Impacts of sugar mill’s wastewater use on physical and hydraulic properties of soil: evidence from North Bengal Sugar Mill, Natore, Bangladesh

A proper knowledge of the impact of wastewater on soil is important to diagnose for successful irrigation with this water. An experiment was planned to investigate the physical and hydraulic properties of soils irrigated with a sugar mill’s wastewater of different dilutions at North Bengal Sugar Mill (NBSM), Bangladesh. Soil samples were collected from irrigated wheat fields (under investigation) of the sites after harvesting of the crop at 20 cm increments to a depth of 60 cm. Then, the physical and hydraulic properties of the soil samples were determined in the laboratory. Irrigation with sugar mill’s wastewater altered soil physical and hydraulic properties considerably. Mixed water reduced bulk density (from 1.44 to 1.42 g/cm³) and porosity elevated by 2.17% under wastewater compared to freshwater irrigation. It also raised field capacity by 1.98% water holding capacity by 0.19% and saturated hydraulic conductivity (from 0.20 to 0.25 cm/h,) of the soils. Moreover, wastewater irrigation altered soil–water retention curves and van Genuchten’s parameters too.