What is Screw Press Dewatering? Sludge Treatment and Disposal

Screw Press Dewatering

The screw press dewatering machine is integrating with auto-control cabinet, sludge thickening & dewatering body liquid collection tank. Therefore, the high efficiency flocculation, continuous sludge concentration, dewatering and filtrate collection can be automatically completed all-in-one, the collected liquid will be reflux or emissions finally.

Application of Dewatering Screw Press:

Dewatering screw press  is used for municipal sewage petro-refining, leather making, printing and dyeing paper, coalification dressing, biochemical biochemical pharmacy, steel pickling and chemical sugar, food processing etc.

Advantages of Screw type Activated Sludge Treatment:

The advantages of screw type activated sludge treatment is given here shortly-

• Low operation cost: below 30% of belt press and 10% of centrifuge.
• Power saving: less than 6% of centrifuge required for activated sludge treatment process
• Water-saving: less than 0.1 % of belt filter press.
• Saving-drugs saving around 60%.
• Compact: saving more than 60% of the investment for dehydration room.
• Non clogging: handling the fiber sludge perfectly for activated sludge treatment process.

Features of Screw Dewatering:

• Very simple processing,
• Very low investment in system,
• Energy efficient for dewatering
• Activated sludge treatment
• System can be programmed to make the operation more convenient and accurate
• Different flocculating that make sludge dewatering easier
• Uniform and accurate dispensing, saving costs

Flowchart of Dewatering Screw Press:

The process of dewatering screw press –

• Soleenoid valve
• Dry powder
• Elec-control box
• Polymer flocculants
• Gutter
• Design pump
• Measuring tank
• Flocculation tank
• Again Elec-control box
• Filterate
• Screw Conveyor
• Sludge thickner

Equipment of Screw Press Dewatering:

The equipment’s of screw press dewatering are listed below –

• Counter seizing grate cleaner
• Spiral screen
• Circulation toothed harrow mid cleaner
• Dosing system
• Spiral conveyer
• Sand separation
• Solution preparation system

Sludge Treatment and Disposal Process:

When the machine starts running, the activated sludge tank treatment and disposal system is pushed into the filter cartridge from the feed inlet and then transfer to the sludge cake passage under the pushing of the helical axis blades. Because the gaps among the helical axis blades will gradually getting narrower, the sludge is undering heavier pressure. After that the water slowly comes from it as a result of burden differential and issues from the filtering space between the fixed plates and the moving plates. Trusting on the self cleaning functionalities of the stable plates as well as the moving plates block can be well avoided. At the end, the sludge treatment and disposal cakes are pushed by helical axis after being completely dewatered and then discharged from the outlet.

ETP Wastage Management Policy:

Applicable for:This policy is applicable for all the units of Auto Group.

Objective: The objective of this policy is to ensure proper management or disposal of wastages

Basis: To maintain clean and tidy workplace organizations need to properly manage its wastages and get rid of those. As Auto Group produces readymade garments, it produces lots of fabric wastages and worn out machine parts which required to be disposed properly. To address this issue and establishing a formal written guideline this policy has been formulated.

Policy: In broad category the wastages are classified in 4 categories which are –

• Scrap fabrics & accessories wastage
• Sludge from ETP
• Soled waste
• Defective products

The wastages which are sellable must be sold to the buyers based on bidding and that amount should be contributed to the Worker Welfare Fund. In case of hazardous and toxic wastages, proper disposing procedures will be followed to ensure health safety. Workers should be given training so that the rate of fabric wastages and defective products are lowered.

Regulations & Procedures: In case of disposing scrap fabrics and accessories wastages the steps which should be followed are as bellows –

• Production department will gather the fabric and accessories wastages
• Items should be weighed and chart should be maintained based on their categories and quantities.
• Operation department will arrange bidding for the potential buyers and sale the wastages to the highest bidder and the amount should be contributed to the Welfare Fund (WF).

ETP sludge disposal –

• The sludge which is being produced from ETP should be gathered and stored properly in containers or barrels.
• These containers should be stored in a separate storage area rather than the places which are being used for storing other kinds of wastages.
• Sludge should be taken away by government for treatment and landfilling.

Regulations and procedures for dealing solid wastes are –

• Tube lights, electric item wastes will be charted and kept in separate area for disposal. These items should be returned to suppliers for recycling.
• Worn out machine parts will also be gathered all together then charted and stored properly. These items should be sold to the scrap metal purchasers or to light engineering workshops (Dholaikhal).
• Paper and wood wastes will be shredded and stacked. These will be given away to concerned parties for recycling.
• Plastic items, office items should also be weighed and stored and later sold to recycling agencies.

Regulations and procedures regarding defective products –

In case of having defective products (garments) the labels should be removed at the first place, then those will be charted and contained.

Merchandisers will try to bring foreign stock lot buyers for buying the defective garments or those will be sold to local market for domestic consumption

Responsible Parties: Management will be responsible for deciding selling off the defective garments.

• Merchandisers will be responsible for getting foreign stock lot buyers
• Admin department will be responsible for storing wastages properly.
• Operation department will be responsible for getting buyers and selling wastages
• CSO will ensure security while selling wastage items

Communication & Implementation: The policies are to be communicated to all levels of management through regular and repeated discussions during meetings and implemented and followed up on accordingly.

The policy is to be published in the policy book, so it will be visible to all the employees. A Bangla version of the policy will be provided to the junior factory level staffs and workers.

Exceptions: Exceptions must have the prior approval of MD or management.

Feedback & Control: Factory heads will check whether all the wastages are properly being collected and stored. Also he will ensure transparency was maintained in the whole wastage disposal procedure.

Principal of Dewatering Screw Press:

The filter main part is formed by screw axis with fixing and moving plates overlapping. It dewaters adequately by the gravity and the power from back pressure plate during the process of propagation, the filter comes out form the space between fixing and moving plates, the sludge cake discharged from the discharged outlet.

Rational model should be selected according to technical parameters