不同填料对曝气生物滤池除污效果的影响

采用臭氧/BAF组合工艺处理制革园区污水处理厂的二级生化出水,考察了不同填料BAF挂膜启动的运行情况,探讨了臭氧投加量为25 mg/L时不同填料BAF稳定运行的除污效果及机理。平行运行3个BAF,其填料分别为活性炭、陶粒、活性炭/陶粒(体积比为1∶1)。在挂膜启动期间,活性炭和混合填料BAF对COD的去除率表现为先下降再上升最后趋于稳定,32 d后出水COD<60 mg/L,而陶粒BAF对COD的去除效果不明显。稳定运行期间,进水COD、色度平均值分别为117 mg/L和112.5倍,活性炭BAF的出水值则降至50 mg/L和6倍,达到《城镇污水处理厂污染物排放标准》(GB 18918—2002)中的一级B标准。在此期间活性炭、混合填料和陶粒BAF中的生物量分别为30.69、25.87、15.18 nmol/g。     

曝气生物滤池中填料的研究进展

曝气生物滤池（BAF）是一种新兴的污水处理工艺,填料是曝气生物滤池的核心元素,填料的选择是滤池设计和影响出水水质的关键因素。综述了近几年来填料在国内外的研究现状和进展,并展望了其在今后的研究方向。     

不同填料曝气生物滤池处理微污染河水的效果

分别以陶粒、沸石-陶粒、两种弹性纤维材料为填料,在有效体积为150 L的填充床中,对曝气生物滤池(BAF)处理模拟城市微污染河水中氨氮和有机物的效果进行了试验,并对比了4种填料的特点和运行效果。结果表明:两种颗粒填料的氨氮硝化负荷要高于纤维填料,颗粒填料和纤维填料BAF的最佳HRT分别为1 h和1.5 h。在HRT为1 h时沸石-陶粒组合填料和陶粒填料的平均氨氮去除率分别为94.6%和93.7%,在HRT为1.5 h时两种纤维填料的平均氨氮去除率分别为89.5%和92.6%,且颗粒填料对氨氮的去除主要集中在填料高度60～100 cm的部分。水力停留时间对两种颗粒填料的进水压力和出水浊度影响较大,而对纤维填料影响较小。在气水比为2时,4种填料对氨氮和COD的去除效果好于气水比为1和3时的去除效果。纤维填料BAF的投资成本更高,但运行成本要明显低于颗粒填料BAF。     

新型填料曝气生物滤池去除氮化合物的效果

采用聚丙烯腈中空纤维膜段作为上流式曝气生物滤池的填料,就系统启动期间生物膜的形成以及对生活污水中氮化合物的去除规律进行了研究,并考察了稳定运行阶段的气水比、水力停留时间等对硝化和反硝化的影响.试验发现:在载体的外表面进行硝化反应的同时,其内部还发生了反硝化反应;中空纤维膜段的形状结构和表面特点使其适宜作为生物膜的载体.     

气水比对高分子填料BAF脱氮效能的影响

采用高分子载体作为生物填料,以模拟生活污水为处理对象,对两级曝气生物滤池(BAF)的脱氮效能进行了试验研究,着重考察了气水比对BAF去除COD、NH3-N和TN的影响,并探讨了系统内氮素的转化规律和提高脱氮效能的途径。结果表明,当平均水温为22~32℃、进水流量为4 L/h、进水COD为150 mg/L左右、进水NH3-N为60 mg/L左右、一级BAF的气水比为4∶1、二级BAF的气水比为2∶1时,系统的处理效果最佳,对COD、NH3-N和TN的总平均去除率分别达到84.33%、87.84%和56.06%。系统通过同时短程硝化反硝化实现了低能耗、高效率的脱氮。     

水力负荷对木炭填料生物滤池处理污水的影响

以木炭作为曝气生物滤池的填料,并与陶粒填料作对比,考察了其在不同水力负荷下对污水的处理效能.结果表明,改变水力负荷对两个反应器的出水COD影响不大,但对其脱氮除磷效果的影响较显著.木炭滤池对氨氮和TN的去除效果要好于陶粒滤池的,当水力负荷为4m~3/(m~3·d)时,两反应器的脱氮效果最佳,此时木炭和陶粒滤池的出水氨氮浓度分别为4.7、7.7mg/L(去除率分别为80%和65%).综合考虑木炭滤池对COD、NH_4~+-N、TN和TP的去除效果,确定其最佳水力负荷为4 m~3/(m~3·d).     

