"Problem solving in solid waste engineering" is primarily designed as a supplement and a complementary guide to municipal solid waste engineering. Nonetheless, it can be used as an independent problem solving text in solid waste collection, treatment and disposal. The book targets university students and solid waste engineering candidates taking first degree courses in environmental, civil, mechanical, construction and chemical engineering or related fields. The manuscript is expected to be of beneficial use to postgraduate students and professional engineers. Likewise, it is hoped that the book will stimulate problem solving learning and facilitate self-teaching. By writing such a script it is hoped that the included worked examples and problems will ensure that the booklet is a valuable aid to student-centered learning. To achieve such objectives immense care was taken to present solutions to selected problems in a clear and distinct format using step-by-step procedure and explanation of the related solution utilizing necessary methods, approaches, equations, data, figures and calculations. The book is mainly used as a course supplement and support in problem solving issues. Constructive comments, valuable remarks, precious notes and helpful observations were received from students, users within the college, colleagues, engineers, officials at solid waste departments and municipalities, members of engineering societies and enterprises. In this second issue problem modeling techniques has been introduced. Visual Basic.NET, programmed using Microsoft Visual Studio 2010 IDE was used in writing computer programs for selected examples in the book. Set programs are constructed using the IDE designing and buildings tools, and were tested and run on a MS-Windows XP and 7 workstations.