多介质地下渗滤系统脱氮影响因素及强化措施

与传统的污水处理工艺相比,地下渗滤在处理分散污水中具有天然的优势,因此逐渐受到了广泛关注与深入研究。地下渗滤对COD和TP的去除率较高,但较低的脱氮率有待加强。笔者通过详细介绍地下渗滤系统氧化还原电位、碳源、运行工况、外部环境等影响脱氮因素,系统地总结了地下渗滤强化脱氮的措施,并对今后的研究方向进行了展望。通过对影响因素进行权重排序,多种强化措施和作用联合应用,提升微生物功效等方法强化氮的去除率,旨在丰富系统除氮的理论内涵,拓展地下渗滤的应用空间。     

木块气化过程焦油联合脱除工况优化

基于松木块气化试验数据,建立了燃气焦油炉内、炉外联合脱除过程最小二乘支持向量机模型（LS—SVM）。在燃气焦油炉内脱除工况优化基础上,针对催化剂活性进一步拟合了燃气焦油炉外催化裂解脱除过程多目标优化模型,优化计算得到气化燃气焦油联合脱除工况的Pareto最优解集。寻优结果表明,气化炉出口燃气焦油质量浓度低于2g/m3,满足焦油催化裂解器对入口燃气焦油含量要求;焦油催化裂解器出口燃气焦油质量浓度降低至0.126~0.340g/m3之间,同时满足燃气热值大于4MJ/m3的工程要求,燃气总体品质明显优于试验结果。     

曝气复合式生态浮床强化修复污水厂尾水的试验研究

采用曝气复合式生态浮床强度修复污水厂尾水,在水力停留时间为1.5d和水温为17.8～21.5℃的条件下,研究了曝气复合式生态浮床对COD、氨氮、总氮和总磷的去除效果。研究结果表明,曝气复合式生态浮床对COD、氨氮、总氮和总磷的平均去除率分别为33.9%～53.1%(平均值44.0%)、37.97%～64.45%(平均值50.8%)、33.46%～57.25%(平均值44.9%)和去除率5.43%～72.62%(平均值50.97%),其出水COD浓度远低于《城镇污水处理厂污染物排放标准》(GB18918-2002)的一级A标准。对比无/有曝气复合式生态浮床发现,曝气强化作用对复合式生态浮床修复效果的改善具有较重要的效果。曝气复合式生态浮床强化系统是一种运行管理方便、成本低廉、无需占有耕地。     

Separation of fine organic particles by a low-pressure hydrocyclone (LPH)

The separation performance of a low-pressure hydrocyclone was tested using fine organic particles from 1 to 700 μm. The dimensions of the low-pressure hydrocyclone were an inflow diameter of 30 mm, a cylinder length of 575 mm, an overflow diameter of 60 mm, an underflow diameter of 50 mm, a cylinder diameter of 335 mm and a cone angle of 68°. The low-pressure hydrocyclone was operated with a lower inlet pressure (average 1.38–5.56 kPa) that could be maintained under water level differences that ranged from 17.5 to 53.5 cm between the water surface of the feeding mass cylinder and the middle of the inlet pipe of the low-pressure hydrocyclone. By varying the inflow rate, underflow ratio and feed concentration, the separation performance of the low-pressure hydrocyclone was affected. The separation performances were determined from total separation efficiency and grade efficiency. Separation performances were determined according to the different inflow rates of 400, 600, 800 and 1000 ml s⁻¹ and their respective underflow ratios that ranged from 5% to 30%. The maximum total separation efficiencies for each inflow rate were 41%, 46% and 46% at 400, 800 and 1000 ml s⁻¹ inflow rates, respectively, and at underflow rates of 30% of the inflow rates. In addition, a total separation efficiency of 46% was employed at 600 ml s⁻¹ of inflow rate and with an underflow rate of 25% its inflow rate. As the feed concentration increased from 25 to 150 mg l⁻¹, the separation performances were gradually decreased. For the fine particles ranging 1–200 μm, the grade efficiency was higher at the higher inflow rate (higher than 600 ml s⁻¹) and higher underflow rate. However, for the coarse particles ranging 400–700 μm, the grade efficiency was higher at the lower inflow rate (lower than 600 ml s⁻¹) and higher underflow rate. The cut-point (d₅₀) values ranged from 30 to 200 μm for a feed size range of 1–700 μm. The Response Surface Method (RSM) model predicted an optimum operating inflow rate and underflow ratio of 721 ml s⁻¹ of inflow rate and 30%, respectively, for the low-pressure hydrocyclone at a maximum total separation efficiency. Based on these findings, further design and operating adaptation of low-pressure hydrocyclones used for fine solids removal in recirculating aquaculture systems is expected.     

弯囊苔草和石菖蒲对生活污水的净化效果比较

通过漂浮栽植弯囊苔草和石菖蒲,分别研究了它们在单独种植和混合种植方式下对低,中、高3种浓度生活污水中的生长特性及其净化效果.结果表明:2种种植方式下供试植物都能在3种浓度中正常生长,且在中、高浓度污水中的生长状况均优于低浓度中;综合各指标,2种种植方式间,石菖蒲的根数差异显著,弯囊苔草的分蘖数和最长根长均差异显著.种植20 d后,单独种植弯囊苔草对3种浓度污水中NH3-N的去除率为中浓度(86.64)>高浓度(83.95)>低浓度(70.84);对TN的去除率为高浓度(87.04)>中浓度(85.53)>低浓度(73.48);对TP的去除率为中浓度(91.77)>高浓度(81.84)>低浓度(78.22);对CODcr的去除率为高浓度(70.261>中浓度(67.74)>4g浓度(66.72).单独种植石菖蒲对NH3-N的去除率为高浓度(93.73)>中浓度(85.43)>低浓度(73.22),对TN的去除率为高浓度(93.15)>中浓度(89.27)>低浓度(88.30),对,TP的去除率为中浓度(92.08)>高浓度(91.04)>低浓度(90.42),对CODcr的去除率为高浓度(80.17)>中浓度(73.64)>低浓度(72.05).混合种植对NH,一N的去除率为中浓度(85.09)>高浓度(84.80)>低浓度(77.17);对TN的去除率高浓度(89.12)>中浓度(86.43)>低浓度(81.97),对TP去除率为中浓度(92.43)>高浓度(92.27)>低浓度(88.56),对CODcr的去除率为高浓度(73.56)>中浓度(72.69)>低浓度(69.65).综合各个指标,3种植方式下2种植物都能有效净化污水,其中对TN、CODcr的去除率以单独种植石菖蒲的去除效果最好;对TP去除率效果为混合种植的最好.     

