基于海绵城市视角的城市雨水湿地设计初探

为夯实城市雨水湿地设计的理论基础,针对我国目前城市雨水湿地设计理论不足的现状,基于海绵城市视角,对城市雨水湿地设计方法进行系统研究。根据城市雨水湿地与普通人工湿地的共性,借鉴人工湿地理论及技术,通过文献综合、理论分析、定量研究等方法,提出了城市雨水湿地设计思路。从设计的角度对城市雨水湿地选址、面积定量确定、湿地选型、工艺流程、基质选择、植物选择、景观设计等方面进行阐述。     

对低影响开发中雨水调蓄设施的分析和思考研究

随着海绵城市规划建设的陆续开展,低影响开发(LID)的理念也深入人心并得到广泛应用,国内各地均结合自身实际情况提出了年径流总量控制率的目标.事实上,各地在实践中也都逐渐总结出,将年径流总量控制率的目标转化为控制的雨量更容易落地实施,而实现目标的其中一个关键抓手就是雨水调蓄设施.通过对调蓄设施的类型、用途及标准等内容的分析和思考,提出规划建设中应当注意的问题和建议,为海绵城市建设提供一些参考,促进调蓄设施更好的发挥作用.     

基于污泥资源化利用的粗放型绿色屋顶生长基质的组成

构建了8个不同基质组成的粗放型绿色屋顶小试装置,通过累积650 mm模拟降雨实验,研究厌氧稳定污泥应用于粗放型绿色屋顶生长基质时的合理组成,考察使用过程中装置出水水质情况与基质自身营养物质含量变化情况,结合厌氧稳定污泥资源化利用时带来的N、P淋出问题,讨论不同改良材料的效果.结果表明:厌氧稳定污泥能够显著增加植物量,实验期间植物平均增重808%;厌氧稳定污泥会造成TP的大量淋失,给水厂污泥能够有效控制TP淋失并且不会影响植物对P的吸收,实验期间给水厂污泥累计减少TP淋出质量68.66%,且稳定后出水TP达到地表水Ⅴ类标准;厌氧稳定污泥会造成TN的严重淋失,淋失TN的主要形态是NO_3~--N,稻壳炭能够减少NO_3~--N的淋失,累计减少NO_3~--N淋出质量28.86%,增加稻壳炭用量,有助于控制NO_3~--N淋出;淋出液中SS和COD能够迅速下降并稳定,稳定后COD含量约为30 mg·L~(-1),优于地表水Ⅴ类标准;在以中小降雨为主的实际降雨条件下,基质中厌氧稳定污泥所含营养物质的保留时间能超过1 a,可以满足植物较长时间的生长需求.     

Biosorption characteristics of unicellular green alga Chlorella sorokiniana immobilized in loofa sponge for removal of Cr（Ⅲ）

Loofa sponge （LS） immobilized biomass of Chlorella sorokiniana （LSIBCS）, isolated from industrial wastewater, was investigated as a new biosorbent for the removal of Cr（Ⅲ） from aqueous solution. A comparison of the biosorption of Cr（Ⅲ） by LSIBCS and free biomass of C. sorokiniana （FBCS） from 10-300 mg Cr（Ⅲ）/L aqueous solutions showed an increase in uptake of 17.79% when the microalgal biomass was immobilized onto loofa sponge. Maximum biosorption capacity for LSIBCS and FBCS was found to be 69.26 and 58.80 mg Cr（Ⅲ）/g biosorbent, respectively, whereas the amount of Cr（Ⅲ） ions adsorbed onto naked LS was 4.97 mg/g. The kinetics of Cr（Ⅲ） biosorption was extremely rapid and equilibrium was established in about 15 and 20 min by LSIBCS and FBCS, respectively. The biosorption equilibrium was well defined by Langmuir adsorption isotherm model. The biosorption kinetics followed the pseudo-second order kinetic model. The biosorption was found to be pH dependent and the maximum sorption occurred at the solution pH 4.0. Desorption studies showed that 98% of the adsorbed Cr（Ⅲ） could be desorbed with 0.1 mol/L HNO3, while other desorbing agents were less effective in the order： EDTA 〉 H2SO4 〉 CH3COOH 〉 HCl. The regenerated LSIBCS retained 92.68% of the initial Cr（Ⅲ） binding capacity up to five cycles of reuse in continuous flow-fixed bed columns. The study revealed that LSIBCS could be used as an effective biosorbent for the removal of Cr（Ⅲ） from wastewater.     

