For the study of the composts, different plants' debris were collected and prepared by crashing them separately in some containers with EM and in other separate containers without EM which are referred to as Normal Composts. In the case of the study of the wastewater, the water was mixed with waste matters of both inorganic and organic wastes which were BOD, COD and TSS. The antimicrobial activity of Aloe vera extract was tested against S. aureus, Salmonella spp., and E. coli strains tested at different dose of the Aloe vera extract. One of the Plant species involved in this study includes that known as Plectranthus barbatus. Its medicinal importance has been recorded to be useful in treating from severe skin and abdominal infections to life - threatening diseases such as Pneumonia and Meningitis. The other reviewed work was on the outcomes of the studies on the bacteriological quality analysis of Raw Milk samples collected from various Diary and family households of the various sectors of Kigali city.