Please help with question 4a,b and c with a step by step solution. Thanks!

Asap please!

4. Reklatis pg 101 Q2.31: A counter-curent thickener consising of three stages is shown in Figure 3 is used in a Kraft paper mill to wash a 'white mud' consisting of 35% solids ( CaCO3) and 17%NaOH in water. Two wash streams are used, the first (stream 5) contains 4% suspended solids, 6%NaOH, and the rest H2O, the second (steam 8) contains no solids, 2%NaOH, and the rest H2O. The clear liquid from stage I and stage II contain 0.5% suspended solids; the clear liquid from stage III contains 0.4% solids. The flow of wash liquid to stage II (stream 5) is 1.5 times the flow ofthe feed sludge (stream 1), and the washed sludge from stage II contains one third solids The washed sudge from the third stage (stream 9) contains 325% solids and 25%NaOH, and the flow rates of steams 7 and 9 are equal. All compositions are given on a mass basis. Assume that in each stage the clear solution and the solution contained in the washed sludge have the same concentration. Figure 3 a) Calculate the concentation of NOOH in stream 4 . Explain your solution strategy and show all calculation steps. b) Suppose we assume that the solids content of the recycle steam (10 and 6 ) is negligible. How does this affect yoursolution strategy? c) Suppose the specified flow ratio of stream 5 and 1 is replaced by the NaOH composition of stream 7 (i.e. W7, NaOH is given). How does this affect your solution strategy