Precision seals manufacturer in China implements wastewater-free production

The solution

By recycling the distillate of the VACUDEST back to the production, the company can fulfill the requirements of the local government and in addition save water. The wastewater treatment system from H2O GmbH Germany was delivered, installed, and commissioned by H2O`s own subsidiary, H2O Kunshan. The water treated with VACUDEST vacuum distillation system is ideally suited for their own processes and can be reused as rinsing water without further treatment. The remaining evaporation residue is only a fraction of the original wastewater amount and can be disposed of at minimum cost.

Crystal clear distillate thanks to Clearcat technology

Vacuum distillation is a very efficient separation process for separating high-boiling impurities from industrial process water. Nevertheless, oils and fats from degreasing steps cannot be completely separated by distillation due to certain physical effects and traces are transferred to the distillate. This effect is known to all system manufacturers and can often lead to a cloudy distillate. Common follow-up treatments are based on coalescence separators and activated carbon stages. In addition to the running costs, there is also the increase in maintenance work.

Not so with the patented H2O Clearcat technology - this guarantees highest distillate quality without the use of the usual post treatment and consumables. This additional option for the innovative VACUDEST vacuum distillation system allows the safe and efficient treatment of industrial wastewater containing oil and grease in a single process step. The operating principle of the Clearcat condensation stage is based on physical and catalytic effects. Therefore, this cutting-edge technology requires neither energy nor auxiliary or operating materials. H2O improves the quality of treated water and sets new standards. The distillate thus becomes completely colorless and clear.

Evaporation Process

To keep the customer’s water budget cost-efficient and environmentally friendly, the distillate generated during vacuum distillation can be channeled back into the phosphating process. Of course, this can only be done if the water meets certain quality requirements. These requirements differ for each treatment or rinsing bath and are usually set by the suppliers of the degreasing, pickling and activation agents. The most important parameter is conductivity. At BRUSS, the distillate generated during the vacuum distillation process does meet the necessary conductivity requirements and needs no further treatment.

How does it work? All the rinse water and spend active baths are collected and neutralized before the wastewater is fed to the evaporator. Vacuum evaporation relies on the principle of difference in boiling points. When evaporating phosphating wastewater substances having higher boiling points than water (oil, fat, heavy metal salts) remain in the evaporation residue, like for instance lime and salts precipitate in a tea pot which has been forgotten on the oven. Industrial wastewater from phosphating is evaporated under vacuum of about 650 mbar at a temperature of about 86 °C. The emerging steam, free of heavy metals and salts, is compressed in a roots pump to atmospheric pressure. During compression the steam is heated to about 120 °C. This super-heated steam is then used to provide energy to the evaporation process. Compared to atmospheric evaporation the energy recovery is up to 95 %. Another advantage is that the distillate is free of bacteria.

All goals met

For the high-end seal manufacturer, a holistic optimization of their production processes is important. The H2O VACUDEST evaporation system helps to achieve and implement these and other sustainability activities like the environmentally sustainable and efficient use of the resource water. Zero Liquid Discharge.