This study tests the effectiveness of biological treatment for drinking water (BioDWT) as a way of removing bacterial contaminants from drinking water by inhibiting biofilm-forming bacteria using different Streptomycetes isolates from marine water and their capacity to produce biologically active secondary compounds. Samples are collected, and isolate 23 bacterial isolates from different stages of drinking water treatment plant from River Nile of new Mansoura water plant in Mit-Khamis, Dakahlia governorate, Egypt. Then purification the bacterial isolates on R2A agar media. The capacity of the bacterial isolates to produce biofilms was studied. Following the sending of the nucleotide sequence to the GenBank sequence database, it was discovered that the bacterial isolate belonged to the genus Enterobacter (Enterobacter cloacae strain HMA). Marine samples were isolated and purified 12 streptomycetes from the Red Sea beach, Hurghada city, Red Sea governorate, Egypt, in different locations (marine water in the depth of ±3-5 m and sediment-water). We examined the antimicrobial activity of the purified actinomycetes acetate extracts and examined their potential to generate biologically active secondary compounds, or natural products (NPs), against biofilm-forming bacteria. Several isolates exhibited antimicrobial activity against 23 bacterial isolate but one isolate (H7) from the 12 streptomycetes isolates showed potent antimicrobial, and were the most effective (82.8 %). While the most of crude isolate have a variable activity against 23 bacterial isolate. The antimicrobial isolate was of the genus Streptomyces (Streptomyces sp. strain HMA). The HMA strain was cultured on rice medium and then extracted with an ethyl acetate solution. Using flash column chromatography, the resulting extract was essentially separated into seven parts. Seven fractions obtained were biologically screened by evaluating their antimicrobial activity against Enterobacter cloacae strain HMA. The result of Antibacterial activity of Fractions Fr.1 (54.9 %) against Enterobacter cloacae strain HMA. Based on the antimicrobial results, the most active fragment (Fr.1) was structurally determined using GC-Ms.