| Title |
A study on Calcium Removal in Liner Paper Whitewater and Variation of Paper Quality |
| Authors |
이원근 ( Won Kwon Lee ) ; 신응배 ( Eun Bai Shin ) ; 박대원 ( Dae Won Pak ) ; 손성섭 ( Seong Seop Son ) ; 이상봉 ( Sang Bong Lee ) |
| Abstract |
These days many mills began to reduce the amount of water consumption by reusing treated water, which resulted in sharp elevation of organics level in their white water. In addition to the increase of organics, calcium hardness also increases since recycled paper is used as raw material in liner paper industry. Detrimental effects which high level of organics and calcium hardness may cause in paper industry were well reported. In this paper new process using UASB+CO_2 Stripping unit was suggested to remove both organics and calcium hardness from wastewater of liner paper industry, Furthermore effects of treated process water on paper quality were also elucidated using paper sheet former. As results, the removal efficiency of COD was maintained more than 70 % till COD loading was up to 18 kg COD/㎥d, methane gas production rate increased in proportion to COD loading and its ratio was estimated about 0.15 ∼ 0.25 g CH_4/g COD removed. CO_2 Stripping unit was not influenced greatly in HRT`s change, and removed calcium hardness effectively without additional chemical reagents like as sodium hydroxide. Since treated water by UASB+CO_2 stripping unit contains less VFA and calcium ions, paper sheet formed in treated water showed fairly good improvement in the aspects of mechanical property and mill operation. |