9. Valorization of Solid Waste Products from a Variety of Sectors in Wastewater Treatment Processes

There is an urgent need for the “circular economy” trend and a “zero waste” society. Even though complete waste recycling and a fully circular economy may not be possible in all circumstances, striving for this objective can still lead to a sustainable future. This chapter discusses the potential utilization of solid waste products from different sectors (agriculture, demolition, and construction, domestic, and industrial) for the treatment and removal of contaminants from wastewater. These solid wastes that are investigated are assessed as filters or absorbents for contaminants in wastewater. As such, the use of alternative, low-cost materials could address the limitations of using some expensive traditional treatment methods. Bayer residue, waste slurry, fly ash, blast furnace slag, coffee and tea waste, lignin, sugar cane bagasse, rice husk, sugar beet pulp, coconut shell, wood waste, some fruit peel, red mud, cement kiln dust, etc. are investigated. It is to be mentioned that these waste products achieve different potentials for wastewater treatment and the removal of some contaminants, but there is still a need for certain precautions to be taken to ensure that any concerns are mitigated. Additionally, for commercial, large-scale applications, more research should be conducted in this direction. A few problems and disadvantages of using industrial waste as inexpensive adsorbents have also been discussed.