Use of paper mill sludge and sewage sludge powder as nitrogen and phosphorus sources with bacterial consortium for the treatment of paper industry wastewater

Abstract

In this work, urea and diammonium phosphate (DAP) was replaced with paper mill sludge (PMSP) and sewage sludge powders (SWSP) individually as the source of nitrogen and phosphorous and treated by using a consortium isolated from i) sediment of final discharge (ii) sediment of secondary sludge (iii) sediment of equalization tank and named as Bacillus sp. IITRDVM-5, Pseudomonas sp. IITRDVM-10, and Pseudomonas stutzeri IITRDVM-16. The optimum conditions for treatment of the sequence batch biological process were: 48 h reaction time, temperature 37 °C, 150 rpm, and pH 7.0 ± 0.2 using 8% consortium inoculum. The maximum reductions in total organic carbon (TOC), chemical oxygen demand (COD), biochemical oxygen demand (BOD ), and color at PMSP 3.16 g/500 mL were 79.7, 78.3, 83.2, and 73.9% whereas at SWSP 1.392 g/500 mL were 72.6, 71.4, 76.1 and 69.3% respectively compared to their respective controls. Both PMSP and SWSP individually showed a higher reduction in TOC, COD, BOD , lignin, total phenol, adsorbable organic halids (AOX), nitrogen, phosphate, and color compared to the final discharge of paper industry wastewater. Besides, a 74.2% reduction was observed in Kraft lignin (2000 ppm) prepared with MSM at a reaction time of 48 h. Fourier transforms infrared spectrophotometry (FTIR) was done to observe the significant changes in the functional groups of organic pollutants after the treatment of the wastewater samples. Finally, phytotoxicity analysis of the final discharge of the paper industry, untreated and treated wastewater sample was studied on seed (Vigna radiata) germination in which treated effluent showed lesser phytotoxicity.