Karl-Uwe Schmitz
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Sludge scraper mechanisms – Removal of settled sludge
Sludge scraper mechanisms – Removal of settled sludge One of the most important treatment steps in wastewater and drinking water plants is sludge removal by sedimentation. Sludge i…
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Tube settler vs. plate settler – Best option for clarifier capacity improvement
One of the first technology for drinking water and wastewater treatment is sedimentation. Conventional sedimentation often utilizes large basins called clarifiers to settle out suspended solids by gravity. However, depending on solid density and size, settling by gravity might take a long time and requires therefore large clarifiers. In 1904 it was discovered by Allan […]
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Turbidity I wastewater treatment – How to reduce turbidity
Turbidity I Wastewater treatment – How to reduce turbidity? Turbidty in wastewater treatment describes the clarity or haziness of a wastewater sample. The level of cloudiness or the presence of suspended particles in the wastewater sample is usually measured in FTU. FTU stands for Formazin Turbidity Unit. Samples with less than 20 FTU are very […]
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Tube settler design basics – Solid settling with lamella clarifiers
Already in 1904 Allen Hazen defined the laws of sedimentation. He noticed that a particle in water can only settle down when its sedimentation velocity Vs is higher than the result of Flow Q divided by tank area A. Q divided by A is called surface loading qa. Except with flocculation the sedimentation velocity Vs […]
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Tube settler comparison – best lamella clarifier for high particle settling velocity
Allen Hazen defined in 1904 the law for sedimentation: Vs – settling velocity of a particle divided by settling height – has to be bigger as – Water flow Q divided by tank volume. Applied to a lamella clarifier this means that a particle is only settled down when the settling velocity of the particle […]
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How to calculate particle settling velocity – tube settlers I Stokes law
In 1851 George Gabriel Stokes defined how drag forces effect spherical objects in a viscous fluid in the formula: Fd = 6pi * u * R * v. An object in a viscous fluid like water always experiences a downward force – because of its weight and gravity – as well as an upward force. […]
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Clarifier basics: How do clarifiers work I Clarifier design
Throughout history, sedimentation has served as a tried and true method for wastewater treatment. Gravity forces contaminants to settle downward in the surrounding liquid whereas clarified water can be removed separately. The same principle is used by wastewater treatment clarifiers: Large tanks provide enough retention time to slow water down and to separate out suspended […]
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Tube settler|Plate settler maintenance – How to clean tube settlers?
Tube settlers which are also known as plate settlers or lamella clarifiers are used in drinking- and wastewater treatment plants to settle out suspended solids. Depending on the application the TSS (total suspended solids) loading can vary between 50 to 500mg/l or more. When the solid settling force is higher as all drag forces, solids […]
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Wastewater treatment: Film fill plastic media and attached biofilm growth
Biological processes in wastewater treatment can be classified into two main categories: suspended growth and attached growth/ biofilm processes. In suspended growth processes the microorganisms responsible for wastewater treatment are maintained in liquid suspension by appropriate mixing and aeration. The most common suspended growth process is activated sludge. Instead in the attached growth process, the […]
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How does simultaneous nitrification/denitrification work in attached growth systems?
In Wastewater treatment denitrification describes the final step of the conversion from ammonium NH4+ to Nitrogen gas N2. After ammonium is oxidized by microorganisms in a 2-step process ammonium is at first converted to Nitrate NO3-. Nitrate NO3- is still in the wastewater and although is less harmful than ammonia it can still cause diseases. […]
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Trickling filter design guideline – How do trickling filters work?
Trickling filters are biological reactors within wastewater treatment plants which are used to remove organic matter and/or ammonia from wastewater. Compared to the activated sludge process the microorganisms are not suspended in the mixed liquor but they are attached to a fixed bed surface. Nowadays, the fixed bed surface is usually provided by structured plastic […]
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Tube settler guideline – lamella clarifier design and CFD simulation (Video animation)
Apart from the selection of the right lamella clarifier module the design of lamella clarifier tanks requires several design considerations. More details on the selection of the right lamella clarifier module can be found in the linked video. Other parts of a lamella clarifier tank are the water inlet, sludge settling and water outlet zone. […]
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MBR, MBBR and FBBR – Comparison of wastewater treatment technologies (PART 1)
MBR, MBBR and FBR are widely used technologies in wastewater treatment, especially for industrial applications with a high BOD loading such as food and beverages, dairy, chemical, leachate and others. As industrial applications usually have volatile water inflows, equalization tanks are used for water storage and eventually PH neutralization as well as flocculation. Afterwards screens and […]
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