AB Mauri, a division of Associated British Foods (ABF), is one of the world’s largest producers and distributors of bakery ingredients such as yeast, spices, and bread and cake mixes. AB Mauri’s holistic approach to baking includes a wide range of chemistry and technology applications in addition to its high-quality end products.
Challenge
AB Mauri was constructing a large, state-of-the-art yeast manufacturing plant in Veracruz, Mexico. The project included the need for a unique wastewater treatment facility. Sugarcane molasses used as the fermentation growth substrate for the yeast during production results in wastewater containing high concentrations of organic matter. AB Mauri needed to treat this wastewater on-site before it was discharged into the environment.
A large portion of the organic matter in the wastewater is composed of nondegradable or slow-degrading compounds, making it difficult to treat.
The wastewater at the yeast manufacturing plant also contains high concentrations of soluble and insoluble inorganic compounds such as calcium, potassium, sodium, sulfate, and chloride. This results in waste streams with high total dissolved solids (TDS) concentrations and high conductivity, which can be problematic for biological treatment.
AB Mauri needed a solution that could effectively treat this challenging wastewater in order to comply with regulated discharge requirements. Additionally, AB Mauri wanted to recover energy from the wastewater in the form of biogas to fuel the plant’s boiler.
Solution
Although yeast processing wastewater is a strong candidate for anaerobic and aerobic treatment, the use of sugarcane molasses presented particular challenges. AB Mauri entrusted ADI Systems to custom-design a wastewater treatment system that would successfully treat the effluent at its new manufacturing plant.
ADI Systems’ biological wastewater treatment solution for AB Mauri consists of an anaerobic-aerobic treatment train. This treatment train comprises of a 1,500 m3 (0.4 MG) equalization tank that equalizes wastewater flows and loads, and reduces variability in biogas production. This is followed by a 90,000 m3 (24 MG) ADI-BVF® low-rate anaerobic reactor, which treats the bulk of the organic load and converts the majority of this load into biogas.
The ADI® sequencing batch reactor (SBR), which consists of two 6,600 m3 (1.7 MG) reactor tanks, removes the remaining biochemical oxygen demand (BOD) and degradable chemical oxygen demand (COD), as well as a large portion of the nitrogen remaining in the wastewater. The last component is a 400 m3 (0.1 MG) post-equalization tank that both equalizes and stores treated effluent prior to post-treatment and/or final discharge.
Results
The treatment technology that ADI Systems designed and delivered for AB Mauri has helped the manufacturer of baker’s yeast rise above its wastewater challenge. It has allowed the company to remain environmentally compliant by reducing the organic load from its wastewater, while at the same time reducing its carbon footprint.
ADI Systems’ waste-to-energy solution also produces green energy, helping to reduce operation costs at the processing plant. Biogas generated in the anaerobic reactor provides an attractive supply of renewable energy; approximately half of the production plant’s steam requirement in one of AB Mauri’s process boilers is being met by utilizing the biogas.
