Thickener design methods pdf

Since this course is just an introduction to sewage treatment, the design methods you learn. The talmage and fitch and other methods of thickener design require the determination of the critical point on the sedimentation curve. The use of centrifugation and screen filters based techniques has been extended its presence in. At this time the maximum underflow solids concentration of the slurry at the base of the tank is attained. Shear effects, introduced by raking within a thickener for example, are known to affect the. Dissolvedair flotation is another type of sludgethickening process. Outotec thickening technologies leading edge technologies for thickening and clarifying outotec is a global leader in the design, fabrication and supply of thickening and clarifying solutions for the minerals industry. Work done by kynch 12 was quite important as it was the basis of many further studies of thickening. The monroe environmental secondary clarifier often called final clarifier effectively separates the biological floc and colloidal solids to produce wastewater with very low levels of organic material and suspended matter.

The method predicts the por 24hr, v is the settling rate in minimum. Service should mechanical or process problems arise, an experienced. A retrofit service is offered to enhance performance of existing thickeners and clarifiers. These theories have been applied to the solution of the same problem, wherever applicable, to reveal the relative outcome of the solutions for comparison. Several iterations of area may be required to achieve a practical thickener size and pumping rate. In this lecture and syllabus we make use of general rules of thumb and maybe somewhat old design methods.

Yoshioka developed a graphical method for designing. Process design manual sludge treatment and disposal. Application of theory to practice is explained at each stage, helping operators understand associated implications in each unit process. Substantial advances have been made in recent years. Thickening is a process where a slurry or solidliquid mixture is separated to a dense slurry containing most of the solids and an overflow of essentially clear water or liquor in leaching processes. Thickener design procedure and method thickening, filtering. Small air particles attach to the suspended solid material. The objectives of the project were to focus on the following areas. The torque, in turn, depends on a k factor and the thickener diameter based on the following formula. Dunn 6 paste 2014, vancouver, canada compressive yield stress forces of the mud bed. A randomized, doubleblind, controlled, parallel group study.

Part one gives a brief history of design, argues that new methods are needed for todays more complex realities, breaks down the design process into three stages, and shows us how to choose a design method for each stage. A description of the sedimentation process during dynamic thickener operation a. The amira p266 improving thickener technology series of projects has sought to provide a firm scientific basis for feedwell and thickener design, a requirement as pressures on water usage in the. What is the sludge thickening process in water treatment. A description of the sedimentation process during dynamic. Flocculation of sludge is the step in the process where destabilized particles are agglomerated in aggregates called flocs. Download download thickener design methods pdf read online read online thickener design methods pdf continuous thickener design thickener sizing calculation thickener operation manual thickener volume calculation thickener design calculations pdf high rate thickener design calculations thickener design equations thickener area calculation thickening of nonideal. Instead, current full scale gravity thickener models result in an under estimation of thickener solids flux by a factor up 100 usher 2002. Cationic flocculants represent the large majority of the chemicals used in sludge dewatering.

Pdf techniques and methodologies for improving thickener. This setup includes both clarification and thickening zones of clarifierthickener units, while the earlier ideal continuous thickener ict concept explicitly models the thickening zone only. Mineral processing design and operations 2nd edition. The gravity thickening design is similar to a clarifier. An authoritative critique of the established and recently proposed methods of thickener design. Contents of the larger thickeners represent a significant. They differ from conventional thickeners in feed well design, size and control. The torque capability of a thickener drive is specified as duty rating being the maximum mechanism design strength or the 100% setting on the torque control box. Solids contact and clean water treatment circular clarifiers. In wsec2017fs002municipal resource recovery design committeeanaerobic digestion fundamentals. Such jumbo thickeners, when centrally driven, require for most demanding applications extra heavy duty drive heads some of which reach a continuous operating torque of 3.

