Modeling combined technological, environmental and economic considerations in domestic sludge reuse via the Analytic Hierarchy Process (AHP)

An optional method of using recycling and reuse efficiently of sludge is presented. Sludge can be originated from a number of sources, although the one obtained from wastewater is the most common one. It composes around 30% percent of the wastewater treated by activated sludge or other similar methods. It always creates problems related to environmental. A multi-objective function is defined. It consists of treating the sludge by four alternatives: (i) disposal of the sludge untreated to the sea; (ii) incineration of sludge for energy generation; (iii) treatment of the sludge via anaerobic digestion, and; (iv) using the treated sludge as a soil amendment, primarily for agriculture. Comparisons of the treatment and disposal method were made. Comparison is based on the Analytic Hierarchical Process (AHP) model. The comparison criteria included similarly also five criteria. These criteria included the cleanness of the environment (environmental criteria), the cost of treatemnt according to the final product, benefit to society in terms of energy generation, benefits to agriculture in terms of food production and public acceptance. There is no doubt that the solutions will be location dependent however, they demonstrate the options in each region.