Wastewater pollution is a severe problem in the world. Nejayote is a highly polluting by-product, it is the wastewater of the nixtamalization process. Nejayote was filtered in a press filter to reduce its environmental impact. The filtration was performed with a small-scale filter, previously built to use minimal suspension volume. The needs of the filter aid as precoat and dosage were determined. The method was applied at a constant pressure regime with different area and pressure conditions. The lowest values with area 0.046 m2 and pressure 137.3 kPa were: oxygen biochemical (BOD5) 3875mg/L, oxygen chemical (COD) 16560.15mg O2/L, calcium content 421.65mg/L, reducing between 66 and 78% of the polluting agents. The scaling was carried out at these conditions in a filter of larger dimensions and pressure 160.2 kPa. This work methodology is applicable to obtain the filtration conditions of nejayote to any industrial press filter. All rights reserved, Elsevier.