- Wastewater Recycling Using Ceramic Membranes
An aerospace manufacturer faced challenges increasing production rates due to insufficient capacity in its existing industrial wastewater treatment and process water plants. To combat this, our team executed a series of projects to increase wastewater treatment and reuse capacities allowing the manufacturer to meet both current and future production goals.
Existing Industrial Wastewater Treatment Plant
We studied the plant’s hydraulics to assess the current flows and identify equipment that would require upgrades to handle increased future flow rates. After the study, detailed design began on a series of improvements aimed at removing hydraulic bottlenecks and increasing the performance and operational flexibility of the industrial wastewater treatment plant (IWTP). The improvements increased the maximum treatment capacity by nearly 20 percent to 3,400 gpm, which, in combination with the installation of a membrane side stream plant (MSSP), provided for increased flexibility in handling the wide range of wastewater flows.
Membrane Side Stream Plant
Ceramic membranes can stand up to the harsh and highly variant conditions of the manufacturer’s wastewater, with pH ranging from 2 to 10, and concentrations of oil, grease and hexavalent chromium in excess of 10 mg/L. We worked in conjunction with the manufacturer and the membrane vendor to design the treatment process and upstream pretreatment process. Design of equipment to support the membrane process included equalization and reaction tanks, pumps and chemical feed systems. A 4,000-square-foot building was constructed to house the membrane equipment, and an electrical building was built nearby to provide power. The first phase of the project is designed to treat 450 gpm; at full buildout, the MSSP will have a total treatment capacity of 1,350 gpm. At completion, the MSSP was the second-largest ceramic membrane installation in the United States and the largest installation designed for metals precipitation.
Process Water Improvements
Our team assessed the current process water plant (PWP) and designed improvements to increase the production of process water. Upgrades included installation of two ultraviolet (UV) disinfection units, two additional bag filters, and two reverse osmosis (RO) skids with a design permeate capacity of 450 gpm each. Modifications were made to repurpose an existing RO skid to concentrate RO reject, increasing the amount of water that can be reused within the manufacturing process. To feed the newly repurposed concentrating skid, two new 500 gpm vertical centrifugal pumps were installed. A 20,000-gallon tank was installed for short-term storage of RO reject. The installation of these upgrades provides increased production capacity and greater reuse capabilities.