人工湿地的反硝化能力研究

利用人工湿地的反硝化作用进行去除硝态氮的试验,其反硝化碳源主要为植物根系的分泌物及湿地内腐败的死亡植株.结果表明,人工湿地内有着适宜反硝化的反应环境,反硝化茵能够很好地利用湿地内产生的碳源进行反硝化作用来去除硝态氮,且不会出现亚硝态氮的大量积累.在进水(NO3-)-N浓度为20-50 mg/L、水力停留时间为24 h的条件下,夏季运行时,湿地系统对硝态氮的去除率为20%～30%;冬季运行时,对硝态氮的去除率在10%左右.提供充足的反硝化碳源是硝态氮去除率进一步提高的瓶颈.     

不同湿地组合工艺处理小规模生活污水效果比较

对处理小规模生活污水的3种人工湿地组合系统的设计和实际使用效果进行了比较.为期1～2年的运行结果表明：水平流湿地＋垂直水平复合流湿地对生活污水净化效果最好;下行垂直流湿地＋下行垂直流湿地＋水平流湿地有利于氮的去除;在厌氧状态下补充碳源会大大增强反硝化作用,提高对氮的去除效果.     

低氧接触氧化/微曝气人工湿地工艺净化污染河水

采用低溶解氧接触氧化与微曝气垂直流人工湿地的组合工艺对滇池入湖污染河水进行处理,以解决人工湿地在高负荷下运行时易堵塞和效率低的问题。结果表明,在低溶解氧条件下接触氧化反应器对SS、COD的平均去除率分别为86.2%和57.4%,且运行稳定。新型轮换式微曝气系统的开发与应用使垂直流人工湿地中的溶解氧环境得到了改善,悬浮物及脱落的生物膜在气流作用下不易沉降堵塞,在气水比为1∶1的条件下湿地的进水氨氮负荷可达15 g/(m2.d),平均去除率为89.6%,硝化效率明显提高。TN的去除主要依靠湿地内部的硝化/反硝化作用,轮换式曝气使溶解氧梯度随时间和空间而变化,当出水溶解氧为2~4 mg/L时,湿地单元对TN的平均去除率为40.6%。该组合工艺整体运行稳定,除污效率高,为污染河水的净化提供了一种新的方法。     

脉冲垂直流人工湿地处理污染河水的试验研究

将脉冲布水引入垂直流人工湿地,考察了其与普通垂直流人工湿地对受污染河水处理效果的差异。结果表明,在水力负荷为0.6 m3/(m2.d)下,脉冲布水明显提高了人工湿地系统的复氧效果,普通垂直流人工湿地一级出水DO为零,而脉冲垂直流人工湿地一级出水DO平均为0.5 mg/L;两者对COD和TP的去除效果相当,脉冲和普通垂直流人工湿地对COD的去除率分别为59.2%和58.4%,对TP的去除率分别为83.6%和83.4%;但脉冲垂直流人工湿地对NH3-N和TN的去除效果优于普通垂直流人工湿地,脉冲垂直流人工湿地及其第一级湿地对NH3-N的去除率分别为38%和30%,对TN的去除率分别为40%和26.3%,而普通垂直流人工湿地及其第一级湿地对NH3-N的去除率分别为31.6%和22.1%,对TN的去除率分别为33.2%和23.9%。     

潮汐流人工湿地不同位置脱氮效果及外加碳源对其影响

以潮汐流人工湿地小试系统为研究对象,采用碱处理玉米秸秆作为反硝化碳源补充材料,探讨了潮汐流人工湿地系统不同位置TN、NH+4-N、NO-3-N、NO-2-N、COD的去除效果及添加碱处理秸秆对其效果的影响。结果表明,潮汐流人工湿地装置各点位之间的NH+4-N平均去除率大小为BCAD;NO-2-N去除率大小为BCAD;TN去除率大小为BCAD;NO-3-N去除率大小为DBCA;COD去除率大小为BACD。添加碱处理秸秆的装置A、B、C、D各个点位NH+4-N、NO-2-N、TN、NO-3-N平均去除率均大于未添加空白装置,且添加碱处理秸秆的潮汐流人工湿地反硝化速率常数是未添加装置的2.05倍。潮汐流人工湿地NH+4-N、NO-2-N、TN的去除主要发生在中上层;NO-3-N的去除主要发生在底层,其次是中层;COD的去除主要发生在中部砾石层。添加碱处理秸秆可以显著增强潮汐流人工湿地的反硝化作用,提高人工湿地的脱氮能力。     

