Utilization of sludge in building material.

Several thermal solidification processes have been developed mainly in Japan. They are lightweight aggregates, brick, interlocking tile, char, and slag. A full-scale plant of them has been successfully operated for more than 10 years. The quality of the end products is better than the traditional ones. They are all substitutive to existing ones. The Japanese experience proves that all the processes are technically feasible, but not economically. Their manufacturing cost is always higher than market price. In addition, they consume large amounts of energy. However, if they are identified for a process of sludge disposal, all of them are worth considering for a big city where there is no place for the sludge to go. The end products can be reused inside the city. A new alternative is "Portland cement". A Portland cement manufacturer accepts sewage sludge, if being paid some amount of money. An average payment is US$100 each 1,000 kg of ash or sludge cake. The Portland cement manufacturer accepts either cake or ash at the same price. It is about 50 to 30% of the energy cost of thermal solidification. The question is which is the better, dewatered cake or incinerated ash, for the Portland cement application. The answer is "it depends on the distance between the sewage plant and the Portland cement plant."     

海水环境下水泥加固不同土质土体的效果研究

结合港珠澳跨海大桥西人工岛桥隧段软土地基处理工程,通过室内模拟试验,在已知固定水泥掺入比为18%的前提下,开展了水泥土在不同土质(淤泥、淤泥质黏土、粉质黏土)、不同龄期、不同养护环境条件下的力学性能试验。分析了土样的矿物成分、有机质含量,不同养护环境对水泥土无侧限抗压强度的影响规律及水泥的加固机理。结果表明:海水环境下水泥加固效果最好的是粉质黏土,其次是淤泥质黏土,最差的是淤泥;海水环境对3种水泥土的前期增益效果顺序依次是淤泥质黏土、淤泥、粉质黏土,后期增益效果顺序依次是粉质黏土、淤泥、淤泥质黏土。     

水泥固化东湖淤泥的工程性质试验研究

利用将水泥、化学固化剂和机械力脱水三种方法相结合的方式对东湖淤泥进行固化处理,通过界限含水率、强度试验(包括CBR和直剪试验)以及渗透试验研究了在使用水泥固化过程中水泥掺量、养护龄期以及压实度对固化土工程性质的影响。结果发现:仅使用化学固化剂和机械脱水固化处理后的淤泥属于高液限粉土,CBR强度低,不能满足路基填料的要求。使用水泥能够有效提高一次改性固化土的CBR强度和直剪黏聚力,养护龄期对CBR强度影响很小,而水泥掺量、养护龄期和压实度对内摩擦角的影响均不大。此外,在水泥掺量从0%增大到8%的过程中,渗透系数呈现出先增大后减小的趋势,在水泥掺量为2%时达到最大值。综合分析,在水泥二次改性过程中,为符合路基填筑要求,水泥掺量宜为8%,压实度宜大于92%。     

Utilization of dried sludge for making ceramsite.

Dried sludge as additive for making ceramsite is a new effective approach for disposal of sludge. In this study sewage sludge, water glass and clay were chosen as the components, the optimal ratio of the components and the most appropriate conditions were obtained. The functions of primary components in the sintering process, porosity formation mechanism and solid phase reaction also have been discussed. The optimized process parameters were shown as follows: the ratio of dried sludge/clay (wt%) was 33%, ratio of adherent /clay (wt%) was 15%, sintering temperature was 1000 degrees C, sintering time was 10 min. Bulk density was 582 kg m(-3), particle density was 1,033 kg m(-3), water absorption was 9.5%, porosity was 43.7%. SEM, EDS, XRD and XRF analyses were also carried out. The results indicate that dried sludge as raw material is a good way for making ceramsite. Biological Aerated Filters (BAFs) with filter media of Guangzhou ceramsite, Jiangxi ceramsite, activated carbon and ceramsite (obtained in test) were selected to treat municipal wastewater. The average removal efficiencies of ceramsite (obtained in test) for turbidity, COD, SCOD and NH3-N were about 96.4%, 76.2%, 59.6% and 82.3% respectively and were higher than those of other ceramsites.     

