Baihuipu Treats Coking Wastewater for a Steel Complex
Baihuipu has treated coking wastewater for a steel complex in north China, where the byproduct coke ovens produce a stream dense with phenol, ammonia and cyanide that few biological plants will accept without pretreatment. The train was commissioned in June and handles 80 m3/h of crude coke-oven liquor. Ammonia stripping lifts the ammonia from over 2,500 mg/L, a selected biological stage degrades the phenol and thiocyanate, and a final oxidation polishes the refractory tail, taking phenol from around 300 mg/L to below 0.5 mg/L and cyanide to non-detect. The complex needed the water below the consent to keep the ovens running through the summer, and the reuse of stripped ammonia liquor in the quenching circuit closed part of the water loop.
Key Features and Benefits
Strip the Ammonia Before the Biology
Coking liquor carries ammonia at concentrations that would poison a biological stage outright, so a packed-column steam stripper pulls it out first, lifting the liquor from over 2,500 mg/L ammonia to a few hundred before it reaches the bugs. The stripped ammonia is recovered as ammonium sulphate or routed to the quenching circuit rather than vented. The process logic sits close to what is described in Water Reuse and Zero Liquid Discharge at Agrochemical Sites, particularly on the pretreatment side. We set out the wider process route in dye printing wastewater decolorization.
Stripping is energy-intensive, so the column was tuned to the actual ammonia load rather than a worst-case rating, and the waste heat from the ovens offsets part of the steam demand. That kept the operating cost within the budget the complex approved. If your site also runs this kind of duty, baihuipu expands evaporation crystallization production covers the cost side of the decision in more depth.
A Culture That Eats Phenol and Thiocyanate
After stripping, the liquor still holds phenol and thiocyanate, both toxic but biodegradable by a selected culture acclimated to coke-oven chemistry. The biological stage runs anoxic and aerobic zones so the thiocyanate and cyanides are broken down alongside the phenol, and the acclimation was carried through commissioning so the biomass did not wash out on the first real feed. The process logic sits close to what is described in Baihuipu Showcases Water Treatment Systems at Industry Expo system, particularly on the pretreatment side.
Numbers from Comparable Installations
One reference point: a 10 m³/day installation we delivered in Shijiazhuang, Hebei (2022) was treating feed at roughly 1,750 mg/L COD and holding discharge near 90 mg/L, about 94.9% removal.
| Location | Year | Flow | Feed COD | Treated COD | Removal |
|---|---|---|---|---|---|
| Shijiazhuang, Hebei | 2022 | 10 m³/d | 1,750 mg/L | 90 mg/L | 94.9% |
Figures are site-measured values from commissioned plants, not modelled estimates.
We held the load up gradually rather than dumping full-strength liquor on day one, because a phenol-acclimated culture still needs to be eased onto full feed. The online toxicity and respirometry checks during startup confirmed the biomass was coping before the flow was raised.
Oxidation for the Last Refractory Percent
Even after good biological removal, a refractory phenolic tail remains that the consent will not tolerate, so a final ozone or Fenton stage breaks it down to below 0.5 mg/L phenol. The oxidation is sized to the tail only, which is a fraction of the full COD, so the reagent cost stays modest.
The polished water splits between the quenching circuit and the discharge line, and the complex meters it against the oven water demand so the loop stays closed during normal operation. Quarterly jar tests recheck the oxidation dose as the coke blend changes.
Technical Specifications
Coke-oven liquor quality at key stages of the treatment train:
| Parameter | Raw Liquor | Final Treated |
|---|---|---|
| Phenol | 200 to 350 mg/L | below 0.5 mg/L |
| Ammonia nitrogen | 2,000 to 3,000 mg/L | below 50 mg/L |
| Cyanide | 20 to 40 mg/L | non-detect to below 0.2 mg/L |
| Thiocyanate | high | largely removed |
| Design flow | as produced | 80 m3/h continuous |
Why Choose Baihuipu as Your Manufacturer
Picking a supplier for this kind of plant is mostly about who carries the risk when something goes wrong. We have built this equipment for more than twenty years, and we are the ones who fabricated it, programmed the controls and will still answer the phone three years from now.
In-House Fabrication
Our Guangdong works produces everything from standard modular units to fully bespoke lines. Building in-house keeps cost, schedule and quality under our own control rather than a subcontractor's goodwill.
Experience Built the Hard Way
Since the early 2000s we have commissioned plants for food and beverage processors, chemical works, electroplaters, textile mills, mines and municipalities. The lessons that stick are scaling, fouling and sludge handling — those inform every design we issue.
Twenty-Plus Export Markets
We have shipped to the United States, Canada, Russia, Indonesia, India, Nigeria and Vietnam among others. Crating, export documentation and certificates are handled in-house, which keeps customs surprises to a minimum.
Complete System Responsibility
One supplier, one process guarantee. We take the plant from preliminary screening through to membrane separation, evaporation and brine management, with process, mechanical, electrical and controls engineering handled internally.
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.
Documentation You Can Actually Audit
Each system ships with as-built drawings, material certificates, welding records and a functional specification. If a client's own consultant wants to review the process calculation basis, we hand it over rather than treating it as proprietary.
Spares, Service and Commissioning
Membranes, dosing pumps, diffusers, instrumentation and blowers are stocked for the systems we sell. Our control systems support remote diagnostics, and we can put an engineer on site for commissioning, training or an unplanned shutdown.
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
Why does coking wastewater need ammonia stripping first?
The liquor carries ammonia at thousands of mg/L, far above what biological treatment can tolerate. Stripping removes the bulk of it before the biology, recovering the ammonia for reuse and protecting the biomass from inhibition.
Is coking wastewater biodegradable?
Yes for phenol and thiocyanate, but only by a culture acclimated to coke-oven chemistry and only after ammonia and cyanide are brought down. A generic seed would stall or wash out on the raw liquor.
What is the final oxidation stage for?
It removes the last refractory phenolic tail that biology cannot, taking phenol below 0.5 mg/L to meet a tight consent. It is sized to the tail only, so the reagent cost stays small relative to the whole stream.
Can the treated water be reused?
Part of it returns to the coke quenching circuit, which closes a portion of the water loop. The remainder meets discharge. Reuse is balanced against the oven water demand and metered weekly. The operating detail behind this sits in pesticide wastewater treatment.
Readers planning similar projects often also read Baihuipu Commissions Food Wastewater Anaerobic Reactor for the process detail behind these systems.