侧向流曝气生物滤池处理城市污水效能研究

通过试验,研究了新型曝气生物滤池对城市生活污水的处理效果,考察了水力停留时间(HRT)和温度等的影响。结果表明,曝气生物滤池试验装置在流量为25.2~72 L/h、含氧量为2~4 mg/L、水温为10~25℃时滤池水中COD和SS的去除率为85%和95%。     

侧向流曝气生物滤池处理城市污水效能研究

通过试验研究新型曝气生物滤池对城市生活污水的处理效果。考察了水里停留时间(HRT)和温度等的影响。结果表明,曝气生物滤池在流量为25.2～72L/h、含氧量为2～4mg/L、水温为10～25℃时滤池水中COD和SS的去除率为85%和95%。     

滤料粒径对曝气生物滤池硝化性能的影响

为研究滤料粒径对曝气生物滤池(BAF)硝化性能的影响,分别采用粒径为2～3mm和4～5mm的沸石滤料在直径为0.2m的BAF中进行了试验,结果表明,前一种滤料比后一种滤料对氨氮去除率高,20℃时两者的硝化速率常数分别为16.8mg/(L·h)和10.3mg/(L·h),前者比后者高63.1%;同一条件下前一种滤料比后一种滤料硝化强度大39.7%。两种粒径沸石比表面积的比值为1.8,这是引起硝化性能差异的主要原因。在硝化滤池中选择粒径为2～3mm沸石滤料比较适宜,既不影响运行周期,又提高了硝化性能,从而减小了滤池的体积,降低了工程投资。     

贝壳填料曝气生物滤池的硝化特性研究

贝壳粗糙的表面及其合有的大量碳酸钙，可作为生物膜的载体及硝化反应的碱度来源。以海产弃物贝壳为生物膜载体，通过改变进水氨氮浓度及pH值，考察了贝壳填料曝气生物滤池的硝化脱氮规律。结果表明：对于氨氮〈120mg／L的原水，贝壳溶解提供的碱度能够满足硝化反应的需要，因此硝化反应进行得比较完全，对氨氮的去除率不受进水氨氮浓度的影响，可达90％以上；而当进水氨氮浓度达240mg／L时，因贝壳溶解提供的碱度不能完全满足硝化反应之所需，硝化反应将停滞，但对氨氮的去除率仍可达65％左右。此外，进水pH值对贝壳填料曝气生物滤池去除氨氮的效果及出水pH值基本没有影响。     

Elimination of hydrogen sulphide from odorous air by a wood bark biofilter

Wood bark, used as biofilter material, gives less back pressure than fibre peat or household compost and is therefore cheaper in variable costs than the other materials. With a filter bed height of 0.9 m and with a surface load of 65 m³ m⁻² h⁻¹, 10 ppm hydrogen sulphide is efficiently eliminated from odorous air by a wood bark biofilter. The most important parameter for a good functioning of the filter is the water content of the filter material. The optimum for wood bark is about 65%. Unnecessarily high back pressures are recorded during sprinkling water on top of the filter. Therefore, it seems preferable to condition the relative humidity of air entering the filter. If absorption and adsorption were the only factors in the biofilter mechanism, hydrogen sulphide would, in the given circumstances, break through after about 7 h. It is shown that hydrogen sulphide is oxidized to sulphate. According to literature data, chemical oxidation is too slow and therefore hydrogen sulphide oxidation in the biofilter is attributed to microbiological action.     

Effect of reduced evaporator airflow on the high temperature performance of air conditioners

Two residential sized air conditioners were tested in psychrometric rooms at reduced evaporator airflows ranging from 0 to 50% below that recommended by the manufacture of each of the units. Outdoor temperatures ranged from 35 to 49°C. One of the units used a thermal expansion valve for flow control while the other unit used a short tube orifice. Performance of the units was quantified by the capacity, power, coefficient of performance, and sensible heat ratio. Results at 35°C indicated that the reduction in air produced a larger drop in capacity and coefficient of performance for the orifice controlled unit than the thermal expansion valve controlled unit. The power showed less than a 4% reduction for either unit as the airflow was reduced by 50%.     

