Baihuipu Completes Zero Liquid Discharge Retrofit Project
Baihuipu has completed a zero liquid discharge retrofit for a fine chemical plant in eastern China. The project converted an existing discharge-compliant biological treatment train into a ZLD system by adding membrane concentration, evaporation and crystallization stages. Retrofit work was sequenced around the client's production calendar and completed without a single day of stopped production. Treated water is now reused in the plant's cooling circuit, and the remaining salt is discharged as a solid cake for licensed disposal.
Key Features and Benefits
Working Around a Running Plant
The main challenge was integration: the new stages had to tie into existing equalization tanks and effluent lines while the plant kept producing. Tie-ins were executed during two planned weekend windows, with prefabricated spools lifted into position and welded on site. The same selection criteria reappear in Zero Liquid Discharge for Industrial Effluent system, which is worth opening alongside this one.
We set out the wider process route in RO brine concentration.
Existing civil structures were reused where condition allowed. A structural survey confirmed the concrete clarifier walls were sound, so the membrane skids were placed on the original plinth instead of new foundations — saving both cost and schedule. Plants dealing with comparable loads face many of the same trade-offs covered in An Honest Look at the Boundary.
From Effluent to Cooling Water
Permeate from the membrane stage is polished and routed to the cooling tower make-up line. Conductivity at the reuse point holds below the value agreed in the design basis, verified during the 30-day performance test. A related discussion worth reading here is What the Numbers Actually Bind On.
Concentrate flows to the evaporation stage, where mixed salts are crystallized and dewatered by filter press. The plant's liquid discharge pipe has been decommissioned — the boundary sample point now reads zero flow.
Measured Performance
During the performance test the retrofit train handled design flow with feed COD typical of fine chemical effluent, and reuse water quality stayed inside specification across the full test period. Figures come from the client-commissioned third-party sampling, not internal estimates.
Our project records include dozens of commissioned plants with complete COD data across chemical, electroplating, food and municipal duties — evidence that the numbers quoted in proposals are measured, not modelled.
Technical Specifications
Scope and headline figures of the completed retrofit are summarized below.
| Item | Before Retrofit | After Retrofit |
|---|---|---|
| Liquid discharge | treated effluent to municipal pipe | zero liquid discharge |
| Water reuse | none | permeate to cooling tower make-up |
| Salt handling | dissolved in effluent | solid cake, licensed disposal |
| Added footprint | — | two skid rows on existing plinth |
| Production stoppage | — | 0 days (weekend tie-ins only) |
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.
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.
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.
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.
Talk to Our Engineers
Send through your raw water data and we will advise on the viable process route and realistic operating cost before you commit to anything. We can be reached on WhatsApp: +86 13631765076 or through hkbhp.com.
WhatsApp: +86 13631765076
Customer FAQs
Can an existing treatment plant be converted to zero liquid discharge?
Often yes. A structural and process survey decides what can be reused. In this project the existing biological train kept running and the ZLD stages were added around it, so the conversion cost far less than a new build.
How is the solid salt from a ZLD system handled?
Mixed salts are crystallized and dewatered by filter press into a solid cake, which goes to licensed disposal. The disposal route is confirmed with the client before commissioning so there are no surprises.
What does a ZLD retrofit cost to run per cubic metre?
Energy dominates — evaporation and pumping — followed by chemicals and sludge handling. We provide a per-cubic-metre breakdown during proposal so the client can compare it against current discharge fees.
How long does such a retrofit take?
From contract to performance test, this project ran about five months, with the site tie-ins executed in two planned weekends. Timelines depend mainly on equipment lead time and the client's production calendar. The operating detail behind this sits in after-sales service.
Readers planning similar projects often also read Cassava Starch Effluent system and MVR Evaporator Systems for High-Salinity Industrial Wastewater system for the process detail behind these systems.
