The cans were manufactured on 10 process lines, each with different throughputs, and different water and chemistry requirements. Production and water usage varied tremendously from day to day. No information was available as to wastewater composition over the varying production schedules. Chemical baths were dumped on varying schedules as well, which overwhelmed average water chemical composition. The origin of the levels of certain heavy metals in the wastewater was difficult to determine as it did not appear that the client was using these metals in their process.
The Interdisciplinary Approach
When Chester first came on-site, the city was fining the client for non-compliance. Chester was able to convince the city to an agreement whereby if the client had brought the facility into compliance by a certain date that the city would return the fines. The city agreed.
Chester Engineers initiated the project by having their technical team spend several weeks on site to develop a better understanding of production, water usage, and chemicals used in the manufacturing process. This included the raw aluminum billets and their chemical compositions. The technical team set up a portable lab in the clients QA/QC lab to do on-site treatability testing using several different chemistry to treat the generated wastewater under varying production and chemical dumping conditions. From developed data a wastewater solution was developed.
The project was turned over to Chester Process Engineering, and the findings of the in-plant study were converted into a wastewater treatment system design and report. The design and approximate cost was reviewed with the Client and the City municipality.
Based upon the review and the confidence that Chester had built with the client, Chester Engineers was requested to provide the wastewater treatment plant on a design-build basis. The engineering design and construction management team put together a complete drawing package, specified and bought all required equipment, selected contractors, oversaw construction, and successfully started up the system. The project was brought in ahead of schedule and at budget. The wastewater consistently has exceeded the requirements set by the EPA and City.
The Sustainable Result
Through the design process, Chester was able to provide for the customer water savings measures. The system is also designed to allow for complete recycle of the wastewater in the future as water rates increase. Approximately 90% of the wastewater will be recoverable. Chester is currently investigating potential uses for the produced solids from the wastewater plant to further reduce operating costs and provide a valuable commodity to the market.