Biological treatment technologies consist of technologies that use microorganisms to break down organic matter found in waste water, and energy recovery technologies using bio-metabolism such as methane fermentation.
For example, there are two types of wastewater treatment: treatment using aerobic organisms that can only survive if there is oxygen in the water (aerobic treatment), and treatment using anaerobic organisms that can only survive in the absence of oxygen (anaerobic treatment). Aerobic treatment works on the basis that microorganisms multiply by using the oxygen dissolved in water to break organic matter down into carbon dioxide and water. Anaerobic treatment works on the basis that, in aquatic environments lacking dissolved oxygen, microorganisms multiply by breaking organic matter down into methane gas, carbon dioxide and water.
Kurita uses these biological treatment technologies in the development of various wastewater treatment systems.