Water treatment chemicals: Emissions
Why a polymer weighs far more on the climate than alum
What this tab covers The greenhouse-gas footprint per tonne, split by lifecycle phase (feedstock, production, movement, use, end of life), the global total, other environmental impacts, levers and low-carbon routes, India's position, and where the investment opportunity lies. Emission intensity 1.00 t CO2e per t range 0.3-4.8 (iron sulphate 0.29, alum 0.79, 40% ferric chloride 1.44, polyacrylamide about 4.8) · indicative family value weighted towards coagulants, which dominate tonnage; per-product factors from AusLCI and CarbonfactPer t of product, cradle-to-gate. Intensity: Tushar et al., Water 18, 472 (2026), Table 4; Carbonfact polyacrylamide average 4.76 kg CO2e/kg (indicative). Global total: not published.
Share of footprint by lifecycle phase
Feedstock 60% Production / process 30% Movement 10%Footprint by lifecycle phase
| Phase | Intensity | Share | Main sources of emissions | Notes | Source |
|---|---|---|---|---|---|
| Feedstock | about 0.6 t CO2e per t (indicative) | 60% | acrylonitrile (propylene and ammonia), chlor-alkali electricity behind HCl and chlorine, alumina refining | polymers are far more carbon-intensive per tonne than coagulants | indicative, based on per-product factors above |
| Production / process | about 0.3 t CO2e per t (indicative) | 30% | heat for dissolution and polymer drying; electricity | powder polymer drying is energy-intensive | indicative |
| Movement | about 0.1 t CO2e per t (indicative) | 10% | road haulage of liquid products that are mostly water | transport was about 1.5% of an Australian treatment plant's footprint, where electricity was 59% and ferric chloride 31% | Tushar et al. 2026 |
| Use | not applicable as direct emissions | – | chemicals are consumed in water; the larger footprint is treatment-plant electricity | chemicals were about 39% of one industrial plant's CO2e per m3 (Tushar et al. 2026) | Tushar et al. 2026 |
| End of life | not published | – | coagulant and polymer end up in sludge that is landfilled, incinerated or spread on land | polymer carbon is released if sludge is incinerated | indicative |
Other environmental impacts
Aluminium and acrylamide residuals in drinking water; disinfection by-products; phosphonate and biocide discharge to rivers; added salinity in treated water; extra sludge volume.
Levers to cut emissions
- Dose optimisation with online sensors and digital dosing, which can cut chemical use (savings vary by site, not published)
- Coagulants from waste acids and by-product iron chloride (TiO2, steel pickling) instead of virgin inputs
- Bio-based flocculants and coagulants (tannins, starch, chitosan); Kemira's renewable solutions revenue was EUR 240 million in 2024 with a target over EUR 500 million by 2030 (Kemira AGM 2025)
- Renewable power for chlor-alkali and polymer plants; Kemira targets a 51.23% cut in scope 1 and 2 emissions by 2030 from 2018 (Kemira AGM 2025)
India
India's footprint is not published. Growth in reuse and zero liquid discharge will raise chemical and power use per m3; domestic coagulants from chlor-alkali by-product HCl are lower-carbon than imported polymers (indicative).
Emission figures are indicative global averages from the life-cycle studies named; actual footprints vary widely by site, energy mix and method.Low-carbon routes
| Route | Intensity | Cost premium | Status | Source |
|---|---|---|---|---|
| Bio-based polymers and coagulants (tannin, starch and chitosan derivatives) | not published | not published; generally higher than polyacrylamide (indicative) | commercial in niche uses; Kemira renewable solutions EUR 240 million revenue (2024) | Kemira AGM 2025 |
| On-site electrochlorination and electrochemical peroxide | depends on grid | not published | commercial for disinfection at plant scale | hydrogen peroxide tile (indicative) |