How To Design 50 KLD MBBR Sewage Treatment Plant

Designing a 50 KLD MBBR Sewage Treatment Plant requires proper planning, correct biological design, accurate tank sizing, and proper selection of equipment. The MBBR (Moving Bed Biofilm Reactor) process is one of the most widely used technologies for sewage treatment plants in apartments, hospitals, hotels, commercial buildings, and industries because it gives high efficiency in less space.

In this detailed article, we will explain how to design 50 KLD MBBR STP step-by-step, including flow calculation, tank size, media quantity, blower selection, pump selection, filters, sludge system, civil design, electrical system, and cost estimation.

This guide is useful for:

• STP manufacturers
• Water treatment companies
• Civil engineers
• Environmental engineers
• Pollution control consultants
• Builders & contractors
• Students

This is a complete practical design guide for 50 KLD MBBR Sewage Treatment Plant design.

What Is MBBR Technology in Sewage Treatment Plant

MBBR stands for Moving Bed Biofilm Reactor. It is a biological wastewater treatment process where plastic bio media moves inside the aeration tank. The media provides surface area for bacteria growth, and these bacteria break down organic waste present in sewage.

In MBBR technology, we do not need sludge return like ASP. The bacteria grow on media surface, so the system becomes stable and easy to maintain.

Advantages of MBBR STP:

• Compact design
• High treatment efficiency
• Low maintenance cost
• No return sludge required
• Suitable for small capacity STP
• Works well for load variation
• Easy to operate
• Less manpower required

Because of these advantages, most modern 50 KLD STP plants are designed using MBBR technology.

What Does 50 KLD STP Capacity Mean

KLD means Kilo Liter Per Day.

50 KLD means:

• 50,000 liters per day sewage flow
• 50 cubic meter per day
• 50 m³/day wastewater

For design calculation, we convert daily flow into hourly flow.

Flow per hour:

50 ÷ 24 = 2.08 m³/hr

For safety, always take higher flow.

Design flow = 2.5 m³/hr

This flow will be used to design tanks, pumps, filters, and blowers.

Typical Sewage Characteristics for STP Design

Domestic sewage normally has the following values:

For design, we take:

BOD = 250 mg/L
COD = 500 mg/L
TSS = 250 mg/L

After treatment, required values:

This quality is suitable for:

• Flushing
• Gardening
• Cooling tower
• Reuse
• Discharge as per PCB norms

Process Flow Diagram for 50 KLD MBBR STP.

Standard process flow for MBBR sewage treatment plant:

Screen Chamber → Equalization Tank → MBBR Tank → Secondary Clarifier → Filter Feed Tank → Pressure Sand Filter → Activated Carbon Filter → Treated Water Tank → Disinfection → Reuse

Detailed process steps:

1. Bar Screen Chamber
2. Oil & Grease Trap (optional)
3. Equalization Tank
4. MBBR Aeration Tank
5. Tube Settler / Clarifier
6. Filter Feed Tank
7. Pressure Sand Filter
8. Activated Carbon Filter
9. Treated Water Tank
10. Sludge Tank
11. Sludge Drying Bed

This is the most common layout for 50 KLD MBBR Sewage Treatment Plant design.

Design Criteria for 50 KLD MBBR STP

Standard design parameters:

These values are commonly used in India for STP design.

Screen Chamber Design

Purpose:

• Remove plastic
• Remove cloth
• Remove solid waste

Provide:

• Manual bar screen
• Stainless steel screen
• Chamber before EQ tank

Size:

1 m × 1 m × 1 m

Provide drain and cleaning space.

Equalization Tank Design for 50 KLD STP

Purpose of equalization tank:

• Store sewage
• Maintain constant flow
• Mix wastewater
• Prevent shock load

HRT = 8 hours

Formula:

Volume = Flow × HRT / 24

Volume = 50 × 8 / 24
= 16.6 m³

Take = 18 m³

Tank size example:

3 m × 3 m × 2 m = 18 m³

Provide:

• Air diffuser for mixing
• Transfer pump
• Level controller

Equalization tank is very important in MBBR STP.

