Among the factors that affect the quality of the environment, liquid and solid wastes seem to play an essential role. They appear more and more invasive and their elimination poses problems. Each one of us is responsible for it, since we personally produce increasing quantities of household waste, and the production is increasing with the evolution of the industrial sector in the last decades. Today, it is essential to do everything possible to reduce the quantities of waste to be treated and to better manage their elimination. This book is set in two general contexts: the first is the purification of liquid effluents by the infiltration-percolation process, which generates sewage sludge, and the second context is the valorization of this sludge in the field of artisanal pottery.