How Much Can a Factory Save by Implementing Scrap Recovery? A Cost-Benefit Calculation Guide

Introduction

"Is investing in scrap recovery equipment worth it?" The answer to this question should not be the vague "it depends" — it needs concrete numbers to support the decision. How much disposal cost is saved, how much regrind revenue is generated, how long before the equipment pays for itself — all of these critical figures should be calculated before purchasing equipment, not discovered to be disappointing after the machine arrives.

This article provides a complete calculation framework: clarifying current disposal costs, estimating regrind revenue potential, computing investment payback period, and evaluating indirect costs and benefits — illustrated with three differently scaled case examples.

Step 1: Calculate Your Current Waste Disposal Costs

Many factories have no clear picture of how much they spend annually on waste handling, because these costs are often scattered across different budget lines — charged against equipment maintenance, buried in miscellaneous purchases — rather than tracked separately.

Components of disposal cost

Waste disposal costs typically include the following items:

• Haulage service fee: the transport fee the contractor charges per load, per collection, or per month. This is the most visible component.
• Waste processing/treatment fee: for some waste types — particularly hazardous waste, mixed scrap, or low-value plastic — contractors charge an additional processing fee on top of haulage. The rate varies significantly by waste type and final disposition method (incineration or landfill). This cost is frequently overlooked.
• Container rental fee: if the contractor provides dedicated waste skips, bins, or containers, there is typically a monthly rental charge.
• In-plant labor cost: the labor hours of plant staff sorting waste and moving it to the collection area, plus the cost of using forklifts or other equipment internally. Many factories do not calculate this, but it is a real cost in human resources and equipment time.

How to calculate it

The most accurate method is to compile all disposal-related invoices and payment records from the past twelve months, total them, and divide by twelve to get monthly average disposal cost. If records are incomplete, use this estimate:

Monthly disposal cost = (average per-collection fee × collections per month) + monthly waste processing fee + monthly container rental + in-plant labor cost

In-plant labor cost estimate: total labor hours spent sorting waste per event × average hourly rate of operators (including forklift operators) × number of events per month.

Step 2: Estimate Potential Recovery Revenue

Recovery revenue comes from two directions: income from selling regrind pellets produced from the waste, and savings in virgin raw material procurement from using processed waste as re-feed in production.

Regrind sales revenue

Regrind market prices vary significantly by material, purity, color, and form (granulated particles or pelletized regrind). The following are approximate reference ranges for the Taiwan market — these fluctuate substantially, so always obtain current quotes:

• PP regrind pellets: approximately NTD 15,000–25,000/ton (virgin PP approximately NTD 25,000–35,000/ton)
• PE regrind pellets: approximately NTD 12,000–22,000/ton
• ABS regrind pellets: approximately NTD 20,000–35,000/ton
• PC regrind pellets: approximately NTD 30,000–50,000/ton

Important: these prices fluctuate with international crude oil prices and market supply and demand. Before any formal evaluation, strongly recommend obtaining actual current purchase quotes from 3–5 regrind traders or pelletizing plants before running calculations.

Basic formula for monthly regrind revenue:

Monthly regrind revenue = monthly waste volume (tons) × effective pelletizing yield × regrind pellet price (NTD/ton)

Effective pelletizing yield: the proportion of waste that becomes finished regrind pellets after granulation, washing, and pelletizing. Mixed or contaminated waste with labels or oil is typically 60–80%; clean plant edge trim can reach 90–95% or higher. The remaining proportion represents process losses (dust, moisture, contamination removal).

Virgin material savings from re-feed

If recovered waste is granulated and blended back into the production process at a set proportion, the saving is the cost of displaced virgin material:

Monthly virgin material savings = re-feed waste volume (tons) × current virgin material procurement unit price

Key consideration: re-feed proportion typically needs to be held to 10–30% (depending on product quality requirements). Exceeding this range may affect finished product physical properties and appearance (color variation, dark specks). Quality risk at different blend ratios requires separate evaluation.

Step 3: Calculate Equipment Investment and Payback Period

Complete equipment investment cost

Equipment investment is not just the purchase price. A complete initial investment cost includes:

• Equipment purchase cost: granulator, conveying equipment, dust collection unit, and other hardware.
• Installation and engineering: positioning, lifting, electrical wiring (if upgrade required), acoustic enclosure, etc. — typically 5–15% of equipment cost.
• Initial spare parts: strongly recommended to purchase a first set of spare blades, screens, and belts at the same time, to avoid equipment downtime waiting for parts.
• Annual operating cost (affects cash flow): electricity (total motor HP × operating hours × electricity rate); annual maintenance consumables (blade sharpening or replacement, screen replacement, belt replacement); additional operator and management labor.

Payback period formula

Payback period (months) = Total initial investment ÷ Monthly net cash inflow

Monthly net cash inflow = Monthly disposal cost saving + Monthly regrind revenue (or virgin material savings) − Monthly new operating costs

Three Illustrative Case Examples

(All figures are scenario simulations for illustrative purposes — use actual quotes for your own calculations.)