Effect of colloids on the survival of bacteriophages in seawater

A study was undertaken on the effect of colloids on the survival of bacteriophage T₇ in natural seawater. It was found that the biological inactivation of virus T₇ was controlled by the addition of inorganic and organic colloids. Colloidal montmorillonite and Escherichia coli K cells protected the virus from inactivation in natural seawater. The nature of this protective effect is discussed.     

Effect of roughness height ratio in V down perforated baffle roughness on thermohydraulic performance of solar air heater: an experimental study

A substantial improvement in the thermal performance of solar air heater is found by using roughness on the underside of the absorber plate. In the present investigation, the effect of relative roughness height of roughness element on the thermohydraulic performance of solar air heaters is carried out. The range of roughness and flow parameters for the investigation are relative roughness height (e/H): 0.285–0.6, relative roughness pitch (P/e): 2, angle of attack (α): 60°, open area ratio (β): 12% and Reynolds number (Re): 3800–19,000. The relative roughness height of 0.285 is thermohydraulically better in comparison to other relative roughness heights. The results show that the V down perforated baffles is thermohydraulically better than the solid baffles.     

气浮工艺用于海水淡化预处理试验研究

以三氯化铁和聚合氯化铝作为混凝剂,氯水作为氧化剂,考察了气浮工艺用于海水淡化预处理的运行效果.结果表明:预氧化可以强化混凝+气浮预处理工艺对浊度、CODMn、UV254和TOC的去除效果,三氯化铁的最佳投加量为15～20 mg/L,聚合氯化铝最佳授加量为6～10mg/L,最佳气浮回流比为15％;在最佳运行条件下,预处理...     

大掺量粉煤灰混凝土在海水中冻融循环后的试验研究

为研究粉煤灰混凝土的抗冻性能,研究了水胶比为0.35,粉煤灰掺量为52%的大掺量粉煤灰混凝土在海水中的抗冻性能,利用混凝土快速冻融试验机,对海水中粉煤灰混凝土分别进行了0、100、200、300、400次快速冻融循环试验,并对冻融循环后的混凝土进行了单轴压力学性能试验。测得了冻融循环后混凝土的质量损失,动弹性模量以及单轴抗压强度。根据试验结果,系统地分析了冻融循环次数对大掺量粉煤灰混凝土单轴抗压强度的影响。结论表明:随冻融循环次数的增加,海水中大掺量粉煤灰混凝土的单轴强度逐渐降低,并具有一定规律性。这些结论可以为粉煤灰混凝土在寒冷地区海工混凝土构筑物的应用提供理论依据。     

海水空调的发展及在中国应用前景分析

介绍了海水空调的两种形式。介绍了国外此项技术的研究和应用状况,以及系统设计形式,在经济性方面与传统空调系统进行了比较。通过对我国黄海、渤海地区历年冬、夏两季海水温度场的分布情况和目前所具备的技术基础状况的分析,得出此项技术在我国应用技术上可行,会有很好的应用前景的结论。针对目前存在的问题,指出今后研究的主要方向。     

热泵空调与海水淡化系统联合运行方式探讨

论述了热泵空调与海水淡化系统联合运行的方式。夏季,热泵从空调用户中提取热量为海水淡化供应热量;冬季,热泵从海水中提取热量为海水淡化和空调用户供热,可实现减少热量与电能消耗和温室气体排放,还可为工业或生活用户提供淡水。     

海水源热泵空调系统的经济与环境评价研究

结合一典型工程介绍了海水源热泵空调系统的设计方案。对传统系统和海水源热泵空调系统的经济性进行了对比,结果表明只有在一定的优惠政策下,海水源热泵空调系统才在经济上可行。对海水取排水区域温度场的模拟结果表明,在规模适度和合理设计取排水口位置的条件下,海水的温升满足国家海水排放标准。     

Effect of seawater for mixing and curing on structural concrete

In this article, the effects of mixing and curing concrete with seawater on the compressive, tensile, flexural and bond strengths of concrete are investigated. Concrete mixes were prepared by varying coarse aggregates, cement proportions and types. Six groups of concrete mixes were mixed and cured in fresh water, six groups were mixed and cured in seawater, while four groups were mixed with fresh water and cured in seawater. The compressive strength and subsequently the other related strengths of concrete were shown to increase for specimens mixed and cured in seawater at early ages up to 14 days, while a definite decrease in the respective strengths was observed for ages more than 28 days and up to 90 days. The reduction in strength increases with an increase in exposure time, which may be due to salt crystallisation formation affecting the strength gain.