Performance of wetland roof withMelampodium paludosumtreating septic tank effluent

Abstract

Wetland roof (WR) system was developed to apply for building terrace and top roof in the urbanized area of Ho Chi Minh City. This study aims to improve the green area of the city and to treat domestic wastewater through a shallow horizontal subsurface constructed wetland that is located in a household roof. The pilot-scale unit of horizontal subsurface flow WR system with Melampodium paludosum, an indigenous emerging plant in Vietnam, was experimented at the average hydraulic loading rate (HLR) of 338 m 3 /ha d ($36 kg COD/ha d) corresponding to HRT of 18 h. The treatment performance was not significantly different for rainy and sunny days at various HLRs. It was observed that the average removal efficiency of COD was 77-78% or 20-28 kgCOD/ha d for both sunny and rainy days. It is apparent that nutrient removal was greatly achieved as indicated by TN removal efficiency of 88-91% or 17-20 kg TN/ha d. In addition, TP removal reached 72-78% or 1.6 kg TP/ha d for different HLRs. The treated effluent could comply with the standard limits of Vietnam national technical regulation for domestic wastewater. It was also observed that the growth rate of M. paludosum was 0.1 cm/day in length. The ratio between nitrogen uptake by plants over nitrogen removed by WR was 0.13, while the higher ratio of 0.68 was obtained for the case of phosphorus. The temperature of WR units was 4 ± 1˚C lower than that on concrete floor that likely help saving energy for building cooling if applying WR on the top roof. Based on the experimental results obtained to date, the WR system would be a promising system for domestic wastewater treatment especially for urbanized city, where green area is of high demand.

Removal of chemical and microbial contaminants from greywater using a novel constructed wetland: GROW

“…In-order to improve the green area of the city and to treat domestic greywater through a shallow horizontal subsurface constructed wetland that can be located in a household roof. A Wetland roof (WR) system was developed by Thanh et al (2014), the system achieved an average COD removal efficiency of 77-78% or 20-28 kg COD/ha d for both sunny and rainy days. The system was able to remove nutrients also effectively with a TN removal efficiency of 88-91% or 17-20 kg TN/ha d, and a TP removal efficiency of 72-78% or 1.6 kg TP/ha d for different HLRs.…”

Blue–Green Infrastructure for Flood and Water Quality Management in Southeast Asia: Evidence and Knowledge Gaps

“…Several studies also examined other design options, e.g. roof wetland (Bui et al 2014), or different feeding strategies (Ni et al 2013).…”

A mini-review on shallow-bed constructed wetlands: a promising innovative green roof

“…In addition, Bryum muehlenbeckii, Iris pseudacorus, and Juncus effucus were also used [22,24]. Recent studies (Table 1) of SCWs or WRs focused on studying other plant species, which could adapt to rooftop conditions and increase landscape aesthetics [10,12,25]. Generally, plants have positive effects on the performance of SCWs.…”