PONDS CAPACITY & HYDRAULIC RETENTION TIME (HRT)

Main parameters ;

• Mill throughput
• Operation hour
• Estimate effluent production - 0.8 to 1.0 t/t FFB
• Daily effluent production
• HRT = Liquor volume / Daily effluent production

Legend ;

1. d - Working depth of liquor
2. L1 - Length of pond at top water level
3. L2 - Length of pond at bottom water level
4. W1 - Width of pond at top water level
5. W2 - Width of pond at bottom water level
6. Tph - Tonne per hour of FFB process
7. t/t - Tonne per tonne

Formula used for calculating pond/liquor volume ;

V = Depth [ A + a + /A.a ] x 1/3

Where,

• V - Volume
• A - Area of pond at top water level or L1 x W1
• a - Area of pond at bottom water level or L2 x W2
• d - Working depth of water or liquor

# /A - square root of A