Chlorine Dioxide Generator Selection Guide
Chlorine dioxide isn’t a chemical you buy and dose — it’s a chemical you generate on-site, on demand. That means the equipment decision and the chemistry decision are the same decision, from precursor selection through tank material to venting. I’m not going to separate them into two conversations when the vendors don’t.
30+ years spec experience. Send James the process data and get a real answer — not a catalog page.
Request a Spec Review →Most chemical feed specs separate cleanly into two steps: pick the chemistry, then pick the pump and tank to handle it. Chlorine dioxide (ClO2) doesn’t work that way. It’s too unstable to store or transport in bulk concentrated form, so it has to be produced on-site, on demand, by a dedicated generator reacting precursor chemicals together in real time. Picking a chlorine dioxide system means picking the generation chemistry, the generator model, and the downstream storage/venting materials all at once — get the chemistry wrong and the equipment choice doesn’t matter.
Two Generation Chemistries, Not One Chemical
Every on-site ClO2 generator falls into one of two precursor families, and the choice determines what you have to store, handle, and permit on-site as much as it determines the generator model:
- Acid/chlorite (diluted-chemical) process — sodium chlorite solution reacted with hydrochloric acid. Used by ProMinent’s Bello Zon CDLb, Xylem’s DIOX-A 10K, and De Nora’s T70 and OXICORE U. No chlorine gas on-site, but you’re handling and storing an acid feed.
- Gas/chlorite process — chlorine gas reacted with sodium chlorite (liquid or solid). Used by De Nora’s G50, Xylem’s DIOX-C, and CDG Environmental’s GAS:SOLID system, which reacts chlorine gas with a thermally stable solid sodium chlorite cartridge (SAF-T-CHLOR™) rather than a liquid feed — a distinct sub-variant worth knowing about if avoiding bulk liquid sodium chlorite storage matters for your site.
Real Generator Models, Capacity Ranges & Chemistry Inputs
Four manufacturers publish current, real spec data for on-site chlorine dioxide generation. Capacities span three orders of magnitude — from a single-digit-gram-per-hour Legionella unit to a 50 kg/hr municipal-scale system — so matching capacity to actual demand matters as much as matching chemistry.
| Vendor / Product Line | Capacity Range | Chemistry Input | Notes |
|---|---|---|---|
| ProMinent — Bello Zon® CDLb | 6–120 g/h (5 models: CDLb 06/12/22/55/120) | Diluted sodium chlorite + hydrochloric acid (acid/chlorite), batch process | DVGW W224/W624 compliant; buffer-tank storage to 60 g ClO2; sized to average, not peak, demand. |
| CDG Environmental — GAS:SOLID™ | GS-8 documented at 8 lb/day (one confirmed data point, not a published model range) | Chlorine gas + SAF-T-CHLOR™ thermally stable solid sodium chlorite | >99% purity guaranteed, no chlorite/chlorate/perchlorate/Cl2 in the generated product. SAF-T-CHLOR is NSF/ANSI 60 certified and EPA-FIFRA registered. |
| De Nora — Capital Controls® G50 / T70 | G50: 5–50 kg/hr (2,500 ppd); T70: 1–10 kg/hr (500 ppd) | G50 = chlorine gas + 25–31% sodium chlorite; T70 = 30–38% HCl + 25–31% sodium chlorite | All-vacuum eductor design. G50 yield >95%, T70 up to 95%. NSF61 certification called out specifically for the G50. |
| De Nora — OXICORE™ U-Type | 1–17 kg/hr (900 ppd) | 30–38% HCl + 25–31% sodium chlorite | Underwater reactor — generation happens inside the water stream itself, up to 99% practical yield. |
| Xylem — DIOX-A 10K | Up to 10 kg/h | 24.5% NaClO2 + 30–38% HCl | Reaction tank to DVGW W624. A separate, much smaller “DIOX-A 10” bench unit (10 g/h, 9% HCl/7.5% NaClO2) shares a near-identical name — do not confuse the two on a spec sheet. |
| Xylem — DIOX-C | Up to 4.5 kg/h (1,500 / 3,000 / 4,500 g/h models) | 24.5% NaClO2 + chlorine gas | Batch configuration, PLC-controlled, Cl2+ClO2 mixed mode adjustable. |
Sources: ProMinent Bello Zon product page; CDG Environmental product pages, registrations page, and Canton, MA pilot case study; De Nora Capital Controls/OXICORE brochure 150-0092; Xylem DIOX-A/DIOX-C spec sheets (WT.085.215.000 and WT.085.210.000).
Matching the Generator to the Named Application, Not Just the Flow Rate
ProMinent publishes its own performance-overview table mapping each Bello Zon model to specific real applications, rather than treating the six-model family as interchangeable. CDKd (7,500–12,000 g/h) is reserved for the largest municipal and industrial scale and isn’t listed for food and beverage use at all; CDLb is the only model named for Legionella control specifically.
| Application | Recommended Bello Zon Model(s) |
|---|---|
| Legionella control | Bello Zon CDLb (0–120 g/h, diluted HCl + NaClO2, discontinuous batch process) |
| Food & beverage | CDLb, CDLb H2SO4, CDEb, or CDVd — selected by scale |
| Municipal drinking water / wastewater | CDLb, CDEb, CDVd, or CDKd — selected by scale |
| Industrial cooling tower water | Any Bello Zon model — all 6 support this application |
Matching application to the vendor’s own table — instead of treating the family as interchangeable by capacity alone — avoids over- or under-sizing a disinfection system before it ever ships.
