Baihuipu Enhances Refractory Wastewater Biodegradability
Baihuipu has enhanced refractory wastewater biodegradability at an industrial park where the biological plant was meeting ammonia but the COD limit stayed out of reach because most of the organic load was simply not edible by the biomass. The pre-treatment and bioaugmentation upgrade was commissioned in January and lifts the Biochemical Oxygen Demand to COD ratio from below 0.2 to around 0.4 across 120 m3/h of mixed industrial effluent. Hydrolysis and low-dose ozonation break the stable molecules into more degradable fragments, and a selected culture then removes the newly available COD, taking the final COD under the consent without expanding the biotanks. The park avoided a costly biotank expansion by making the existing biology actually able to eat the water.
Key Features and Benefits
Measure the Ratio Before You Spend Money
The BOD to COD ratio tells you how much of the organic load biology can realistically remove, and a ratio below about 0.2 means most of the COD is refractory. We measured it on the actual mixed effluent before proposing anything, because the right fix for a low ratio is pre-treatment to raise it, not a bigger biotank that still cannot eat the water. The process logic sits close to what is described in Sandblasting Underway at Baihuipu Qinzhou Chemical Project, particularly on the pretreatment side. We set out the wider process route in landfill leachate treatment.
The park had been asked to double its biotank volume, which would not have helped because the bottleneck was feed quality, not retention. Raising the ratio with pre-treatment let the existing tanks do the job. The process logic sits close to what is described in Baihuipu Publishes Desalination Energy Cost Benchmark, particularly on the pretreatment side.
Break the Molecules So Biology Can Eat Them
Hydrolysis under controlled pH and a low ozonation dose crack the stable ring and chain structures into smaller fragments with more accessible carbon, lifting the ratio without the cost of full oxidation. The aim is to make the COD biodegradable, not to mineralize it, which is the cheaper target. Much of this mirrors the situation set out in Baihuipu Upgrades Integrated MBR Sewage Treatment Unit.
The pre-treatment dose was set from batch tests on the mixed effluent so the ozone and chemical spend bought the most ratio gain per unit cost. Over-dosing would have oxidized carbon the biology could have removed for free.
A Culture Matched to the New Feed
Once the feed is more degradable, a culture selected for the park mixture removes the newly available COD at a rate the old seed could not, and the bioaugmentation kept the reactor stable through the tenant mix changes that used to cause upsets. Online respirometry confirmed the culture was earning the augmentation.
The upgraded train holds the final COD under consent with the original tank volume, and the park meters the BOD to COD ratio at the pre-treatment outlet so the dose tracks the feed. Quarterly jar tests recheck the ratio as tenants change.
Technical Specifications
Effluent biodegradability and COD before and after the upgrade:
| Parameter | Before Upgrade | After Upgrade |
|---|---|---|
| BOD to COD ratio | below 0.20 | around 0.40 |
| COD | above 300 mg/L | below 120 mg/L |
| Biodegradable COD | minority | majority |
| Pre-treatment | none | hydrolysis and low-dose ozone |
| Throughput | baseline | 120 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.
Manufacturing Base in Guangdong
Owned production lines mean we control tolerances, materials and delivery. Standard modular units and bespoke skids are both built by our own people, so schedule commitments are ours to keep.
20+ Years Across Dozens of Industries
Experience matters most when your waste stream behaves nothing like the textbook example. We have dealt with toxic organics, heavy metals, extreme salinity and refractory COD in food processing, chemical manufacturing, electroplating, mining and municipal projects.
We Engineer the Whole Train
Screening, equalisation, biological or chemical treatment, membranes, evaporation, brine handling — the complete line comes from one organisation. Process design, mechanical, electrical and PLC programming sit under the same roof, so there is no gap for finger-pointing at handover.
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.
Getting Started
Send us a water analysis and your production profile and we will tell you honestly what the process should look like and roughly what it costs to build and run. Reach our engineering team on WhatsApp: +86 13631765076 or via hkbhp.com.
WhatsApp: +86 13631765076
Customer FAQs
What does the BOD to COD ratio tell you?
It shows how much of the organic load biology can remove. A ratio below about 0.2 means most COD is refractory and a bigger biotank will not help; the fix is pre-treatment to raise the ratio so the existing biology can eat the water.
How do you raise refractory wastewater biodegradability?
Hydrolysis and low-dose ozonation break stable molecules into more degradable fragments, lifting the ratio without fully oxidizing the carbon. The goal is to make the COD biodegradable, which is cheaper than destroying it outright.
Is bioaugmentation necessary after pre-treatment?
Often yes. A culture selected for the specific industrial mixture removes the newly available COD more reliably than a generic seed and stays stable through feed changes that would upset an unselected biomass.
When is this better than expanding the biotank?
When the bottleneck is feed quality rather than retention time. If the ratio is low, expanding tanks adds cost without removing the refractory COD; pre-treatment and bioaugmentation let the existing tanks meet the limit. The operating detail behind this sits in leachate membrane bioreactor.
For adjacent technical angles, baihuipu signs overseas epc wastewater plant contract and Baihuipu Delivers Electroplating Heavy Metal Recovery system covers the same equipment from a different duty.