玉米芯与海绵铁复合填料的反硝化脱氮特性

在实验室条件下分别运行以玉米芯/海绵铁复合填料和单纯玉米芯填料的反硝化滤池,分析两类填料的反硝化脱氮效果,考察复合填料对硝态氮的去除率及出水水质。结果表明,复合填料反硝化滤池以生物异养反硝化作用为主,较单纯玉米芯填料反应器表现出更加稳定的反硝化脱氮效果。当进水硝态氮浓度为20 mg/L、停留时间3 h时,复合填料反应器对硝态氮的去除率可以维持在90%以上,出水硝态氮浓度2 mg/L,没有出现亚硝态氮、氨氮的积累和pH值升高现象;3个月的运行期间单位质量玉米芯的脱氮量为0.42 kg/kg,比单纯玉米芯高0.05 kg/kg。因此,玉米芯/海绵铁复合填料作为反硝化滤池的碳源和生物载体具有脱氮效果好、无需连续添加碳源、出水pH值稳定的特点。     

电化学产氢自养反硝化去除水中硝酸盐的研究

随着硝酸盐氮的污染问题日益严重,人们对水质的要求也逐渐提高,寻求高效且经济的方法来去除水中的硝酸盐氮成为了一个重要的课题。本研究以此出发,研究了建立在电极生物膜反应器中的氢自养反硝化去除水中硝酸盐的方法。本实验采用碳棒作为阳极,活性炭纤维毡为微生物载体,水被电解后在阴极表面产生氢气,供固定在阴极表面的反硝化细菌直接利用进行氢自养反硝化作用。无需外加有机碳源,即可去除水中的硝酸盐氮,具有处理费用低、无二次污染、剩余污泥少等特点。     

垂直流人工湿地组合工艺在绿色建筑中的应用

在某房地产公司深圳总部绿色建筑工程中,采用水解酸化/垂直流人工湿地组合工艺处理优质杂排水,采用接触氧化/反硝化沉淀/垂直流人工湿地处理生活污水,对实际设计参数、水质监测数据进行分析可知,垂直流人工湿地组合工艺对污染物的总体去除率较高,出水水质完全能满足回用要求.垂直流人工湿地组合工艺完全可满足绿色建筑对节约水资源、保护环境、减少污染的要求.     

表面流-垂直流复合湿地去除低碳氮比河水中氨氮

为了研究丹河人工湿地在不同温度下对低C/N值河水中氨氮的去除能力,于2015年1月—6月对丹河人工湿地各处理单元进、出水中NH_4~+-N和COD进行了逐日监测。结果显示,沉水植物型表面流-垂直流复合人工湿地对河水中NH_4~+-N的平均去除率随温度的升高从50.1%上升到80.2%,低温条件下,NH_4~+-N主要在垂直流湿地单元中被去除。温度15℃时,复合系统中垂直流单元对NH_4~+-N的去除率介于50.6%~72.3%之间,显著高于单一垂直流人工湿地(27.5%~45.8%),说明表面流人工湿地有助于后续垂直流人工湿地对氨氮的去除。通过对湿地各单元进、出水中溶解氧含量的测定,推测表面流湿地单元的增氧作用可能是保证后续垂直流单元在低温条件下具有高氨氮去除能力的主要原因。     

