A sustainable business is one that is commercially viable while taking a long-term intergenerational view.
As well as being the right thing to do, reducing your waste and emmissions is a useful tool for marketing and can become a valuable part of your brand. Consumers want to buy goods and services from those that are aiming for the greater good, and are willing to pay more to those that are walking the talk.
A good business should be looking to reduce inefficiencies wherever possible. It might take some up-front investment, but reducing your impact on the world is likely to save you money in the longer term as well as make your brand more attractive.