Krishna Lunch Project
Overview
By: Ajoke Agboola and Cherona Levy
Over the past year there has been a lot of discussion concerning the Krishna lunch and what should be done with the waste produced. The Hare Krishna recently decided to buy plates and cups made from bagasse, in addition to forks from potato starch. a biodegradable byproduct of sugarcane. With this switch many groups were interested in the possibility of composting the waste or anaerobically digesting it into methane. Before endorsing a project it is important to get some base data, and that is exactly what the Bioenergy Interns set out to do. The interns conducted a Krishna Lunch waste audit throughout most of June, collecting waste, analyzing the waste, and experimenting with various digesting methods.
Beginning June 6th -8th with the aid of two teaching assistants, the interns collected preliminary data. This was an important step as it helped the interns formulate a proper plan to efficiently and successfully collect as much of the generated waste as possible. The week of June 11th the interns collected, sorted and counted the waste daily. This provided good insight into the proportions of the waste, food, cups, plates, forks and napkins. On June 18th and 19th the interns collected more Krishna Waste in order to test different digesting methods.
The interns tested many different composting methods in order to acquire data on how long each method took and to figure out which method was best. With the waste from the preliminary collections, the interns created a combined compost bin, putting hand ripped plates and cups into the bin along with the food waste and a variety of compostable food waste the interns generated. The second compost batch contained the waste from June 18th ans was composted on June 19th. This batch the interns simply poured all of the waste into the compost bin to test the composting feasibility. The third compost batch contained the waste from June 19th and was composted on June 22nd. This waste was shredded into coin size particles, testing the benefit of smaller particle size on decomposition. Some of the unshredded plates were laid down on a plot of grass where mulch will be applied to beatify our outdoor energy lab. The plates will kill the grass before the mulch is applied and hopefully be decomposed under the mulch. The final aspect of our project is anaerobic digestion. The food waste from the week of June 11th was saved for anaerobic digestion.
On June 22nd the Bioenergy Interns began the anaerobic digestion portion of the project. The anaerobic digester is an oxygen free system that utilizes bacteria cultures to convert the waste into methane. The methane can be burned and is very similar to natural gas. A byproduct of the digestion process is effluent, which can be used as fertilizer or a feedstock for other processes. The digester is fed ever other day with a mixture containing 276 grams of food waste and 2.8 liters of deionized water. The diluted mixture is then added to the inlet of the anaerobic digester. Recordings of the temperature, pH, feeding times, and water displacement (approximates gas production)are completed daily.
There are several observations that have been made concerning the Krishna Lunch waste. First, the majority of the waste is plates and cups. There is only a small amount of food waste to aid in decomposition or to be anaerobically digested. Second, the forks are very dense and will likely take a very long time to biodegrade. Finally, the effort required to separate the food waste from the bagasse based products might outweigh the benefit considering the small amount.
Krishna Lunch Waste Photos
Krishna Lunch Waste Data
The data from the 5 days of collection is organized into a spreadsheet, showing the amount of each item collected, along with the weight of the food waste, food waste per plate, and averages for the week . The data for the final two days is also shown, listing the total weight of waste collected for those days, waste per plate, and estimated food waste.