DEWATERING OF WASTE ACTIVATED SLUDGE VIA CENTRIFUGAL FIELD

While conducting centrifugal dewatering tests on waste activated sludge, this work considered how the rotational speed and the application of cationic polyelectrolyte flocculation affected the sludge. Increased rotational speed and/or conditioning the sludge to a charge neutralization point could enhance dewatering efficiency. A model was proposed to estimate the disruption energy exerted on the sludge body using centrifugation. Experimental results indicate that the disruption energy level provided by the centrifuge increases with rotational speed and decreasing water content in the filter cake. Moreover, polyelectrolyte flocculation may significantly reduce the disruption energy level of the water from sludge particles and the residual water contents at the end of the test.     

碳酸氢钠对微波预处理剩余污泥的促进作用研究

为提高城市生活污水厂剩余污泥的微波预处理效果,研究了碳酸氢钠(NaHCO3)对微波处理污泥的促进作用.结果表明,加NaHCO3不仅能提高污泥碱度,而且NaHCO3与微波联合处理后污泥溶解性化学需氧量(SCOD)和挥发性脂肪酸(VFA)的含量都随NaHCO3加入量的增加而大幅增大,Zeta电位绝对值增大.加入2g·L-1NaHCO3并于功率为800 W的微波下作用50 s,SCOD上升至8001 mg·L-1,VFA的质量浓度上升至969.9 mg·L-1.预处理后的污泥可望增强污泥后续厌氧消化反应的稳定性和效率.     

久置、好氧及厌氧污泥对亚甲蓝的吸附性能研究

用久置污泥、好氧活性污泥、厌氧活性污泥对阳离子染料亚甲蓝进行吸附研究,考察了吸附平衡时间、吸附等温线、吸附动力学、pH、离子浓度.污泥量对吸附亚甲蓝的影响.结果表明,3种污泥对亚甲蓝都具有良好的吸附效果,好氧活性污泥对亚甲蓝的吸附等温式同时符合Langmuir和Freundlich方程,久置污泥和厌氧活性污泥对亚甲蓝的吸附更符合Freundlich 方程;3种污泥对亚甲蓝的吸附行为符合很2级反应动力学;pH<2时3种污泥对亚甲蓝的去除率偏低,久置污泥和好氧活性污泥在pH3～12、厌氧活性污泥在pH5～12对亚甲蓝的吸附性能稳定;10mg·L~(-4)的醋酸钠可以有效促进3种污泥对亚甲蓝的吸附,促进作用随着醋酸钠浓度的升高逐渐减弱,但高浓度的醋酸钠对亚甲蓝的吸附没有明显影响.     

复合铁酶促活性和普通活性污泥系统低温启动对比研究

对比研究了＜15℃的低温条件下复合铁酶促活性污泥和普通活性污泥系统的启动过程.结果表明,向2个平行试验装置投加等量的接种污泥,两系统在以下工况条件经32 d均成功启动:HRT为20 h,污泥龄30d,进水体积流量与回流污泥体积流量比200％,DO的质量浓度2.0～4.0 mg·L-1;培养过程中,复合铁酶促活性污泥系统比普通活性污泥系统污泥含量更高,系统启动速度快;对COD、NH3-N、PO43--P的平均去除率较普通活性污泥系统分别提高6.10.11个百分点;脱氢酶活性、NH3-N硝化速率、吸磷速率分别提高了5.20 μg·mg-1·h、3.15 mg·L-1.h-1、2.0mg·L-1·h-1,表明复合铁活性污泥系统在低温条件下较普通活性污泥系统具有更高的微生物活性.     

COMBINED FIELD DEWATERING: BRIDGING THE SCIENCE-INDUSTRY GAP

The author's group is active in research on a wide variety of solid-liquid separation and dewatering methods. Processes examined include coagulation/flocculation, sedimentation, consolidation, drainage, filtration, compression/expression, and desaturation. A number of mechanical and electrical techniques have been used. These have been applied to a few well-defined systems such as clays, and to a wide variety of real suspensions from different industry sectors, from small laboratory to large demonstration scale. The experience of a range of techniques allied widi knowledge of the characteristics and behaviour of suspensions is helping to bridge the gap between scientific understanding and practical application. The present paper, based on both published and unpublished CSIRO work with an emphasis on fine and ultrafine coal and coal tailings, summarises the position. The analysis includes: • conceptual evaluation of the applicability and limitations of established dewatering techniques, • considering better ways of using these techniques, • assessing the potential for combining force fields (how many, what type, what sequence) to provide improved dewatering technologies.     

