Grantee Research Project Results
2012 Progress Report: Renewable Energy-Powered Bulk Milk Cooling for Smallholder Dairy Farmers
EPA Grant Number: SU836006Title: Renewable Energy-Powered Bulk Milk Cooling for Smallholder Dairy Farmers
Investigators: Kisaalita, William S.
Current Investigators: Kisaalita, William S. , Rush, Bryan , Ndyabawe, Kenneth , Ssonko, Richard
Institution: University of Georgia
EPA Project Officer: Page, Angela
Phase: II
Project Period: August 15, 2011 through August 14, 2012 (Extended to August 14, 2014)
Project Period Covered by this Report: August 15, 2011 through August 14,2012
Project Amount: $75,000
RFA: P3 Awards: A National Student Design Competition for Sustainability Focusing on People, Prosperity and the Planet - Phase 2 (2011) Recipients Lists
Research Category: Pollution Prevention/Sustainable Development , P3 Challenge Area - Sustainable and Healthy Communities , P3 Challenge Area - Air Quality , P3 Awards , Sustainable and Healthy Communities
Objective:
- Objective 1: Construct and start-up a cow-dung anaerobic digester to produce biogas and demonstrate that the regeneration of zeolite can be accomplished under this field condition.
- Objective 2: Install a second generation renewable-energy (biogas) powered milk cooler on a small-scale dairy farm and show that the cooling achieved in the laboratory (to 4 oC within 4 hours) can be replicated under field conditions and establish the cooling cost per liter of milk.
- Objective 3: Establish the greenhouse gas (methane) production from smallholder farm cow dung open pits. This will enable a more accurate estimate of difference in greenhouse gas-methane - emission due to wide spread cooler use.
Progress Summary:
Experiments to determine the optimal temperature for zeolite regeneration of 200oC were determined with a high temperature oven, acquired during Phase I. While work has continued on refining the second generation cooler, it was not possible for the work to be completed in time for the cooler to be tested in Uganda in summer. The reason for this has been a need to modify the design, to achieve a lower (cooled product) temperature. It is anticipated that the “lower temperature” version will be tested next summer; the prototype will be ready by December, 2012. We originally proposed to construct a 24 m3 digester (CAMARTC design) and to use the cow-dung on Smallholder Fortunes Farm to run the digester. On closer examination, we found that the CAMARTEC design digesters are not working well in the field. Often they experience leakage due to poor cement mixes from builders that are not well skilled. Many larger capacity types exhibit channeling due to linear scale-up from the well proven 6 m3 to larger capacities. The resulting poor performance has eroded confidence among current and possibly future users in the CARMATEC design. We decided to assemble a different type of digester – one made with existing components that are mass produced for a different purpose. For the main vessel, we have repurposed polyethylene water tanks that are readily available in Uganda (Figure 1). The most economical capacity was 10 m3. The second modification that required innovation was sealing the top of the water tank to achieve anaerobic conditions. The rest of the components used are identical to those used with the CARMATEC design. To address the reduced capacity, we decided to construct an additional identical unit after satisfactory construction and testing of the first unit. The two units will provide a capacity of 20 m3 that is close to the original target of 24 m3. The 10 m3 unit produces enough gas for the target cooler user.
Figure 1. Top left: 10 m3 repurposed polyethylene water tank to which cow dung slurry input and outlet as well as gas outlet were incorporate. Top right: installation in the ground. Bottom left: installed seal plate and expansion chamber construction. Bottom right: tank top sealing achieved with clay that is kept wet.
Objective 2: Install a second generation renewable-energy (biogas) powered milk cooler on a small-scale dairy farm and show that the cooling achieved in the laboratory (to 4 oC within 4 hours) can be replicated under field conditions and establish the cooling cost per liter of milk.
As explained above the laboratory cooling target of 4oC within 4 hours has not yet been achieved. As such field testing of the cooler has been delayed. However, the infrastructural requirement (room, plumbing for biogas, have been completed (Figure 2).
Figure 2. This room was added to provide a dedicated space close to the biogas digester for the cooler testing. The blue PVC pipe delivers biogas directly from the digester.
Objective 3: Establish the greenhouse gas (methane) production from smallholder farm cow dung open pits. This will enable a more accurate estimate of difference in greenhouse gas-methane - emission due to wide spread cooler use.
The original experimental design that called for work on many smallholder farms was very ambitious and cannot be achieved with the current budget. We decided to scale the activities so the results from this study will serve as a pilot to establish procedures and generate preliminary data that will be used in support of a larger proposal for a wider study that will cover many smallholder farms in Wakiso disctrict. The work is therefore being limited to two Smallholder Fortunes cow dung pits (Figure 3). So far, the static collection chamber has been installed. As originally proposed, the chamber was connected to a tube that releases the gas in an inverted water-containing second chamber to trap the emitted biogas. Using a syringe through a septum connected to the inverted water chamber gas from the pit has been sampled. Unfortunately, an independent reliable gas composition analysis was not found this summer. A PID portable CH4 /CO2 Analyzer (+/- 2% error) has been procured and will be put in operation during our second trip in January, 2013.
Figure 3. One of three biogas-emitting cow dung pits to which the static collection chamber (not shown) was attached. Gas production will be monitored with the PID analyzer.
Journal Articles:
No journal articles submitted with this report: View all 5 publications for this projectSupplemental Keywords:
Well water, drinking water, effluent-irrigation, biosolidProgress and Final Reports:
Original AbstractP3 Phase I:
Renewable Energy-Powered Bulk Milk Cooling for Smallholder Dairy Farmers | Final ReportThe perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.