Single-Line Capacity Worked Example
A step-by-step worked example of the CPCB single-line capacity formula for an e-waste recycling plant — showing how a 4 TPH bottleneck stage, 20 operating hours per day, and 330 operating days per year combine to give an authorised capacity of 46,200 TPA.
| Component | Value | Role / Notes |
|---|---|---|
| A1 — Faster stage (e.g. shredder) | 5 TPH | Not the bottleneck — has spare capacity |
| A2 — Bottleneck stage (e.g. separator) | 4 TPH | Determines actual plant throughput |
| Operating Hours/Day | 20 | Max per CPCB rules (3 shifts + maintenance) |
| Operating Days/Year | 330 | Max per CPCB rules (holidays + shutdown buffer) |
| Annual Capacity | 46,200 TPA | A2 (4) × 20 × 330 — this is the SPCB authorised capacity |
Beyond definitions
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How to read this table
- Each row is one input to the formula or the formula result; columns show the component name, value, and its role in the calculation.
- The bottleneck stage (A2 at 4 TPH, highlighted in red) is the constraint that limits the entire line — it is the value used in the annual capacity formula, not the faster stage A1.
- Annual Capacity = A2 × Operating Hours × Operating Days = 4 × 20 × 330 = 46,200 TPA.
About this table
Before applying for a Consent to Operate from the SPCB, an e-waste recycling plant must calculate and declare its authorised processing capacity in Tonnes Per Annum (TPA). The CPCB formula for a single-line plant is: Annual Capacity = Bottleneck Stage Throughput (TPH) × Operating Hours per Day × Operating Days per Year. This table walks through that formula with specific numbers.
The bottleneck principle is the core concept: in any processing line with multiple stages, the throughput of the entire line is limited by the slowest stage. In the example, Stage A1 (the shredder) can process 5 tonnes per hour, but Stage A2 (the separator downstream) can only process 4 tonnes per hour. The line's actual throughput is therefore 4 TPH — feeding the shredder faster than 4 TPH just creates a queue at the separator. The bottleneck determines capacity, not the fastest stage. This is why plant designers deliberately spec equipment above the bottleneck throughput — to ensure no single piece of equipment limits the line.
The operating hours limit under CPCB rules is 20 hours per day maximum — this accounts for three production shifts with 4 hours reserved for maintenance, cleaning, and changeover. The operating days limit is 330 days per year — accounting for public holidays, planned maintenance shutdowns, and an allowance for unforeseen downtime. Applying the formula: 4 TPH × 20 hours × 330 days = 46,200 TPA. This is the capacity that would be declared in the CTO application. In practice, plant operators typically declare authorised capacity at 1.2–1.5× their planned actual production to leave regulatory headroom — declaring capacity equal to planned production means any upside is technically a consent violation.
Key insights
- Annual capacity is determined by the slowest (bottleneck) stage, not the average or the fastest — operators must identify and plan around the bottleneck when sizing equipment and declaring capacity.
- CPCB allows a maximum of 20 operating hours per day for e-waste processing — planning for 24/7 continuous operation without a maintenance window is both non-compliant and operationally impractical.
- Declaring authorised capacity at 1.2–1.5× planned actual production is standard practice — it provides regulatory headroom for processing above the planned rate without a consent violation when a good feedstock opportunity arises.
- A 1 TPH increase in the bottleneck stage throughput adds 20 × 330 = 6,600 TPA to the plant's authorised capacity — quantifying the value of debottlenecking before deciding whether to invest in upgrading the bottleneck equipment.
Methodology & sources
Operating hours (20 per day) and operating days (330 per year) are standard CPCB parameters for e-waste recycling plant capacity calculations as referenced in course materials. Actual operating parameters in CTO applications may vary by state SPCB — confirm the accepted operating parameters with your specific SPCB before filing the CTO application.
Related data tables
Capacity Ranges by Plant Type
Recommended starting capacity ranges for the four e-waste recycling plant types — mechanical (2–5 TPD), PCB (0.5–2 TPD), pyrometallurgical (1–5 TPD), and hydrometallurgical (50–500 kg/day of concentrate) — with the commercial and operational reasoning for each range.
Independent vs Dependent Lines
Five aspects comparing independent and dependent processing lines in a multi-line e-waste plant — a critical regulatory distinction where CPCB counts only independent lines toward authorised TPA capacity, and dependent lines are excluded from the capacity calculation.
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Two worked examples of the CPCB multi-line capacity formula for e-waste recycling plants — one with all-independent lines and one mixing independent and dependent lines — showing how only the independent line throughputs are summed to reach the SPCB authorised capacity.
Total Equipment Capex by Plant Type
Master capex reference for four e-waste recycling plant types — mechanical, PCB, pyrometallurgical, and hydrometallurgical — showing required equipment, indicative total machinery investment, skill profile, and ideal operator profile for each plant type.