Natural ibers are low cost, abundant, and biodegradable. Application of natural ibers and their composites in wastewater treatment is a fascinating idea. Generally wastewater treatments include physical, chemical, biological, and mechanical methods with primary, secondary, and tertiary procedures. This chapter is mainly focused on recent survey on technology, preparation, and improved methods in utilizing cellulosic nanocomposites for handling organic waste materials. The work is highlighted on using natural ibers in obtaining activated carbon ibers for adsorbing waste particles and can be used for the treatment of wastewater. High porosity and structures are helpful in trapping low molecular weight chemicals and organic compounds. Cellulosic nanoparticles such as cellulose nanowhiskers, nanocrystalline cellulose, and nanoibers are used as

reinforcement in polymer matrices. These renewable nanoparticles are used for the treatment of wastewater.