Ecological engineering is an emerging study of integrating ecology and engineering, concerned with the design, monitoring and construction of ecosystems. The design of sustainable ecosystems intends to integrate human society with its natural environment for the benefit of both . This particular type of engineering emerged in the early 1960s. It utilized natural energy sources as the predominant input to manipulate and control environmental systems.
Mitsch and Jorgensen were the first to define ecological engineering in five concepts :
- It is based on the self-designing capacity of ecosystems
- It can be a field test of ecological theory
- It relies on integrated system approaches
- It conserves non-renewable energy
- It supports biological conservation
Ecological engineering design follow a similar cycle to engineering design problem formulation, problem analysis, alternative solutions search, decision among alternatives and specifications of a complete solution. Typically the design goal involves protecting an at-risk ecosystem, restoring a degraded ecosystem or creating a new sustainable ecosystem to satisfy need of nature and society.
 W.J. Mitsch & S.E. Jorgensen (1989), "Introduction to Ecological Engineering", In: W.J. Mitsch and S.E. Jorgensen (Editors), Ecological Engineering: An Introduction to Ecotechnology. John Wiley & Sons, New York, pp. 3-12.