As the solids settle they pass from free settling to hindered settling to compression conditions. This chapter presents different theories of thickener design. Critical in the design of the thickener area is the minimum solids handling capacity. The basic design of a high rate thickener is below. Theory and application of thickener design sciencedirect. Theory and application of thickener design a g waters abstract theory the sedimentation vessel has a constant crosssectionalarea the process is onedimensional and so there is no radial variation in concentration for any horizontallaycr iii the slurry can be treated as a continuum with a continuous liquid and solid phase interacting with each. High rate thickeners are designed specifically to maximise the flocculation efficiency of flocculants. The flux curve determined by the method of coe and. Thickener tanks, rakes and feedwells are custom designed, based on the feed conditions and raking capacity. Some examples of successful bolted thickener installations are shown. Subjects started with a 3day runin period on a starchbased thickener and continued with a 14day intervention on eitherthestarchbasedorgumcontainingthickener. At each of these transitions there is a discontinuity in the sedimentation curve. Thickener design configuration s usually consider the high rate or paste thickener options, with a tradeoff between capital cost and process performance. Kynch carried out a theoretical analysis of concentration changes which can occur during.

Reliability over fifty years of experience in the design and manufacturing of sedimentation systems allows us to produce mechanisms that are characteristically troublefree in both installation and operation. Calculation of thickener area and depth based on the data of. Techniques and methodologies for improving thickener performance conference paper pdf available september 2003 with 1,229 reads how we measure reads. Improve clarifier and thickener design and operation. The flux curve determined by the method of coe and clevenger was invalid for all feed fluxes. Design and selection of separation processes customer, contact person, address order reference project name project numbershort name chemsep 104341 authors pages lotta sorsamaki, marja nappa 68 keywords report identification code separation processes, economic evaluation, equipment cost estimation, modelling, balas vttr0614315 summary. Grant road, suite 106 tucson, arizona 85745 introduction feed dilution or solidsliquid weight the english word sedimentation ratio is derived from the latin verb sedere size and shape of the particulate meaning to sink down. Pretreatment and design considerations for largescale. Similar to the digesters, there are two design approaches in thickeners too.

Using add reply allows you to attach images or pdf files and provide a more complete input. Dewatering is a physical mechanical unit operation used to reduce the moisture content of sludge so that it can be handled andor processed as a semisolid instead of as a liquid. Nov 25, 2017 download download thickener design methods pdf read online read online thickener design methods pdf continuous thickener design thickener sizing calculation thickener operation manual thickener volume calculation thickener design calculations pdf high rate thickener design calculations thickener design equations thickener area calculation thickening of nonideal suspensions such as. Recall that gravity thickener operation varies between.

The thickening process is the primary method of producing high solids slurries to bring the two together to make rational improvements to thickener design and. Most common techniques of thickening in sludge processing are given in table 1. A case study shows how the required thickener area would vary. Mar 06, 2018 a gravity thickener has a similar process to the tanks, but it has a sloped design so that solids collect at the base. Tolerability and product properties of a gumcontaining. Calculation of thickener area and depth based on the data of batchsettling test received 7 june 1983. Advantages of bolted tank construction for paste thickeners.

An introduction, second edition, helps further understanding of the various methods commonly used in mineral beneficiation and concentration processes. In this study an experimental method for obtain ing the data is outlined and flux curves determined by the three methods are compared with. High rate thickener feed wells are designed to disperse flocculants thoroughly into the feed end to admit the flocculated slurry into the settling zone of the thickener without destruction of the newly formed floccules. Interestingly, the drying time in the pilot plant ranged 710 days. In this chapter we analyze different methods of thickener design that have been proposed in the literature, in the light of their physical foundations. A gravity thickener has a similar process to the tanks, but it has a sloped design so that solids collect at the base. Design based on experience solids throughput is an important criterion in the design of thickeners. Steadystate, control, and capacity calculations for flocculated. The revolutionary outotec high rate thickener has pioneered and redefined thickening and clarifying methods around the world. Design of gravity thickener is the concern of this chapter. Recall two of three types of control for operating. High rate mesophilic digesters may employ an srt between 15 and 30 days. Simplified empirical methods are available for use during design.

Flocculants, with their very high molecular weights long chains of monomers and their. The report addresses key issues of concern regarding the design and operation of seawater desalination facilities in the united states. Use add reply to replyparticipate in a topicdiscussion most frequent. Barrientos department of metallurgical engineering university of concepcion abstract in this work we analyze, in the light of their physical foundation, the different methods of thickener design that have been proposed in the literature. Mip thickener design the following is a short cut to designing your own thickener. Design data for thickener henan zhengzhou mining machinery. Design procedure the thickener area is also required for this calculation. Laboratory testing for design of thickener circuits joseph m. Unlike conventional thickeners, high rate thickeners must use flocculants.