Limiting drainage criterion for groundwater of mountain tunnel

Large amount of groundwater discharging from tunnel is likely to cause destruction of the ecological environment in the vicinity of the tunnel, thus an appropriate drainage criterion should be established to balance the tunnel construction and groundwater.To assess the related problems, an limiting drainage standard ranging from 0.5 to 2.0 m3/（m·d） was suggested for mountain tunnels based on survey and comparative analysis. After that, for the purpose of verifying the rationality of the standard, a calculated formula for dewatering funnel volume caused by drainage was deduced on the basis of the groundwater dynamics and experience method.Furthermore, the equation about the relationship between water discharge and drawdown of groundwater table was presented. The permeability coefficient, specific yield and groundwater table value were introduced, and then combined with the above equation, the drawdown of groundwater table under the proposed limiting drainage criterion was calculated. It is shown that the proposed drainage standard can reach the purpose of protecting ecological environment under the following two conditions. One is the permeability coefficient ranges from 10-4 to 10-5 m/s and the specific yield ranges from 0.1 to 0.001. The other is the permeability coefficient varies from 10-6 to 10-8 m/s and the specific yield varies from 0.1 to 0.01. In addition, a majority of common geotechnical layers are involved in the above ranges. Thus, the proposed limiting drainage standard which ranges from 0.5 to 2.0 m3/（m·d） for mountain tunnel is reasonable.     

济南城区地下水补给试验及供水模式研究

文章基于济南市资源性缺水、地下水过量开采、水位下降、城市供水以地表水源为主的现状,围绕泉水的持续喷涌及济南城区居民家庭生活饮用优质地下水,通过地表水补给地下水的试验研究,探索了试验实施的可能性,提出了济南城区分质供水模式。结果表明:补源试验对玉符河、巴漏河部分河床渗透带补渗效果明显,为枯水期稳定地下水位提供了技术保障;在原有市政管网供给生产和居民家庭盥洗用水,城区新敷设地下水水源供水管网供给居民家庭厨房餐饮用水及2020年城区规划人口430万条件下,新设管网日生活供水规模约1.2×105m3。     

灌浆工程中水泥水溶性铬（Ⅵ）对地下水的影响

水泥因其较好的综合性能而广泛应用于灌浆工程中,但多数水泥存在水溶性铬（Ⅵ）,可通过施工活动直接带入地表水及地下水中。本文分析了水泥中铬（Ⅵ）的现状,并以某大（2）型水库帷幕灌浆工程为对象,进行了地下水水质调查,结果表明：（1）采用水溶性铬（Ⅵ）含量为2.39 mg/kg的水泥产品进行灌浆,可引起周围地下水水质超标,超标持续时间随地下水更新速度变化,长可达2个月;（2）含铬（Ⅵ）水泥是一种灌浆过程中持续性、硬化后间断性的地下水铬（Ⅵ）污染源,以含铬（Ⅵ）水泥作为主要原材料进行大范围灌浆,存在对地下水造成污染的风险。     

Preparation and antimicrobial activity of terpene-based polyurethane coatings with carbamate group-containing quaternary ammonium salts

A series of novel carbamate group-containing quaternary ammonium salts (QASs) have been synthesized, which were subsequently used as antimicrobial agent and incorporated into polyurethane coatings through crosslinking with terpene-based polyol and polyisocyanate. The chemical structures of QASs were characterized by FT-IR, ¹H NMR, and ¹³C NMR. The effects of QASs on the properties of coatings were investigated. The results showed that the resulting coatings exhibited significant antimicrobial activity against both Staphylococcus aureus and Escherichia coli by introducing QASs into the polyurethane networks. Furthermore, with the increasing of QAS content, the antimicrobial activity and adhesion of the coatings were enhanced, while the pencil hardness, water resistance and thermal stability of the coatings were decreased.     

原子荧光光谱法测定地下水中锡

原子荧光光谱法测定地下水锡试验中,选择最佳的硼氢化钾溶液和硫脲-抗坏血酸溶液浓度,反应体系中加入浓度为20 g/L硼氢化钾溶液,100 mL试样溶液中加入10 mL硫脲-抗坏血酸溶液作为还原剂,方法检出限为0.02μg/L,测量精密度为0.33%～1.24%,加标回收效率为100%～102%。     

Synthesis of Quaternary Ammonium Salts with Novel Counterions

The preparations of quaternary ammonium compounds from various tertiary amines and the (environmentally friendly) alkylation agent dimethyl carbonate were carried out. The effects of reaction temperature, reaction time, material mol ratio and solvent dosage on quaternization were examined, and the optimum reaction conditions were determined. Under the optimum conditions, the conversions of mono-alkyl tertiary amines could attain over 99%, while the conversions of di-alkyl tertiary amines reached over 95%. Moreover, a series of quaternary ammonium salts with new counterions (HCO₃, CH₃COO, CH₃CH₂COO, CH₃CH(OH)COO) were synthesized by the hydrolysis of methyl carbonate quaternary ammonium salts or by ion exchange reaction of methyl carbonate quaternary ammonium salts with corresponding acids.     

