Caloris Rinse Water RO Case Study (Wastewater)

A Caloris customer had an issue with discharging a high volume of industrial wastewater into their wastewater lagoon. The discharge stream was “rinse water,” which is used for clean-in-place (CIP) flushes and rinses of dairy processing equipment before and after various chemical washes. More voluminous wastewater discharge meant increased hydraulic loading on their lagoon and less processing capacity.

The goal for Caloris was to decrease the volume of the waste stream to decrease the hydraulic loading on the lagoon with an unchanged amount of total solids, meaning that the wastewater treatment system could process the stream more efficiently. A secondary goal, or added benefit, of this project was the production of a clean stream of water from the original waste volume that could be reclaimed as surface water discharge.

Caloris provided a solution to reduce the volume of industrial wastewater by separating the waste stream from a “clean” water stream, which can be safely discharged as regular surface water. To accomplish this goal, Caloris designed and installed a Reverse Osmosis (RO) membrane  skidded system in the customer’s chemical room. CIP Rinse Water is the feed stream, discharging a “concentrate” waste stream to the lagoon and a clean “permeate” stream as surface water that can be discharged to the ground. The RO system contains 2 small pre-filters and 20 polymeric membranes, which can process 30,000 gallons per day of rinse water at a rate of 90% recovery of clean water.

Rinse Water RO

Feed Flow (Fresh): 25 gallons per minute (GPM) with ~500 mg/L total dissolved solids (TDS)

  • If operating 20 hours/day: 30,000 gallons per day (GPD) capacity
  • Recirculation Flow: ~360 GPM (stage is recirculated to increase flow rate to membrane)

Permeate Flow: 22.5 GPM with < 62 mg/L TDS

  • 27,600 GPD clean surface water discharge

Concentrate Flow: 2.5 GPM with > 4500 mg/L TDS

  • 3,600 GPD waste water discharge to lagoon

The efficient RO system offers a 10x volume reduction of the dirty stream.

Despite its small footprint, the RO system has the capacity to add more membrane housings to expand capacity up to 50,000 gallons per day if needed in the future.This project was designed and installed in 12 weeks. This included all phases of the project such as process engineering calculations and equipment sizing followed by mechanical design of technical 2D and 3D drawings. This enabled fabrication shops and vendors to build the membrane housings, piping, and supports as well as supply the tanks, pumps, and instrumentation. Included with the RO system was a control panel and automation program, which drives the RO system through:

  • Startup
  • Production
  • Flush
  • Cleaning
  • Shutdown

Caloris met the ambitious 12-week goal of designing, testing, delivering, installing, and commissioning this RO system to accomplish the customer’s goal of reducing the amount of industrial wastewater entering their wastewater lagoon. Caloris also met the surface water discharge requirement of < 30 BOD, a pH of between 6 and 9, and a temperature < 90°F.

The design for the RO system was based on pilot-scale testing for 3 days using the same rinse water polymeric membrane, pressures, temperatures and related parameters. The pilot test met the thresholds of conductivity and turbidity of the permeate stream to make it viable for surface water discharge.

The customer was satisfied with the results and the project continued to the design and installation of the complete RO system. The commissioning of the complete RO system met targets as designed in relation to water quality of the permeate stream and capacity of the system. In conclusion, the customer was impressed by the quick turnaround of the project as well as the clean water quality and wastewater volume reduction. This successful project has led to discussions of potential new projects at the customer’s plant with Caloris Engineering.

CALORIS ENGINEERING LLC offers a variety of product designs that can be configured to accommodate the complex processing needs for numerous product streams and wastewater applications. Contact our sales and technical specialists at 410-822-6900 or email to discuss your specific needs. Caloris has several small pilot evaporators that can be used to evaluate opportunities.


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About Caloris

Caloris transforms process systems design for the better with unexpected, future-focused solutions that solve real operational problems. We engineer efficient, dependable and productive solutions that also improve environmental sustainability where practical. Designed with the end user in mind to drive plant productivity. Caloris offers evaporation, membrane filtration and spray drying process systems for food and dairy industries, as well as for water reuse and wastewater treatment applications. Both Caloris’ custom and pre-engineered packaged systems are designed to meet our customers’ specific concentration/purification needs utilizing the most cost effective and energy efficient technologies available. Whether concentrating dairy, food or juice products at a high-volume production facility, or processing industrial wastewaters to reduce transportation and treatment costs and recover re-usable water, Caloris provides a range of options and technologies.