INTRODUCTION
Sludge dewatering represents the general process of removing moisture from a sludge in order to reduce its total volume, and this is desirable in most cases for minimizing downstream sludge management and transportation costs.
FILTER PRESS
A filter press is a batch operation, fixed volume machine that separates liquids and solids using pressure filtration. A slurry is pumped into the filter press and dewatered under pressure. It is a type of filter used for water and wastewater treatment in a variety of different applications ranging from industrial to municipal. A plate and frame filter press is the most fundamental design.
There Are Four Main Components To A Filter Press
- Frame (Skeleton): The steel filter press frame acts as a clamping device for the filter plates.
- Filter Plates: There are three basic categories of filter plates all with different functions. Plate and frame, recessed chamber (or recessed plate) and diaphragm squeeze (also known as membrane squeeze).
- Manifold: Our standard manifold consists of piping and valves. They control the slurry inlet and connect the four corner filtrate discharge ports into a common discharge pipe.
- Filter Cloth: A cloth filter that is attached to the filter plate is the filtering media . Solids build up on cloth to form a filter cake, separating liquids from solids.
How Does A Filter Press Work?
During the fill cycle, the slurry pumps into the filter press and distributes evenly during the fill cycle. Solids build up on the filter cloth, forming the filter cake in the void volume of the plate. The filtrate, or clean water, exits the filter plates through the ports and discharges clean water out the side of the plates.
Filter presses are a pressure filtration method. As the filter press feed pump builds pressure, the solids build within the chambers until they are completely full of solids. This forms the cake. The filter cakes release when the plates are full, and the cycle is complete. Also, many higher capacity filter presses use fast action automatic plate shifters which speeding cycle time.
MULTI-DISK SCREW PRESS
The Multi-Disk Screw press (MDS) is a solid−liquid separator, which can achieve significant dewatering.
The sludge is thickened and dewatered progressively along the length of the vessel, which comprises a series of fixed and rotating rings, via the inner screw conveyor. The special tungsten carbide coating of the inner screw and its slow rotation reduces friction and assures a long life span of the system components. The filtrate is drained from the gaps between the rings, creating a thickening and a dewatering zone in different regions of the vessel. The sludge cake is discharged at the end plate, achieving a minimum solid content of 20%.
The advanced design of the MDS makes it a self-cleaning unit due to the friction free movement between the rings, is applicable across a wide range of sludge concentrations (2000 mg/L – 50000 mg/L), and is highly suited to oily sludge.
PROCESS
- Flow Control Tank
Flow Control Tank feeds fixed amount of sludge to Flocculation Tank and the excess amount of sludge returns to storage tank
- Flocculation Tank
Polymer is mixed with sludge in Flocculation Tank for liquid-solid separation process
- Thickening Zone
Filtrate is discharged from Thickening Zone and the thickened sludge is pushed towards Dewatering Zone by screw
- Dewatering Zone
In Dewatering Zone, the gaps between rings reduces towards the End Plate and the pitch of the screw reduces by half
- End Plate
End Plate increases pressure further to give a drier sludge up to 25% solids content
APPLICATION
| · Textile industry
· Chemical industry · Waste management · Iron and steel industry · Petrochemical industry · Galvanizing, electroplating · Municipal wastewater treatment |
· Dairies
· Tannery industry · Paper Industries · Cosmetics industry · Food processing industry · Meat processing & packing · Industrial kitchens and canteens |
ADVANTADGES
Low operation cost : Below 40% of belt press and 20% of centrifuge.
Power-saving : Less than 5% of centrifuge.
Water-saving : Less than 0.1% of belt filter press.
Drugs-saving : Saving around 60%.
Compact : Saving more than 60% of the investment for dehydration room.
Non-clogging : Processing the fats & oils and fibre sludge perfectly.
