Caustic recovery by filtration with ceramic membranes

Filtration of used caustic soda with atech ceramic membranes: caustic recovery and reuse in the process, reduction of wastewater volume, cost reduction, environmental protection

Key technology for the treatment of emulsions

In the food industry, regular cleaning of machinery and equipment is an essential process. Sodium hydroxide, mostly in the form of caustic soda, is used for this purpose in many applications.

Instead of disposing of this substance with the contaminants as waste after the cleaning process, it can be filtered with the help of atech ceramic membranes and reused in the process. Thus, atech contributes to the reduction of waste with its high-performance membranes.

The filtration and reuse of the cleaning liquid reduces the consumption of sodium hydroxide, water and wastewater, as well as COD (chemical oxygen demand) and energy costs, because thanks to the temperature resistance of the membrane, the caustic soda can be filtered even when hot. In addition, atech ceramic membranes are extremely resistant to aggressive chemicals, so their longevity is a decisive factor for many customers.

Advantages of the membranes in the application

  • Recycling of caustic to reduce consumption
  • High reliability under difficult operating conditions
  • Long service life, high sustainability
  • Energy and cost savings
  • Constant process stability
  • Low operating costs
  • Reduce water consumption
  • Reduce energy consumption
  • Cooling of caustic soda before filtration not required, can be returned hot to the process without reheating

CIP solutions produced can be reliably recirculated with use of ceramic membranes by atech

The use of an ultrafiltration plant in several large breweries in Mexico, supplied by a reputable German plant manufacturer and equipped with ceramic membranes from atech, finally ensured that the CIP solutions produced can be reliably recirculated.  After prefiltration to remove coarse components, the ultrafiltration system continuously cleans the heavily contaminated CIP solution in a full-flow process. The permeate is returned to the cleaning process. A reduction of the operating temperature during filtration is not necessary, as the membranes can also be operated at 80-90 ° C without any problems. This save enormous costs for energy for heating and cooling.  Furthermore, the cost of disposing of used CIP solutions has been drastically reduced, since the solution can be recycled almost indefinitely. Only the concentrate is discharged at regular intervals.  This and carry-over losses are supplemented by replenishing fresh lye, and washing-active additives are re-sharpened if necessary. The UF has been running trouble- free since 2015 and is reaching the planned capacity.

Membranes suitable for filtration of used emulsions and oily wash waters

Channel Diameter (mm) Pore size Permeate performance (l/m²h) Temperature TMP Velocity in channel
3.3 - 4 UF approx. 100 - 250 (depending on pollution level) 60 - 80 °C 140 - 176 °F approx. 1,5 – 3 bar approx. 21,7 - 43,5 PSI 4 – 6 m/s 13-19 ft/s

Comparison of water quality: raw CIP on the left, filtered CIP on the right