Challenged by low-volume, high concentration wastewater
The primary operation at the Fresno facility is manufacture of carbonated and non-carbonated beverages in bottles and cans, but PepsiCo also has crushing operations to handle plant waste and market returns of out-of-date products. The incoming crusher wastewater includes a diverse and variable array of different beverage products including sodas, energy drinks, teas and ready-to-drink coffee.
Aquacycl’s BETT system
The BETT system is the only technology for treatment of such highly concentrated organic wastewaters without dilution. The system operates with very low power consumption, and generates direct electricity, mitigating greenhouse gases that would otherwise be generated by use of conventional approaches.
The BETT systems use natural bacteria to clean the wastewater, reduce sludge and produce direct electricity (no methane). Locally sourced bacteria break down organic matter in the wastewater and release electrons during their natural process of respiration. The released electrons are captured as direct current and can be used to offset the power consumption of the system. Higher electrical currents enable faster treatment rates due to enhanced microbial respiration, resulting in treatment rates in hours instead of the days or weeks required by other anaerobic processes. The generated electrical current also enables remote, real-time monitoring of system performance and offsite troubleshooting capabilities. The system is provided as a service, which includes all monitoring, maintenance and sludge management, providing hands-off operations for the customer.
Validating the technology
Aquacycl and PepsiCo installed a demonstration project to validate the business case for using BETT to treat wastewater. The system was equipped to treat half the volume during the demonstration stage and was validated over a seven-month period showing reliability and cost savings across a variable range of operational conditions. The first month onsite was used to start up the system, and the system was operated under continuous flow for six months thereafter.
During the demonstration period, PepsiCo and Aquacycl agreed on the following KPIs: removal of 800 pounds (lbs) Biological Oxygen Demand (BOD) per day when incoming BOD was greater than 60,000 mg/L or 85% BOD removal when BOD was lower than 60,000 mg/L. By achieving these levels, Aquacycl’s BETT system could prove cost-effective and justify expansion to treat the full volume.
During the continuous flow operation, the system demonstrated removal rates that exceeded KPIs, with BOD removal of more than 1,350 lbs/day and Total Suspended Solids (TSS) removal of up to 140 lbs/day. The system performed well under variable organic loads and wastewater compositions, with inflow BOD as high as 149,500 mg/L, which was more than twice the expected concentration.