ACIDOGENIC FERMENTATION OF LIGNOCELLULOSIC SUBSTRATE WITH ACTIVATED SLUDGE

The lignocellulosic residues accumulated in municipal solid waste and agro-residues represent potential organic fractions preferably to be treated by anaerobic digestion in an energy recycle and/or value-added-product-type solid waste disposal system. Hydrolysis and acidification are predominant reactions in organic fermentation. Owing to the complicated physiochemical structures, the initial hydrolysis and acidification of the lignocellulosic residues into soluble forms are critical to the anaerobic digestion of the residues. This research focused on the promotion of solid-state acidogenic fermentation of two natural lignocellulosic residues in a pure form from the tobacco industry and urban turf grass by a combined pretreatment and thermophilic co-digestion with concentrated activated sludge from a biological municipal wastewater treatment plant. Laboratory-scale experiments were conducted in a batch and semi-continuous mode, with and without leachate recirculation. The results showed that the mechanophysicochemical pretreatment (roll milling-freezing-thawing-alkali wetting agent), followed by thermophilic co-digestion with activated sludge, substantially increased the solubility and fermentation efficiency of the natural lignocellulosic residues, leading to value-added utilization of these residues. In addition, leachate recycling appeared to be beneficial to acidogenesis.     

活性污泥法在喷射鼓泡环流三相反应器中处理染料废水的研究

采用活性污泥法,以牛粪浆作污泥源,结合新型的射鼓泡环流三相生物反应器,试验研究了三苯甲烷类碱性染料废水降解过程。选用粉煤灰为载体,研究了废水降解过程中的影响因素,确定了最优操作条件;通过流量为６ｍ＾３／ｈ,操作温度为２８℃左右,ＰＨ介于６．５－７．５,废水处理量为４０Ｌ／ｈ;连续降解时脱率大于９０９％ＣＯＤｃｒ的去除率大于７０％。     

干法离心分级机的分级性能研究

介绍干法离心分级机的分级基本原理,讨论了转子转速、加料量、气流量等因素对ＵＣＭ－４型分级性能的影响。     

剩余污泥转化为SCFAs及用于增强生物除磷的研究进展

发酵城市污水处理厂的剩余污泥可产生易于生物利用的短链脂肪酸(SCFAs),针对某些城市污水处理厂进水中所含溶解性有机物不能满足生物法需求的情况,可采用投加污泥发酵液作为外碳源来解决.SCFAs是增强生物除磷(EBPR)中聚磷菌厌氧合成聚羟基烷酸(PHAs)的重要基质,其浓度与类型对除磷效果有重要影响.本丈就剩余污泥发酵产酸、SCFAs对EBPR的影响及剩余污泥发酵液用于EBPR的研究进行了综述.     

ASSESSMENT OF RED BLOOD CELL DEFORMABILITY BY CENTRIFUGAL SEDIMENTATION

A centrifugal sedimentation method (CSM) is proposed for the assessment of deformability of red blood cells. The method is based on the premise that a red blood cell (RBC) should deform in a centrifugal field due to the variation of the centrifugal acceleration with the distance from the center of rotation. This change in shape of the RBC leads to a change in the rate of sedimentation in the centrifugal field. The rate of sedimentation, which serves as a measure of deformability, is characterized by an apparent sedimentation coefficient (ASC) and its normalized value (NASC), which is calculated by comparison with a control group of normal RBCs. It has been shown that the NASC is sensitive to the speed of rotation, to treatments with glutaraldehyde, diamide, or chlorpromazine, to heat treatment and to osmotic pressure variations.     

好氧污泥对季铵盐吸附性能的研究

试验对比了苄基季铵盐(BAC)在好氧活性污泥和灭活好氧污泥的吸附平衡和吸附动力学。结果表明,2种污泥对BAC的吸附都在30 min达到平衡;随着BAC初始含量的增大,好氧污泥的吸附量增大,吸附率降低;伪2级较伪1级反应动力学模型更符合吸附试验。15～35℃下,BAC在好氧活性污泥的吸附行为可以很好地用Langmuir和Freundlich吸附等温方程描述,温度升高吸附能力降低,在15、25、35℃时,最大吸附量分别为315、307、277mg·g-1;25℃时灭活好氧污泥对BAC的吸附方程也同时符合Langmuir和Freundlich方程,最大吸附量为210.7 mg·g-1。好氧活性污泥的吸附性能强于灭活好氧污泥,2者都能有效地的吸附去除BAC。     

固定生物膜-活性污泥工艺研究与应用进展

总结了国外固定生物膜-活性污泥(IFAS)工艺的研究与应用进展,主要包括IFAS工艺的研究现状、优缺点分析以及应用现状。IFAS将附着生长的生物膜和悬浮生长的活性污泥相结合,该工艺占地面积小,可有效脱氮除磷,在传统活性污泥工艺的升级改造上具有很大优势。同时,对IFAS未来的研究重点与方向进行了分析探讨,认为该工艺在国内的相关研究还很少,应结合我国污水处理实际情况,展开IFAS应用于升级改造的相关研究,对于我国节能减排具有重要意义。     

REMOVAL OF HEAVY METALS IN ACTIVATED SLUDGE TREATMENT SYSTEMS

Studies were conducted to determine the removal of heavy metals in three normally operating activated sludge wastewater treatment plants having only moderate industrial inputs. The removals of the soluble and particulate fractions varied with primary and secondary treatment, and in one instance a tertiary sand filter.     

