Simple processes for contamination removal in cheesemaking wastewater: CaCO3, Mg(OH)2, FeSO4 and FeCl3

•CaCO3 is the most efficient process for total phosphorus with removals ≥ 94%.•CaCO3, Mg(OH)2, FeCl3 reduced by about half the total phenols content.•CaCO3 and FeCl3 reduced the organic matter concentration up to 36%.•All processes were effective in removing turbidity (16–93%).•These processes can be pre-treatments of physicochemical and biological processes. The treatment of cheesemaking wastewater by means of four processes (CaCO3, Mg(OH)2, FeSO4 and FeCl3) has been investigated in order to reduce the total phosphorus, turbidity, total phenols, chemical oxygen demand (COD) and absorbances. It has been demonstrated that CaCO3 is the most efficient process studied for total phosphorus removal, with reductions ≥94% for precipitant concentrations ≥75 g L−1. CaCO3 process was also effective in reducing turbidity (73–88% at high precipitant concentrations), total phenols (44–58%), absorbances (up to 66%) and COD (36% at a precipitant concentration of 75 g L−1). Mg(OH)2 process was capable of decreasing around 66% the total phosphorus content when applying low concentrations of precipitant (12.5 and 25 g L−1). However, high turbidity removals (>90%) were achieved for Mg(OH)2 concentrations ≥ 50 g L−1.Mg(OH)2 precipitation can reduce by about half the content of total phenols, under optimal conditions. Under the maximum concentration tested, FeCl3 was able to decrease the total phosphorus concentration in approximately 67%. Turbidity (61–89%), COD (around 30% for low and high concentrations), total phenols (53–57% for precipitant concentrations of 0.8 and 1.0 g L−1) and absorbances (30–83%) were also reduced in Fe(III) precipitation. Fe(II) precipitation removed total phosphorus in the range of 29–37%, as well as turbidity (16–42%), total phenols (18–28% for low concentrations) and absorbances (up to 32%). The studied processes can be an option to reduce the contamination of industrial wastewater in terms of total phosphorus, turbidity, COD, total phenols and absorbances and treated wastewater can be used for irrigation purposes.