Biological Layer in Household Slow Sand Filters: Characterization and Evaluation of the Impact on Systems Efficiency

Lubarsky, Helen; Fava, Natália de Melo Nasser; Freitas, Bárbara Luíza Souza; Terin, Ulisses Costa; Oliveira, Maquele Antunes De; Lamon, Atônio Wagner; Pichel, N.; Byrne, John; Sabogal-Paz, Lyda Patrícia; Fernández‐Ibáñez, Pilar

doi:10.3390/w14071078

Cited by 10 publications

(6 citation statements)

References 48 publications

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“…To remove colloidal particles that cause turbidity in water, size exclusion is utilized, which leads to the deposition of particles within the sand matrix. This deposition and subsequent decay of the organic matter it contains predominantly occur at the top of the sand bed, resulting in the formation of a biologically active surface layer called Schmutzdecke (Guchi, 2015;Lubarsky et al, 2022).…”

Section: Head Loss In the Slow Sand Filtermentioning

confidence: 99%

Integrated treatment of stormwater using multistage filtration (MSF) for domestic application (reuse)

Chekwubechukwu V Chibueze,

Chidozie C Nnaji,

Cordelia N Mama

et al. 2024

WSA

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Stormwater harvesting is a promising solution for global freshwater depletion, particularly in tropical regions with abundant rainfall. However, it is not widely used due to the lack of suitable treatment technologies for domestic applications. Multi-stage filtration (MSF) is an effective integrated treatment technology that provides a cost-effective alternative for stormwater treatment. This study investigated MSF's capacity for treating stormwater at different stages. The MSF designed and built comprised the down-flow roughing filter (DRF) and slow sand filter (SSF). The results achieved by the MSF for the treated effluents were: pH (7.1–8.1), temperature (27.6–29.4°C), electrical conductivity (EC) (100–190 µS/cm) and total dissolved solids (TDS) (70–130 mg/L). Turbidity removal efficiency of the MSF was in the range of 36–99% (5.825–164.05 NTU) and the overall average removal efficiency of the MSF was 74%, 90% and 86% for total coliforms (TC) (360–11 800 CFU/100 mL), faecal coliforms (FC) (0–1 300 CFU/100 mL) and Enterococcus spp. (120– 1 400 CFU/100 mL), respectively. The study identified stormwater reuse potentials based on international guidelines and benchmarks. For the treated effluent, pH, temperature, EC and TDS were all within the permissible limits for toilet, laundry, bathing, recreational and agricultural water reuse, while turbidity suited agricultural (non-food crop) and restricted urban reuse. 46% of the effluent was suitable for recreational purposes as this satisfied the 50 NTU standard. 62.5% of the effluent satisfied the FC standard for toilets and urinals and agricultural reuse (non-food crop) purposes, while 87.5 % of the effluent satisfied urban reuse purposes (restricted access). 66.67% of the effluent satisfied the Enterococcus spp. standard for agricultural reuse (non-food crop). All treated effluents satisfied the TC bathing standard. This study shows that after minimal disinfection, stormwater effluents offer potential reuse in household applications, thereby reducing potable water demand.

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Section: Head Loss In the Slow Sand Filtermentioning

confidence: 99%

Integrated treatment of stormwater using multistage filtration (MSF) for domestic application (reuse)

Chekwubechukwu V Chibueze,

Chidozie C Nnaji,

Cordelia N Mama

et al. 2024

WSA

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“…If these particles are composed of organic matter, they will further undergo biological decay. Particle removal occurs predominately at the top of the sand bed, in the surface layer known as the Schmutzdecke or biofilm layer [8,16]. Dissolved organic matter that enters the filter, or that is created from particle decay in the Schmutzdecke layer, can be mineralized lower in the filter.…”

Section: Mechanisms Of Pollutant Removalmentioning

confidence: 99%

Slow Sand Filters for the 21st Century: A Review

Maiyo

Dasika

Jafvert

2023

IJERPH

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Safe drinking water remains a major global challenge, especially in rural areas where, according to UNICEF, 80% of those without access to improved water systems reside. While water, sanitation, and hygiene (WASH)-related diseases and deaths are common outcomes of unsafe water, there is also an economic burden associated with unsafe water. These burdens are most prominent in rural areas in less-developed nations. Slow sand filters (SSFs), or biological sand filters (BSFs), are ideal water treatment solutions for these low-resource regions. SSFs are the oldest municipal drinking water treatment systems and improve water quality by removing suspended particles, dissolved organic chemicals, and other contaminants, effectively reducing turbidity and associated taste and odor problems. The removal of turbidity and dissolved organic compounds from the water enables the use of low-cost disinfection methods, such as chlorination. While the working principles of slow sand filtration have remained the same for over two centuries, the design, sizes, and application of slow sand filters have been customized over the years. This paper reviews these adaptations and recent reports on performance regarding contaminant removal. We specifically address the removal of turbidity and microbial contaminants, which are of great concern to rural populations in developing countries.

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“…Langenbach et al [60] found that slow sand filters removed E. coli and Enterococcus by 98.6-99.8% and 98.9-99.9%, respectively. On the surface of slow sand filters, a biofilm is formed, which has a biological activity and can therefore remove bacteria, organic matter, particles, and nutrients [61][62][63]. Sun et al [62] observed that slow filtration with aerobic heterotrophic biofilm exhibited higher removal of ARGs than slow filtration without any biofilm.…”

Section: Sand Filtrationmentioning

confidence: 99%

The Fate and Occurrence of Antibiotic-Resistant Bacteria and Antibiotic Resistance Genes during Advanced Wastewater Treatment and Disinfection: A Review

Kalli

Noutsopoulos

Mamais

2023

Water

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Antimicrobial resistance (AMR) is a serious problem for modern society, not only associated with clinical environments, but also the natural environment. Conventional wastewater treatment plants (WWTPs) are important nodes for the dissemination of antibiotic resistance to the aquatic environment since they are reservoirs of antibiotic-resistant bacteria (ARB), antibiotic resistance genes (ARGs), and antibiotic residues. WWTPs are not designed to remove these antibiotic resistance determinants from wastewater, and as a result, they are present in treated effluent, leading to environmental and public health concerns regarding wastewater disposal and reuse. Additional treatments combined with conventional WWTPs can be barriers to the spread of AMR to the environment. In order to understand the effect of wastewater treatment methods on the removal of ARB and ARGs, an extensive bibliographic study was conducted. This review summarizes the efficiency of conventional disinfection methods, tertiary wastewater treatment, and advanced oxidation processes (AOPs) to remove ARB and ARGs from wastewater. In the context of the revised Urban Wastewater Treatment Directive 91/271/EEC, further studies are needed on the removal potential of AOPs on a full-scale, as they offer great potential for the removal of ARB and ARGs with a low formation of toxic by-products compared to conventional disinfection methods.

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Biological Layer in Household Slow Sand Filters: Characterization and Evaluation of the Impact on Systems Efficiency

Cited by 10 publications

References 48 publications

Integrated treatment of stormwater using multistage filtration (MSF) for domestic application (reuse)

Integrated treatment of stormwater using multistage filtration (MSF) for domestic application (reuse)

Slow Sand Filters for the 21st Century: A Review

The Fate and Occurrence of Antibiotic-Resistant Bacteria and Antibiotic Resistance Genes during Advanced Wastewater Treatment and Disinfection: A Review

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