Cost-effective distillery wastewater treatment

Sustainable water management practices are crucial to ensure the long-term viability of Sugar & Ethanol production because water is vital to the Sugar & Ethanol production process. In sugar production, water is used extensively in irrigating sugarcane fields, washing and extracting juice from the harvested cane, and in subsequent refining and crystallization stages. Similarly, in ethanol production from sugarcane, water is essential for fermentation, where yeast converts sugars into ethanol, and in distillation processes to separate ethanol from water.

However, the significant challenge lies in managing water resources sustainably to avoid straining local water supplies and the impact on water quality due to the discharge of processing effluents. Addressing these challenges requires implementing efficient irrigation practices, optimizing water use in processing plants through recycling and reuse, and adopting advanced wastewater treatment technologies to minimize environmental impact. Paques’ biotechnologies revitalize resources and make sugar and distillery wastewater treatment much more sustainable.

Distillery wastewater treatment is full of variables. The substrates vary from beet to sugarcane, from wheat to cassava or agave. Likewise, the end product can be sugar, ethanol and a variety of spirits. There are also multiple effluents from sugar & ethanol production: condensates, thin stillage, vinasse and conventional wastewater from the production process.

Paques has broad experience with a wide variety of distillery effluents due to our worldwide presence and more than 100 references in distillery water treatment & sugar industry. These include evaporator condensates, thin stillage (grain, agava and/or fruit as feedstock) and sugar cane vinasses.

• Wastewater streams from the production of (bio) ethanol or ethanol spirits are generally well suitable for anaerobic treatment as they contain organic compounds. We have pioneered anaerobic solutions that transform organic pollutants from sugar & ethanol production into valuable biogas and clean water, such as BIOPAQ^® UASB, BIOPAQ^® IC and BIOPAQ^® ICX.
• When the amount of solids in distillery water treatment is too high, we offer our CBD^® technology, which eliminates pre-treatment.
• ANAMMOX^® allows excessive nitrogen to be removed, using up to 60% less aeration energy compared to conventional systems and without the need of using an external carbon source like methanol. This can be applicable for treatment of stillage when grain is used as feedstock.
• We are also able to remove the H2S from the biogas generated by our anaerobic technologies using the THIOPAQ^® system.
• Paques has even supplied a great number of complete turnkey wastewater treatment plants to sugar & ethanol producers worldwide, combining our technologies with pre-treatment and water reuse technologies.

Recommendations per industry niche

The two most efficient processes for treating vinasse effluent, which typically contains 45,000–50,000 mg/L of COD, are:

1. First, separate the solids from the vinasse using a centrifuge. This reduces the solids content, leaving a liquid vinasse stream with less than 500 mg/L of suspended solids. Treat this liquid fraction in a BIOPAQ® ICX or BIOPAQ® UASBplus reactor, specifically designed for high volumetric loading rates. Optionally the separated solids can be mixed with filter cake and treated in a BIOPAQ® CBD reactor, which is optimized for effluents with high solids concentrations. These two technologies operate in parallel: one tailored for effluents with low solids concentrations and the other for high solids concentrations, ensuring maximum biogas production. Jose Cuervo and Patron Tequila already use this process to treat 100 tons of tequila vinasse COD per day in Mexico.

2. Alternatively, treat more concentrated vinasse, that is high in suespended solids and salts directly in our next-generation BIOPAQ® CBD reactor, which is designed for high COD, suspended materials and difficult to treat effluents that are high in salts. Optionally, filtercake can be added to the influent as well to further boost gas production, also in the off-season when no sugar cane harvesting takes place.