This book is based on the original research in one of Ethiopian Leather Industry in 2012. As it is known waste is the most horrible thing to our environment especially a waste from tannery industries, which have been affecting the people and brings drastic to the environment. In this research book an aerobic pond was designed by taking appropriate assumptions and we hope this book is used as a guide for chemical engineering and environmental engineering undergraduate students. In addition to that for engineers who work in industries like leather engineers, it has immense use. We can make our environment suitable by treating industrial wastes and therefore we may create our globe again by decrease the degree of toxicity and hazard of industries.