限量曝气进水时间对硝化颗粒污泥的影响特性研究

缺氧-好氧环境的交替循环对氨氧化细菌和亚硝酸盐氧化细菌具有重要影响.本研究通过逐渐增加限量曝气进水时间(从10 min至120 min)延长缺氧时段,考察柱形SBR中硝化颗粒污泥对不同缺氧-好氧环境交替循环的响应特性.整个研究过程中,硝化颗粒污泥保持着稳定的颗粒特征,粒径大于0.8 mm的颗粒污泥占总污泥量的质量分数始终在95%以上,颗粒平均沉降速率维持在125～130 m·h-1之间.尽管缺氧时段不断延长,但NH+4-N去除率和NO-2-N累积率分别稳定在(60±5)%、(85±5)%;此外,在每个周期的曝气反应时段,NH+4-N的去除速率以及NO-2-N和NO-3-N的累积速率分别保持在90mg·(L·h)-1、70 mg·(L·h)-1和15 mg·(L·h)-1左右.以上结果表明,限量进水时间的延长及其所造成的不同时间跨度的缺氧环境对硝化颗粒污泥没有较为显著的影响.     

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.     

Effect of alkalinity on nitrite accumulation in treatment of coal chemical industry wastewater using moving bed biofilm reactor

Nitrogen removal via nitrite （the nitrite pathway） is more suitable for carbon-limited industrial wastewater. Partial nitrification to nitrite is the primary step to achieve nitrogen removal via nitrite. The effect of alkalinity on nitrite accumulation in a continuous process was investigated by progressively increasing the alkalinity dosage ratio （amount of alkalinity to ammonia ratio, mol/mol）. There is a close relationship among alkalinity, pH and the state of matter present in aqueous solution. When alkalinity was insufficient （compared to the theoretical alkalinity amount）, ammonia removal efficiency increased first and then decreased at each alkalinity dosage ratio, with an abrupt removal efficiency peak. Generally, ammonia removal efficiency rose with increasing alkalinity dosage ratio. Ammonia removal efficiency reached to 88% from 23% when alkalinity addition was sufficient. Nitrite accumulation could be achieved by inhibiting nitrite oxidizing bacteria （NOB） by free ammonia （FA） in the early period and free nitrous acid in the later period of nitrification when alkalinity was not adequate. Only FA worked to inhibit the activity of NOB when alkalinity addition was sufficient.     

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.     

基于环境因子的异养硝化菌Providencia rettgeri strain YL脱氮性能研究

初步研究了不同温度、pH值、摇床转速和C/N环境因子对Providencia rettgeri strain YL菌株脱氮作用的影响。研究结果表明:Providencia rettgeri strain YL菌株在以葡萄糖和氯化铵为碳氮源的培养基中,温度为35℃,pH为7,摇床转速为120r/min,C/N=10时具有最佳的脱氮效果。     

石油污染物对海底微生物燃料电池性能的影响及加速降解效应

海底石油污染物在缺氧环境下导致其生物降解过程缓慢,对海洋环境造成长期危害.本文利用海底微生物燃料电池(BMFCs)原理,尝试通过电催化作用提高海底石油污染物的降解速率.对比测试了含油电池装置(BMFCs-A)与无油电池装置(BMFCs-B)的电化学性能,研究了石油污染物对电池性能的影响;比较了含油通路(BMFCs-A)和断路状态下(BMFCs-C)的石油降解率和细菌聚集量,分析了BMFCs对石油污染物降解的加速作用.结果表明,BMFCs-A和BMFCs-B阳极的交换电流密度分别为1.37×10-2A·m-2和1.50×10-3A·m-2,最大输出功率密度分别是105.79 m W·m-2和83.60 m W·m-2,BMFCs-A装置的抗极化能力增强,交换电流密度提高近9倍,最大输出功率密度提高1.27倍.BMFCs-A和BMFCs-C阳极表面的异养菌数量分别是(66±3.61)×107CFU·g-1和(7.3±2.08)×107CFU·g-1,细菌数量增加了8倍,高的异养菌数量导致石油降解加速进行,BMFCs的石油降解率是自然条件下的18.7倍.BMFCs在电化学性能提高的同时,加速石油污染物的降解.本文同时提出了一种海底微生物燃料电池对石油污染物加速降解的新模式.     

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.     

水力停留时间对活性污泥系统的硝化性能及其生物结构的影响

利用微生物呼吸醌指纹谱图结合传统分析方法研究了水力停留时间(HRT从30 h逐步缩短至5 h)对活性污泥硝化性能及种群结构的影响.结果表明,对于NH₄⁺-N浓度为500 mg·L^-1的废水,在HRT≥20 h时,氨氮去除率可达98%以上.若继续缩短HRT,污泥流失严重,尽管进水NH₄⁺-N浓度降低,出水NH₄⁺-N和NO₂     

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。