The wet mount is a preparation of a sample to observe structure of microorganisms. A sterile inoculating loop was used to place a loopful of sample on a slide. It was then covered immediately with a cover slip. Before the preparation dried, it was observed under microscope. Monochrome staining was also carried out to study the sludge. Smear was prepared and heat fixed. Then smear was treated with 5–7 drops of crystal violet stain. It was allowed to react for 60 to 120 s. The staining solution was poured off and the slide was washed by gentle flow of tap water. The slide was dried in air and finally examined under oil emulsion lens.