Removal of faecal bacteria and nutrients from domestic wastewater in a horizontal surface flow wetland vegetated with Echinochloa pyramidalis

Abstract

The aim of this study was to evaluate the removal of faecal bacteria and nutrients from domestic wastewater, in surface flow wetlands vegetated with Echinochloa pyramidalis. Horizontal surface flow (HSF) wetlands were fed with primarily treated domestic wastewater at organic loading rates varying from 20.74 to 27.15 g BOD/m 2 /day for two consecutive years. Water samples were collected at two weeks interval from the inflow and the outflow of the treatment wetlands for physicochemical and faecal bacteria analyses. Physicochemical parameters with highest removal rates were total suspended solids (TSS, 62-80%), Nitrates (57-73 %) and PO 4-3 (57-84 %). Faecal indicators reductions of 1.4 and 0.3 log units (1 st year) and 1.15 and 0.65 log units (2 nd year) were respectively recorded in the vegetated and the control wetlands. Reductions of total coliforms, faecal coliforms and faecal streptococci were significantly higher in the vegetated wetland than in the non-vegetated control in both seasons of the first year. In the contrary, there was no significant difference in the removal rates of faecal indicators between vegetated wetland and the non-vegetated control during the dry season of the second year. Wetlands vegetated with E. pyramidalis was proven to be continuously efficient in the removal of faecal indicators for the two years of study, with no significant differences between the seasons of the year and between the years.

Wastewater Treatment Potentials of Vegetated Beds with <i>Brillantaisia cf. bauchiensis</i> Hutch & Dalz and <i>Polygonum salicifolium</i> Brouss ex Wild in the Western Highlands of Cameroon

“…Nevertheless, there was more phosphate in the outflow effluent than in the inflow of the beds indicating that aerobic and anaerobic breakdown of organic matter occurred in the treatment beds such that reduction efficiency had negative values. Moreover, since there was no significant difference between the inflow and outflow in nutrient reduction, these could be as a result of more aerobic breakdown of the organic matter in the presence of oxygen released at rhizosphere in the vegetated beds and anaerobic breakdown and filtration time in both the vegetated and non vegetated beds [13] [31]. A high concentration of phosphorus in the outflow wetland bed vegetated with Brillantaisia bauchiensis than the inflow was prove that more breakdowns occurred in the beds.…”

“…Therefore, wetland macrophytes should be identified locally for ecological wastewater management. Some wetland macrophytes tested for this purpose proved to produce high biomasses with high remediation potentials [16] [13] [14] [15] but these were not wetland species of medicinal importance like Brillantaisia bauchiensis or B. fulva (Acanthaceae) and Polygonum salicifolum (Polygonaceae) used as food for welfare and healthcare in the Western Highlands of Cameroon [22].…”

Evaluación del Aporte de las Plantas Acuáticas Pistia stratiotes y Eichhornia crassipes en el Tratamiento de Aguas Residuales Municipales

“…Contrario a los resultados del control donde se alcanzaron eficiencia del 25,0% y 33,0% para la DQO y DBO5 respectivamente. Esta diferencia puede deberse a un medio de soporte para fijar el sistema radicular de las Lekeufack et al (2012) usaron Echinochloa pyramidalis a escala piloto y encontró una remoción del 49% de DQO y DBO5 en los humedales con vegetación, y menores de 28,0% en los sistemas control (sin vegetación). El humedal con vegetación fue significativamente más eficiente (p ˂ 0.05) que el control en la reducción de DBO5 y DQO; explicando que estas diferencias se deben al papel que juegan las raíces de las plantas en la matriz sustrato-raíz, especialmente cuando se adhieren a un medio de soporte.…”

“…Todos los sistemas (con y sin plantas) alcanzaron eficiencias superiores al 99,8%. Lekeufack et al, (2012), realizó un estudio para evaluar la eliminación de microrganismos del ARM en humedales a escala piloto. Afirman no encontrar diferencias significativas en los CF y estreptococos; esta diferencias solo ocurre en los CT en época seca.…”

Macrófitas aquáticas do rio Paraíba do Sul: correlação entre diversidade vegetal e algumas caracteristícas físicas da água e do sedimento

“…No entanto, no aspecto ecológico, a presença de um número, mesmo que elevado, de coliformes termotolerantes em bancos de macrófitas, não precisa necessariamente ser interpretada como um efeito negativo desses vegetais sobre a qualidade da água. Essas plantas podem ter efeito biocida sobre vários patógenos de origem sanitária, funcionando, desta forma, como filtro biológico para águas poluídas (CHANG, 2012;MARTIN et al, 2012;MOLISANI, 2006;PEREIRA et al, 2007).…”