低温和干湿循环双重环境下水泥砂浆抗硫酸盐侵蚀试验研究

结合我国西北地区实际情况,对低温、干湿循环双重环境下水泥砂浆抗硫酸盐侵蚀性能进行了试验研究。试验采用0.5和0.36两种水灰比,胶凝材料采用普通硅酸盐水泥、中抗硫酸盐硅酸盐水泥和在普通硅酸盐水泥中分别掺入15%矿粉+1%硅灰和15%矿粉+3%硅灰4种方案。结果表明：在低温、干湿循环双重环境作用下,化学侵蚀非常缓慢,砂浆的劣化主要是硫酸钠结晶导致的;降低水灰比能显著提高水泥砂浆抵抗硫酸盐侵蚀的性能;使用抗硫酸盐硅酸盐水泥能在一定程度上改善抗侵蚀性能;不同水灰比下,复掺矿粉和硅灰会表现出不同的效果,在低水灰比情况下能提高抗侵蚀性能,在高水灰比下反而会降低抗侵蚀性能。研究结果可为低温和干湿循环双重环境下的工程建设提供参考。     

氯离子掺量对硅酸盐水泥和复合水泥浆体流变性能的影响

为实现海砂的直接使用,对不同氯离子掺量对PⅡ水泥和复合水泥在标准稠度用水量、凝结时间和流变性能的影响进行研究。结果表明:随着氯离子含量的增加,PⅡ水泥的标准稠度用水量上升,复合水泥的标准稠度用水量下降;PⅡ水泥和复合水泥浆体均出现促凝现象;PⅡ水泥和复合水泥浆体均属于宾汉姆模型,相关性良好;氯离子对复合水泥浆体的影响较大且其流变参数均大于PⅡ水泥,在水灰比一样的条件下,复合水泥浆体的工作性能较差。     

高铁酸钾预处理对水泥固化淤泥强度的影H向

淤泥的有机质中含氧官能团易与水泥水化产生的铝和钙相结合,延缓水泥水化的进程,阻碍水泥发生硬化,影响水泥固化淤泥强度的形成。为消除有机质对水泥水化的不利影响,选择高铁酸钾作为外掺剂对淤泥进行预处理,通过无侧限抗压试验和直剪试验,研究高铁酸钾对水泥固化淤泥强度的影响规律,并利用扫描电子显微镜分析水泥固化淤泥的微观结构。研究结果表明:高铁酸钾预处理可有效提高水泥固化淤泥的无侧限抗压强度和抗剪强度,其原因在于淤泥中的有机质被高铁酸钾氧化分解,保证了水泥水化反应和火山灰反应的充分进行,利于水泥水化产物的生成。同时,高铁酸钾被有机质还原,游离的Fe(III)吸附在黏土颗粒表面上,减薄了扩散层厚度,引起了黏土颗粒的絮凝。高铁酸钾预处理,通过改变水泥固化淤泥的微观结构,从而提高水泥固化淤泥强度。     

The effects of nano-materials on the behaviors of sludge mortar specimens.

In this research, nano-composites are added to sewage sludge ash to create a mixture, which then replaces part of cement. Nano-composites are manufactured from pure quartzose sand. The influences of different amounts of nano-composites and sludge ash on mortar are evaluated. Cement, sludge ash (0%, 10%, and 20%), and nano-composites (0%, 0.5%, 1%, 2%, and 3%), which defined as the percent weight of cement and sludge ash, are mixed together in batches to make mortar specimens. Results show that the flowability of sludge ash mortar reduces with increasing amount of cement replaced and of nano-composites added. The compressive strength of mortar lowers when more amounts of cement are replaced by sludge ash, but increases with more quantity of nano-composites added. Moreover, the study shows that nano-composites can fortify the compressive strength of mortar. With the help of efficiency of compressive strength, nano-composites benefit most to the mortar with replacement of 10% sludge ash, followed by the substitution of 20% and 0%.     

污泥固化土强度特性研究

为明确污泥固化处理后的强度变化特征,并从水分转化角度揭示其变化机理,对不同水泥添加量和不同养护龄期条件下污泥固化土的强度特性进行了室内试验研究。结果表明:(1)污泥固化土的无侧限抗压强度与水泥添加量呈线性正相关,固化系数k随着养护龄期的增加而增大。0~14 d,k由0.807 9增大到1.251 8,增长幅度较大,为54.94%;14~28 d,k由1.251 8增大到1.488 7,增长幅度明显减小,为18.92%。(2)无侧限抗压强度与养护龄期之间呈现良好的正相关性,二者拟合的相关系数在0.969 8~0.999 7之间。(3)水泥主要与污泥中结合势能较低的自由水发生水化反应,随着水泥添加量的增加,自由水百分量降低明显,下降幅度达到47.7%,结合水百分量降低缓慢,下降幅度仅9%;且水化反应在14 d内基本完成,14 d内水化反应消耗的自由水含量约为28 d内的80%。研究成果可为污泥固化土这种特殊性质土体的基本力学性质研究提供基础参数,为实际固化施工工艺的选择提供了参考。     

