Baihuipu Applies Advanced Oxidation for Refractory COD

Baihuipu has applied advanced oxidation to refractory COD at a chemical park wastewater plant, where the biological stage was meeting its ammonia target but stalling on the persistent organic fraction that no amount of extra retention would remove. The ozone and Fenton units were added in a shutdown window and commissioned in August. They treat the biologically stable effluent at 50 m3/h, and cut the residual COD by 40 to 60 percent depending on the feed, which took the plant from just over the limit to comfortably under it without expanding the biotreatment. The choice was between ozone for the steadier fraction and Fenton for the shock loads, and the plant runs both in series so each handles the duty it does best.

Key Features and Benefits

Why Biology Hits a Wall on Refractory COD

Biodegradation needs a molecule the microbes can metabolize, and many industrial organics are too stable or too toxic to be eaten at treatment concentrations. Once the easy carbon is gone, extra retention time and more biomass only nudge the residual COD, which is why plants with this profile sit just above the limit no matter how the biotank is tuned. If your site also runs this kind of duty, Baihuipu Expands Overseas After-Sales Spare Parts Service covers the cost side of the decision in more depth.

We set out the wider process route in petrochemical wastewater treatment.

Advanced oxidation breaks those stable molecules by generating hydroxyl radicals, the strongest practical oxidant in water treatment. The radicals attack the ring structures and long chains that biology ignores, converting them into smaller, more biodegradable fragments or mineralizing them outright. We have written about the downstream implications separately in Baihuipu Completes FGD Wastewater ZLD Retrofit system.

Ozone for the Steady Load, Fenton for the Spikes

Ozone is clean and leaves no sludge, so it carries the baseline refractory load through a contact column with a catalyst bed that keeps the dose efficient. Fenton, which mixes iron and hydrogen peroxide, is dirtier but faster and tolerant of swings, so it is staged for the batch discharges and shock COD the park sends on bad days. Much of this mirrors the situation set out in baihuipu delivers brackish water ro system to industrial park.

Running them in series rather than alone lets each operate in its sweet spot: ozone trims the steady tail, Fenton absorbs the spikes. The result is a more stable final COD than either process would deliver on its own, and a lower chemical bill than oversizing Fenton for the peak.

Dosing Decided by the Water, Not the Brochure

The ozone dose and Fenton ratio were set from jar tests on the actual effluent, not from a generic table, because refractory COD responds differently to oxidation depending on what is in the stream. We measured COD before and after each stage during commissioning and trimmed the doses to the point where marginal cost equalled marginal removal.

The control panel modulates ozone and peroxide against an online COD surrogate so the plant does not over-dose on a clean day or under-dose on a bad one. Quarterly jar tests recheck the response as the park tenant mix changes.

Technical Specifications

Effluent COD across the advanced oxidation train during the commissioning runs:

Why Choose Baihuipu as Your Manufacturer

Choosing a manufacturer here comes down to one question: who is still accountable once the commissioning team flies home. Our answer is that we build and programme our own equipment, then stand behind it for the life of the plant.

Own Factory, Real Capacity

Tanks, skids, control panels and membrane housings are built in our own Guangdong facility. Nothing critical is subcontracted, which is why we can commit to delivery dates and hold quality across a batch instead of hoping the shop floor gets it right.

Two Decades of Field Data

Food and beverage, chemicals, electroplating, textile dyeing, mining, municipal work — we have commissioned across all of them. The useful part is not the project count, it is having seen how plants fail in year seven and designing those failures out.

Complete Units and Turnkey Plants

Whether you need a single package unit or a turnkey installation with civil works, we deliver the entire treatment scheme. Our engineering team covers process, mechanical, electrical and automation so one party owns the outcome.

Certification and Export Practice

CE marking is standard and we work to ISO 9001 procedures. Where a project calls for specific material grades, pressure vessel certification or ATEX-rated equipment, we build to that standard and ship the full documentation pack.

After the Handover

Spares for everything we install are held in stock. Remote telemetry is available on most systems, and our service engineers commission, train your operators and turn out for emergencies.

Let's Look at Your Numbers

Share your water analysis and site constraints and we will give you a straight assessment of the process route and the realistic operating cost before you commit to anything. Contact our engineers at WhatsApp: +86 13631765076, or find us at hkbhp.com.

WhatsApp: +86 13631765076

Customer FAQs

When is advanced oxidation worth adding to a wastewater plant?

When the biological stage meets ammonia and biodegradable COD targets but a persistent organic fraction keeps the final COD above limit no matter how the biotank is tuned. Oxidation pays for itself when it removes the last refractory portion without a large biotank expansion.

Is ozone or Fenton the better choice?

Neither is universally better. Ozone is clean and sludge-free for steady loads; Fenton is fast and tolerant of shock COD but produces iron sludge. Many plants run ozone for the baseline and Fenton for spikes, or pick one based on the feed profile and sludge handling capacity.

Does advanced oxidation remove ammonia?

Not effectively. Ammonia is better removed by biological nitrification or, at low levels, by selective ion exchange. Oxidation is aimed at refractory organics, and over-oxidizing for ammonia wastes reagent and can form byproducts.

What controls the cost of an oxidation stage?

Ozone cost is driven by generator efficiency and contact design; Fenton cost is hydrogen peroxide and iron, plus sludge handling. Dosing to the measured response rather than a fixed rate is the main lever, since over-dosing buys little extra removal. The operating detail behind this sits in coking wastewater treatment.

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