Fate of filter materials and microbial communities during vermifiltration process

Abstract

The fate of filter materials and microbial communities during the vermifiltration process were studied for 5 months while treating the concentrated greywater. Four filters were filled with 10 cm gravel of which a layer of medium size gravel (5 cm thickness, aggregate size 20–40 mm) at the bottom and a layer of coarse gravel (5 cm thickness, aggregate size 10–20 mm) at the top, then filled with 20 cm sand (d 60 = 0.2 mm, d 10 = 0.118 mm). Finally, Vermifilter 1 (VF1), control unit and Vermifilter 2 (VF2), were filled with 40 cm fine sawdust (0.05–5 mm) but Vermifilter 3 (VF3), was filled with 40 cm cow dung (0.05–5 mm). Three filters were inoculated with 200 individuals of Eudrilus eugeniae except for the control unit which was filled with sawdust. Five sampling ports were installed on the wall of the filters at 10 cm intervals with reference to the surface of the top layer. Three of the filters were supplied with concentrated greywater and VF1 was supplied with drinking water at the hydraulic loading rate of 16 L m −2 .d −1 on batch basis, i.e., four times a day at 8:00 a.m., 11:00 a.m., 2:00 p.m. and 5:00 p.m. Weekly, samples from influent and effluent, and monthly, samples of filter materials collected via sampling ports, were collected and analyzed.The removal efficiencies of biological oxygen demand (BOD 5 ), total chemical oxygen demand (tCOD), and dissolved chemical oxygen demand (dCOD) of VF2 and VF3 were 5–7% higher than the control unit, but little differences were observed in terms of total suspended solids (TSS). However, the removal efficiencies of nutrients for the control unit was slightly better than VF2 and VF3. The pH and Moisture content (MC) of filter materials increased along the depth, but percentage of volatile solids to total solids (VS/TS) decreased through time due to the high number of microbial communities and earthworms dominating the top layer compared to the bottom. The performance of VF2-sawdust was slightly better than VF3-cow dung to treat concentrated greywater.

Domestic Wastewater Treatment Using Vermifilter Combined With Canna Indica

“…The early wastewater pH affects the survival of bacteria and earthworms, which will degrade organic substances (Singh et al, 2019). The optimal pH for worm growth is 6.2-9.7 (Adugna et al, 2019). PH wastewater before treatment 4.31±0.01.…”

“…Office building wastewater in one city contains Chemical Oxygen Demand (COD) 106 mg/L -432 mg/L, Dissolved Oxygen (DO) 3.2 mg/L, and Total phosphate (TP) 3.66 mg/L (Va et al, 2018). Domestic waste treatment should use easy processing of operation and maintenance, does not require large land, can be done on an individual scale, and is environmentally friendly (Adugna et al, 2019;Samal et al, 2018b).…”

“…Vermibed is at the very top layer of the vermifilter. Media growing worms often use wood powder, bark, peat, straw (Lourenço & Nunes, 2017), garden soil, cow dung (Rustum et al, 2020), vermicompost (Samal et al, 2018b), sawdust (Adugna et al, 2019), Filter media often use gravel and sand (Koslengar et al, 2020).…”

Eficiencia en la remoción de materia orgánica mediante lombrifiltros (Eisenia foetida) en aguas residuales domésticas para zonas rurales

“…Similar comportamiento reportó el estudio de Adugna et al (2019) en el proceso de vermifiltración, en el cual, durante el tratamiento biológico, el pH se estabilizó con rangos similares.…”

Vermifiltração: o uso de minhocas como uma nova alternativa para o tratamento de esgoto

“…Desde então, o vermifiltro tornou-se uma alternativa de tratamento de efluentes sanitários, tanto para o tratamento de esgotos domésticos (SINHA et al 2008;LIU et al 2013;NIE et al 2014) como para águas cinzas (ADUGNA et al 2019) e águas de vaso sanitário (FURLONG et al, 2015). Sua construção e operação simplificadas viabilizam sua aplicação em sistemas descentralizados, podendo ser dimensionado para unidades unifamiliares ou para estações semicoletivas .…”