Dear Senthil,
Considering ISO 14001, you need to focus on following
1. Things that are linked with air,water and land (i.e the environment)
2. How do these react with the surrounding environment. Ex. Air emission(exhaust from generator),Water disposal(sewage and industrial effluent) etc.,
3. In addition you need to consider about chemical used throughout operation and its safest disposal as given by the local laws and regulations
4. Your entire process, capturing things/activities that are related with the environment(land,air, water,flora and fauna etc.,) in such a way it does not harm the environment and is safe to the environment in all activities(Usage and disposal etc.,)
Best wishes