Food, Energy and Water Nexus: Co-digestion of Food Wastes with Municipal Sewage Sludge
Citation:
Clark, S. Food, Energy and Water Nexus: Co-digestion of Food Wastes with Municipal Sewage Sludge. AIChE Annual Conference on Water, Washington, DC, December 01 - 03, 2021.
Impact/Purpose:
The presentaion is to an institute of chemcial engineers from a variety of industrial sectors. The purpose is to inform and interest them in the use, application and adoption of this emerging technolgy. Energy is expensive and renewable energy is offering opportunities for reducing cost (wastewater utilities use lots of energy). Muncipal wastewater treatment plants settle biosolids from wastewater, then treat and dispose of those biosolids. One way of treating biosolids is using anaerobic digestion, which produces methane gas (natural gas). There are two emerging trends: 1) new laws requiring separate collection and disposal of food waste and 2) distributing sources of energy – electricity and gas (on-site vs. grid). Currently, Sanitary Landfills are an improvement over burning dumps used in the 1960’s. Methane emissions and leachate might create pollution. Food waste are opportunity for “waste haulers” -- collection is not disposal. Anaerobic digestion can create methane and some parts of the food and agricultural industry are already building digesters.
Description:
The presentaion will describe the current state of the art for co-digestion of prepared food wastes with municipal sewage sludge. The mixture enhances the production of methane. That methane can then be sold as natural gas or used to create heat or electrical energy for use on site. There are multiple benefits -- lower energy cost, less pollution from food wastes entering landfills and improeved resiliance to electrical power loss due to onsite electrical generation. There is also a reduciton in green hosue gases