Winery Wastewater Treatment: Grape Pressings, Tank Wash and the Seasonal Harvest Peak

A winery crushes and presses grapes, ferments the juice, matures the wine and bottles it, and most of that work lands in a short annual window. The water it leaves is strongly seasonal: a low, almost clean trickle through winter and a flood of high-COD, acidic, sugary water through harvest and vintage. Grape pressings and lees are the strongest fraction. Tank and barrel washing add tartrate, sulphur dioxide and the last of the wine. Floor wash dilutes the lot. The effluent is biodegradable but arrives in bursts, and the plant that ignores the seasonality undersizes the equalisation and watches it overflow at the worst possible time.

Where the Water Comes From

Grape pressings and lees are the load that sizes the train. The pomace carries juice, skins and seeds, and the lees from the tanks carry dead yeast and tartrate — both are strong, sugary and acidic.

Tank and barrel washing follows fermentation. These streams carry wine residues, tartrate crystals and the sulphur dioxide used as a preservative, and they arrive hot from clean-in-place. Where several streams need joint treatment, Juice, Mud and the Hot Condensate Stream is the more detailed reference.

Cellar floor wash is the dilution stream. It is weak but continuous and it keeps the hydraulic load up even when nothing else is happening.

Bottling and lab rinse water are the clean end. They are low in COD and often reused in the plant, which shrinks the discharge the treatment train actually sees.

Pressings and Lees

Pressings are removed at the source wherever a market exists. Pomace goes to distilleries or compost, and taking it out of the drain removes the bulk of the seasonal COD.

Lees are the yeast-rich sediment. They are nitrogen-heavy and putrescible, so they are moved quickly rather than held, because a septic lees stream is a worse problem than a fresh one. Where several streams need joint treatment, Pulp, Pectin and the Wash-Down Slug is the more detailed reference.

The residual juice is fully biodegradable. Once the solids are out, the dissolved sugar and acid are easy biology — the difficulty is the volume and the timing, not the chemistry.

Acidity from the grape and the wine is the first thing to correct. The pH swing during vintage is wide, and the equalisation tank is sized to absorb it rather than pass it on.

Tank wash is screened for the coarse solids. Grape skins and tartrate crystals blind screens fast, so the screening is on a schedule tied to the cleaning shift.

Measured Results from Plants We Built

We commissioned a 5 m³/day plant for this duty in Taishan, Guangdong back in 2021. Feed COD came in around 1,000 mg/L and left at 50 mg/L — 95% removal.

Figures are site-measured values from commissioned plants, not modelled estimates.

Sulphur dioxide in the wash water is oxidised in the head of the plant. A small amount of air or a holding step removes it before it can inhibit the biomass.

Tartrate is recovered where the volumes justify it. The crystals have a value and removing them reduces both scaling in the pipework and the load on the biology. Much of this mirrors the situation set out in Mayonnaise and Salad Dressing Wastewater Treatment.

Floor wash is blended in. It is the steady diluent that keeps the combined stream from being too strong, and a mixed tank turns a vintage spike into a manageable average.

Seasonality and Biology

The design follows the harvest. A plant sized on the annual average will flood during vintage, and the equalisation volume is the difference between coping and overflowing.

Through the quiet months the load is light and the biology runs easily. The same plant that handles vintage has spare capacity most of the year, which is the correct trade to make.

Aerobic treatment suits this duty. The load is moderate after the pressings are removed, and a compact activated-sludge or biofilm stage brings it to consent.

Sludge is stable and settles well. It is dewatered and sent under the disposal route the local rules allow, and the volumes are modest compared with the throughput.

Operating Notes

Remove the pomace at the source. Taking pressings out of the drain removes most of the seasonal COD and pays a small credit.

Size the equalisation for vintage, not the average. The harvest spike is the event the whole plant is built around. If your site also runs this kind of duty, Evaporated and Condensed Milk Production Wastewater Treatment system covers the cost side of the decision in more depth.

Oxidise the sulphur dioxide early. It is a preservative in the wine and an inhibitor in the treatment plant.

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.

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.

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.

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.

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.

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.

Spare Parts and After-Sales Support

We carry membranes, pumps, blowers, diffusers and instruments for every system we supply. Remote support through the PLC is standard on most builds, and on-site service covers commissioning, training and urgent callouts.

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

Frequently Asked Questions

Can the plant be modified later if our production changes?

Yes, if you tell us about likely expansion up front. Leaving room in the civil works and oversizing the equalisation tank costs far less than retrofitting later. Winery Wastewater Treatment rarely fails because of bad chemistry — it usually fails because nobody planned for the second production line.

Which discharge standard will the treated water meet?

We design against whatever consent applies at your boundary — GB 8978, local sewer limits, or a ZLD target with no liquid discharge at all. The design basis is agreed in writing before fabrication, so there is no argument later about what "compliant" meant.

What treatment capacity do you normally design for winery?

Skid-mounted units cover roughly 29 to 518 m³/day depending on the duty, and parallel trains extend that further. We size against your actual peak hour flow rather than the daily average, because equalisation rarely absorbs the whole spike.

What spare parts should we hold on site?

Critical spares are pumps, dosing valves, instrumentation sensors and any specialty media. We ship a recommended spares kit with the plant and hold stock for everything we supply, so lead times on replacements stay short.

How long does a winery system take to deliver?

Standard units ship in about 10 to 13 weeks. Custom trains with pressings and lees included run longer — plan for 16 to 22 weeks once detailed engineering starts. Site installation and wet commissioning add another few weeks.

Do you handle installation and operator training?

Every unit we supply is commissioned by our own engineers. Training happens on site with your actual operators, and the O&M manual covers routine work plus troubleshooting. Remote diagnostics through the control system are included for the first year.