Food waste and other biodegradable matter in the municipal solid waste stream are a source of environmental and
public health concern in cities of developing countries. Anaerobic digestion applied to urban solid organic waste treatment is
an option to address those issues and to produce biogas, a renewable energy source. This paper presents the design and
economic evaluation of a prototype biogas plant fed by food waste from a restaurant in Mexico City. On average, the
restaurant produces 40.5 kg/day of food waste with 23.0% total solids (TS) and 94.2% total volatile solids (TVS). With this
amount of food waste, around 69.2 L/day of feeding substrate with 12.7% TVS are produced. Considering an operating
temperature of 20°C, total anaerobic digester volume required was calculated at 6.0 m3
. Plant design comprises a continuous
stirred tank reactor (1 m3
) coupled with a conventional digester (5 m3
). Organic loading rate and hydraulic retention time were
1.9 kg-TVS/(m3
·day) and 86 days, respectively. The plant is expected to produce 6.1 m3
/day of biogas for use as a cooking fuel
at the same restaurant, leading to LP gas savings of 692 kg/year. Plant investment cost was estimated at MXN 129,000 (~9,550
USD). Economic evaluation showed that the biogas plant profitability is highly dependent on LP gas price and its annual
growth rate. The prototype biogas plant described here is a step forward in the conception of a biogas facility suitable for cities
in developing countries to collaborate in solving their environmental, public health, and energy concerns.