Anaerobic co-digestion of sludge with other organic wastes in small wastewater treatment plants: an economic considerations evaluation.
This paper deals with an economic comparison between costs and incomes in small wastewater treatment plants where the anaerobic co-digestion process of sludge and biowaste with energy recovery is operated. Plants in the size range 1,000-30,000 persons equivalent (pe) were considered in the study: typical costs, comprehensive of capital and operating costs, were in the range euro69-105 per person per year depending on the plant size: the smaller the size the higher the specific cost. The incomes deriving from taxes and fees for wastewater treatment are generally in the range euro36-54 per person per year and can only partially cover costs in small wastewater treatment plants. However, the co-treatment of biowaste and the use of produced energy for extra credits (green certificates) determine a clear improvement in the possible revenues from the plant. These were calculated to be euro23-25 per person per year; as a consequence the costs and incomes can be considered comparable for wastewater treatment plants (WWTPs) with size larger than 10,000 pe. Therefore, anaerobic co-digestion of biowaste and sludge can also be considered a sustainable solution for small wastewater treatment plants in rural areas where several different kinds of biowaste are available to enhance biogas production in anaerobic reactors.
Department of Environmental Sciences, University of Venice, Dorsoduro 2137, Venice, Italy.
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Cecchi
D000383:Agriculture; D000693:Anaerobiosis; D003365:Costs and Cost Analysis; D007182:Income; D010865:Pilot Projects; D012722:Sewage; D014865:Waste Disposal, Fluid / Q000191:economics* / Q000379:methods; D014866:Waste Products
D012722:Sewage; D014866:Waste Products