改造迫在眉睫,而提标改造中普遍遇到的难题是总氮的达标,同时,在总氮达标的情况下,如何以最经济的方式实现其它指标也同步达标。本文通过某污水处理厂的提标改造工程设计和调试分析来介绍一种能够综合实现提标改造各项指标达标的工艺。     

废水生物脱氮处理方法研究

氨氮是水体富营养化的主要成分之一,本文介绍污水生物脱氮技术原理,并对比介绍生物脱氮法几种主要工艺的基本原理、工艺特性和研究进展,并结合国内外的生物脱氮最新研究进展,对同时硝化反硝化的形成机理及其对SBR工艺、氧化沟、MBR工艺等的应用进行了分析。最后指出生物脱氮处理方法的研究前景。     

金属矿井主扇反风技术分析及数值模拟研究

立足于现有的计算流体力学方法,提出了对轴流式风机反风的数值仿真模拟。运用CFD软件Fluent对轴流式风机正反转都进行了三维数值模拟,选用K40-4-15型轴流风机作为研究对象,重点研究了轴流式风机的反风性能以及叶片安装角、叶型拱度和转速对其反风量的影响。模拟结果为提高轴流式风机的反风量提供了科学的依据。     

焦化废水生物脱氮的试验研究

采用单相活性污泥法对焦化废水进行了试验研究。研究结果表明:当进水NH_3—N浓度为300mg/L左右,COD为1200～1500mg/L,酚浓度为100～380mg/L,CN~-为10～30mg/L,在系统总水力停留时间为27h和混合液回流比为400％的条件下,出水各项污染指标均达到国家排放标准。