特大型污水处理厂沿程氮分布规律研究

基于上海某特大型污水处理厂现状条件,开展进、出水中氮的组成以及污水处理过程中沿程氮分布转化规律研究,为该厂优化运行提供依据。结果表明,该厂进水中溶解性总氮占68%,其中无机氮占82%;出水中溶解性总氮占89%,其中无机氮占93%。通过氮平衡分析得到系统对TN的去除率为56%,除缺氧反硝化脱氮和同化作用外,二沉池及污泥回流过程内源反硝化和好氧段同步硝化反硝化作用对TN的去除率达到37.5%,这主要由于该厂构筑物尺寸大、管道输送距离长的特点所致。鉴于反硝化过程受温度的影响相对较小,污水处理厂可在冬季缩短缺氧反应时间,增加曝气量,强化氨氮去除效果,提升生化处理系统的处理能力。     

广西乡村景观村民满意度评价及障碍 因子分析——以北流市北部乡村为例

村民是乡村的主体,为探讨北流市北部乡村景观村民 满意度水平及影响因素,选取6个一级指标和25个二级指标, 采用AHP-熵权组合法确定指标的权重,然后运用TOPSIS-灰 色关联评价模型对村民满意度进行测评,并利用障碍度模型对 障碍因子进行诊断,得出如下结果。1)在8个乡建示范点中, 木棉村满意度水平为良好,灰色关联相对贴近度为0.731 5; 田心村满意度水平为较差,灰色关联相对贴近度为0.243 9; 其余6个村子的满意度水平均为一般,说明总体上北流市北部 乡村景观村民满意度还有较大提升空间。2)4种建设类型的灰 色关联相对贴近度从高到低排序为：休闲旅游型(0.659 0)、 生态保护型(0.571 6)、文化传承型(0.538 4)、环境整治型 (0.407 9)。3)从障碍因子的出现频次来看,民俗文化活动形 式多样C21、直接或间接参与方案设计C24、交通通畅C16、 公共空间种类丰富C20、宗祠建筑特色鲜明C10和水质清洁C5 是影响北流市北部乡村景观村民满意度的主要障碍因子,应重 点关注。研究结果可为北流市乃至岭南地区的乡村景观建设提 供理论依据     

Chlorine disinfection of grey water for reuse: effect of organics and particles

Adequate disinfection of grey water prior to reuse is important to prevent the potential transmission of disease-causing microorganisms. Chlorine is a widely utilised disinfectant and as such is a leading contender for disinfection of grey water intended for reuse. This study examined the impact of organics and particles on chlorine disinfection of grey water, measured by total coliform inactivation. The efficacy of disinfection was most closely linked with particle size. Larger particles shielded total coliforms from inactivation and disinfection efficacy decreased with increasing particle size. Blending to extract particle-associated coliforms (PACs) following chlorine disinfection revealed that up to 91% of total coliforms in chlorinated grey water were particle associated. The organic concentration of grey water affected chlorine demand but did not influence the disinfection resistance of total coliforms when a free chlorine residual was maintained. Implications for urban water reuse are discussed and it is recommended that grey water treatment systems target suspended solids removal to ensure removal of PACs prior to disinfection.     

Review of the technological approaches for grey water treatment and reuses

Based on literature review, a non-potable urban grey water reuse standard is proposed and the treatment alternatives and reuse scheme for grey water reuses are evaluated according to grey water characteristics and the proposed standard. The literature review shows that all types of grey water have good biodegradability. The bathroom and the laundry grey water are deficient in both nitrogen and phosphors. The kitchen grey water has a balanced COD: N: P ratio. The review also reveals that physical processes alone are not sufficient to guarantee an adequate reduction of the organics, nutrients and surfactants. The chemical processes can efficiently remove the suspended solids, organic materials and surfactants in the low strength grey water. The combination of aerobic biological process with physical filtration and disinfection is considered to be the most economical and feasible solution for grey water recycling. The MBR appears to be a very attractive solution in collective urban residential buildings.     

