In water, growing algae has the capacity to consume nutrients and absorb co2 and release oxygen by photosynthesis. diatoms are one of the species which contribute to about 50% of world’s food produced in oceans. an organic solution that can grow diatom algae in any water – saline, fresh water, polluted water, sewage water etc is used to clean and reuse the waste water. the growth of diatoms is very fast and happens within 5 minutes and continues till the nutrients lasts. the growing diatoms absorb co2 and release o2 at micro plant level. the o2 helps aerobic bacteria breakdown organics into its constituents and thus cleans up the waste water. the suspended solids break down into nutrients, gases and sludge. the nutrients are further absorbed by the diatoms to grow. the diatom algae produce food by photosynthesis and this becomes food for zooplankton. zooplankton in turn becomes the food for the fishes. therefore, by making use of this natural process, to clean up any water bodies such as river, lakes. if there are no fish the zooplankton become part of sludge and become excellent manure for plants. there is no bad smell in water and in sludge. the dissolved oxygen content of treated water improves considerably.