Our Client decides to call upon the NISKAE team with the first objective of bringing the "metallic" effluent into compliance and, on the other hand, the possibility of treating the "organic" effluent. Once the samples of the two discharges were received, NISKAE experts could undertake a series of laboratory tests to develop a specially adapted coagulation-flocculation formulation. The so-called "metallic" waste has an initial pH value of 2.27. The first step of the treatment is therefore a neutralization of the pH by sodium hydroxide (NaOH). Subsequently, the addition of a decomplexing product and a custom-made flocculant simultaneously reduced the copper concentration from 188 mg/L to 0.10 mg/L and allowed a substantial reduction in the chemical oxygen demand, which will allow discharge into the natural environment. This coagulant-flocculant mono-reagent also significantly reduces iron from 3.71 mg/L to 0.21 mg/L and lead from 4.24 mg/L to 0.05 mg/L.

Laboratory tests carried out on the "organic" waste sample confirmed that no pH neutralization is necessary and that a single reagent can be used to treat both effluents, which can then be mixed in the same storage tanks. 

The advantage of the proposed process is a considerable simplification of the current treatment, with the reduction of the number of reagents, the reduction of dosages and the reduction of treatment times. The generated sludge is non-sticky and well dewaterable, which will allow a fast and uncomplicated filtration and gravity separation. The filtrate is clear and translucent and will be suitable for discharge.