NO_3~-与NO_2~-对反硝化除磷性能的影响研究

硝酸盐和亚硝酸盐反硝化的对比试验研究结果表明：以硝酸盐为电子受体的反硝化污泥的驯化速率要快于以亚硝酸为电子受体的反硝化污泥驯化速率,无论是以硝酸盐还是亚硝酸盐作为电子受体,缺氧吸磷量均与厌氧释磷量正相关关系,厌氧释磷速率VNO3-∶VNO2-=1∶1.386 0;缺氧吸磷速率VNO3-∶VNO2-=1∶1.027 8。反硝化聚磷过程中电子受体的消耗量和磷酸盐的吸收量之间呈线性相关。以NO2-为电子受体的反硝化除磷速率是NO-为电子受体的2.7倍。     

木棉花加工中护色与脱除茸毛工艺研究

[目的]解决木棉花花脯产品护色和表面粗糙、入口有轻微毛感的问题。[方法]对木棉花加工中护色和脱除表面毛的工艺进行研究。[结果]采用3.0%柠檬酸溶液浸泡20 min或1.0%氯化钙溶液浸泡15 min控制褐变效果明显,干花产品贮存3个月无褐变现象。纤维素酶脱除木棉花表面茸毛的效果比果胶酶效果好,30℃下,0.5%纤维素酶处理木棉花60 min,脱除表面茸毛效果最好。[结论]氯化钙和纤维素酶是一种较好的护色和脱除茸毛的药剂。     

Effects of granivorous rodents on direct seeding of oak and beech in relation to site preparation and sowing date

Planting bare-rooted seedlings is a rather expensive method to regenerate oak (Quercus robur) and beech (Fagus sylvatica). Direct seeding could reduce artificial regeneration costs substantially, but the method currently suffers from a number of problems, one of which is seed consumption by rodents. In the present study clear-cut areas in southern Sweden were prepared using one of four different mechanical site preparation methods – disc trenching, patch scarification, topsoil removal or mounding – then manually sown with acorns and beech nuts. Acorns were sown in May and July 2006, and both acorns and beech nuts were sown in May 2007. Three years following sowing, best seedling establishment from viable acorns, 60–70%, was achieved after sowing in mounds in May, and the subsequent survival reached 90–100%. After the first growing season for beech, both seedling establishment and subsequent survival was lower than for oak, which coincides with a higher number of lost beech nuts at the excavation to investigate the fate of seeds. Granivorous rodents (Apodemus flavicollis, A. sylvaticus, Mus musculus, and Myodes glareolus) were live-trapped more frequently in the vicinity of slash piles compared to other micro-site features, such as uprooted stumps, snags and stones. In 2006, no connection was found between number of rodents captured and proportion of lost seeds, while in 2007 the two were in good accordance. No clear relationship was found between number of captured rodents, vegetation cover class and mechanical site preparation method. More rodents were captured in 2007 than in 2006, and there was an increase in captures from spring until late summer/autumn for both years, which was mirrored in the seedling establishment result from the three different times of sowing. Based on experiences from the present study the recommendation for successful direct seeding of oak on clear-cuts is a combination of mounding site preparation, removal of slash and sowing in May rather than July. However, the results indicate that successful direct seeding of beech is more difficult to achieve.     

土壤-植被-大气连续体中的尺度转换问题

土壤-植被-大气间的相互作用强度高度地依赖于时空尺度。其中,反馈机制贯穿于土壤-植被-大气相互作用的始终。在各个时空尺度中,多因子交互作用,尺度不同起主导作用的过程和控制因子可能有所不同,从而增加了土壤-植被-大气连续体尺度转换研究的难度。从空间和时间尺度上总结了近年来有关学者对尺度转换及反馈机制在模拟中如何应用的研究结果,并在该基础上指出了当前合理描述土壤-植被-大气连续体区域尺度系统行为需要关注的问题和挑战。     

深海盐单胞菌产生的微生物絮凝剂HBF-3对刚果红模拟染料废水脱色的研究

以深海盐单胞菌V3a′(Halomonas sp.V3a′)合成的新型微生物絮凝剂HBF-3对刚果红模拟染料废水进行脱色试验,探讨HBF-3加入量、溶液pH、温度对脱色效果的影响,并与活性炭和壳聚糖对刚果红染料的脱色效果进行对比。结果表明:增加HBF-3的加入量可以提高对刚果红溶液的脱色效果,HBF-3质量浓度为100mg/L时对200mg/L刚果红的去除率达83.7%;HBF-3对染料废水脱色效果受pH值的影响大,pH值在5.0～6.0时,HBF-3对刚果红溶液的脱色效果较弱,为41.1%左右;pH值在7.0～9.0之间变化时,脱色率稳定在88.7%左右;在10～70℃范围内絮凝率随温度变化而改变的幅度小。