As you recycle paper microbial contamination can be an issue. Generally that is not something recycled paper mills worry about. How do you think it is addressed? ( think about how you can kill microbes)

Describe how the following paper properties change during beating/refining.  tensile strength density of sheet tear strength drainage of water during paper formation Explain why the properties change in this way. That is, why does tensile strength increase or decrease? What changes are made to the pulp that result in the paper properties changes?

Describe a forward cleaner. Be sure to address the following questions.  Where is the pulp inlet? Separation is accomplished based on what principles? Where do rejects and accepts exit?

What thickening device would you use if you wanted to get your pulp consistency from 1 percent up to around 4 to 8 percent?

Why is it that you generally have a washing stage after every bleaching stage? Do you normally send the bleach plant effluent to chemical recovery section? If not why not? Where do you send the bleach plant effluent then?

Sort the following chemicals into the three given categories. Some chemicals might belong in two different categories. Categories:Lignin removing chemicalsLignin retaining chemicalsReducing agentsChemicals to sort:sodium hydrosulfitechlorineFASchlorine dioxideozoneoxygenhypochloritehydrogen peroxide

What are some of the key considerations (4) in choosing up flow vs down flow towers or a combination while designing a given bleaching stage? Use known bleaching stages as examples to explain your answer.

The pH in peroxide bleaching of mechanical pulps has to be adjusted in a way so it is above 9.5 at the end of the reaction. Why is that ?

Why is Mg salt added to the oxygen bleaching system?

Why is the air supply for the primary air inlet in a recovery boiler generally “starving” the system (not enough air is provided to completely burn organic material to CO2)?