第二龄期老混凝土与新混凝土粘结劈拉强度研究

实际工程混凝土浇筑意外中断时有发生,恢复浇筑新混凝土时,中断前的老混凝土很多处于第二龄期。为提高第二龄期老混凝土与新混凝土的粘结性能,通过采用不同水灰比水泥净浆和不同掺量粉煤灰水泥浆界面剂,研究不同水泥第二龄期老混凝土与新老混凝土7 d和28 d粘结劈拉强度的变化规律。结果表明:三种水泥混凝土粘结劈拉强度均随水泥净浆界面剂水灰比的增大而减小;水泥净浆(使用水泥为普通硅酸盐水泥)界面剂对普通硅酸盐水泥的粘结效果最好,次之为矿渣硅酸盐水泥,最差为复合硅酸盐水泥。界面剂中掺加粉煤灰可在一定程度上改善第二龄期老混凝土与新混凝土的粘结性能。     

核磁共振技术在非饱和渗透特性研究中的应用

瞬时截面法因能快速地测定岩土材料的非饱和渗透系数,而在非饱和土的渗透特性研究中得到了广泛应用,该方法需要在渗流过程中及时测定非饱和土的含水率(吸力),但目前测量方法存在含水率(吸力)探头尺寸较大、探头与试样贴合不紧密以及测量时间较长等问题。针对上述问题,将核磁共振技术应用于非饱和土渗透特性的试验研究,对白色硅酸盐水泥试样实现快速、无损的探测,获得了试样不同截面处的含水率随时间的变化情况,并用瞬时截面法计算得到白色硅酸盐水泥的非饱和渗透系数。结果表明:白色硅酸盐水泥的非饱和渗透系数随吸力的变化很大,在4.61×10^-12～7.59×10^-8 m/s之间;当吸力>1 MPa时,渗透系数随吸力的降低而缓慢提升;而当吸力降至1 MPa以下时,渗透系数呈现明显的陡升,量值提高多个数量级。与传统的水分测试技术相比,核磁共振技术在非饱和土渗透试验应用中有更大的适应性。     

中热水泥质量控制应注意的问题

介绍了贵州江电葛洲坝水泥有限责任公司对生产的中热硅酸盐水泥的质量和各个环节进行严格控制的措施：对进厂的原料、燃材料把好质量关，并按材料质量搭配使用；在生产过程控制环节中充分关注影响水泥水化热的原因，并控制好出厂水泥的水化热及有害成分，同时还要控制好水泥与外加剂的相容性。采取这些措施后，该公司所生产的中热硅酸盐水泥质量综合性能好，满足了GB200--2003技术标准的要求和贵州构皮滩水电站工程建设对水泥质量的特殊要求。     

北京市高效循环水洗车技术应用研究

在对洗车用水特点及高效循环水洗车技术进行分析的基础上,针对当前洗车行业耗水量大、洗车废水污染环境等问题,结合北京社会发展、水资源状况、节水力度、行业节水推广情况,阐述了基于WR-RO、WR-UF技术的洗车循环用水设备的工艺流程、技术特征、运行工况及处理效果。洗车废水中含有油污、泥砂、表面活性剂及其他可溶性有机物。以超滤为核心工艺处理洗车废水,对浊度、COD、阴离子表面活性剂的去除率分别为98%、68%、69%。高效循环水洗车技术具有可操作性强、处理水质安全、运行成本低、效益可观等特点,应用推广价值高。     

隔河岩工程帷幕灌浆效果物化检测研究

 用物化综合检测技术，对隔河岩工程帷幕灌浆部位所取芯样进行了化学分析和矿物成分、微观结构及微区元素等项试验研究。结果表明： 经高压灌入岩石裂隙、断层和粘土中的水泥浆体水化较完全，结石与岩石、粘土胶结良好，灌浆处理后所取试样物理化学性能得到改善，防渗帷幕质量达到设计和施工要求。     

Capillary impregnation of concrete and its seepage structure

Conclusions The given method of examining capillary impregnation of dense concretes enables determining their seepage structure and comparing the permeability of various concretes. The results obtained for certain sand concretes with Portland cement and hardened cement are shown in the present work. Activated cast mixes, despite the comparatively high water/cement ratio, can create concretes with a low permeability.Translated from Gidrotekhnicheskoe Stroitel'stvo, No. 4, pp. 11–14, April, 1994.     

