Rotating Drum Screen Solid Separator Design for 500 KLD Slaughter House ETP

Application: Slaughterhouse Wastewater ETP (India)

Recommended Final Specification for 500 KLD ETP  Of slaughter house waste water

This configuration is commonly used in Indian slaughterhouse ETPs of 500 KLD capacity and provides adequate robustness for high-fat, high-solids wastewater. One extra separator is to be installed as standby.

Item	Specification
Drum Dia	1000 mm
Drum Length	2000 mm
Material	SS316
Perforation	2.5 mm
Rotation Speed	5 rpm
Gearbox	Helical, 300:1
Output Torque	800 N·m minimum
Drive Motor	1 HP, 415V, TEFC
Spray Pump	1 HP
Solids Removal	225 kg/day dry solids
Hydraulic Capacity	30 m³/hr
Installation	RCC platform above EQ tank inlet

RCC Platform Recommendation

• Platform Size: 3.5 m × 2.5 m
• Operating Width around drum: minimum 1.0 meter clear
• RCC M25 grade
• Platform elevation: 1.2–1.5 m above EQ tank inlet level
• Hot dip galvanized handrails (1.1 m height)
• Drain collection channel below screen
• FRP/SS access staircase

1. Design Basis

Hydraulic Data

Parameter	Value
Plant Capacity	500 KLD
Operating Hours	24 hr/day
Average Flow	20.83 m³/hr
Design Average Flow	21 m³/hr
Peak Factor	1.2
Peak Flow	25.2 m³/hr
Design Flow Adopted	30 m³/hr
Wastewater Type	Slaughterhouse
Influent TSS	1805 mg/L
Influent BOD	2000 mg/L
Influent COD	5000 mg/L
Influent Oil & Grease	400 mg/L

Design Objective

Removal of:

• Paunch contents
• Hair
• Fat particles
• Flesh particles
• Bone fragments
• Coarse suspended solids

before Equalization Tank.

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2. Design Criteria

Based on CPHEEO, Metcalf & Eddy and Indian slaughterhouse ETP practices:

Parameter	Design Value
Drum Loading Rate	150–250 m³/m²/hr
Adopted Loading	200 m³/m²/hr
Screen Opening	0.75–1.5 mm
Adopted Opening	1.0 mm
Drum Submergence	25–35%
Drum Speed	3–8 rpm
Adopted Speed	5 rpm
Screen Material	SS316
Internal Flights	Yes
Spray Washing	High-pressure SS nozzles

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3. Required Screen Area

Design Flow

Q = 30 m³/hr

Hydraulic Loading

HLR = 200 m³/m²/hr

Required effective area:

$$A=\frac{Q}{HLR}$$ $$A=\frac{30}{200}$$ $$A=0.15\,m^2$$

Considering:

• 50% clogging allowance
• peak solids loading
• slaughterhouse shock loads

Adopt Safety Factor = 3

$$A_{design}=0.45\,m^2$$

Required effective screening area:

A = 0.45 m²

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4. Drum Diameter and Length

Effective screen area:

$$A=\pi D L$$

Adopt:

D = 0.80 m

Then

$$L=\frac{0.45}{3.14\times0.8}$$ $$L=0.18m$$

This is too short.

For better solids retention, adopt practical industrial dimensions.

Recommended Drum

Diameter = 0.80 m

Length = 1.50 m

Screen Area:

$$A=3.14\times0.8\times1.5$$ $$A=3.77m^2$$

Hydraulic Loading:

$$HLR=\frac{30}{3.77}$$ $$HLR=7.95m^3/m^2/hr$$

Very conservative and ideal for slaughterhouse wastewater.

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Final Drum Size

Item	Value
Drum Diameter	0.80 m
Drum Length	1.50 m
Effective Area	3.77 m²
Screen Material	SS316
Perforation	1.0 mm

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5. Screen Perforation Size

Slaughterhouse wastewater contains:

• Hair
• Tissue
• Fat globules
• Rumen particles

Recommended:

Option	Opening
Fine	0.75 mm
Standard	1.0 mm
Coarse	1.5 mm

Adopt:

Screen perforation = 1.0 mm round holes

Material:

SS316 wedge wire/perforated sheet

Thickness:

2–3 mm

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6. Drum Rotation Speed

Typical:

3–8 rpm

For slaughterhouse solids:

Adopt 5 rpm

This provides:

• Good drainage
• Good solids lifting
• Low wear

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7. Torque Calculation

Drum weight (SS316)

Approx:

250 kg

Solids load:

50 kg

Total rotating mass:

300 kg

Radius:

$$r=0.4m$$

Torque:

$$T=300\times9.81\times0.4\times0.25$$ $$T=294N.m$$

Factor of Safety = 2

$$T=588N.m$$

Design Torque:

600 N·m

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8. Gearbox Selection

Motor speed:

1440 rpm

Required drum speed:

5 rpm

Reduction Ratio:

$$i=\frac{1440}{5}$$ $$i=288$$

Adopt:

Helical Gearbox

Ratio = 300:1

Output Torque ≥ 800 N·m

Service Factor = 1.5

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9. Motor Sizing

Power:

$$P=\frac{2\pi NT}{60}$$ $$P=\frac{2\times3.14\times5\times600}{60}$$ $$P=314W$$

Considering:

• startup load
• solids shock load
• wet conditions

Adopt:

Motor = 1 HP (0.75 kW)

TEFC

415 V

3 Phase

IP55

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10. Spray Wash System

Essential for slaughterhouse wastewater.

Spray Pump

Capacity:

5–7 m³/hr

Head:

25–30 m

Motor:

1 HP

SS316 nozzles

Operating Pressure:

2.5–3 bar

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11. Solids Handling Capacity

Influent TSS:

1805 mg/L

Flow:

500 m³/day

TSS Load:

$$500\times1.805$$ $$902.5kg/day$$

25% removal:

$$902.5\times0.25$$ $$225.6kg/day$$

Expected captured solids:

225 kg/day (dry basis)

Equivalent wet solids:

600–800 kg/day

(70–75% moisture)

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12. Expected Performance

Parameter	Inlet	Removal	Outlet
BOD	2000	10%	1800
COD	5000	10%	4500
TSS	1805	25%	1354
Oil & Grease	400	5%	380

Matches your process assumptions.

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