不同类型透水砖对雨水径流水量的控制效果

透水铺装是目前海绵城市建设中应用较广泛的技术措施之一,对雨水径流的促渗减排发挥着重要作用。选择2种不同类型透水砖为研究对象,采用人工模拟降雨实验方法,研究了降雨重现期分别为1、3、5、10 a条件下,2种不同类型透水砖对雨水径流总量控制、峰值削减和峰值延迟等方面的控制效果。结果表明：在降雨重现期小于10 a的条件下,构造透水砖和普通透水砖的场次降雨总量控制率平均值均超过95%;峰值流量均随着重现期的增加而增大,构造透水砖的峰值削减效果优于普通透水砖,平均峰值削减率提高了8.6%;构造透水砖和普通透水砖的出流延迟时间平均值分别为11.3 min和13.8 min,平均峰值延迟时间分别为6.3 min和16.3 min。构造透水砖对径流总量、峰值流量的控制效果要优于普通透水砖,因此,在透水铺装应用中,应结合项目设计目标和当地的水文地质条件,宜优先考虑采用构造透水砖铺装方式。     

AAOA-MBR工艺污水脱氮特性及脱氮机制

为了提高污水脱氮效果,在传统A2O工艺的基础上,增加后置缺氧段并与膜生物反应器相结合,构建了AAOA-MBR污水处理中试装置,进行了中试实验。实验结果表明,在进水COD浓度为100.00~280.00 mg/L、TN浓度为18.32~31.86 mg/L、NH4+-N浓度为12.78~24.44 mg/L时,COD、TN和NH4+-N的平均去除率分别达到了90.0%、72.1%和99.0%,出水水质达到《城镇污水处理厂污染物排放标准》(GB 18918-2002)中的一级A标准;通过多点进水优化了内源配置,节约了碳源,强化了脱氮效果;采用膜池回流供氧,可在节能的同时保证缺氧池1的缺氧环境,提高了反硝化效果。本文的研究成果为实际污水处理工程市场提供了一套高效脱氮的新工艺。     

不同工况条件混合赤泥力学特性变化规律

在利用常规土工实验和XRF、XRD、SEM等微观测试手段分析了刚出厂混合赤泥化学成分、矿物组成、微观结构的基础上,通过无侧限抗压强度实验和固结排水三轴剪切实验对自然风干、浸水饱和、非饱和-饱和干湿循环3种工况条件下混合赤泥不同龄期力学特性的变化规律进行了研究。结果表明,自然风干试样的无侧限抗压强度和粘聚力要明显大于相同龄期浸水饱和试样和干湿循环试样,说明混合赤泥的强度形成与滤水过程有一定联系,且其强度的增长均主要集中在脱水龄期前70天内;混合赤泥在3种不同工况条件下无侧限抗压强度和粘聚力均有一定程度的增长,说明混合赤泥可在浸水环境下生成不可逆增长的具有水硬性的胶结矿物,使其在水环境中不发生崩解,可保证混合赤泥堆体在自然堆存过程中其力学特性满足安全堆载要求。     

Treatment of wastewater from red and tropical fruit wine production by zeolite anaerobic fluidized bed reactor

A study of the anaerobic treatment of wastewaters derived from red (RWWW) and tropical fruit wine (TFWWW) production was carried out in four laboratory-scale fluidized bed reactors with natural zeolite as bacterial support. These reactors operated at mesophilic temperature (35°C). Reactors R1 and R2 contained Chilean natural zeolite, while reactors R3 and R4 used Cuban natural zeolite as microorganism support. In addition, reactors R1 and R3 processed RWWW, while reactors R2 and R4 used TFWWW as substrate. The biomass concentration attached to zeolites in the four reactors studied was found to be in the range of 44–46 g volatile solids (VS)/L after 90 days of operation time. Both types of zeolites can be used indistinctly in the fluidized bed reactors achieving more than 80%–86% chemical oxygen demand (COD) removals for organic loading rates (OLR) of up to at least 20 g COD/L d. pH values remained within the optimal range for anaerobic microorganisms for OLR values of up to 20 and 22 g COD/L d for RWWW and TFWWW, respectively. Toxicity and inhibition levels were observed at an OLR of 20 g COD/L d in reactors R1 and R3 while processing RWWW, whereas the aforementioned inhibitory phenomena were not observed at an OLR of 24 g COD/L d in R2 and R4, treating TFWWW as a consequence of the lower phenolic compound content present in this substrate. The volatile fatty acid (VFA) levels were always lower in reactors processing TFWWW (R2 and R4) and these values (< 400 mg/L, as acetic acid) were lower than the suggested limits for digester failure. The specific methanogenic activity (SMA) was twice as high in reactors R2 and R4 than in R1 and R3 after 120 days of operation when all reactors operated at an OLR of 20 g COD/L d.     

