Pharmaceutical Process Water Clarification Belt Filter

Pharmaceutical Process Water Clarification Belt Filter

Category： Belt Filter
Energy Consumption: <15 kW/h
Water Recycling: Closed-Loop System
Noise Level: <65 dB
Certifications: CE
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Belt filter press description

A belt filter press (BFP) provides sludge dewatering by pressing the sludge to force the water through a permeable medium. The process produces a cake (the dewatered product) having a dry solids (DS) content of 30% or more in the case of primary sludge. This is to be distinguished from the lower-energy gravity belt thickener process which achieves a maximum DS content of ~10%.

A BFP combines drainage and mechanical pressure sequentially to remove water. The equipment normally comprises 2−3 recirculating belts, with two belts combining at some point to compress the sludge and squeeze water from it.

Belt filter press principle

Chemical Conditioning – Sludge is blended with polyelectrolyte or polymer feed in a conditioning tank. This allows solid particles to clump into agglomerate or flocs. The amount of polymer feed is a critical component to cakes with consistent thickness and moisture content.
Gravity Drainage – Sludge is fed onto the main filter belt, a monofilament woven fabric designed with high flow rates. Gravity dewaters the sludge as the belt approaches the next zone.
Low-Pressure Dewatering – The sludge travels into contact with the pressure belt, or top belt, gradually squeezing until they have sandwiched the forming cake.
High-Pressure Dewatering – Staggered rollers cause the two belts to shear as the main belt goes from direct contact with one roller to being pulled by the other belt’s contact with the next roller. At this stage, sludge has become dewatered cake.
Discharge – Scraper blades removed the cake from both belts, which separate and run through a spray wash before repeating the cycle.

Belt filter technical sheet

Sludge Kinds	Input Concentration %	Capacity m³/h	DS Capacity kg/h	Moisture of Cake %	PAM Consumption %(DP/DS)
Unconcentrated Aerobic Sludge	0.5~1.5	15~30	150~300	~80 (+2)	2~5
Concentrated Aerobic Sludge	2~4	6~12	200~300	~80 (+2)	2~5
Digested Sludge	3~6	7~15	300~400	<80	2~5
Unconcentrated Primary Sludge	0.8~2.0	18~35	300~400	<80	2~5
Concentrated Primary Sludge	3~5	6~12	300~400	<80	2~5
Paper-making Activated Sludge	0.5~2.5	15~35	200~400	<78	3~7
Printing and Dyeing Mixed Sludge	1~3	10~25	180~350	75~78	3~10

Model selection

Model	Belt Width	Sludge Concentration	Outlet Concentration	Capacity	Power
DNT-1000	1000mm	2-4%	15-25%	6-12	1.49kW
DNT-1500	1500mm	2-4%	15-25%	12-15	2.05kW
DNT-2000	2000mm	2-4%	15-25%	15-25	2.6kW
DNT-2500	2500mm	2-4%	15-25%	35-50	4.1kW

Belt Filter Press Advantage

Belt filters are considered simple and reliable, with good availability, low staffing, easy maintenance and a long life. The belt filter is most advantageous when installed such that it is open and viewable at floor level for easier adjustment and monitoring. This is of course subject to what lighting and ventilation will allow.

The belt filter press is often used in wastewater treatment, and thus the odour of the feed sludge, volatile emissions and the chemicals used in treatment, may become a problem. One control method is to use odour-neutralizing chemicals such as potassium permanganate. However this only neutralizes odours and doesn’t affect any gases or chemicals involved. Although all problems can be controlled by enclosing the filter, the enclosure reduces essential visibility and easy access to the machine for maintenance and repairs, leading to the expensive automation of the process.

Belt filter press features

Belt press filters are designed for solids capacity, by weight or volume, rather than wastewater flow. Solids concentration must be determined based on the concentration of primary solids in the feed and further solids that may precipitate during treatment. Solids concentration for a process will vary, thus the design must have the capacity to deal with varying feed solids concentration.

The feed to a belt press filter depends on the type of solids, desired product and filter design. For most sludge types the feed dry solids concentration is typically in the range of 1-10%. The resulting dewatered sludge (or cake) dry solids concentration typically falls in the range of 12-50%. Dilute feed solids concentration results in a cake of higher moisture content whilst a higher feed solids concentration yields an improved solids filtration rate and drier end product.

Belt filter press applications

The belt filter is mainly used for dewatering of sludge and slurry and juice extraction from apples, pears and other fruits, as well as grapes for winemaking, etc. Belt filters are used both municipally and industrially in a range of areas including urban sewage and wastewater treatment, metallurgy and mining, steel plants, coal plants, breweries, dyeing, tanneries, as well as chemical and paper factories.

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