Thickening Equipment is principally used for primary sludge and mixtures of primary and waste activated sludges. Due to the better performance of other thickening methods, gravity thickening has limited application for such sludges.

Other variables that impact the selection of a thickening process are: subsequent processing steps; operation and maintenance (O/M) cost; and the reliability required for meeting successful operational requirements.

Gravity belt thickeners are a very cost effective means of thickening sludge. The simplicity of the gravity belt thickening equipment & machinery makes it easy to maintain and its low power consumption makes it inexpensive to operate. Thickening equipment, also known as gravity belt thickeners, are typically found in municipal wastewater plants, but may also be used in industrial wastewater facilities. Compositech gravity tables are designed to concentrate sludge, by means of gravity drainage of water through a permeable synthetic belt. Our design provides for extended drainage of dilute, high volatile and unstable sludges. Our gravity tables are designed for continuous 24-hour per day, 365 day per year operation with minimal maintenance.

The main design variables to be considered in selecting a thickening process are

• Solids concentration and volumetric flow rate of the feed system

• Chemical demand and cost if chemicals are employed

• Suspended and dissolved solids concentration and volumetric flow rate of the clarified stream

• Solids concentration and volumetric flow rate of the thickened sludge

Centrifuges are used both in thickening and dewatering of sludge. Centrifugal thickening involves the settling of particles in watery sludge under the influence of centrifugal forces. Application of centrifuges is limited to the sludge from activated sludge. The advantage of centrifugal thickening is its ability to thicken some difficult sludge. The downside of the centrifuges for sludge thickening are costs associated with power, maintenance, and skilled operators. Other types of sludge thickening equipment are the rotary drum thickener and gravity belt thickener; they are less common in sludge thickening operations.

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