芦苇碳源-表面流人工湿地对农田退水脱氮的长期效能研究

针对农田退水NO₃^--N占比高、C/N低,氮污染难以去除的问题,将经济易得的芦苇(Phragmites australis)茎叶碎段装填在表面流人工湿地(packed surface flow construct wetland,PSFW)的表层作为外加碳源,以研究其长期运行情况下的脱氮效能。结果表明：第29~149天,外加芦苇茎叶碎段的PSFW的脱氮效能明显高于无芦苇茎叶碎段的空白PSFW₀;进水NO₃^--N和TN浓度分别为(16.4±1.0)和(17.7±2.0)mg/L,HRT按3、4和2 d运行时,HRT为4 d时脱氮效能最优,PSFW对NO₃^--N和TN去除率分别为(87.4±6.0)%和(74.1±6.0)%,PSFW₀去除率仅为(14.4±4.0)%和(14.4±3.0)%;第150~269天,PSFW的脱氮效能稍高于PSFW₀,在进水NO₃^--N和TN浓度分别为(10.4±1.0)和(10.8±1.0)mg/L,HRT按3、2和1 d运行时,HRT为3 d时脱氮效能最优,PSFW对NO₃^--N和TN的去除率分别为(91.9±7.0)%和(90.2±7.0)%,PSFW₀去除率分别为(91.3±5.0)%和(86.4±6.0)%。第270~334天,PSFW的脱氮效能稍低于PSFW₀;进水NO₃^--N和TN浓度分别为(5.7±0.4)和(7.2±0.8)mg/L,HRT为3 d时,PSFW对NO₃^--N和TN的去除率分别为(88.6±10.0)%和(82.5±7.0)%,PSFW₀去除率分别为(94.0±6.0)%和(87.8±3.0)%。     

基于降水等级分异方法的低影响开发小区雨水径流污染负荷削减率的评估

为定量评估低影响开发(LID)技术对雨水径流污染负荷的削减率,选取嘉兴市柳岸禾丰小区作为LID小区,与其临近且下垫面类型相似的浅水湾小区作为传统小区,同步监测小区的外排水量和TP浓度,根据降水等级分异计算2个小区同等降水情景下单位面积污染负荷量,再以传统小区的单位面积污染负荷量为基准核算LID小区的雨水径流污染负荷削减率。结果表明：小雨时,LID设施可消纳其服务范围内的所有径流及所携带的污染物,污染负荷削减率达100%;当降水量增至超过LID设施功能阈值时,污染物削减率开始降低,中雨时降至67%,大雨时降至46%,年均雨水径流污染负荷削减率约为66%。整体来看,LID设施雨水径流污染负荷削减率表现出明显的降水等级差异。采用降水等级分异的方法能够减少降水等级所造成的误差,确保评估结果的精准程度,为小区LID设施建设提供可靠的决策依据。

     

华北油田二连分公司蒙古林作业区生态环境质量状况研究

本文选取二连油田蒙古林作业区生态环境质量为研究对象,对该区域内的土地利用／覆盖状况、植被状况、景观类型及其破碎度进行定性、定量研究。结果表明：（1）2008年,该区域土地利用类型主要为有林地、中覆盖度草地、低覆盖度草地、工矿交通建设用地和盐碱地等;工交建设占地明显。（2）该区2008年主要植物群落类型有：克氏针茅＋羊草＋杂类草、克氏针茅＋锦鸡儿＋杂类草、羊草＋针茅＋杂类草等;受到气候变暖等原因影响,小针茅已经在本区广泛分布。（3）该区2008年主要景观类型为针茅＋锦鸡儿草原景观、针茅草原景观、羊草草原景观、林地景观、人工建设区景观和道路景观;景观破碎度较高,人为干扰较为严重。建议相关单位足够重视并采取切实可行的措施,防止本区生态环境恶化。     

SUSPENDED SEDIMENT AND METALS REMOVAL FROM URBAN RUNOFF BY A SMALL LAKE1

ABSTRACT: A small lake in the Chicago Metropolitan Area was from 91 to 95 percent efficient in removing suspended sediment and from 76 to 94 percent efficient in removing copper, iron, lead, and zinc from urban runoff. Sediments accumulated in the lake in the form of an organic-rich mud at an average rate of 20 millimeters per year; this reduced lake storage and covered potential habitat for aquatic organisms. Copper, lead, and zinc concentrations were closely associated with suspended-sediment concentrations and with silt- and clay-sized fractions of lake sediment. Although concentrations of mercury and cadmium were near detection limits in runoff, measurable concentrations of these metals accumulated in the lake sediments.     

MINIMIZING THE IMPACT OF URBANIZATION ON LONG TERM RUNOFF1

Increasing concern about the problems caused by urban sprawl has encouraged development and implementation of smart growth approaches to land use management. One of the goals of smart growth is water resources protection, in particular minimizing the runoff impact of urbanization. To investigate the magnitude of the potential benefits of land use planning for water resources protection, possible runoff impacts of historical and projected urbanization were estimated for two watersheds in Indiana and Michigan using a long term hydrological impact analysis model. An optimization component allowed selection of land use change placements that minimize runoff increase. Optimizing land use change placement would have reduced runoff increase by as much as 4.9 percent from 1973 to 1997 in the Indiana study watershed. For nonsprawl and sprawl scenarios in the Michigan watershed for 1978 to 2040, optimizing land use change placement would have reduced runoff increase by 12.3 percent and 20.5 percent, respectively. The work presented here illustrates both an approach to assessing the magnitude of the impact of smart growth and the significant potential scale of smart growth in moderating runoff changes that result from urbanization. The results of this study have significant implications for urban planning.     

MANAGEMENT OF INSTREAM FLOWS THROUGH RUNOFF DETENTION AND RETENTION1

ABSTRACT: The use of reservoirs and land treatments to manage streamflow for the maintenance or enhancement of instream flow values is a valid concept. Historically, large reservoirs have been used for flood control and water-supply regulation. Smaller structures have enjoyed widespread use for soil and water conservation in headwater areas. Where reservoir releases can be controlled, it is technically feasible to regulate flows for the enhancement of instream values. However, institutional and political obstacles may preclude the operation of some reservoirs for this purpose. Retention and detention structures and land treatments, implemented for soil and water conservation purposes, have often had favorable effects on the streamflow hydrograph. Decreases in peak flows and increases in low flows have been documented. Design concepts for runoff-control structures are discussed in relation to instream flow management objectives. Hydro-logic simulation is offered as a potential tool for project design and feasibility analysis.