间歇梯度曝气下缩短SRT强化短程SNEDPR系统脱氮除磷

为了探究间歇梯度曝气下污泥龄对氨氧化菌（AOB）和亚硝酸盐氧化菌（NOB）的影响,研究短程硝化内源反硝化除磷系统对于处理低C/N比生活污水的优势作用,本文采用SBR反应器培养好氧颗粒污泥,实验进水采用实际生活污水.结果表明,在SRT由50 d逐渐降低至30 d过程中,比氨氧化速率由3.16 mg·（g·h）^-1增加至4.38 mg·（g·h）^-1,比亚硝酸盐氧化速率由3.4 mg·（g·h）^-1降为1.8 mg·（g·h）^-1左右,可知NOB活性降低约44%,从而使系统实现了短程硝化.当SRT为30 d时,由典型周期实验可知亚硝酸盐最大积累量可达6.93mg·L^-1.由于系统中污泥浓度随SRT的减少而略有降低,因此在反应进行至40 d左右时根据DO曲线采取降低曝气量的策略,最终SRT为30 d时系统出水COD浓度为40.76 mg·L^-1,TN浓度为12.4 mg·L^-1,TP浓度为0.31 mg·L^-1,强化了系统中C、N和P的同步去除,最终得到了稳定运行的短程硝化内源反硝化除磷系统.同时好氧颗粒污泥EPS含量与SRT呈现负相关性,蛋白质含量由污泥龄为50 d的66.7 mg·g^-1升为30 d的95.1mg·g^-1,多糖保持在12.1~17.2 mg·g^-1的范围内,说明SRT的降低对蛋白质含量的影响较多糖大,当SRT为30 d时,PN/PS值保持在6.2左右,好氧颗粒污泥在该条件下仍能保持较好的结构稳定性.     

高频曝停下停曝时间对亚硝化颗粒污泥性能的影响

间歇曝气中停曝时间对于NOB的抑制是积累亚硝酸盐的关键,为探究曝气频次相同、停曝时间组合不同亚硝化颗粒污泥的稳定运行,在25～28℃,接种好氧颗粒污泥于SBR(R0)反应器中,通过间歇曝气与DO限制驯化为亚硝化颗粒污泥,采用3组规格相同的SBR反应器(R1、R2和R3)分析停曝时间组合(3 min∶3 min、4 min∶2 min和2 min∶4 min)对亚硝化颗粒污泥性能的影响.实验表明,R1、R2亚硝酸盐积累率较高,平均亚硝酸盐积累率分别为89%和95%,R3亚硝化性能较差,运行周期末期亚硝酸盐积累率仅为57%.结果表明,在停曝时间为2～4 min下,停曝时间越长,越有利于颗粒污泥结构的稳定,同时可保持良好的亚硝化性能;停曝时间小于2 min时,厌氧好氧交替的环境不能完全实现,致使其运行效果倾向于连续曝气,失去了间歇曝气的环境优势,NOB菌得不到抑制,颗粒污泥呈现解体的趋势,导致亚硝化性能恶化;此外,较长曝气时间会有助于不规则形状颗粒的发展,停曝时间越长,PN/PS值越高,有利于颗粒表面疏水性的增强,污泥沉降性能越好.     

化学防护服渗透性试验方法比较研究

渗透性是衡量化学防护服防护性能好坏的一项重要指标。本文就美标、欧标和ISO三大标准体系所涉及的渗透性测试相关试验方法进行了比较研究,找出了三种方法的相通之处以及其差异所在,对化学防护服渗透性测试研究提供指导。     

LOW FLOW SPATIAL CHARACTERISTICS IN FORESTED HEADWATER CHANNELS OF SOUTHWEST WASHINGTON1

ABSTRACT: Patterns of dry season surface flow in forested headwater channels of southwest Washington were observed during August to September 2001 and July to October 2002. In 2001, 17 channels were sampled once, and the uppermost points of continuous flow (CF) and surface water (SW) were located. In 2002, sampling was replicated three to five times at each of 21 channels. Annual and seasonal data suggested that the location of SW varied less than CF. In most channels, SW remained at or near the channel head year around. The pattern of surface flow between CF and the channel head was used to test alternative hypotheses describing dry season recession patterns: (A) surface flow consistently retreats in a downstream direction, and (B) flow comes from fixed sources along the channel, thus surface flow retreats up‐channel towards these sources. The dominant surface flow spatial pattern in streams less than 30 percent slope was increased intermittency without a clear pattern of retreat, and thus inconsistent with either hypothesis. High gradient channels (< 30 percent slope) exhibited a combination of increased intermittency, and extensive upward retreats of surface water consistent with Hypothesis B. Differences between 2001 and 2002 suggest late summer flows in small headwater basins were controlled by spring precipitation, rather than the typically greater winter precipitation.     

