Influence of sand depth and pause period on microbial removal in traditional and modified biosand filters

A critical overview of household slow sand filters for water treatment

“…A small hole at the top end of the outlet tube (i.e., no-siphon device) can reduce the effects of siphoning and possible emptying of the HSSF (Palmateer et al, 1999), while a valve at the end of the tube can control the maximum filtration rate (Devi et al, 2008). (Maciel and Sabogal-Paz, 2020;Napotnik et al, 2020).…”

“…However, concrete as an HSSF structure, in addition to its limiting portability, is susceptible to cracks and leaks when subjected to disturbances that can occur in a home (e.g., accidental collisions and impacts caused by transport) (Earwaker and Webster, 2009;Fiore et al, 2010). Therefore, studies began to evaluate the use of plastic in other HSSF components in addition to the outlet tube, as the body, lid, diffuser, and valves (Jenkins et al, 2011;Mahaffy et al, 2015;Napotnik et al, 2020). Despite being easier to acquire and handle, some of these novel designs have never been field-tested, whereas some of the old BSFs have shown high rates of sustained use in diverse field settings.…”

“…Developed by Dr. David Manz in the early 1990s, the BSF presents specific construction instructions in which only the intermittent operation is recognized (i.e., ondemand operation) (CAWST, 2012). Meanwhile, HSSF also encompasses continuous operation (Maciel and Sabogal-Paz, 2020;Souza Freitas and Sabogal-Paz, 2019;Terin and Sabogal-Paz, 2019;Young-Rojanschi and Madramootoo, 2014) and different designs (Ahammed and Davra, 2011;Napotnik et al, 2020;Ngai et al, 2007;.…”

Granular media filtration for on-site treatment of greywater: A review

“…Larger particles are removed by straining while colloidal particles are removed by attractive forces(Song et al 2020). Straining, adsorption, interception and diffusion are principal mechanisms responsible for removal of bacteria(Weber-Shirk & Chan 2007;Schijven et al 2014;Napotnik et al 2021). Contaminants such as nitrogen, phosphorus, potassium, chloride, aluminium and enzymes along with microorganisms can also be trapped since sorption is not specific with the compound(Flemming et al 2016; Sabogal-Paz et al 2020).…”

Filtros lentos domiciliares com operação contínua como alternativa para sistemas de tratamento de águas superficiais em comunidades isoladas: uma avaliação comparativa para redução do leito filtrante

“…A Tabela 9 apresenta os intervalos de redução microbiológica para bactérias do grupo coliformes (i.e., coliformes totais e E. coli) obtidas por filtros lentos domiciliares. As eficiências de remoção reportadas variaram de 0,33 a 2,07 log para coliformes totais (DEVI et al, 2008;SIZIRICI et al, 2019) e de 0,72 a 4,80 log para E. coli (BAIG et al, 2011;JELLISON, 2020). Apesar da diversidade nos valores, as eficiências de redução de E. coli mais relatadas foram aquelas compreendidas entre 1e 2 log.…”