温度和pH值对活性污泥法脱氮除磷的影响

温度和pH值是影响污水脱氮除磷效果的2个重要因素.试验采用连续搅拌槽式反应器(continuous stirred tank reactor,CSTR),通过对不同温度和pH值条件下的硝化、反硝化、释磷和吸磷反应速率的测定,总结出温度和pH值对活性污泥生化反应速率的影响规律.试验表明,硝化和反硝化速率随温度的升高而加快.在5℃和33℃时,硝化速率分别为0.01 kg NH4 -N/(kg VSS·d)和0.28 kg NH4 -N/(kg VSS·d);在5℃和30℃时,反硝化速率分别为0.097 kg NO3--N/(kg VSS·d)和0.476 kg NO3--N/(kg VSS·d);但温度对吸磷和释磷速率的影响不大.pH值对硝化、反硝化、吸磷和释磷速率均有显著影响,在pH值为7.74时,硝化速率为0.095 kg NO3--N/(kg VSS·d);而在pH值为4.9和10.08时,硝化速率仅为0.005 kg NO3--N/(kg VSS·d)和0.006 kg NO3--N/(kg VSS·d).在pH值为7.85时,反硝化速率达到最大值0.36 kg NO3--N/(kg VSS·d);而在偏酸性和碱性条件下,反硝化速率显著下降.     

Beyond hypoxia：Occurrence and characteristics of black blooms due to the decomposition of the submerged plant Potamogeton crispus in a shallow lake

Organic matter-induced black blooms(hypoxia and an offensive odor) are a serious ecosystem disasters that have occurred in some large eutrophic shallow lakes in China. In this study, we investigated two separate black blooms that were induced by Potamogeton crispus in Lake Taihu, China. The main physical and chemical characteristics, including color- and odor-related substances, of the black blooms were analyzed. The black blooms were characterized by low dissolved oxygen concentration(close to 0 mg/L), low oxidation-reduction potential, and relatively low pH of overlying water. Notably higher Fe2+and∑S2-were found in the black-bloom waters than in waters not affected by black blooms. The black color of the water may be attributable to the high concentration of these elements, as black FeS was considered to be the main substance causing the black color of blooms in freshwater lakes. Volatile organic sulfur compounds, including dimethyl sulfide, dimethyl disulfide, and dimethyl trisulfide, were very abundant in the black-bloom waters. The massive anoxic degradation of dead Potamogeton crispus plants released dimethyl sulfide, dimethyl disulfide, and dimethyl trisulfide, which were the main odor-causing compounds in the black blooms. The black blooms also induced an increase in ammonium nitrogen and soluble reactive phosphorus levels in the overlying waters. This extreme phenomenon not only heavily influenced the original lake ecosystem but also greatly changed the cycling of Fe, S, and nutrients in the water column.     

粒状羟基氧化铁对废水中硝酸盐的吸附

本实验研究了粒状羟基氧化铁(GFH)对人工配制含氮废水中NO3--N吸附的影响因素、吸附等温线和吸附动力学。结果表明,GFH的吸附平衡时间为80 min,增加NO3--N溶液的初始浓度,去除率下降;pH值为5时GFH对NO3--N的吸附能力最强,pH值升高和降低,吸附能力均下降;GFH对NO3--N的吸附能力随着温度的升高略有降低;在25℃下,以Langmuir方程和Freundlich方程分别对GFH吸附NO3--N的等温线进行拟合,拟合效果以Langmuir方程较好,相关性达到0.9930。GFH吸附NO3--N的过程符合拟二级动力学方程,初始时刻的吸附速率h在35℃时最大,为1.653 mg/(g.mg),吸附速率常数随温度的升高而增大;吸附反应的活化能Ea为54.72 kJ/mol。本研究结果表明,GFH在饮用水脱氮和含氮浓度较低的污水再生回用领域有实际应用的潜力。     

垂直厌氧折流板反应器处理树脂废水的中试研究

介绍了采用垂直厌氧折流板反应器(VABR)处理离子交换树脂生产废水的中试实验装置以及实验研究过程,并着重分析了COD容积负荷和盐分对COD的去除率及出水VFA的影响,并确定了该废水的厌氧产沼气率。研究结果表明,在中温(37±1℃)环境下,容积负荷在9 kg COD/(m3.d)左右时,HRT为24 h的条件下,VABR对COD的平均去除率保持在70%左右,平均每去除1 kg COD约产生沼气0.44 m3,且运行稳定。     

Safety management in a relationship-oriented culture

A relationship-oriented culture predominates in the Greater China region, where it is more important than in Western countries. Some characteristics of this culture influence strongly the organizational structure and interactions among members in an organization. This study aimed to explore the possible influence of relationships on safety management in relationship-oriented cultures. We hypothesized that organizational factors (management involvement and harmonious relationships) within a relationship-oriented culture would influence supervisory work (ongoing monitoring and task instructions), the reporting system (selective reporting), and teamwork (team communication and co-ordination) in safety management at a group level, which would in turn influence individual reliance complacency, risk awareness, and practices. We distributed a safety climate questionnaire to the employees of Taiwanese high-risk industries. The results of structural equation modeling supported the hypothesis. This article also discusses the findings and implications for safety improvement in countries with a relationship-oriented culture.     

从废催化剂中回收钼的新工艺

确定了用新型复合浸取剂从废催化剂中回收钼的最佳工艺条件废催化剂颗粒度１００目焙烧温度７５０℃,焙烧时间１ｈ复合浸取剂中助浸剂质量为５％,浸取固液质量比１：３,浸取温度６０℃,浸取时间６ｈ,在该条件下,钼的浸取率达到９２．７％～９５．５％。     

盐分对一株硫氧化细菌氧化能力的影响

通过液体选择培养基、平板划线的方法从脱硫污泥中分离筛选出一株硫氧化细菌,并对其进行初步鉴定和生长特性的分析。结果表明,该细菌为化能自养型细菌,短杆状,大小为0.5~0.8 μm × 1.2~3.0 μm,革兰氏染色显阴性。以5%的接种量接种于富集培养基,S2-初始浓度为100 mg/L时,SOB在60 h内基本将还原态硫氧化完全,pH最低降到2左右。当溶液中有SO42-量积累和电导率升高后,对SOB氧化S2O32-过程有明显的抑制作用。该菌株对盐分的耐受值为7 650 μS/cm(以电导率计)。     

低温季大型表流湿地对微污染水体脱氮效果及优化运行

低温季表流湿地脱氮效果下降是业内公认的难题,长期以来备受人们的关注,但针对大型表流湿地处理微污染水体的相应研究开展较少。综述了表流湿地脱氮机理及低温季限制因素,同时以盐龙湖工程的表流湿地单元为实例,分析了其在低温季对微污染水体中各形态氮素的净化效果,从优化湿地运行角度出发开展研究。结果表明,在低温季表流湿地进水的TN平均值为1.16~3.35 mg/L条件下,TN、NH3-N、硝态氮、Org-N的平均去除率为13%、35%、15%、-14%;显著影响表流湿地出水TN浓度的因素为湿地运行面积、进水负荷、温度以及进水浓度(p 湿地运行面积(负相关)> 进水负荷(负相关)> 温度(负相关)。显著影响表流湿地NH3-N出水浓度的因素为温度与进水浓度(p温度(负相关);当HRT从3-N的平均去除率分别由6%、26%提升到17%与41%。