MBBR Tank Design for 50 KLD Sewage Treatment Plant

HRT for MBBR = 6 hours

Volume = 50 × 6 / 24
= 12.5 m³

Take = 15 m³

Tank size:

3 m × 2.5 m × 2 m = 15 m³

Media filling = 50%

Media required:

15 × 50% = 7.5 m³

Use MBBR bio media:

• K1 media
• K3 media
• HDPE material
• Surface area 500 m²/m³

Provide:

• Fine bubble diffuser
• Air blower
• Media retaining screen

MBBR tank is the main treatment unit.

Secondary Clarifier Design

Purpose:

• Settle sludge
• Separate solids
• Clear water overflow

HRT = 3 hours

Volume = 50 × 3 / 24
= 6.25 m³

Take = 7 m³

Tank size:

2.5 m × 2 m × 1.5 m

Provide:

• Hopper bottom
• Sludge outlet
• Weir channel
• Overflow pipe

Clarifier improves water clarity.

Filter Feed Tank Design

Purpose:

• Store water before filters
• Provide constant flow

Volume = 5 m³

Tank size:

2 × 2 × 1.5 m

Provide:

• Filter feed pump
• Level control

Pressure Sand Filter Design for 50 KLD STP

Flow = 2.5 m³/hr

Select filter:

900 mm diameter
1500 mm height

Media:

• Gravel
• Sand

Removes:

• TSS
• Turbidity
• Suspended solids

Material:

• FRP / MS / SS

Activated Carbon Filter Design

Same size as PSF.

900 mm × 1500 mm

Removes:

• Color
• Odor
• COD
• Organic matter

Use:

• Activated carbon media
• Support gravel

PSF + ACF gives clear water.

Treated Water Tank Design

Storage = 1 day

Volume = 50 m³

Tank size example:

5 m × 5 m × 2 m

Use for:

• Flushing
• Gardening
• Cooling
• Reuse

Provide:

• Chlorine dosing
• Pump

Sludge Tank Design

Sludge generation = 1%

50 × 1% = 0.5 m³/day

Provide 3 day storage

= 1.5 m³

Tank size:

1.5 × 1.5 × 1 m

Provide:

• Sludge pump
• Sludge drying bed

Blower Selection for MBBR STP

Air required:

10 m³/hr per m³ tank

Tank = 15 m³

Air = 150 m³/hr

Select:

2 blowers

100 m³/hr each

1 working + 1 standby

Provide:

• Air header
• Diffuser line
• NRV

Pump Selection for 50 KLD STP

Provide pumps:

Capacity:

3 m³/hr

Head:

10–15 meter

Material:

• SS / CI / PVC

MBBR Media Specification

Type:

K1 / K3

Material:

HDPE

Surface area:

500 m²/m³

Media required:

7.5 m³

Good media gives good treatment.

Piping Design

Use:

• UPVC
• HDPE
• SS

Lines:

• Raw sewage
• Air line
• Sludge line
• Treated water

Provide valves:

• Ball valve
• Gate valve
• NRV

Electrical Panel Design

Include:

• Blower control
• Pump control
• Auto / manual
• Overload protection

Panel type:

MCC Panel

Provide:

• Float switch
• Timer
• Starter

Civil Construction Design

Use RCC tanks.

Provide:

• Waterproof plaster
• Epoxy coating
• 150 mm wall thickness
• 200 mm base slab

Proper civil work increases life.

Expected Output Quality from 50 KLD MBBR STP

Water can be reused safely.

Space Requirement for 50 KLD STP

Approx space:

8 m × 6 m

Compact design possible.

Underground STP also possible.

Cost of 50 KLD MBBR Sewage Treatment Plant in India

Total cost:

₹10 – ₹12 lakh

Cost depends on:

• Make
• Material
• Automation
• Brand

Common Mistakes in STP Design

Wrong EQ size
Less media
Small blower
No sludge tank
Wrong filter size

Always follow standard design.

Conclusion

Designing a 50 KLD MBBR Sewage Treatment Plant requires correct calculation of:

• Flow
• Tank size
• Media quantity
• Blower capacity
• Pump size
• Filter size
• Sludge system

MBBR STP is best for small and medium projects because it gives:

• High efficiency
• Compact size
• Low maintenance
• Stable performance

If designed properly, a 50 KLD MBBR STP can produce reusable water suitable for flushing, gardening, and cooling.

Contact V Aqua Water Treatment Company