Physicochemical and Biological Contribution of Native Macrophytes in the Constructed Wetlands to Treat Municipal Wastewater: A Pilot-Scale Experiment in a Sub-Tropical Climate Region

TY - JOUR

T1 - Physicochemical and Biological Contribution of Native Macrophytes in the Constructed Wetlands to Treat Municipal Wastewater: A Pilot-Scale Experiment in a Sub-Tropical Climate Region

AU - Aalam, Tofeeq

AU - Arias, Carlos Alberto

AU - Khalil, Nadeem

PY - 2022/2/17

Y1 - 2022/2/17

N2 - In this study, the physicochemical and biological contributions of different macrophytes in horizontal sub-surface flow constructed wetlands (HSSF-CWs) to treat low-strength municipal wastewater operated at high hydraulic loads under a sub-tropical climatic region is investigated. Out of the four identical beds, three were planted with locally available macrophytes (P. australis, Sagittaria,and Iris), whereas one bed was kept as a control. The beds were filled with media and operated in parallel continuously for eight months, with increasing the surface loading rate (SLR) from 0.19 to 2.78 m day1. The results indicate that the planted beds performed significantly (p < 0.01) better to remove TSS (70% to 78%), BOD5 (66% to 77%), COD (59% to 75%), NO3-N (56% to 64%), NH4-N (41% to 69%), TN (36% to 41%), and TP (44% to 61%) as compared to the unplanted bed for the same parameters (48%, 39%, 40%, 33%, 18%, 20%, and 29%, respectively). The presence of macrophytes in HSSF-CWs was found to be highly significant. The average relative growth rate (RGR) was observed in the order of P. australis (0.0086 day1) > Sagittaria (0.0061 day1) > Iris (0.0059 day1). When compared to the performances of the species used, Sagittaria and P. australis produced better results than Iris. The investigations on biomass showed that Sagittaria yielded higher production, followed by P. australis and Iris. The proportions of uptake by the macrophytes were found to be 9.3%, 6.3%, and 3.9% of mass N removal, and 7.6%, 5.1%, and 4.4% of mass p removal in Sagittaria, P. australis, and Iris, respectively. This study contributes to the effective response to the environment, which validates a major role of macrophytes and their disparate response to pollutant removal processes bydifferent species from municipal wastewater through HSSF-CWs

AB - In this study, the physicochemical and biological contributions of different macrophytes in horizontal sub-surface flow constructed wetlands (HSSF-CWs) to treat low-strength municipal wastewater operated at high hydraulic loads under a sub-tropical climatic region is investigated. Out of the four identical beds, three were planted with locally available macrophytes (P. australis, Sagittaria,and Iris), whereas one bed was kept as a control. The beds were filled with media and operated in parallel continuously for eight months, with increasing the surface loading rate (SLR) from 0.19 to 2.78 m day1. The results indicate that the planted beds performed significantly (p < 0.01) better to remove TSS (70% to 78%), BOD5 (66% to 77%), COD (59% to 75%), NO3-N (56% to 64%), NH4-N (41% to 69%), TN (36% to 41%), and TP (44% to 61%) as compared to the unplanted bed for the same parameters (48%, 39%, 40%, 33%, 18%, 20%, and 29%, respectively). The presence of macrophytes in HSSF-CWs was found to be highly significant. The average relative growth rate (RGR) was observed in the order of P. australis (0.0086 day1) > Sagittaria (0.0061 day1) > Iris (0.0059 day1). When compared to the performances of the species used, Sagittaria and P. australis produced better results than Iris. The investigations on biomass showed that Sagittaria yielded higher production, followed by P. australis and Iris. The proportions of uptake by the macrophytes were found to be 9.3%, 6.3%, and 3.9% of mass N removal, and 7.6%, 5.1%, and 4.4% of mass p removal in Sagittaria, P. australis, and Iris, respectively. This study contributes to the effective response to the environment, which validates a major role of macrophytes and their disparate response to pollutant removal processes bydifferent species from municipal wastewater through HSSF-CWs

KW - experimental botany; native macrophytes; municipal wastewater; sub-tropical climate; constructed wetlands 1. Introduction

KW - Constructed wetlands

KW - Native macrophytes

KW - Sub-tropical climate

KW - Experimental botany

KW - Municipal wastewater

U2 - 10.3390/recycling7010008

DO - 10.3390/recycling7010008

M3 - Journal article

SN - 2313-4321

VL - 7

JO - Recycling

JF - Recycling

IS - 1

M1 - 8

ER -