Highly contaminated wastewater
The tanning process produces highly contaminated wastewater, especially very high COD loads. The so-called COD is the chemical oxygen demand, which is used as a parameter for the degree of contamination of wastewater with organic impurities. This COD content can be reduced with the help of the ceramic membranes in order to relieve the corresponding governmental wastewater treatment plant.
Filtration with ceramic membranes from atech ensures that the authority's specifications are met
The use of an ultrafiltration plant in Johannesburg, South Africa, from memcon with ceramic membranes from atech finally ensured that the authority's specifications were met. The 400 m³ of polluted wastewater produced daily in the tannery had already been aerated there (SO2 oxidation) and pretreated by dissolved air flotation (flotation with dissolved air to remove suspended or solid matter). This pre-treated wastewater is now passed through a self-cleaning edge-cleaning filter into the ultrafiltration plant with atech membranes. The plant removes undissolved COD, TSS (total suspended solids), agglomerates, precipitated metals and undissolved fats. The permeat - which is the filtered liquid - from the ultrafiltration plant is then suitable for further purification of dissolved salts via reverse osmosis (RO). The RO permeate is reused as process water in the tanning process. The UF and RO concentrate containing the filtered-out contaminants is disposed externally. The UF achieves a yield of > 90 %, has been running trouble-free since June 2019 and is reaching the planned capacity.
