Wastewater isn’t usually the first thing people think about when they picture an ice cream factory, but for many food and beverage manufacturers, it’s one of the toughest parts of the job. Behind every pint or popsicle is a messy mix that makes treating wastewater complicated, expensive and tightly regulated.

Traditional metal-based chemical treatments can work, but they often lead to other problems, such as unstable water pH or heavy sludge that clogs downstream systems. With tightening environmental rules regarding metal-based chemicals and sustainability targets looming, more companies are looking for better answers.

That was the case for one Spanish ice cream manufacturer, juggling compliance demands while looking for a way to simplify and improve its treatment process.

What Led to Exploring New Treatment Options

For years, the ice cream producer had been using aluminum-based coagulants and caustic soda to control pH during the dissolved air flotation (DAF) stage of wastewater treatment. It worked well enough but was unstable and challenging.

The treatment was highly sensitive to pH fluctuations, which meant operators had to constantly adjust with large doses of caustic soda, up to 1.5 liters per cubic meter. That alone pushed the system’s conductivity well beyond legal discharge limits, sometimes spiking 6,000 µS above threshold. At the same time, the process generated high volumes of oily sludge and triggered performance issues in downstream biological treatment.

And the financial impact was great. Treating each cubic meter cost €1.48 (about $1.60), and with 275,000 cubic meters processed every year, the expense added up quickly.

Unlike other parts of the process, there wasn’t much buffer here. Variations in the incoming wastewater often forced operators to adjust chemical levels on the fly to avoid compliance issues.

A Shift to Plant-Based: What That Actually Looks Like

Looking for a more stable, cost-effective and sustainable approach, the manufacturer turned to Veolia Water Technologies. After reviewing the site conditions, Veolia’s team proposed switching from poly aluminium chloride (PAC) to a Hydrex plant-based coagulant.

Unlike traditional metal-based coagulants, the plant-based version is made from renewable raw materials and is well-suited for the oily effluent commonly produced in food and beverage facilities. Operating at a lower dose rate, these solutions minimize impact on water pH, reducing or eliminating the need for caustic soda while cutting sludge volume by up to 50%.

Veolia ran a series of jar tests and field trials to see how the plant-based coagulant would perform. The results were strong enough that the manufacturer felt confident moving forward. The team initially expected to use around 100 tons per year but once they adjusted the dosage to 175 ppm, actual use dropped closer to 40 tons per year.

Measurable Results, Real Payoff

Switching to the Hydrex plant-based coagulant brought meaningful improvements to the treatment process. Chemical costs dropped by 40% as PAC dosage fell from 1,000 ppm to 300 ppm, and caustic soda use decreased just as sharply. Factoring in the lower price per cubic meter, the change is projected to save €80,000 (about $86,500) annually.

Discharge quality also improved as conductivity, an important compliance metric, fell from 6,000-7,000 µS to 4,500 µS – comfortably within legal limits. The DAF unit started producing less oily sludge, which made things easier for the downstream biological treatment and cut down on overall waste handling and associated carbon emissions.

Despite these changes, treatment performance remained strong. Hydrex 67991 achieved comparable or better results than PAC, cutting chemical oxygen demand (COD) by 50% and total suspended solids (TSS) by 85-95%. Operations became more stable overall, with the process proving less sensitive to pH fluctuations and requiring fewer adjustments.

Looking Ahead

Many food and beverage manufacturers face the same wastewater challenges – unpredictable effluent loads, rising chemical costs and stricter discharge regulations. While metal-based coagulants can be effective in many applications, some situations may benefit from alternative solutions, particularly when dealing with pH stability or specific compliance requirements.

Changing out a single chemical made more of a difference than expected. The treatment process became more stable, the plant used fewer materials and the discharge readings started landing where they needed to be.

And while the decision was driven by operational needs, the sustainability benefits weren’t lost in the process. Using a renewable, less toxic material supports broader ESG goals and reflects the direction the industry is already moving toward. Consumers are paying attention. Regulators are demanding more. And manufacturers that align day-to-day decisions with long-term responsibility are better positioned to succeed.