Phosphate removal from phosphorus containing waste water by coagulation/flocculation process using Gossypium spp. (GS) as coagulant

Abstract

Phosphate removal from phosphorus containing effluent was carried out using bio-coagulant. Gossypium Spp (cotton seed) an eco- friendly biomass was used as a coagulant in this work for the wastewater treatment through Nephelometric method. The study evaluates the coagulation/flocculation efficiency of GS. Parameters such as pH levels of the effluent, dosages of GS and settling time were varied. Statistical (via 2 3 Central Composite Design, CCD) modeling for process optimization was carried out. The results obtained showed that, maximum coagulation performance E(%) >70 was obtained at 500mg/l GS concentration and pH=6.The most significant main effect for performance of GS as a coagulant is its dosage (Pvalue=0.0006) while pH (Pvalue=0.2070) is the least significant. Keyword:Phosphate;Coagulation/Flocculation; Biomass; Gossypium Spp.; Phosphorus; Effluent I. INTRODUCTION Coagulation and flocculation provide the water treatment process by which finely divided suspended and colloidal matter in the water is made to agglomerate and form flocs. This enables their removal in subsequent sedimentation and filtration stages.(1).Coag-flocculation of wastewater may be accomplished with any of the common water coagulants including lime, iron and aluminum salts and synthetic polymers. However, the search for a better alternative to conventional coagulants has become an important challenge in the water treatment process with the aim of minimizing the detrimental effects associated with the use of such coagulants. The use of coagulants of biological origin has become essential. Some of the coagulants and flocculants of biological origin that have been used include chitosan (2) tannins (3) , aqueous extract of the seed of Moringa Oleifera (4), extracts of Okra, nirmali seed(5) and cotton seed (Gosspium Spp) which is the subject of the study. Cotton is currently the leading plant fibre crop worldwide and is grown commercially in the temperate and tropical regions of more than fifty countries (6) Cotton is primarily grown as fibre crop. It is harvested as 'seed cotton' which is then 'ginned' to separate the seed and lint. The delinted cotton seed can be processed to produce oil, meal and hulls. Oil produced from the seeds has achieved GRAS (Generally Recognized As Safe) status under the United States Federal Food Drug and Cosmetic Act (7). They are also used as a viscosity enhancer (thickener) in ice cream, salad dressing and tooth paste (8).