THE IMPACT OF SOLID WASTE LANDFILLS IN NIGERIA (ENVIRONMENTAL SCIENCE PROJECT TOPICS AND MATERIALS) INTRODUCTION Solid wastes comprise all the wastes arising from human and animal activities that are normally solid, discarded as useless or unwanted. Also included are by products of process lines or materials that may be required by law to be disposed of (Okecha 2000). Solid waste can be classified in a number of ways, on the basis of sources, environmental risks, utility and physical property. O