A vermicomposting system for treating waste water streams that includes a pretreatment stage for converting liquid or semi-liquid organic waste streams into a feedstock for vermicomposting; a vermicomposting digestion stage having populations of worms and beneficial bacteria which consume and break down organic material and nutrients present in the feedstock from the pretreatment stage to create worm castings, vermicompost, and a liquid compost tea that contains plant nutrients, plant growth promoting substances, and beneficial bacteria; and a post-treatment stage in which the liquid compost tea is removed for use as an soil amendment or inoculant, or is further treated in a separate containment tank where nutrients and oxygen levels are controlled to increase specific bacterial and fungal populations.