EFFECTS OF VARIABLE DISCHARGE SCHEMES ON DISSOLVED OXYGEN AT A HYDROELECTRIC STATION1

ABSTRACT: The effects of variable discharges during the summer on the dissolved oxygen (DO) content and water temperature upstream and downstream of the Conowingo Hydroelectric Power Station were investigated. The DO dynamics are controlled primarily by meteorological factors that are independent of the mode of hydrostation operation. DO stratification occurred during the summer in Conowingo Pond, but thermal stratification was not observed. The magnitude and duration of off-peak discharges including a run-of-the-river operation did not affect DO stratification in Conowingo Pond; little vertical mixing occurred. However, strong winds and/or high river flows temporarily destroyed DO stratification. The run-of-the-river operation or off-peak continuous discharge schemes did not provide better DO conditions downstream of the hydrostation than the peaking operation with intermittent off-peak releases. A statistical model predicted that a DO of 5 ppm occurs 0.6 miles downstream of the powerhouse when the natural river flow is consistently greater than 15,000 cfs and water temperature is less than 80°F. A mean daily DO of at least 4 ppm was predicted to occur over 80 percent of the time during the 92-day summer period. Farther downstream (1.3 miles from the powerhouse) a mean daily DO of at least 4 ppm was predicted to occur 90 percent of the time in summer.     

城镇污水处理厂低浓度连续进水间歇曝气运行模式分析

根据南方城镇污水处理厂建成运行初期的实际运行情况,对低浓度进水的运行模式进行了分析和研究。运行中,污水处理厂MISS浓度调整为25g／L,采用曝气3h、停曝5h、连续进水的运行模式,实现了生物系统稳定运行,出水达标。     

活性炭吸附缓冲非稳态VOCs研究进展

活性炭类吸附剂可以有效地缓冲挥发性有机物(VOCs)的浓度负荷波动。综述了活性炭对非稳态VOCs吸附缓冲的作用原理及类型,从吸附剂、吸附质、进气性质和设备及操作条件等方面讨论了影响吸附缓冲性能的因素,并对今后该领域的研究方向提出了展望。指出:应当进一步研究吸附剂和吸附质的交互作用、波动负荷的影响以及VOCs在活性炭中的迁移扩散现象;同时,通过深层次的实验测试和模型模拟为反应器的设计和操作参数的估算提供指导。     

碳素纤维泛氧化塘治理高寒地河水的试验研究

采用碳素纤维生态草填料和间歇曝气强化的泛氧化塘对长春新凯河河水展开了异位式治理的试验研究,考察了单一的填料强化和"间歇曝气+填料强化泛氧化塘"对污染物的年度去除效果。试验过程中发现COD、NH4+-N、TP的去除效果受温度的影响比较明显,四季平均去除率分别为16.85%~34.19%、13.6%~53.14%、9.22%~26.08%;NH4+-N去除率同时受DO的影响也很明显,夏季间歇曝气可提高NH4+-N去除率27%左右。全年监测结果表明:曝气强化作用在夏季最为明显,在停留时间为36 h、曝气时间为18 h/d、曝气量为0.4 m3/min时,碳素纤维曝气泛氧化塘对COD、NH4+-N、TP的平均去除率分别为34.19%、53.14%、26.08%,这表明采用碳素纤维曝气泛氧化塘对受污染河水的治理是可行的。     

阶段曝气和植物对人工湿地处理城镇污水厂尾水的影响

采用人工配水模拟城镇污水处理厂尾水水质,利用3套阶段曝气垂直潜流人工湿地（VSFCW）对其进行处理。结果表明：当水力负荷分别为30、90和180 cm·d-1时,3套人工湿地对COD具有较好的去除效果,其去除率都大于66.7%;在处理总磷（TP）和总氮（TN）方面,VSFCW-1（无植物-曝气垂直潜流人工湿地）去除效果远远低于VSFCW-2（芦苇-曝气垂直潜流人工湿地）和VSFCW-3（芦苇-不曝气垂直潜流人工湿地）,VSFCW-2（芦苇-曝气垂直潜流人工湿地）和VSFCW-3（芦苇-不曝气垂直潜流人工湿地）对TP和TN的去除率分别在80.0%和75.0%以上且具有较强的抗水力负荷冲击能力。VSFCW-2（芦苇-曝气垂直潜流人工湿地）和VSFCW-3（芦苇-不曝气垂直潜流人工湿地）对COD、TP的去除主要是集中在沿程的前1/4段（0~24 cm）,后3/4段（24~115 cm）保证了出水水质的稳定。     

微孔曝气器脉冲式充氧效果

针对生化池连续曝气过程中氧转移率低的问题,结合污水处理中的实际情况,提出了盘式微孔曝气器脉冲式充氧方法来提高氧的转移率。通过4组不同类型的盘式微孔曝气器分别在脉冲式和连续曝气下的实验对比发现,脉冲式曝气产生的是气泡簇,对生成的气泡进行图像统计分析,得出同一区域范围内脉冲式曝气生成的气泡数量多、平均直径小。实验数据分析显示,脉冲式曝气达到氧饱和所需的时间较连续曝气方式增加了10%左右,但氧的利用率增加了50%以上,且动力效率提高了28%以上。脉冲式曝气方式大幅度提高了氧的利用率,节约能耗的同时具有更好的充氧效果,为活性污泥好氧生化处理系统工艺提供了新的研究思路。