Treatment of Pulp and Paper Industrial Effluent Using Physicochemical Process for Recycling

Abstract

Physicochemical treatment, consisting of a combination of primary settling, coagulation–flocculation-aided clarification (alum, lime and magnesium sulfate as coagulants) and activated carbon adsorption, was employed for the treatment of pulp and paper mill wastewater. Treatability studies were undertaken to assess the feasibility of recycling the effluents from a paper mill. The results of laboratory scale investigation showed that the hydraulic retention time (HRT) of four hours for plain settling was effective to reduce 30% of the pollution load from pulp and board mill wastewater (PBMWW). The chemical secondary treatment reduced turbidity (89%), Chemical Oxygen Demand (84%), total suspended solids (90%) and color (89%) at the mass loading of 3400 mgl-1 of magnesium sulfate (MgSO4), when primary-treated effluent was subsequently treated by the coagulation–flocculation process. The combination of primary settling and lime coagulation (optimum dosage of 1400 mgl-1) resulted in a turbidity removal of 94%, a COD (Chemical Oxygen Demand) reduction of 86%, a Total Suspended Solids (TSS) removal of 93% and color removal of 91.6% at an initial pH of 11. The combination of this primary settling and coagulation–flocculation treatment trial indicated that the pollutant reduction efficiency of alum was better than the other two coagulants (MgSO4, lime), because the plain settling and coagulation–flocculation process with alum (optimum dosage of 1200 mg/L) resulted in a turbidity removal of 98%, COD reduction of 93%, TSS removal of 98% and color removal of 96% at the pH 6.0 with the sludge volume index of 156 mg/L. This chemically-treated water required further treatment with activated carbon in a batch reactor for up to four hours to meet the paper mill water quality standards. Pollutant reductions at the rate of 99.5%, 99.1%, 99.4% and 99.5% were obtained for turbidity, COD, TSS and color, respectively, with the combination of the sedimentation, coagulation–flocculation process and activated carbon adsorption meeting the production process quality standards. The study revealed that a hybrid end-of-pipe physicochemical treatment was effective in reducing the pollutant load of paper mills effluent and meeting the discharging standards.

Differential evolution-based optimization of corn stalks black liquor decolorization using active carbon and TiO2/UV

“… Author, ref. no Black liquor source Active carbon source/system Decolorization* (%) Shivayogimath and Navaneet 64 Paper mill effluent, India Laboratory prepared activated carbon, from teakwood sawdust 83.19 Singh 65 Paper mill effluent, India Laboratory prepared activated carbon, from coconut jute 90.1 Zhang and Chuang 34 Soft wood Kraft pulp mill, China Commercial, Aldrich 95 Gupta et al 66 Kraft process-based pulp and paper mill, India Laboratory prepared activated carbon, from plastic mix waste 96.48 Sari et al 67 Plant reactor for bioethanol production, Indonesia Laboratory prepared activated carbon, from black liquor coagulated sludge, immobilized enzymes 97.7 This study Laboratory produced from corn stalks, Romania Commercial, Romcarbon Company 99.03 Mehmood et al 68 Paper and board mill, Pakistan Combined physicochemical treatment, granular AC 99.5 *The highest reported value. …”

Siloxane-Starch-Based Hydrophobic Coating for Multiple Recyclable Cellulosic Materials

“…Thus, the water contamination parameters in cycle 3 and 4 for handsheets coated with hydrophobizate are probably due to its use only. Anyway, the COD (less than 800 mg/dm 3 ) and turbidity (less than 30 NTU) of the wastewater are well below typical industrially accepted ranges (COD below 2500 and NTU below 100) for all four cycles for coated samples [ 24 ]. However, in the case of possible practical applications of the tested chemicals, the relatively high pH of the whitewater may necessitate an extra neutralization before it is returned to circulation in the paper machine.…”

Evaluating effects of activated sludge and nanochitosan on physical and strength properties of recycled pulp

“…Additionally, the removal of peaks in the adsorption zones of 1237.0 cm -1 is closely related to the C=O, C=C, and C=O bonds of the carbonyl units, and the adsorption region of 1412.1 cm -1 is related to aromatic C-H and C-H associated with type II alcohols, as well as C=O is treated in activated sludge and attenuates or removes carbonyl groups (Fig. 1) (Mehmood et al 2019). As a strength additive, chitosan has a structure similar to cellulose filaments, and thus it uses hydrogen and Van der Waals bonds to improve bonding between fibers, thereby improving tensile strength (Li et al 2004).…”

“…6). Hemicellulose and lignin are affected by the treatments, which reduces the amount of hydroxyl groups and has a significant effect on lignin (Mehmood et al 2019). Aliphatic groups are seen in the absorption range of 3312 cm -1 (Fig.…”