Rice Noodle and Vermicelli Production Wastewater Treatment: Soak, Mill and the Starch Water
A rice noodle plant soaks the rice, mills it wet into a slurry, sometimes ferments it, steams or boils the sheet into noodles, cools them and washes them before packing. The water it leaves is a starch effluent with a fermentation attached where the plant runs a sour line. Rice soaking water is acidic, white and loaded with the starch the grain released. Wet milling adds the fine rice solids. Fermentation liquor is acidic and smells. Cooking and cooling water carry the surface starch that comes off the finished noodle. The effluent is starchy, it settles fast if it is left alone, and the design that works recovers the starch first and treats only what is left.
Where the Water Comes From
Rice soaking water is the largest stream by volume and the strongest by load. It is acidic, white with starch, and it carries the dissolved and fine solids the grain released during the soak.
Wet milling adds the rice milk itself. Where the mill is rinsed between batches, the rinse water is a concentrated slurry rather than a dilute one. Plants dealing with comparable loads face many of the same trade-offs covered in Butter Churnery Wastewater Treatment.
Fermentation liquor, on plants that run a sour or fermented noodle line, is acidic and smells of lactic acid. It is a small volume with a strong character.
Cooking, cooling and final wash water carry the surface starch that comes off the finished noodle. It is the stream that sets the residual load after recovery.
Starch Recovery First
Starch settles. A simple settling or screening step at the drain recovers most of the solids load before it ever reaches the treatment plant, and the recovered starch has a market in most regions.
The soak water is the richest fraction. Drained, settled and decanted, it yields a wet starch that is sold or returned to the process, and the plant removes most of its organic problem at the source.
Where the site has no starch market, the recovered solids still reduce the load on the biological stage. Transporting wet starch is cheaper than treating dissolved starch. Where several streams need joint treatment, Cultures, Whey and the Cold Ferment is the more detailed reference.
The starch that escapes recovery is the fraction the biology actually sees. Sizing the biological stage on the recovered figure rather than the raw figure is what keeps the operating cost sane.
Soak water is acidic, and the acidity is the reason traditional processes use it at all. It is also the reason a plant that dumps it into a combined tank without control will see its pH swing every time the soak tanks are drained.
What This Looks Like in Practice
We commissioned a 60 m³/day plant for this duty in Foshan, Guangdong back in 2021. Feed COD came in around 2,000 mg/L and left at 90 mg/L — 95.5% removal.
A second unit of the same class, delivered in Hong'an, Hubei during 2021, ran 150 m³/day at 1,961 mg/L feed COD down to 200 mg/L.
| Location | Year | Flow | Feed COD | Treated COD | Removal |
|---|---|---|---|---|---|
| Foshan, Guangdong | 2021 | 60 m³/d | 2,000 mg/L | 90 mg/L | 95.5% |
| Hong'an, Hubei | 2021 | 150 m³/d | 1,961 mg/L | 200 mg/L | 89.8% |
Figures are site-measured values from commissioned plants, not modelled estimates.
Where the plant ferments, the soak water is the culture medium and the fermentation liquor is the strongest fraction. It is segregated and either treated separately or metered into the combined stream.
The odour from soak and fermentation water is a lactic sourness rather than a sulphurous one. Covered tanks and short retention times handle it without special equipment.
Solids that are not recovered settle in the channels. Channels that are not cleaned become anaerobic, and an anaerobic channel is a smell complaint waiting for a warm week. Plants dealing with comparable loads face many of the same trade-offs covered in kombucha production wastewater treatment.
Cooking and Cooling Water
Cooking and cooling water is warm and carries the surface starch. It is the stream that most plants underestimate, because it arrives dilute but continuous.
Heat from the cooking water is recoverable. A simple heat exchanger on the continuous cook line pays for itself in the steam it saves, and it protects the biology from a warm slug.
The final wash water is the cleanest stream of the plant. Where the site recycles it, the fresh water demand drops measurably and the equalisation tank sees a smoother flow.
Recycling inside the plant is not the same as treating to discharge standard. Wash water can be reused on the wash step long before it could be reused anywhere else. Where several streams need joint treatment, Rice Wash, Lees and the Press Water is the more detailed reference.
Operating Notes
Recover the starch before treating anything. The settling pond is cheaper than the biological stage, and the starch has a price.
Control the soak water acidity at the equalisation inlet. A pH swing is a slow way to kill a biomass.
Size the biology on the residual load after recovery, not on the raw soak water. The difference is usually a factor of three.
Combining Treatment Stages
Where several streams need joint treatment, Energy Drink Production effluent is the more detailed reference. Most facilities do not run a single clean stream, and a shared equalisation and biological stage is usually the economical answer once the streams are chemically compatible.
Why Choose Baihuipu as Your Manufacturer
Two decades in this industry teaches you that most treatment problems are procurement problems in disguise. Someone bought the cheapest skid, nobody checked the equalisation volume, and eighteen months on the plant cannot hold its consent limit. We build differently.
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.
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.
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.
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
Frequently Asked Questions
Can you work with our existing equipment?
Often yes. We regularly integrate into existing civil structures where the concrete is sound, replacing internals and controls rather than starting over. We will tell you honestly when legacy kit is beyond economic repair.
What happens if the incoming rice noodle production load exceeds the design figure?
Load swings are the most common reason plants underperform. We set the design envelope from your worst-case samples, not your average ones, and specify enough buffer in the biological stage to ride out shocks. If your process genuinely shifts up permanently, we can usually add capacity in stages.
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.
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.
How long does a rice noodle production system take to deliver?
Standard units ship in about 11 to 12 weeks. Custom trains with starch recovery first included run longer — plan for 17 to 25 weeks once detailed engineering starts. Site installation and wet commissioning add another few weeks.
What information do you need to quote?
Water analysis for your worst-case stream, peak and average flows, discharge limits, available footprint and utilities. If you do not have a full analysis yet, we can start from a partial one and flag the gaps.
