The researchers studied how earthworms can turn rice straw and paper waste into nutrient-rich vermicompost. They mixed the wastes with cow dung and let the worms eat them for 105 days. The vermicompost had more NPK nutrients and less organic carbon and C:N ratio. Heavy metal content increased in the vermicompost. Earthworms grew well in most mixtures, except one with too much rice straw. The type of bulking substrate affected earthworm growth and reproduction.