There were concerns with microbial issues that surfaced periodically in the water treatment system. The water quality met all specifications, but servicing of the system was getting more critical. Lastly, there were also concerns with how various plant operations conformed to regulatory guidelines.
Municipal and plant data was confirmed relative to BOD/COD loading and volumes discharged. The plant was discharging a safe and easy-to-treat wastewater, which posed little concern to a municipal authority. Surcharges were weighed heavily toward strength of waste (BOD5), and an alternative was identified to pre-treat the wastewater for a 50 percent reduction in BOD5 before discharge. Other options included changing plant procedures for using heat exchange waters and disposing of solids.
Stainless steel carbon purifiers were to replace existing units that would not allow steam vapor sanitizing/stripping or hot water sanitizing. It is critical that granular activated carbon be in a vessel that allows easy-to-perform steam stripping of VOCs and hot water sanitizing so that an effective protocol can be developed to control microbes and reduce the buildup of organic contaminants.
The plant was well managed and in compliance with the regulation identified. Changes were initiated, but most were cosmetic and addressed storm water runoff.
Case Study 3
A large beverage plant in South America with six production lines was using coagulation water treatment technology and anaerobic wastewater treatment. The plant, which had an extensive sugar treatment process, was also using water softening for water used in heat exchange equipment and for rinsing requirements.
- Drawings (plant, plant site and function), operating data and laboratory results should be reviewed before starting an audit.
- Always get a complete water analysis (organic and inorganic) before starting the audit.
- On-site testing, particularly microbial, is critical to most water audits.
- Recommended actions should always improve plant operation and performance.
- Do not rule out avoiding a major investment in water or wastewater treatment systems as a result of a proactive audit.
- By doing the work described above in advance, an effective audit can usually be accomplished in two to three days, depending on the objectives.
- Whether by audit, survey, study or experience, never buy or select water treatment technology without a thorough understanding of the following.
- Water source or sources (multiple “sources” has become common).
- Water quality and volume needs for the various plant functions.
- The impact the technology selected will have on sewer surcharges and regulatory compliance.
- All investment and anticipated operating costs, and quick availability of support and services.
The Plant had Six Issues
The cost of water was extremely high; therefore, a reduction in water consumption was critical. In addition, the surface water supply posed a quality and safety threat to the plant.
There was too great a volume of wastewater to the existing anaerobic wastewater plant, necessitating a multi-million-dollar expansion of the system.
The plant was concerned with the quality and inconsistency of the incoming water supply, despite having a complete treatment plant for product water.
The plant needed to verify the risk-free status of the sugar treatment process (hot carbon) and make sure that the bottle-washing operation was delivering a clean and completely sanitary bottle.
The use of paper labels was fouling the bottle washing solutions, requiring frequent dumping of the caustic baths. These caustic solutions were as high as 3.5 percent sodium hydroxide, with additives for chelating and sequestering purposes. This created a huge impact on operating costs and a potential quality issue.
Dumping of caustic solutions was adversely affecting the anaerobic wastewater treatment plant despite neutralization. The plant was concerned with how the operation conformed to regulatory guidelines in a number of areas.
The audit confirmed that plant efforts to minimize unnecessary usage had been highly successful, and most processing systems were operating as designed because of a number of improvements contributed by the plant engineering and maintenance staffs.