Anaerobic biodegradability and treatment of grey water in upflow anaerobic sludge blanket (UASB) reactor

Feasibility of grey water treatment in an upflow anaerobic sludge blanket (UASB) reactor operated at different hydraulic retention time (HRT) of 16, 10 and 6h and controlled temperature of 30 degrees C was investigated. Moreover, the maximum anaerobic biodegradability without inoculum addition and maximum removal of chemical oxygen demand (COD) fractions in grey water were determined in batch experiments. High values of maximum anaerobic biodegradability (76%) and maximum COD removal in the UASB reactor (84%) were achieved. The results showed that the colloidal COD had the highest maximum anaerobic biodegradability (86%) and the suspended and dissolved COD had similar maximum anaerobic biodegradability of 70%. Furthermore, the results of the UASB reactor demonstrated that a total COD removal of 52-64% was obtained at HRT between 6 and 16 h. The UASB reactor removed 22-30% and 15-21% of total nitrogen and total phosphorous in the grey water, respectively, mainly due to the removal of particulate nutrients. The characteristics of the sludge in the UASB reactor confirmed that the reactor had a stable performance. The minimum sludge residence time and the maximum specific methanogenic activity of the sludge ranged between 27 and 93 days and 0.18 and 0.28 kg COD/(kg VS d).     

Ecotoxicological assessment of grey water treatment systems with Daphnia magna and Chironomus riparius

In order to meet environmental quality criteria, grey water was treated in four different ways: 1) aerobic 2) anaerobic + aerobic 3) aerobic + activated carbon 4) aerobic + ozone. Since each treatment has its own specific advantages and disadvantages, the aim of this study was to compare the ecotoxicity of differently treated grey water using Chironomus riparius (96 h test) and Daphnia magna (48 h and 21d test) as test organisms. Grey water exhibited acute toxicity to both test organisms. The aerobic and combined anaerobic + aerobic treatment eliminated mortality in the acute tests, but growth of C. riparius was still affected by these two effluents. Post-treatment by ozone and activated carbon completely removed the acute toxicity from grey water. In the chronic toxicity test the combined anaerobic + aerobic treatment strongly affected D. magna population growth rate (47%), while the aerobic treatment had a small (9%) but significant effect. Hence, aerobic treatment is the best option for biological treatment of grey water, removing most of the toxic effects of grey water. If advanced treatment is required, the treatment with either ozone or GAC were shown to be very effective in complete removal of toxicity from grey water.     

Water-Recycling Technologies in the UK

Urban water recycling in the form of rain, grey or black water is becoming an important element of demand-management practice in the UK, and appropriate technology allows the use of three different water sources for similar applications. The level of pollution in the water source and the application to which it is being recycled, dictate the level of technology which is used. This paper describes current water re-use practices in the UK (in terms of water source, technology scale, type and efficiency) and examines five case studies. Of more than 150 schemes identified, most are rainwater-collection systems and these are generally sited in rural areas. There are various single-house greywater recycling sites, many of which are part of water company or Environment Agency monitoring programmes. Larger-scale schemes employ both natural and hi-tech treatment options. Operationally successful schemes utilise appropriate technology for the end-use, although the economic benefits of many of the schemes are poor.     

基于灰色RBF组合模型的城市用水量预测

为解决城市用水量预测中单一方法预测精度不高的问题,建立了灰色径向基（RBF）神经网络组合模型。对比实验结果表明,灰色GM（1,1）模型、RBF神经网络模型和灰色RBF神经网络组合模型的平均相对误差分别为2．1222％,1．2562％和0．6821％。与灰色GM（1,1）模型和RBF神经网络相比,灰色RBF神经网络组合模型充分发挥了灰色系统的贫乏数据建模和RBF神经网络的高度非线性映射能力的双重优势,具有较高的预测精度,更适合用于城市用水量预测。     

Removal of micropollutants from aerobically treated grey water via ozone and activated carbon

