The present disclosure relates to a method for separation of solid particles from a waterbody. Preferably, the present disclosure relates to a method, wherein a combination of chemicals including coagulant(s) and flocculant(s) are employed for said separation of solid particles, wherein suitable examples of solid particles are living organisms and non-living matter, wherein living organisms include autotrophs such as phototrophs, which are either microscopic or macroscopic in nature (algae). The disclosure thus particularly relates to method of chemical coagulation and flocculation for separating solid particles, preferably either algae or bacteria or both from a waterbody. The present disclosure also provides for an alternate method, wherein the aforesaid method of coagulation and flocculation is combined with electro-coagulation and/or pH modulation strategies for separation of said solid particles in any sequence.