Work

Performance comparison of temperature-based and mass transfer-based horizontal subsurface flow constructed wetland designs

Year: 2025

Type: article

Abstract: ABSTRACT Two similar horizontal subsurface flow constructed wetlands (HSSF-CWs) that only differ in the wastewater flow length were compared in terms of their performances. The HSSF-CW with a longer wastewater flow length has two baffles, implying that interstitial velocity was considered when designing the system. In contrast, the unbaffled HSSF-CW considered temperature when designing. A significant difference (P < 0.05) was observed between the two systems in the removal of biological oxygen demand (BOD), chemical oxygen demand (COD), ammonia nitrogen, and fecal coliform (FC). Baffled system effluent contained mean BOD levels (32 ± 13 mgO2/L), COD (47 ± 15 mgO2/L), ammonia nitrogen (28 ± 8 mgN/L), and FC (4.4 ± 0.2 log unit). Unbaffled system effluent contained mean BOD levels (38 ± 16 mg/L), COD (57 ± 20 mg/L), ammonia nitrogen (31 ± 8 mgN/L), and FC (5 ± 0.2 log unit). No significant difference (P > 0.05) between the two systems was observed for nitrate nitrogen and phosphorus reduction. In general, the performance of the baffled system was better than the unbaffled one, although both systems complied with the WHO discharge limit for the COD (60 mgO2/L). This confirms that the interstitial velocity is an important parameter in HSSF-CW designing in tropical countries.

Source: Water Practice & Technology

DOI: 10.2166/wpt.2025.090

Authors: Anita M. Rugaika, Bart Van der Bruggen, Karoli N. Njau

Institutions: Nelson Mandela African Institution of Science and Technology, Korea University, KU Leuven

Language: English

Topic: Constructed Wetlands for Wastewater Treatment

Subfield: Waste Management and Disposal

Field: Environmental Science

Domain: Physical Sciences

SDG: Clean water and sanitation

Open Access status: hybrid

Funder: VLIRUOS