Shock-Resistant Biogas Digester for Cookstove Fuel

EPA Grant Number: SU836795
Title: Shock-Resistant Biogas Digester for Cookstove Fuel
Investigators: Newton, Susan
Institution: John Brown University
EPA Project Officer: Sergeant, Anne
Phase: I
Project Period: September 1, 2016 through August 31, 2017
Project Amount: $14,999
RFA: P3 Awards: A National Student Design Competition for Sustainability Focusing on People, Prosperity and the Planet (2016) RFA Text |  Recipients Lists
Research Category: Sustainability , P3 Awards , P3 Challenge Area - Energy

Description:

Design an improved residential-scale biodigester for the production of methane gas from food waste.  The system will provide enough methane for four hours of cooking per day and be installed at the CCC Children’s Home orphanage in Wolaita, Ethiopia under Aerie Africa (NGO) oversight and funding.

Objective:

Finding affordable and sustainable sources for cooking fuel that are also clean is a difficult task in developing nations. A constant source of on-site fuel would provide a cleaner, less expensive option for daily cooking needs. Our objective is to put the waste from food production to work in a biogas digester to produce methane gas for fueling a burner range. Bio-digesters have been implemented in the past with some success but tend to require operator attention to details such as pH, temperature, and water content. Our goal is to improve the typical bio-digester design to include a solar-powered management system and a solar thermal hot water system. These systems would be capable of taking some of the maintenance of the digester out of the hands of the operator and make it simpler to operate.

Approach:

Our team of students will design an improved residential-scale bio-digester for the production of methane gas from food waste. This system is being designed with the assumption that the users do not have the technical knowledge needed to understand how to manage an anaerobic digester. For this reason, the proposed design includes equipment for monitoring the pH level and temperature of the reactor. A basic display consisting of LED lights will inform the user about what actions to take in order to ensure the digester maintains its optimal efficiency. The design is based on an up-flow sludge blanket digester. It will include a preprocessing tank in which the input material is blended before it is pumped into the main reaction chamber. Testing will include the tracking of temperature and pH in order to make sure the design effectively operates in the mesophilic temperature range and at pH levels that will not hinder the growth of bacteria necessary for digestion.

Expected Results:

The goal of this project is to design a reliable biogas digester capable of producing 50% methane gas that can be operated in the absence of advanced technical knowledge. The digester will notify the operator via indicators of the need for water, lime, or heat. The digester will be tested under various conditions with different substrates.

Supplemental Keywords:

Renewable energy, waste-to-energy;