A comprehensive review of saline effluent disposal and treatment: conventional practices, emerging technologies, and future potential

An ever-increasing volume of saline effluents from industries, oil–gas fields, and desalination plants has resulted in an enormous amount of pollutants with undesirable effects on the environment and human health. Adequate disposal and treatment of these effluents remains a persistent problem and poses significant technical as well as economic challenges. Saline effluents can have considerable environmental impacts, depending upon the sensitivity of the surrounding ecosystems. Conventional disposal techniques mostly suffer from direct or indirect contamination of water/soil and are no longer preferred. As a result, several advanced treatment methods are being considered for sustainable saline effluent management in recent times. In this context, a comprehensive and updated review of conventional methods, along with emerging technologies for disposal and treatment of saline effluent, is presented. Existing treatment approaches, including membrane operation, thermal processes, chemical techniques, and biological methods, are discussed. The application of innovative hybrid processes (combining two or more treatment methods) aiming at lower energy demand and higher treatment efficiency has also been evaluated. Subsequently, emerging sustainable strategies like waste minimization & water recovery, zero liquid discharge, and resource recovery for saline effluents have been examined. The prospect of integrating the renewable energy sources with energy-intensive saline treatment methods towards energy–water– environment nexus is also explored.