高岭土负载壳聚糖处理铬渣污染地下水

采用高岭土负载壳聚糖复合吸附剂吸附处理铬渣污染的地下水,确定了最佳反应条件:壳聚糖与高岭土质量比为0.06,pH为4,吸附时间60 min,吸附剂用量为2.00 g/L,在此条件下去除率可达94.67%,Cr(Ⅵ)由0.5mg/L降至0.026 mg/L,可满足GB/T 14848—1993的Ⅲ类标准要求。该吸附剂对Cr(Ⅵ)的吸附过程符合Freundlich、Langmuir和D-R吸附等温模型,主要以物理吸附为主。研究表明高岭土负载壳聚糖适于处理铬渣污染的地下水。     

温度对生物净化滤柱中氨氮、铁、锰去除效果的影响

温度是生物净化滤柱运行的一个重要参数,采用生物净化滤柱处理模拟含氨氮、铁、锰地下水,考察水温从约25℃降到约6℃过程中氨氮、铁、锰的去除效果。结果表明,出水氨氮、总铁、锰的浓度分别低于0.15mg/L、0.1mg/L、0.05mg/L,均低于国家标准。出水总铁、锰均未受到水温下降的影响,但是出水氨氮浓度逐渐从约0.02mg/L升高到约0.12mg/L。进一步分析发现,铁主要在滤层的0~0.4m段去除,去除效果没有受到水温变化的影响。氨氮、锰主要在滤层的0~0.8m段去除,其沿程浓度均随水温降低而明显升高。氨氮、锰的生物去除符合一级动力学反应,水温为24.6℃、15.3℃、6.7℃时,两者的动力学常数k分别为0.154min^-1、0.186min^-1,0.143min^-1、0.175min^-1,0.103min^-1、0.163min^-1;半反应时间t_1/2分别为4.51min、3.72min,4.83min、3.96min,6.72min、4.24min。随着试验水温的降低,氨氮、锰的去除效果明显受到影响。     

海藻酸钙固定化零价铁抗团聚及堵塞的作用机制

以海藻酸钠(SA)、氯化钙、微米零价铁(MZVI)为原料,制备了海藻酸钙(CA)固定化MZVI填料(CAZ),通过静态烧杯实验和动态PRB模型实验,探讨了CA运用对Cr(Ⅵ)的去除性能的影响,并通过电镜扫描分析了CA避免团聚、堵塞机制。实验结果表明,CA凝胶颗粒的运用能显著提升MZVI的除Cr(Ⅵ)性能,CAZ相比MZVI对Cr(Ⅵ)的去除率和反应速率分别提升7.1倍、23.0倍;MZVI利用率的提高是CAZ反应器处理Cr(Ⅵ)水量显著大于MZVI反应器的主要原因,MZVI反应速率的提高是CAZ反应器出水Cr(Ⅵ)浓度显著低于MZVI反应器的主要原因。电镜扫描结果表明,SA与氯化钙交联形成的CA具有丰富的骨架孔道结构,具有骨架支撑作用,能有效克服MZVI颗粒因重力作用导致团聚、降低比表面积的缺陷。CA表层固定的MZVI颗粒与Cr(Ⅵ)反应生成的(Fe_xCr_1-x)(OH)₃络合沉淀会冲破CA表层外壳,释放到零价铁-渗透反应墙(Fe⁰-PRB)系统中,导致PRB反应初期出现堵塞现象;大部分MZVI颗粒...     

油污染地下水回用处理工程实例

结合某油污染地下水回用处理工程实例,介绍了含油污水回用处理工艺流程和主要装置;分析了该工艺的水处理成本,指出了降低成本的主要途径;同时分析了装置的运行效果,由于进水水质高于设计值及工艺本身存在的问题,出水水质比控制指标稍差;最后结合装置的运行效果,探讨了工艺存在的问题及解决措施。