Browsing by Author "Johnny, Girma"

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    Recovery of Phosphorus and Nitrogen from Source-Separated Urine: Process Optimization in Bench-Scale
    (Addis Ababa University, 2018-06) Johnny, Girma; Agizew, Nigussie (PhD); Zerihun, Getaneh (Mr.) Co-Advisor
    The main focus of this research is to investigate about the possibility of Nutrient recovery in the form of Magnesium Ammonium Phosphate (Struvite) by determining optimum PH, optimum dosage, suitable mixing time, mixing speed , precipitation time ,and storage time from source separated stored human urine. A laboratory test was conducted using Jar test for the stored human urine. Struvite formation was PH dependent reaction and the experiment was started with PH optimization having six different pH values from PH 6 to 11. The experimental result showed that at PH 10 the percentage removal for N -N and PO4-P was 87.07% and 91.55% respectively, which is greater than other PH’s which implied that the optimum PH was PH 10. Using PH 10 as optimum PH, the determination of optimum dosage (P04-p:M )ratio was conducted using six different mass ratios, i.e. 1:1, 1:2, 1:3, 1:4, 1:5 and 1:6. The result of the experiment showed that, at PH10 and P04-P:M dosage of 1:1, the percentage removal of NH4-N and P04-P was 90.54% and 77.49% respectively which showed the optimum dosage was 1:1. Laboratory tests were also done to determine the optimum mixing time and mixing speed and found to be 30minutes and 60rpm respectively .Two samples were tested to determine the optimum incubation period to recover nitrogen and phosphorus for 25 and 30 days and found to be on 20th and 19th day respectively. Furthermore Basaka water was also used as source of Mg +2 to recover Nitrogen and Phosphorus and about 36% of Phosphorus was recovered and ultimately struvite was produced by the designed stirred reactor.