Lamella inclined plate settlers

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Hi friends , I would like to know up to what ppm of TSS a Lamella inclined plate clarifier/settler can handle and what will be the TSS removal efficiency ? If the feed is having 6000 ppm TSS will it work? What will be the treated water TSS ? What is the best plate spacing for 6000 ppm. If anybody can throw some information on this it will be helpful.

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6 Answers

  1. K.V.

    Depending upon flow rate, micron particle size, a media gravity or vacuum bed filter could work well. It is used in many other industries very successfully. It is commonly used to separate the solids collected from the discharge of a clarifier and much less labor than a filter press. The interesting feature is the solids "cake" build up enhances filtration.

     

    Glenn

  2. The answers provided already cover most aspects, one thing additional you may want to consider, depending on the nature of the incoming wastewater, is pre-screening as this should remove some of the suspended material, depending again on inflow characteristics and screen size, budget etc.

    You should also share more on the incoming and what the target water quality requirement is? Lamella settling may not be the best option??

    Regards

  3. The removal efficiency and its calculations depend on several factors, which some of them are already mentioned in the answers. Keep in mind that, additionally to the above-mentioned factors, temperature, tank and lamella plate design play a major role in sedimentation. Exact forecast of the removal efficiency can be very difficult, e.g. in activated sludge concentrations of around 20 mg/l can be achieved.

    Generally, concentration and amount of wastewater as well as type and spacing of the lamella can have a significant influence on the efficiency. We use tube Lamella for municipal wastewater, which brings considerable benefits. Thanks to the geometric shape of the tubes (in our case equidistant) turbulence phenomena are minimized, which has a positive effect on the hydraulic performance. TUBEdek® FS41. 84 can be an efficient solution as primary settler (please see www.enexio.com). For more detail, please don’t hesitate to contact me: youssef.rannane@enexio.com

  4. The flow rate to, and hence the Lamella Plate Separator rating (Flow Rate) is critical. The surface area of the plate packs is what determines the rating coupled to the volumetric capacity. The calculation for settling is based on the surface area (m2) and the flowrate (m3/hr) resulting in m3/m2.hr which must be less than 1.0 m3/m2.hr for theoretical settling i.e., A flow rate of 35m3/hr/40m2 (plate pack surface area) = 0.875 m3/m2.hr. Additionally the size of the solids and the quiescent settling velocity will determine the settling rate. In order to ensure the solids are of a size sufficient to settle in less than the retention time (clarifier volumetric  capacity) perform jar testing using flocculants to optimise the settling time. The intermittent bleed of the flocculated settled solids from the cone of the clarifier is crucial to ensure the Lamella Plates are working in the ideal zone. 

    1 Comment

    1. Hi Thanks for your reply. I am aware of projected effective surface area calculations based on settling / rise velocity. But I am unable to get any information as to the relationship between feed TSS and projected surface area requirement. General recommendations for plate spacing is 2" but when when we handle 6000 ppm feed TSS what should be the plate spacing. How is it decided? How much TSS lamella can handle? 

      2 Comment replies

      1. Hi K.V. 2 inch plate separation is fine, At 6,000mg/L TSS using the flow rate will provide you with a mass of solids i.e., 10,000L/hr will yield 60kg/hr of settled solids all things being equal. if you remove 60kg/hr of settled solids from the cone of the plate separator, you will have the ideal operating scenario.

  5. Hi, Karl-Uwe gave you already a lot of informations. I advice you to run the settling test with your sample : fill a 1L column with your wastewater and take a picture. After 30 min, take a second picture. Sample the supernatant and do some analysis, it will give you an idea of what can be achieved. You can send me the pictures and the analysys : nicolas@1h2o3.com 

  6. In general 6,000ppm is a lot but it depends on the application, particle sizes, density and shapes. In municipal applications we use tube settlers usually for up to 500ppm but in industrial applications it can be much higher. The removal efficiency depends on many factors especially on the settling velocity of the particles, flow rate/ retention time in the tube settler basin, eventually flocculation and others. You can find some more information on how tube settlers are designed here on the Water Network: HERE

    If you can give us some more information on the application we can give you a recommendation. Please send further information to info@aqua-equip.com