Bag Centrifuge
Batch-operated sludge dewatering unit using centrifugal force and a filter bag — suited for ETPs, STPs, and industrial wastewater plants.
Request a quote
Overview
A Bag Centrifuge is a batch-operated mechanical dewatering machine that separates sludge into a dewatered solid cake and a clarified filtrate using centrifugal force. Inside the machine, a perforated stainless steel basket lined with a replaceable filter bag spins at high speed. Sludge is fed into the basket, and centrifugal force drives the liquid outward through the filter bag and basket perforations, while solids are retained inside the bag as a sludge cake. Once the cycle is complete, the basket slows, the bag containing the cake is lifted out, and the cycle begins again.
How Does a Bag Centrifuge Work?
1. Sludge Feeding
Conditioned or raw sludge is pumped or gravity-fed into the filter-bag-lined rotating basket.
2. Centrifugal Separation
The basket accelerates to operating speed (typically 800–1500 RPM). Centrifugal force pushes liquid through the filter bag and basket perforations into a surrounding collection bowl.
3. Cake Formation
Solids build up inside the filter bag, forming a sludge cake. The cycle continues until the basket is full or the target dewatering time is reached.
4. Bag Removal and Cake Discharge
The basket decelerates and stops. The filter bag containing the dewatered cake is lifted out. A fresh bag is inserted and the next cycle starts immediately.
5. Filtrate Return
The collected filtrate is drained from the bowl and returned to the feed sump or equalisation tank for further treatment.
Technical Specifications (Indicative)
Capacity: 50–500 LPH sludge feed | Basket Speed: 800–1500 RPM | Basket Material: SS 304 / SS 316L | Filtrate Clarity: 95–99% SS removal | Cake Dryness: 60–75% DS | Motor: 0.75–3.7 kW | Cycle Time: 5–15 minutes per batch | Drive: Direct or VFD-controlled
Typical Applications
- Pharmaceutical and API manufacturing ETP sludge
- Chemical and dye industry wastewater sludge
- Food and beverage plant ETPs
- Small and medium STPs up to 500 KLD
- Textile and dyeing unit effluent plants
- Paint and coating industry wastewater
Bag Centrifuge vs Other Sludge Dewatering Options
Compared to a Filter Press, a Bag Centrifuge offers faster cycle time and simpler cake discharge but is better suited to lower sludge volumes. Compared to a Screw Press, it requires less polymer conditioning and handles batch processes more naturally. Compared to a Decanter Centrifuge, it has a lower capital cost and simpler maintenance but lower throughput capacity. Best selected when sludge generation is intermittent, space is constrained, and simplicity of operation is a priority.
Key features
- Centrifugal force-driven solid–liquid separation using a replaceable filter bag inside a rotating basket
- Batch operation with bag removal for easy cake discharge — no scraper or conveyor required
- Handles wide range of sludge types: ETP, STP, chemical, pharmaceutical, and food-processing sludge
- Low power consumption due to single-motor design and short cycle times
- SS 304 / SS 316L contact parts available for corrosive and food-grade applications
- Filter bag replaceable without dismantling the machine — reduces downtime significantly
- Compact footprint suitable for small to medium capacity wastewater plants
- VFD option available for optimised dewatering across different sludge characteristics
Key outcomes
- Reduces sludge moisture content to 60–75% dry solids — significantly cutting sludge volume and disposal cost
- Eliminates or reduces polymer dosing requirements compared to belt press or screw press
- Fast batch cycle (typically 5–15 minutes) enables high throughput in limited floor space
- Recovered filtrate is clean and can be returned directly to the treatment process
- Lower capital cost vs. decanter centrifuge for small to medium sludge volumes up to 500 LPH
- Minimal operator skill required — suitable for sites with limited technical staff
Standards & certifications
Fabricated to IS/BIS standards for rotating equipment; SS 316L contact parts available for pharmaceutical-grade applications; compatible with CPCB ETP/STP consent conditions for sludge disposal norms.
Who it's for
Plant engineers and EPC contractors at small to medium ETPs, STPs, or industrial process plants needing a cost-effective, low-maintenance sludge dewatering solution where floor space is limited and sludge volumes are up to 500 LPH. Particularly relevant for pharmaceutical, chemical, food and beverage, and textile effluent plants where batch dewatering aligns with batch process operations.
Looking for something specific?
Tell us what you need to spec.
Share your capacity, compliance milestone, and timeline. An engineer responds within one business day.