The effectiveness of analog Vertical Flow constructed wetland for treatment of pulp and papermaking wastewater using different substrates

The analog Vertical Flow constructed wetland with different substrates were built to treat chemimechanical pulping wastewater. The anthracite, shale, general biological ceramsite and fine biological ceramsite were selected as substrates and three of them were chosen to have a pairwise testing. The results show that: (1)the four substrates have different removal rates for the wastewater: the anthracite and fine biological ceramsite have a better result: the removal rates of COD can get 98%and 68.5%, respectively when the system runs 8days; the anthracite is the best one for the chroma removal. (2) the pairswise testing shows the group of fine biological ceramsite and anthracite has a better effect on COD removal, and the concentration of COD is abated from 850mg/L to 220mg/L, better than the single fine biological ceramsite substrate (461 mg/L). (3) according to the best removal rates of COD, TP and chroma, the anthracite substrate or the group of anthracite and fine biological ceramsite are suggested to choose for the analog constructed wetland system with the suitable retention time of 3 days, and the longer retention time doesn´t have a better effect.