Composting of the Urban Garbage: Assessment of the Nutrient Elements for the Plants, Case of Niamey in Niger

Composting is a process of natural decomposition of biodegradable waste. It represents one of the waste management techniques that is consistent with sanitation and whose resulting product can serve as a soil remediation agent. The objective of this work was on the one hand to compost the biodegradable urban waste of the city of Niamey and on the other hand to analyze the physic-chemical parameters characteristic of the nutrients of the final product. Thus, three types of composts C1 (waste), C2 (waste + natural phosphate from Tahoua, PNT) and C3 (waste, phosphate rock from Tahoua and manure) were developed using the aerobic composting technique (in pit). The process lasted five months during which we periodically carried out control measures of the physicochemical parameters (T °, pH and C / N). The analysis of the physical parameters of the composts obtained C1 , C2 and C3 are respectively for the pH: 9.5, 9.1 and 8.1 and for the temperature about 33 ° C and the chemical analysis revealed carbon contents (10.99%; 11.89% and 14.07% for C1 , C2 and C3 respectively); in nitrogen (1.12%, 1.40% and 1.57% for C1 , C2 and C3 respectively), the C / N ratios are: 9.81; 8.49 and 8.96 for C1 , C2 and C3 respectively; fertilizer elements: total phosphorus (1110, 7220, 14665 ppm for C1 , C2 and C3 respectively), available phosphorus (322, 458.5, 686 in ppm for C1 , C2 and C3 , respectively), potassium (34,000, 18,000; 10000 ppm for C1 , C2 and C3 respectively); Calcium (48.00, 123.5, 98.00 ppm for C1 , C2 and C3 respectively); magnesium (65.57, 627.87, 609.83 ppm for C1 , C2 and C3 respectively); chlorine( 221.87 ; 207.67 ; 136.67 ppm for C1 , C2 and C3 respectively) and sodium (11600, 5200, 1840 ppm).