Case 1: Small injection molding plant (approx. 4 tons/month of scrap)

Basic conditions: primarily PP and ABS runners and rejects; material is relatively clean. Current monthly disposal cost: approximately NTD 8,000.

Equipment investment: one mid-size granulator; total investment approximately NTD 400,000.

Monthly benefit calculation:

• Monthly disposal saving: NTD 8,000
• Monthly regrind revenue: 4 tons × 90% yield × NTD 20,000/ton = NTD 72,000
• Monthly new operating cost: approximately NTD 12,000 (electricity + blade sharpening + labor)
• Monthly net cash inflow: NTD 8,000 + 72,000 − 12,000 = NTD 68,000

Payback period: NTD 400,000 ÷ NTD 68,000 ≈ 5.9 months

Case 2: Mid-size blown film plant (approx. 13 tons/month of scrap)

Basic conditions: primarily PE film edge trim and color-change purge. Current monthly disposal cost: approximately NTD 15,000.

Equipment investment: film-specific granulator/pelletizer with forced-feed design; total investment approximately NTD 730,000.

Monthly benefit calculation:

• Monthly disposal saving: NTD 15,000
• Monthly regrind revenue (PE film edge trim): assume 10 tons clean material × 85% yield × NTD 15,000/ton = NTD 127,500
• Monthly regrind revenue (color-change purge): 3 tons × 70% yield × NTD 12,000/ton (lower price due to mixed color) = NTD 25,200
• Monthly new operating cost: approximately NTD 20,000 (electricity + consumables + labor)
• Monthly net cash inflow: NTD 15,000 + 127,500 + 25,200 − 20,000 = NTD 147,700

Payback period: NTD 730,000 ÷ NTD 147,700 ≈ 4.9 months

Note: PE film is bulky and low-density. Without a forced-feed design, it genuinely cannot enter a standard pelletizer — forced-feed is a critical equipment specification for this application. See: How to Granulate Plastic Film and Flexible Materials.

Case 3: Large-scale recycling processing plant (50 tons/month throughput)

Basic conditions: purchasing mixed plastic scrap; requires sorting, washing, and pelletizing. Currently fully outsourced; monthly processing cost approximately NTD 80,000.

Equipment investment: complete recovery line (shredder, granulator, washer, pelletizer); total investment approximately NTD 3,950,000.

Monthly benefit calculation:

• Monthly outsourcing cost saving: NTD 80,000
• Monthly regrind revenue: 50 tons × 70% effective recovery rate × NTD 18,000/ton = NTD 630,000
• Monthly new operating cost (electricity + consumables + 3 operators): approximately NTD 120,000
• Monthly net cash inflow: NTD 80,000 + 630,000 − 120,000 = NTD 590,000

Payback period: NTD 3,950,000 ÷ NTD 590,000 ≈ 6.7 months

Key assumptions: stable scrap supply and stable regrind buyers. If either condition is not met, the actual payback period will be substantially longer.

Indirect Costs and Benefits

The calculations above cover only direct financial figures. Scrap recovery also has several indirect benefits and costs worth evaluating.

Indirect benefits

• Storage space freed up: immediate granulation and volume reduction substantially reduces floor area needed for scrap staging. The space released has real value for production or warehousing.
• ESG and supply-chain scoring: higher waste recovery rates and regrind use percentages are concrete positive factors in ESG reports and brand customer supply-chain audits. See: What Is a Circular Economy? and Plastic Regrind vs. Virgin Resin for context.
• Hedge against raw material price volatility: building in-house recovery capability is equivalent to creating an internal raw material buffer — when virgin material prices spike, increasing the regrind blend ratio can help absorb cost pressure.

Indirect costs and risks

• Increased management complexity: waste classification management, daily equipment maintenance, and consumable inventory management all require management labor — this cost should not be ignored.
• Quality risk: if granulated output is insufficiently clean or contains foreign material, re-feeding it to process may increase reject rates. Establishing rigorous incoming material classification and quality control is necessary.
• Equipment downtime risk: during maintenance or breakdown, scrap cannot be processed and accumulates — emergency outsourced disposal may still be needed. Preventive maintenance and spare parts management minimizes this risk.

Conclusion

The financial benefit calculation for scrap recovery is not complicated, but arriving at a realistic payback period requires including all relevant figures: the complete disposal cost, conservative regrind revenue estimates, comprehensive equipment operating costs, and the important indirect benefits and risks.

The three cases show that, with stable scrap supply and confirmed outlets, the payback period for recovery equipment investment can typically be achieved within one year. Before running your own calculation, confirm two core assumptions:

1. Is the waste volume stable? It cannot be intermittent — it must be continuous and predictable output.
2. Is the regrind outlet confirmed? Is it for internal re-use, or have you already identified buyers willing to purchase long-term? Never buy equipment and then start looking for customers afterward.

The answers to these two questions ultimately determine whether the calculated numbers will actually be realized.