| Abstract |
Purpose This study evaluates the suitability of construction and demolition waste (CDW) and a preselected plant palette for removing contaminants from light gray water (LGW) in nature-based solutions. Methods One-liter containers were packed with one of the following types of CDW: concrete aggregates (CAs), crushed permeable pavement (CPP), crushed recycled bricks (CRBs), or crushed recycled tiles (CRTs) as well as a soil layer on top of each type of CDW. Containers were planted with vascular plants (Portulaca grandiflora, Chrysopogon zizanioides, Tradescantia pallida, or Nephrolepis obliterata). Plant-free controls were also prepared for each type of CDW. The containers were fed once a week for eight weeks with real LGW, and the effluents were collected to analyze turbidity, electrical conductivity, pH, ammonia nitrogen, phosphates, and chemical oxygen demand (COD). Results CDW correctly supports the growth of the tested vascular plants and removes the analyzed pollutants in the following order of efficiency: CAs > CPP > CRBs > CRTs. The quality of effluents treated with CAs improved significantly with each tested plant, especially C. zizanioides; this combination removed 32% turbidity, 38% ammonia nitrogen, 33% phosphates, and 34% COD. Conclusions CAs and C. zizanioides are promising elements for nature-based solutions such as rain gardens, bioswales, or green walls aimed to treat LGW. However, the leaching of electric conductivity from CDW, the proportion at which soil and CDW are added, and a more significant hydraulic retention time than the one used in this study must be considered to improve LGW treatment. |
