Recovery of Nitrogen and Phosphorous From Source Separated Urine Using Biochar
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Date
2019-10
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Addis Ababa University
Abstract
Nutrients mainly nitrogen and phosphorous exist in wastewater excessively. If uncontrolled,
they lead to eutrophication problem which has adverse impacts on the social, economic and
ecological values of surface water bodies. Urine is a significant contributor of phosphorus and
nitrogen found in domestic waste water. Therefore, recovery of these nutrients from urine
removes the excess amount of nutrients and prevents environmental pollution. In addition
removal of Phosphorus in wastewater treatment plants is costly and limits its recovery and use
as a resource. Recovery of nutrients from source separated urine would increase the efficiency
in nitrogen and phosphorous removal and reuse capacity. The objective of this research was to
examine different parameters affecting the recovery of nitrogen and phosphorous through
adsorption process by using biochar produced from corn cob(CC), coffee husk(CH) and water
hyacinth(WH) and determine nutrient recovery efficiencies of each biochar from human urine.
In this research, the impacts of different parameters which can affect nutrient recovery from
source separated urine using biochar were examined to get optimal values. The nutrient
recovery process was conducted under different pH (3-8), biochar dosage (0.2-1g) and contact
time (30-150min.) on urines of different storage time (15days, 1 month and 2 month). The
optimum working values of pH and contact time were 6 and 60 minutes, respectively. The
optimum dosages were 0.4g, 0.6g and 0.8g for 15 days, 1 month and 2 months stored urine.
Highest NH4
+
3—
-N and PO4
P recoveries were obtained from urine that had two months of
storage time. Therefore, urine with two months storage time was selected as optimal. Under
these optimum values, the nitrogen recovery efficiencies of biochars produced from CC, CH
and WH were 94.13%, 77.99% and 85.78%, respectively. The recovery efficiencies of
phosphorous from human urine were 68.60%, 71.14% and 57.72 % using CC, CH and WH,
respectively. CC produced biochar was the best compared to CH and WH biochars. Biochars
produced from wastes have good potentials for nutrient recovery from source separated
urines. Besides, the use of waste as resource is in line with sustainable waste management and
contributes to environmental pollution control.
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Keywords
biochar, efficiency, recovery, source separated urine, nitrogen, phosphorous