Structure of Crack in Thermally Dried Sludge Cake

We examined in this work the drying characteristics of wastewater sludge, considering the weight loss using an electronic balance and the morphology change of drying cake by an X-ray micro-computerized tomography scanner (micro-CT). The drying rates for sludge cake was 50-60% of the pure water test. The corresponding micro-CT images were scanned to explore the change in cake volume and development of internal crack over drying. The Otsu's method was applied to bilevel the scanned images, based on which the three-dimensional model for crack's internal structure was reconstructed. The cake porosity and the geometric factors of cracks, such as the compactness, the boundary fractal dimension, and the Sierpinski carpet fractal dimension, were evaluated. The shrinkage of cake volume and the development of internal crack occurred simultaneously. The skin layer formed by the former mechanism retards further drying. On the other hand, the internal cracks were shown to exhibit zigzagging with a noncircular cross section and fractal-like boundary, which should be able to enhance local drying. A possible role of change in crack structure on the rate of drying was discussed.     

CASS法处理含盐废水的研究

采用鱼品加工厂生产废水掺一定比例的海水作为试验用水,通过含盐量的不断增加研究系统的耐盐性,通过含盐量的降低和升高研究系统的抗盐度波动性。试验表明,当Cl-的质量浓度<6300mg/L时,CASS系统可正常运行;当Cl-的质量浓度<4500mg/L时,对于Cl-质量浓度梯度为3600mg/L的冲击,系统可以在1个运行周期内恢复正常运行。     

污水处理厂污泥于陶粒生产中的综合利用

主要从市场、工艺、经济和社会效益方面，对污水处理厂污泥于陶粒生产中的综合利用问题进行了论述。     

生物反应器-中空纤维膜处理医院污水

生物反应器-中空纤维膜处理医院污水试验表明,该工艺在技术上可行,处理效率高,操作管理方便。对COD、NH3-N、大肠杆菌的去除率均达90％以上,出水水质良好、稳定。增设粗分离器后,对延长膜清洗周期、提高膜通量效果明显。     

Solidification of electroplating sludge using alkali-activated pulverized fuel ash as cementitious binder

This work investigated the potential for utilization of alkali-activated PFA as solidification binder to treat electroplating sludge. The sludge was solidified using 30 wt.% of lime and 70 wt.% of PFA. Two alkali activators, Na₂SiO₃ and Na₂CO₃, were added at 0, 4, 6, and 8 wt.%. Results showed that early strength development of lime-PFA cements with Na₂SiO₃ and Na₂CO₃ was considerably higher than those without. Addition of electroplating sludge resulted in reduced strength. The strength reduction was greater when 4% Na₂SiO₃ activator was used than when 8% Na₂CO₃ activator was used. A higher pH of Na₂SiO₃ solution (pH=13.5) compared to that of Na₂CO₃ solution (pH=11.9) resulted in resolubilization of metal hydroxides from the electroplating sludge, which competed with calcium ion for soluble silicate. In addition, Pb, Cd, and Cu were not found in the toxicity characteristic leaching procedure (TCLP) leachates. Cr, Zn, and Fe were detected and in some cases Cr exceeded U.S. EPA allowable limits.     

山梨酸废水的生化处理

山梨酸生产废水有机浓度高、可生化性好、含盐量高。废水中CODCr为8000-16500mg/L，B/C≥0.5，含盐量≥15g/L。本工程通过淹没式厌氧生物滤池和膜分离活性污泥法处理，CODCr总去除率高达93%-99%，出水CODCr≤300mg/L，达到GB8978-1996《污水综合排放标准》行业二级排放标准，顺利通过当地环保部门的验收。     

好氧管式膜生物反应器处理高含盐有机废水的研究

采用好氧管式膜生物反应器处理不同含盐浓度的有机废水 ,研究结果表明 (1)进水COD浓度在 2 0 0 0～ 30 0 0mg/L时 ,出水COD在 179～ 2 2 3mg/L之间 ,COD平均去除率在 89.5 %以上 ;(2 )MBR处理高盐度有机废水耐冲击负荷的能力较强 ,出水水质稳定 ;(3)当膜的TMP =0 .1MPa,盐度为 1.0 %、1.5 %、2 .0 %时 ,管式膜的稳定运行通量分别为30、2 4、2 1L/ (m2 ·h) ,整个运行过程中没有进行膜清洗     

SBBR与SBR氧传质特性比较研究

在试验条件相同的情况下,进行了序批式膜生物反应器SBBR与SBR的清水充氧试验,氧传质特性比较研究结果表明:当曝气强度为0.3m3/h时,SBBR的(KLa)20和Eo2值均为SBR的1.59倍。SBBR具有更好的氧传质能力和更高的氧转移效率。     

电镀污泥中铬的去除工艺优化

以某公司的电镀污泥为研究对象,针对污泥中含铬量高的特点,提出了去除铬的处理工艺.根据铬在污泥中存在的状态,采用硫酸作为浸出试剂.通过正交试验,考察了硫酸浓度、浸出时间、反应温度、搅拌速率等对铬去除率的影响,同时也对去除机理进行了探讨.X射线光电子能谱(XPS)显示,电镀污泥中铬的质量分数为22.05%;取此种污泥2g,用10mol/L的硫酸溶解,在固液比(质量分数)为15∶1,搅拌速率为800r/m,待反应90min后,可使污泥中各种形态的铬溶解于硫酸中,从而去除污泥中的铬.此种方法操作简单可行,污泥中铬的去除率可达90%以上.浸出的铬可进一步综合利用,剩余污泥也可安全填埋,有利于减少此类污泥对环境甚至生态系统的危害.     

污泥热干燥粘结的特征和影响因素

污泥热干燥过程中在干燥设备内部表面的粘结是影响干燥设备性能的重要因素。通过热干燥模拟实验,分析了污泥含水率、加热温度、加热方式、加热界面性质等因素对污泥粘结的影响。结果表明,含水率是影响污泥粘结最主要的因素,污泥含水率较高时,粘结量较少,随着污泥干燥程度增加,含水率降低,粘结量逐渐增加,当含水率达到60%左右时粘结量达到最大,之后转而减少;加热温度不超过120℃时,温度对污泥粘结的影响不明显,加热温度高于120℃时,污泥粘结量随温度升高而显著增加;传导加热方式比对流加热方式更易导致污泥粘结;加热接触界面的表面粗糙度越大则污泥粘结量越大。