Greywater pollutant removal efficiency was similar in tropical horizontal and vertically constructed wetlands

Abstract Centralized wastewater treatment plants are expensive, particularly in countries with significant costs. In such cases, a more suitable option is to adopt low-cost alternative technologies. Constructed wetlands (CWs) are a cost-effective and environmentally beneficial way to treat different kinds of wastewater. It’s a cost-effective and ecologically practical way to treat different types of wastewater. It is also advisable to promote the use of decentralized wastewater treatment systems, specifically by employing constructed wetlands at individual household levels. Therefore, this research sought to evaluate the efficacy of vertical and horizontally built wetlands for treating household greywater. This experimental study used Cyperus alternifolius plant species and allocated one day hydraulic retention time (HRT). The mean removal efficiencies in the horizontal and vertical flow systems were 94.39% and 93.58%, 94.43% and 92.16%, 81.31% and 68.08%, 97.12%, and 99.42%, and 665.18% and 726.53% for BOD, COD, TSS, Detergent and DO increase respectively. Overall, there was a similarity in the effectiveness of removing the measured pollutants in both horizontal and vertical systems. These results showed that flat or vertically constructed wetlands have equal potential as alternative methods for treating household greywater.