基于绿色基础设施的城市非点源污染控制研究

以珠海市西部新城为例,通过监测采样分析现状城市降雨径流污染特征和规划前后城市非点源污染负荷,采用雨洪管理模型（SWMM）模型构建6种基于不同绿色基础设施技术的污染控制情景,并评估分析各情景下的成本效益.结果表明：现状建成区道路和地面铺装的径流污染较重（劣Ⅴ类）;屋顶和地面的初期径流冲刷效应明显;规划后城市径流污染物排放负荷增加至现状的2.9~3.2倍.组合型方案（源头型组合、源头-末端组合）的污染综合控制效果优于单技术方案,但其污染物单位削减成本较高;单技术方案中,末端型的调节塘对各污染物的单位削减成本均最低,且对TN、TP的削减效果较好;源头型的生物滞留池和植草浅沟的单位削减成本也较低,但污染物削减效果较差;而透水铺装的单位削减成本较高.总之,单项技术方案在污染控制的成本效益表现上要优于组合型方案,若要取得更好的污染控制果,则还需投入更大的成本,采取组合型方案进行污染控制.研究可为当前快速城市化新区海绵城市的多目标决策提供科学依据.     

Concurrent adsorption and reduction of chromium(VI) to chromium(III) using nitrogen-doped porous carbon adsorbent derived from loofah sponge

• A high-efficiency N-doped porous carbon adsorbent for Cr(VI) was synthesized. • The maximum adsorption capacity of Cr(VI) reached up to 285.71 mg/g at 318K. • The potential mechanism for Cr(VI) adsorption by NHPC was put forward. • DFT analyzed the adsorption energy and interaction between NHPC and Cr(VI). To develop highly effective adsorbents for chromium removal, a nitrogen-doped biomass-derived carbon (NHPC) was synthesized via direct carbonation of loofah sponge followed by alkali activation and doping modification. NHPC possessed a hierarchical micro-/mesoporous lamellar structure with nitrogen-containing functional groups (1.33 at%), specific surface area (1792.47 m²/g), and pore volume (1.18 cm³/g). NHPC exhibited a higher Cr(VI) adsorption affinity than the HPC (without nitrogen doping) or the pristine loofah sponge carbon (LSC) did. The influence of process parameters, including pH, dosage, time, temperature, and Cr(VI) concentration, on Cr(VI) adsorption by NHPC were evaluated. The Cr(VI) adsorption kinetics matched with the pseudo-second-order model (R²≥0.9983). The Cr(VI) adsorption isotherm was fitted with the Langmuir isotherm model, which indicated the maximum Cr(VI) adsorption capacities: 227.27, 238.10, and 285.71 mg/g at 298K, 308K, and 318K, respectively. The model analysis also indicated that adsorption of Cr(VI) on NHPC was a spontaneous, endothermal, and entropy-increasing process. The Cr(VI) adsorption process potentially involved mixed reductive and adsorbed mechanism. Furthermore, computational chemistry calculations revealed that the adsorption energy between NHPC and Cr(VI) (−0.84 eV) was lower than that of HPC (−0.51 eV), suggesting that nitrogen doping could greatly enhance the interaction between NHPC and Cr(VI).     

基于在线监测和SWMM模型的合流制排水体制系统化提升方案评估研究

合流制溢流污染严重威胁着下游受纳水体的水环境质量.为科学评估基于海绵城市理念的合流制排水体制系统化提升方案在解决老城区合流制溢流污染方面的效果,以嘉兴市老城区为研究对象,采用在线监测技术和SWMM数学模型相结合的方式,对嘉兴市老城区合流制排水体制系统化提升方案进行了全面评估.经在线监测评估发现,完成海绵城市改造后,嘉兴...