Abstract:
According to FOA (Food and Agriculture Organization of the United Nations) 2011, roughly one-third of the edible parts of food produced for human consumption, gets lost or wasted globally, which is about 1.3 billion ton per year. In the case of Bahir Dar City, about 70 % of the generated MSW (69 tons per day) is collected and disposed to the disposal area, which makes the annual municipal solid waste 25,185 tons disposed. About 2% of waste (2 ton per day) is used to produce compost in the city service compost site. Because this kind of waste is a threat to the environment and human well being, this should be managed appropriately. This study has tried to produce quality compost from the food waste by using passively aerated composting technique.
In this study, a total of 9 compost bins have been constructed using woods and plastics and used to process the sampled food waste. Each composter (Compost Bins) has 0.3 meters height, 0.7 meters length and 0.4 meters width. Three different bulking agents have been used with three replication of each. The different mixtures of Food Waste and Bulking Agents are T1 (9.9:1), T2 (6.0:1) and T3 (3.5:1) of the ratio food waste to wood chips. The other treatments were T4(9.8:1), T5(5.9:1) and T6(3.3:1) with the ratio of food waste and chopped teff straw. The remaining three treatments were T7(9.7:1), T8(5.7:1) and T9(3.1:1) in the ratio were food waste to dried leaves. Essential parameters (temperature, pH, bulk density, moisture content, total nitrogen, total phosphorus, total potassium, organic content and heavy metals ) were measured during the two months (60 days) processing of the compost. The mean physic-chemical parameters were found to be acceptable when they were compared with different countries compost guideline. The mean temperature was 29.96oC. The maximum temperature was 65 oC and the minimum was 13 oC. The maximum moisture content was found to be 79.25%. The highest organic content was recorded at Trial 6(32.73%) and the lowest at Trial 7(29.19%).
From all the 9 trials, only mixtures of food waste to chopped teff straw with a ration of 6.1:1 and mixtures of food waste to sawdust with a ratio of 9.8:1 meets the criteria required by different countries compost guideline. The mixtures fulfills the requirement set by Australia which states the process should attain a temperature of > 55C for at least 3 days allowance for variation and lower temperatures in order to kill the pathogens available. Heavy metals lead, cadmium and nickel are within acceptable limits. All these values are acceptable and are in conformity with standards of Germany, Austria and New Zealand. Therefore these final products could be applied for agricultural purposes and other similar purposes.