Ozonation and adsorption onto activated carbon were tested for the removal micropollutants of personal care products from aerobically treated grey water. MilliQ water spiked with micropollutants (100-1600 μgL⁻¹) was ozonated at a dosing rate of 1.22. In 45 min, this effectively removed (>99%): Four parabens, bisphenol-A, hexylcinnamic aldehyde, 4-methylbenzylidene-camphor (4MBC), benzophenone-3 (BP3), triclosan, galaxolide and ethylhexyl methoxycinnamate. After 60 min, the removal efficiency of benzalkonium chloride was 98%, tonalide and nonylphenol 95%, octocrylene 92% and 2-phenyl-5-benzimidazolesulfonic acid (PBSA) 84%. Ozonation of aerobically treated grey water at an applied ozone dose of 15 mgL⁻¹, reduced the concentrations of octocrylene, nonylphenol, triclosan, galaxolide, tonalide and 4-methylbenzylidene-camphor to below limits of quantification, with removal efficiencies of at least 79%. Complete adsorption of all studied micropollutants onto powdered activated carbon (PAC) was observed in batch tests with milliQ water spiked with 100-1600 μgL⁻¹ at a PAC dose of 1.25 gL⁻¹ and a contact time of 5 min. Three granular activated carbon (GAC) column experiments were operated to treat aerobically treated grey water. The operation of a GAC column with aerobically treated grey water spiked with micropollutants in the range of 0.1-10 μgL⁻¹ at a flow of 0.5 bed volumes (BV)h⁻¹ showed micropollutant removal efficiencies higher than 72%. During the operation time of 1728 BV, no breakthrough of TOC or micropollutants was observed. Removal of micropollutants from aerobically treated grey water was tested in a GAC column at a flow of 2 BVh⁻¹. Bisphenol-A, triclosan, tonalide, BP3, galaxolide, nonylphenol and PBSA were effectively removed even after a stable TOC breakthrough of 65% had been reached. After spiking the aerobically treated effluent with micropollutants to concentrations of 10-100 μgL⁻¹, efficient removal to below limits of quantification continued for at least 1440 BV. Both ozonation and adsorption are suitable techniques for the removal of micropollutants from aerobically treated grey water.     

An assessment of the costs and benefits of interventions aimed at improving rural community water supplies in developed countries

We report a cost benefit analyses (CBA) for water interventions in rural populations of developed country sub-regions. A Bayesian belief network was used to estimate the cost benefit ratio using Monte Carlo simulation. Where possible we used input data from recently published primary research or systematic reviews. Otherwise variables were derived from previous work in the peer-reviewed or grey literature. For these analyses we considered the situation of people with small and very small community supplies that may not be adequately managed. For the three developed country sub-regions Amr-A (America region A), Eur-A (European region A) and Wpr-A (Western Pacific region A), we estimate the costs of acute diarrhoeal illness associated with small community supplies to be U$4671 million (95% CI 1721-9592), the capital costs of intervention to be US$13703 million (95% CI 6670-20735), additional annual maintenance to be US$804 million (95%CI 359-1247) and the CB ratio to be 2.78 (95%CI 0.86-6.5). However, we also estimated the cost of post infectious irritable bowel syndrome (IBS) following drinking water-associated acute gastroenteritis to be US$11896 million (95%CI 3118-22657). When the benefits of reduced IBS are added to the analysis the CB ratio increases to 9.87 (95%CI 3.34-20.49). The most important driver of uncertainty was the estimate of the cost of illness. However, there are very few good estimates of costs in improving management of small rural supplies in the literature.Investments in drinking-water provision in rural settings are highly cost beneficial in the developed world. In the developed world, the CB ratio is substantially positive especially once the impact of IBS is included.     

新农村视阈下山东古村落活态景观的发展研究

本文重点阐述了新农村规划背景下山东古村落活态景观发展状态,对发展问题以及新农村形式进行了详细分析,对山东古村落活态景观的可行性发展提出了“灰构意向”的新理念,结合部分实例对其进行了分析。