The ECOWAMA project proposes a new eco-efficient closed cycle management model for the treatment of effluents of the metal and plastic surface processing industry (STM - surface treatment of metals and plastics). Such STM wastewater is extensively contaminated with oils and greases, organic loading, a salt fraction and especially with heavy metals (e.g. nickel, copper, zinc and others).
Hence STM enterprises have high interest on efficient, cost-effective and sustainable treatment of their effluents. ECOWAMA’s approach combines wastewater treatment with recovery of ultrapure water, highly valuable metals and energy. Therefore an environment friendly, effective and innovative system will be developed including electrocoagulation, electrooxidation and electrowinning technologies. Additionally hydrogen produced during electrocoagulation / electrooxidation processes will be used to deal as feed for fuel cells to generate electricity which reduces the energy demand of the overall process. Pre- and post-treatment will be carried out to remove oils/greases and conductivity. The heavy metals will be separated from the wastewater stream through an electro-precipitation process. After metal dissolution from precipitation sludge a novel electrowinning process using novel electrodes, optimised geometry and process management will reduce the dissolved metal ions to a solid aggregate state with high purity. The outcome of this is a valuable raw material that can be easily sold or reused for STM operations.
Due to the extremely high level of prices for metals at the global market ECOWAMA’s participants and post-project clients will have strong economic benefits beside the positive environmental impacts of the process.
Flow-chart of the ECOWAMA process, demonstrating all relevant process steps and mass flows (click to enlarge)