Integration of Pre-Treatment with UF/RO Membrane Process for Waste Water Recovery and Reuse in Agro-Based Pulp and Paper Industry

Abstract

This recent study aims to evaluate the efficacy of membrane filtration on recovery of water resource from agro-waste such as bagasse, crop-based pulp and paper mill waste. A mini pilot scale membrane system having a combination of pre-treatment filter unit (pre-filter, sediment filter and pre-carbon filter), ultra-filtration and reverse osmosis with spiral wound configuration were employed to evaluate the water reuse efficacy of effluent coming from the secondary clarifier of the conventional treatment plant of the mill. The operational conditions were optimized using Taguchi method at pH 8, temperature 32 °C, and pressure 2 bar and a flow rate of 60 l/hr. The qualities of the effluent from the secondary clarifier, and the permeate from both the combination, viz. Combination 1 (pre-treatment + ultra-filtration) and Combination 2 (pre-treatment + ultra-filtration+ reverse osmosis) were analyzed and the percentage reduction in pH, TDS, TSS, BOD, COD, Color, Lignin, Potassium and Sodium were calculated. The elimination of TDS, COD and BOD with Combination 1 was not promising (<22%). However, the installation of a RO membrane greatly reduced (>88%) the contaminants in both paper mill effluents. The obtained qualities of water from all the combinations were compared with the tolerance standard for reuse as process water. The quality of effluent from the secondary clarifier did not agree with any class of water quality. The permeate from the combination of pre-treatment and UF sufficiently reduced the TSS to reach the requirement. However, the combination of (pre-treatment + UF + RO) adequately complied with the quality standard required for reuse in the making of all grades of paper.

A Comprehensive Review on Pulp and Paper Industries Wastewater Treatment Advances

“…The addition of the RO unit, however, resulted in the total degradation of COD, lignin, and color at a pH of 5.74. 87 In a study by Shukla et al, 88 when combined acidic and alkaline bleaching wastewaters were fed to the RO feed side, the removal of color was greater than COD. Even though RO does not require chemicals or thermal energy and can be used for tertiary treatment applications, it is not recommended to use RO directly for highly contaminated wastewater since higher levels of COD and lignin adversely affect the quality of the permeate.…”

“…In optimal conditions, COD, lignin, and color were removed by 20%, 89%, and 74%, respectively. The addition of the RO unit, however, resulted in the total degradation of COD, lignin, and color at a pH of 5.74 . In a study by Shukla et al, when combined acidic and alkaline bleaching wastewaters were fed to the RO feed side, the removal of color was greater than COD.…”

Eco-sustainable paper wastewater management by water-resource recovery and concentrate minimization using a membrane oxidation reactor and membrane distillation system

“…Both the quantity and quality of water to be used in the production of various types of paper, such as white or bleached paper, or brown paper, such as ground wood paper and soda/sulfate (kraft) pulps, vary completely. 57,60,61 Systems widely used for the recovery and reuse of paper wastewater are based on the use of advanced treatment techniques, usually subsequent to biological treatment. 3,16 As noted in BAT, tertiary wastewater biofilters, membrane processes, chemical precipitation, AOP including but not limited to ozonation, and additional techniques for TSS reduction are among the innovative treatment technologies proposed for these purposes.…”

Sustainable Utilization of Pulp and Paper Wastewater

“…Pulp and paper wastewater has agricultural applications; treated pulp and paper wastewater can be used for agricultural irrigation. Organic matter, as well as nitrogen, phosphorus, and potassium in pulp and paper wastewater can provide nutrients to the plants, improve soil fertility, and promote crop growth [73]. Pulp and paper wastewater also has industrial applications; treated pulp and paper wastewater can be used for industrial purposes, which can reduce freshwater consumption as well as replace freshwater usage [74].…”