Abstract
With the recycling of waste paper increasing year by year, the pollution of de-inking wastewater is more and more serious. So the wastewater must be clarified. The de-inking wastewater is often treated with polyaluminum chloride (PACE as a coagulant and polyacrylamide (PAM) as a flocculant, but PAM is relatively expensive. It is expected that a substitute of PAM, which is cheaper and nontoxic, could be found.
The de-inking wastewater in the experiment is treated with cationic polyacrylamide (CPAM), precipitated calcium carbonate (PCC), talc powder and calcium carbonate refined from recycled lime mud as flocculant respectively. The results showed that, about 79% CODcr, 96% SS and 99% turbidity of the de-inking wastewater can be decreased at optimum conditions, respectively. According to the result, PCC and talc powders, as well as calcium carbonate refined from recycled lime mud could substitute for CPAM as the flocculant in the wastewater treatment. Especially, with calcium carbonate refined from recycled lime mud as the flocculant, the waste could be recycled and beneficially used. Finally, calcium carbonate refined from recycled lime mud could be used to substitute PAM in the treatment of deinking wastewater.