Linear PE or PVDF Only — Not XLPE
Once the generator is producing chlorine dioxide, the downstream storage and piping decision follows a different rule than most of the rest of a LibertyCES chemical feed spec. Peabody Engineering’s Special Application Tanks guidance groups chlorine dioxide (1.9 specific gravity) with sulfuric acid, sodium hypochlorite, and hydrogen peroxide as oxidizer chemistries it explicitly does not recommend for a cross-linked (XLPE) tank with a linear liner.
- Tank material: linear PE or PVDF, sized 5–1,300 gallons
- Gaskets: Viton and Teflon most common
- Piping & fittings: Teflon/PVDF most common
- Venting: routed to a scrubbing system — required, not optional
- Containment: double containment required
Closed-System Generation Is the Safety Case, Not a Marketing Line
Because chlorine dioxide has to be generated on demand rather than stored in bulk, the generator itself becomes the primary safety boundary. De Nora describes its OXICORE systems as reacting either underwater or under vacuum, keeping generation fully contained within the water stream itself — no on-site bulk ClO2 storage anyone has to open. ProMinent describes its Bello Zon CDLb the same way: a closed gas-transport system with no ClO2 escape, which it credits for both operator safety and long-term chemical stability.
That closed-generation design doesn’t remove the need for the downstream venting-to-scrubber and double-containment requirements above — it’s a separate layer of the same safety case, not a substitute for it.
Chlorine Dioxide Generator FAQ
Why can’t chlorine dioxide be purchased pre-made and shipped like sodium hypochlorite?
Chlorine dioxide is not stable enough to store or ship in bulk concentrated form the way sodium hypochlorite is. It has to be generated on-site, on demand, from precursor chemicals metered into a reaction chamber just before use. That single fact is what makes a chlorine dioxide project a combined chemistry-and-equipment decision from the start — you’re not choosing a pump and tank for a chemical that already exists; you’re choosing the generator that will make the chemical.
What is the difference between acid/chlorite and gas/chlorite chlorine dioxide generation?
Acid/chlorite generators (ProMinent Bello Zon CDLb, Xylem DIOX-A, De Nora T70/OXICORE U) react sodium chlorite solution with hydrochloric acid. Gas/chlorite generators (De Nora G50, Xylem DIOX-C, CDG’s GAS:SOLID system) react chlorine gas with sodium chlorite instead — CDG’s version uses a thermally stable solid sodium chlorite cartridge rather than a liquid feed. The precursor chemistry you choose determines what you have on-site (an acid delivery system vs. a chlorine gas system) as much as it determines the generator model itself.
Can a standard XLPE chemical storage tank be used for chlorine dioxide?
No. Peabody Engineering’s Special Application Tanks guidance groups chlorine dioxide with sulfuric acid, sodium hypochlorite, and hydrogen peroxide as oxidizer chemistries it explicitly does not recommend for a cross-linked (XLPE) tank with a linear liner. The correct construction is a linear PE or PVDF tank, sized 5–1,300 gallons, with Viton or Teflon gaskets and Teflon/PVDF wetted piping and fittings — the same material logic that governs the other three oxidizers in that group, not the XLPE default used elsewhere on the LibertyCES tank line.
Does an on-site chlorine dioxide generator need to vent to a scrubber?
Yes, per Peabody’s guidance for chlorine dioxide storage and generation equipment — venting routed to a scrubbing system and double containment are both required, not optional, given chlorine dioxide’s 1.9 specific gravity and oxidizer hazard profile. This is consistent with the closed-generation safety framing several generator vendors themselves emphasize: De Nora, for example, describes its OXICORE systems as reacting underwater or under vacuum to keep generation fully contained within the water stream, with no on-site ClO2 storage.
Which ProMinent Bello Zon model is right for Legionella control versus municipal water treatment?
ProMinent’s own performance table names CDLb as the only Bello Zon model listed for Legionella control specifically. Municipal drinking water and wastewater treatment draw from a wider set — CDLb, CDEb, CDVd, or CDKd — selected by scale, with CDKd (7,500–12,000 g/h) reserved for the largest municipal or industrial installations and not listed for food and beverage use at all. Matching the model to the named application on the vendor’s own table avoids over- or under-sizing the generator.
Specifying an on-site chlorine dioxide system?
Send James your target application, required capacity, and whether chlorine gas is already on-site or something you want to avoid — I’ll confirm the generation chemistry, generator model, and downstream storage material spec against your real service conditions, not a generic chart.
Ready to buy or need a fast answer? Call, text, or email James directly — (559) 395-5500 · [email protected].