新型中置式高密度沉淀池优化投药试验研究

通过小试和生产性试验对新型中置式高密度沉淀池的投药系统(包括回流污泥、混凝剂及助凝剂PAM的投加)进行了详细研究.小试研究表明回流污泥和混凝剂投加量的增大降低了上清液浊度,PAM的投加略微降低了上清液出水浊度,但影响不大.生产性试验研究结果表明,实际生产运行中可灵活利用回流污泥来提高絮凝效果,在合理的范围内回流污泥投加量越大,絮凝效果越好;沉淀池随着混凝剂投加量的增大,出水浊度逐渐降低,同时,不同的回流污泥投加量条件下混凝剂投加对沉淀池出水浊度的影响表现出不同特性;增大PAM投加量对直接提高沉淀池的絮凝效果以及降低出水浊度的贡献不明显,PAM投加量的增大间接引起回流污泥投加量变大是导致出水浊度变小的原因.     

大体积混凝土胶凝材料体系水化放热规律研究

为研究低热硅酸盐水泥与大掺量矿物掺合料胶凝材料体系间水化放热规律方面的差异,采用直接法测定两者的水化放热过程,根据计算出的水化放热曲线及水化速率曲线,分析了两者在水化放热规律方面的差异;并采用Krstulovic-Dabic模型3个时期的积分方程进一步对比分析两者在水化进程方面的差异。研究结果表明试验方案中掺有矿粉的胶凝材料体系水化热前期低于低热硅酸盐水泥,而后期高于低热硅酸盐水泥;在水化放热规律方面,掺入一定掺量的矿物掺合料后,与低热硅酸盐水泥相比,初终凝时间延后,加速期与减速期延长;在结晶成核与晶体生长(NG)时期,n值越大,水化阻力越大,初凝时间相对推后,k_NG值越大,水化速率越快,加速期越短,终凝时间相对提前,在相边界反应时期(I)与扩散时期(D),k_I,k_D越大,水化速率越快,减速期越长。研究结果为改善大体积混凝土的温度防裂性能提供参考。     

Saline sewage treatment and source separation of urine for more sustainable urban water management

While energy consumption and its associated carbon emission should be minimized in wastewater treatment, it has a much lower priority than human and environmental health, which are both closely related to efficient water quality management. So conservation of surface water quality and quantity are more important for sustainable development than green house gas (GHG) emissions per se. In this paper, two urban water management strategies to conserve fresh water quality and quantity are considered: (1) source separation of urine for improved water quality and (2) saline (e.g. sea) water toilet flushing for reduced fresh water consumption in coastal and mining cities. The former holds promise for simpler and shorter sludge age activated sludge wastewater treatment plants (no nitrification and denitrification), nutrient (Mg, K, P) recovery and improved effluent quality (reduced endocrine disruptor and environmental oestrogen concentrations) and the latter for significantly reduced fresh water consumption, sludge production and oxygen demand (through using anaerobic bioprocesses) and hence energy consumption. Combining source separation of urine and saline water toilet flushing can reduce sewer crown corrosion and reduce effluent P concentrations. To realize the advantages of these two approaches will require significant urban water management changes in that both need dual (fresh and saline) water distribution and (yellow and grey/brown) wastewater collection systems. While considerable work is still required to evaluate these new approaches and quantify their advantages and disadvantages, it would appear that the investment for dual water distribution and wastewater collection systems may be worth making to unlock their benefits for more sustainable urban development.     

水泥－粉煤灰－矿渣粉三元胶凝体系体积稳定性的研究

研究了不同胶凝材料体系水泥浆体的体积收缩变形特性。试验结果表明：水泥品种与细度是影响硬化浆体体积稳定性的主要因素,水泥细度越大,硬化浆体的体积稳定性越差,低热（高贝利特）硅酸盐水泥浆体的体积稳定性优于中热硅酸盐水泥;矿物掺和料的掺入使得胶凝材料的体积稳定性变得复杂,优质的矿物掺和料能够降低硬化浆体的收缩;水泥－粉煤灰二元胶凝体系的体积稳定性优于水泥－粉煤灰－矿渣粉三元胶凝体系。     

Observations on ozone treatment of excess sludge.

This work experimentally studied the effects of ozonation treatment on waste sludge. During the treatment process, various parameters characterizing sludge were investigated. A substantial reduction in the volume of sludge and the release of intracellular and extracellular materials were observed. With the increase of ozone dose, the settleability and water content of sludge improved obviously, but the filterability of sludge deteriorated drastically. In addition, the evolution of particle size was evaluated, which proved the breakup of sludge flocs and cells. There existed a threshold of ozone dose which was 0.04 gO(3)/gMLSS in this work. Above the threshold, the soluble chemical oxygen demand (SCOD), protein, carbohydrate, total nitrogen and total phosphorus in supernatant increased remarkably and the electron transport system (ETS) sludge activity decreased. Organic nitrogen and organic phosphorus occupied the main part of total nitrogen and total phosphorus in the supernatant.