Use of a cascade system based on marine sand and bottom ash in the treatment of cardboard manufacturing wastewater by infiltration percolation

The production of electrical energy in thermal power plants generates huge quantities of solid waste (fly ash and bottom ash). The valorization of these by-products becomes imperative for safeguarding the environment. The fly ash is used in the manufacture of cement; but locally, it is not the case of the bottom ash that is buried in landfills. In this paper, we present the results of wastewater treatment of a cardboard plant by an optimized prototype cascade station (scale: 1/1000). The succession of filter beds consists of crude bottom ash, crushed bottom ash, and coastal sands in appropriate proportions. The filtrate at the outlet of each floor is analyzed. Respecting the current regulations, the desired parameters are the suspended solids (TSS), COD, BOD5, pH, and trace elements (As, Fe, Zn). The results of the tests allowed us to reach a COD abatement is 85%. When leaving the 3rd floor, it was 94.5% and finally, at the exit of the fourth, it is 95%, an important reduction of BOD5. At the exit of the 2nd floor, the abatement is 75.6%, at the exit of the 3rd, it is 78.6%. Finally, an overall rate of 79% was obtained, a significant TSS reduction up 95.6% at the output of the 2nd floor. By leaving the 3rd floor, it is 96.12%. Overall, the developed system achieves a TSS abatement rate TSS of 96.34%.and the elimination of trace elements such as zinc, iron, and arsenic (84%, 48%, and 57% respectively).