The use of a sequential leaching procedure for assessing the heavy metal leachability in lime waste from the lime kiln at a caustizicing process of a pulp mill

A five-stage sequential leaching procedure was used to fractionate 13 heavy metals (Cd, Cu, Pb, Cr, Zn, Fe, Mn, Al, Ni, Co, As, V, Ba) and sulphur (S) in lime waste from the lime kiln at the causticizing plant of Stora Enso Oyj Veitsiluoto Pulp Mills at Kemi, Northern Finland, into the following fractions: (1) water-soluble fraction (H₂O), (2) exchangeable fraction (CH₃COOH), (3) easily reduced fraction (HONH₃Cl), (4) oxidizable fraction (H₂O₂ + CH₃COONH₄), and (5) residual fraction (HF + HNO₃ + HCl). Although metals were leachable in all fractions, the highest concentrations for most of the metals were observed in the residual fraction (stage 5). It was also notable that the total heavy metal concentrations in lime waste did not exceed the maximal allowable heavy metal concentrations for soil conditioner agents set by the ministry of the Agricultural and Forestry in Finland. The heavy metals concentrations in lime waste were also lower than the maximal allowable heavy metals concentrations of the European Union Directive 86/278/EEC on the protection of environment, and in particular of the soil, when sewage sludge is used in agriculture. The Ca concentration (420 g kg⁻¹; d.w.) was about 262 times higher than the typical value of 1.6 g kg⁻¹ (d.w.) in arable land in Central Finland. However, the concentration Mg (0.2 g kg⁻¹; d.w.) in lime waste was equal to the Mg concentration in arable land in the Central Finland. The lime waste has strongly alkaline pH (12.8) and a neutralizing value (i.e. liming effect) of 47.9% expressed as Ca equivalents (d.w.). This indicates lime waste to be a potential soil conditioner and improvement as well as a pH buffer.     

生物活性炭法深度处理纺织废水二级出水中生物活性的研究

采用上流式曝气生物活性炭法处理碱减量印染废水二级生物处理出水，利用TTC-脱氢酶活性（DHA）法监测反应器内DHA生物活性分布。研究发现反应器内生物炭表面附着生物膜活性较高，特别是反应器上部生物碳粒同样具有较高的DHA活性，这与反应器运行一年多能够保持对COD、色度和UV等较高去除率有一定关系。还研究了活性炭吸附、反应器反冲洗对DHA活性的影响。本研究为曝气生物活性炭法有效去除印染碱减量废水中难降解有机物提供了一定的理论依据。     

酸解破乳作用处理高含固率洗毛废水的研究

洗毛废水是一种高浓度有机废水,含固率高,主要成分是羊毛脂、羧酸盐和土杂,由于强极性物质的存在和胶体强的负电性,导致洗毛废水形成稳定的乳化体系.本试验通过加入硫酸改变洗毛废水的有机组成,降低体系的Zeta电位,破坏体系的稳定性,从而使得有机物发生凝聚沉降,达到去除COD的目的.硫酸加入量达到0.2%或以上时对洗毛废水中SS的自然沉降性、絮凝性和极性有很大影响,比阻从远大于9.81×1013m/kg,下降为5.54×1010m/kg,COD去除率达到86.8%,SS去除率达到98%.因此,洗毛废水加酸处理后通过机械脱水,实现固液分离,以降低原废水的色度和大幅降低COD的方式,是可供考虑的处理工艺.     

造纸中段废水与生活污水合并深度处理工艺

采用水解酸化 CAST 混凝 复合滤池与水解酸化 接触氧化 混凝 复合滤池2种组合工艺对造纸中段废水与生活污水进行合并处理对照试验.结果表明,两种工艺都是切实可行的,二级出水均可达到<污水综合排放标准>(GB8978-1996)二级标准,深度处理出水可达中水水质要求.其中以水解酸化 CAST 混凝 复合滤池组合工艺效果最好.     

