Plastic Flotation Sorting

The ask

Build micro-scale flotation-sorting stations — essentially structured water-bath tanks with agitation — that upgrade mixed plastic waste into separated resin-type streams (PET, HDPE, PP, PS) saleable to Bangladeshi recyclers at a significant premium over mixed bales.

Why now

Bangladesh imports significant virgin resin while sitting on 3 000 tonnes/day of mixed plastic waste that is largely unsorted and therefore low-value. Flotation separation is proven industrial technology adapted from mineral processing; the unit cost per station has fallen to the point where it can be installed in a 200 m² shed for under ৳10 lakh. Recycler gate prices for clean separated-resin feedstock are 40–80 % higher than mixed bales, creating an obvious arbitrage.

Why Bangladesh

Dhaka and Chittagong informal waste-pickers collect roughly 1 000 tonnes of plastic per day but sell into aggregators who pay low mixed-bale prices because they lack sorting infrastructure. A flotation station inserted between picker networks and recyclers captures the sorting margin. Bangladesh's garment sector creates a concentrated, somewhat consistent plastic waste stream (stretch wrap, strapping, soft packaging) that is ideal for this technology.

As a business

The station operator buys mixed plastic at ৳6–8/kg and sells separated streams at ৳12–20/kg depending on resin type; the spread is the margin. A single station processing 3 tonnes/day at ৳5/kg net margin generates roughly ৳45 lakh per year in profit on ৳8–10 lakh of equipment. Scaling is modular — each station is an identical unit; a hub of 5–10 stations run by a district franchise captures a city-level market.

Economics

Move the sliders to model your own flotation sorting station. Defaults are order-of-magnitude estimates — pressure-testing them is part of what a founder pitches us.

What ZEPH would back

A founder running a live station with 30 days of throughput data — buy price, sort yield, sell price, water consumption — and relationships with at least two recycler buyers. We will fund a 5-station cluster as a first institutional cheque, with rollout capital staged against proven per-station economics.

Impact

A flotation station processing 3,000 kg/day upgrades mixed plastic at ~৳7/kg to sorted resin worth ~৳15/kg, unlocking 40–80% more value from the same waste stream and making downstream recycling economically viable. Each tonne of sorted plastic that displaces virgin resin avoids roughly 2–3 t CO₂e; at 300 operating days the default station avoids ~2,700 t CO₂e/year. Bangladesh loses foreign exchange on virgin resin imports estimated at $600 million/year — every tonne of quality recyclate substituted saves roughly $1,000–1,200 in import cost. Sorting stations also create skilled technical roles that upgrade informal waste pickers along the value chain.