Monitoring colour and COD removal capacity of soil and assessment of growth performance of crop growth with paper mill wastewater—A lysimeter study

Evaluation studies on the effect on physico-chemical properties of soils and crops irrigated with paper mill wastewaters in field lysimeters were carried out for three years at the Integrated Paper Mill, Nepanagar, Madhya Pradesh (India). Lysimeters were prepared by excavating pits of 5 m × 2 m × 2 m, lined with polyethylene sheet and filled with sandy loam, clay and loamy sand soils with different physicochemical characteristics and provided with percolate collection system. Lysimetric treatment was used and treated wastewater evaluated for crop irrigation complied to the irrigation water class ‘Moderate to Severe Restriction on use’ for the parameters salinity and specific ion toxicity, and with respect to SAR, it was categorized under the class ‘No Restriction on use’. Sandy loam and loamy sand soils in lysimeter I and III, the percolate was 17% and 20% of irrigation, while for clay soil in lysimeter II it only 15%. Sandy loam and loamy sand soils respectively showed 97% and 96%. The chemical oxygen demand (COD) removal in sandy loam and loamy sandy soils where 97% and 96% respectively while in clay the removal was 99%. The colour removal in both the cases was 100%. The percolates initially showed leaching of calcium and magnesium and retention of sodium, which got stabilized subsequently. The application of wastewater resulted in increase in water holding capacity, pH (0.6–1.3 units), electrical conductivity of saturated extract (ECe, 0.6–2.1 dS m−1) and exchangeable sodium percent (ESP, 8.1–11.6), organic carbon and available nitrogen, phosphorus and potash content of soils; however there was decrease in bulk density. Wastewater irrigation did not affect germination; rather there was increase in grain and straw yield of jowar, wheat and moong. These results showed that the paper mill wastewater can be successfully utilized for crop production.