厌氧折流板反应器处理玉米秆纤维浆粕废水的研究

采用厌氧折流板反应器 (ABR)处理玉米秆纤维浆粕废水 ,研究了工艺条件和工艺特征。试验结果表明 ,在HRT为 2 4h ,OLR为 6 .5 6kgCOD/m3 ·d条件下 ,ABR能有效处理浓度为 6 5 6 0mgCOD/L的玉米秆纤维浆粕废水 ,COD去除率为 75 .1% ;ABR对负荷冲击有良好的适应性 ,且具有推流式和两相式反应器的双重特点。     

Oxidative treatment of simulated dyehouse effluent by uv and near-UV light assisted Fenton's reagent

UV/Fenton, near-UV-visible/Fenton, dark Fenton, and H₂O₂/UV reactions have been used to treat simulated dyehouse effluents representing wastewater from the textile dyeing and rinsing process. Experiments were carried out in a lab - scale photochemical reactor using concentrations of 0.5–25 mM H₂O₂, 0.04-0.5 mM Fe²⁺-ion and different dilutions of textile wastewater. To assess the extent of mineralization, decolourization kinetics and the effect of different fight sources on treatment efficiency, DOC, optical density at 254 nm and 600 nm wavelength and residual H₂O₂ concentrations were measured during the course of the advanced oxidation reactions. Comparative evaluation of the obtained results revealed that the decolourization rate increased with applied H₂O₂ and Fe²⁺-ion dose as well as the strength of the synthetic textile wastewater. The best results were obtained by the near - UV/visible/Fenton process with a decolourization rate constant of 1.57 min⁻¹, a UV_254nm reduction of 97% and a DOC removal of 41% at relatively low doses of the H₂O₂ oxidant and Fe²⁺-ion catalyst within 60 min treatment time.     

Ti/Ru/SnO2+Sb2O5电极的制备及其对垃圾渗滤液的电催化氧化

通过实验探究了不同Ru掺杂量对 Ti/Ru/SnO2+Sb2O5电极电化学性能及表面结构的影响。结果表明：Sb含量10%,溶胶涂覆6层,煅烧温度600 ℃,煅烧时间1 h条件下,Ru掺杂量为10%的涂层电极的加速寿命最长,为50 min;该条件下制备的电极涂层表面金属氧化物 SnO2的特征峰强度较大,峰形窄;涂层表面光滑,无裂缝。同时用Ti/Ru/SnO2+Sb2O5电极处理垃圾渗滤液MBR出水,Ru掺杂为10%的电极对废水COD去除率最高,为93.33%,电解出水芳香化程度大幅降低,对腐殖质和芳香族化合物的去除效果良好。研究对Ti/Ru/SnO2+Sb2O5电极在实际工业生产中的应用具有指导意义。     

厌氧-接触氧化工艺二级出水混凝除磷

为解决厌氧-接触氧化工艺处理生活污水除磷效果欠佳的问题,采用聚磷硫酸铁（PPFS）对该工艺二级出水进行混凝除磷实验研究。考察了PPFS投加量、初始pH值、温度、浊度以及与助凝剂（聚丙烯酰胺）复配对除磷效果的影响。研究表明,PPFS可有效降低出水TP浓度,当投加量为40 mg·L-1时,TP浓度能从3.71 mg·L-1降至0.34 mg·L-1左右,满足《城镇污水处理厂污染物排放标准》（GB 18918-2002）一级A排放标准限值（TP≤0.5 mg·L-1）。利用PPFS对生物除磷工艺二级出水进行化学除磷是一种有效、可行的选择。     

纳米TiO2光催化-超滤法处理模拟二级出水

采用纳米TiO2光催化-超滤对模拟二级出水进行处理。分别考察了纳米TiO2光催化剂的投加量、光催化反应时间、光催化过程曝气量、膜出水通量以及回流比对废水中污染物去除率的影响。结果表明:光催化反应最优处理工况,纳米TiO2投加量250 mg/L、反应时间150 min、曝气量为1.0 L/min、膜出水通量为115 L/(m2·h)、错流过滤的回流比200%;在此工况条件下,出水的UV254和TOC的去除率分别为96%和84%。