Mekelle University The School of Graduate Studies Faculty of ...

Ingredient Characteristics: Moisture Carbon NitrogenCow dung: Q1 = 10M1 = 80.5%H2OC1 = 7.9%carbonN1 = 0.3%nitrogenBiosolid: Q2 =?M2 = 79.8%H2OC2 = 4.4%carbonN3 = 1.3%nitrogenRice husk: Q3 =?M3 = 8.3%H2OC3 = 23.4%carbonN3 = 0.2%nitrogenMixture Goals:Moisture: G = 70%C/N ratio: R = 55We will find:Q2 = 0.22 kg and Q3 = 1.74 kgThus if we mix 0.22kg of biosolid and 1.74kg of rice husk with the initial 10 kg cowdung, the mixture will achieve our goals of 70% moisture and a 55:1 C/N ratio.Note that this simultaneous solution for three ingredients depends entirely on having theright three ingredients to combine. With many combinations the resulting Q2 and/or Q3will be negative, indicating that no solution is possible. In that case you can add anadditional material to add to the mix, such as sawdust or wood chips if the moisture ornitrogen levels are too high. Of course, if we add more ingredients, we also need adifferent formula to determine the solution.For increasing numbers of materials, this formula becomes even more complicated. Thesolution for a mixture of four ingredients follows.42