Description of Compost Samples Prepared in a Teaching Institution
Background: The increased pressure on food consumption has led to enlarged quantities of organic waste which disposal requires both energy and spaceand instigates several damaging environmental impacts. Composting is a solution for organic waste management; it involves the use of organic waste to produce an end product with high bioenergy potential and significant nutritional value for the soil.The objective of this study if to analyse the physico-chemical and microbial properties of compost prepared by students to assessits quality and identify means to improve it.
Methodology: As a project for the microbiology course of Zayed University in Dubai, students prepared compost using home-generated organic wastes. The samples were analysed for various physico-chemical properties and submitted for microbial identification using the FISH technique.
Result: Twelve different compost samples were prepared over a period of 3 months. Parameters related to organic matter, electrical conductivity and pH were within the range of values of a standard compost while the moisture content of the majority of samples was low, probably due to the mixing of compost with desert sand. Concerning macronutrients found in the 12 samples, Potassium (K) was found in high amount between 0.32 to 0.95% followed by Sodium (Na) between 0.11 to 0.45% and Phosphorous (P) between 0.05 mg/kg and 0.31 mg/kg. Nitrogen (N) content was the lowest with quantities between 0.02% to 0.15%. The low availability of nitrogen is strongly related to the immaturity of the compost. Microbial identification revealed the presence of actinobacteria, various proteobacteria, archaea and different nitrifying bacteria which facilitate the decomposition process. The results reveal that the composting duration of 3 months is not long enough to lead to the complete decomposition of organic wastes. Some compost samples need more maturationand have to be decomposed further.Increasing nitrogen content by enriching the compost with fallen leaves, grass clippings, coffee grounds, fruit and vegetable scraps may accelerate the composting process.
Conclusion: The findings reveal the efficiency of the specific composting technique applied by the students to recycle organic waste. They highlight nevertheless the need to lengthen the compositing duration and increase the nitrogen and water content to obtain a fully mature compost. On the long term, this composting technique will allow the development of a rational and efficient way to manage organic wastes all year round and return nutrients back into the soil to make it a beneficial environment for growth of vegetables.
Keywords - Compost, waste management, Electrical Conductivity, pH, moisture, sodium, potassium, phosphorous, nitrogen, bacteria, Fluorescence in-situ hybridization