几种不同活性炭的水力学特性研究

研究了不同粒径球形活性炭固定床层的水力学性能,并与颗粒破碎炭、柱状炭作了对比实验。考察了活性炭形状、粒径、床层空隙率、液体的表观流速和粘度对床层压降的影响,并用Ergun方程对实验结果进行了分析与讨论。结果表明,在粘度较小时,相对于柱状炭和颗粒破碎炭,球形活性炭的水力学性能最好;在粘度较大时,粒径大于1mm的球形活性炭才具有较好的水力学性能。     

超声波对污泥脱水及厌氧消化影响的研究进展

超声波技术作为污泥厌氧消化预处理手段被广泛关注.超声波能改变污泥的性质,改善污泥厌氧消化的性能,但是其处理效果受到频率、强度、作用时间和发生方式等因素的影响,只有在合适的条件下,预处理效果才能达到最佳.本文着重介绍了超声波的频率、强度、作用时间和发生方式对污泥脱水性能、污泥沉降性能、微生物活性和污泥产气等多方面的影响.由于脱水性能和厌氧消化的改善所需要超声波的条件不一样,所以有必要通过进一步实验使预处理效果最优化;同时,为了进一步降低能耗,有效利用超声波与其它预处理技术相结合将是未来的研究方向.     

有机高分子絮凝剂在污泥脱水中的应用研究

选择不同种类的污泥，采用28种有机高分子絮凝剂进行絮凝脱水实验。脱水率与污泥种类、絮凝剂种类、投加量、浓度、环境温度有关。当絮凝剂浓度为0．2％、温度为25～30℃时，对于机车厂的机械加工污泥，最适宜絮凝剂为离子度55％-60％、分子量1500万的阳离子型有机高分子絮凝剂，最佳投加量为100g／m^3,脱水率为74％；对于城市污水处理厂的生活污泥，最适宜絮凝剂为离子度60％～100％、分子量300～600万的阳离子型有机高分子絮凝剂，最佳投加量为100g／m^3，脱水率为79％。     

DRYING OF PULP AND PAPER SLUDGE IN A PULSED FLUID BED DRYER

ABSTRACT

Hydrodynamics and drying kinetics for the pulp and paper primary sludge dried in a pulsed fluid bed dryer with relocated air stream are presented. Batch experiments have indicated that drying of disintegrated sludge to the required 12% moisture content takes place during the first drying period at practically constant material temperature close to the wet bulb temperature with respect to the inlet air conditions. Equations were developed for pressure drop, minimum pulsed-fluidization velocity, dynamic bed height, and volumetric mass transfer coefficient. Continuous experiments under drying conditions determined from the average residence time concept have confirmed that transportation of disintegrated sludge along the dryer follows the plug flow model.

     

DRYING OF PULP AND PAPER SLUDGE IN A PULSED FLUID BED DRYER

Hydrodynamics and drying kinetics for the pulp and paper primary sludge dried in a pulsed fluid bed dryer with relocated air stream are presented. Batch experiments have indicated that drying of disintegrated sludge to the required 12% moisture content takes place during the first drying period at practically constant material temperature close to the wet bulb temperature with respect to the inlet air conditions. Equations were developed for pressure drop, minimum pulsed-fluidization velocity, dynamic bed height, and volumetric mass transfer coefficient. Continuous experiments under drying conditions determined from the average residence time concept have confirmed that transportation of disintegrated sludge along the dryer follows the plug flow model.     

活性污泥对废水中铍的吸附与解吸

本文研究了活性污泥对水中铍的吸附特性。考察了时间、温度、pH、共存离子等对吸附过程的影响,以及吸附过程中溶液pH的变化规律,研究结果表明：铍在污泥上的吸附主要为快速的表面吸附,受温度影响不大,在pH3—7范围,吸附量随pH的升高而增大,铜、铅、锌、钙由于共同竞争吸附电位而使吸附量下降,铁、铝等由于产生微沉淀而致使吸附量增加,钠由于具有竞争和生成复盐双重作用导致吸附量交叉变化,硫酸根和磷酸根由于与铍生成沉淀而增加去除率,而氟和铍生成稳定配离子使去除率下降,溶液pH由于生成配离子而呈现反常的升高;此外,还探讨了不同解吸刑对污泥中铍的解吸效果,结果表明,盐酸解吸效果最佳,解吸率高达96．73％。     

通过电磁场法原位合成WC颗粒(英文)

在1300℃时,对由金属钨丝与灰口铸铁熔体组成的体系施加一电磁场,金属钨原子与灰口铸铁中的碳原子集团原位反应形成WC颗粒和残余钨丝共同增强的铁基复合材料。通过X射线衍射、扫描电镜和能谱分析了复合材料的显微结构和组成。结果表明:当电流为15A时,随着电磁场频率的增加,原位合成的WC颗粒数量增减增多,钨丝的量不断减少。当电磁场频率达到5kHz时,钨丝反应完全。电磁场能够加速质量传递和元素的扩散速率,有助于在钨丝周围形成一系列的Fe-W-C三元体系微区,该微区内的钨浓度较大,改善了原位合成WC颗粒的动力学条件,而在颗粒间隙类似与过滤器降低了元素的扩散速率。