Influence of PPCPs on the performance of intermittently operated slow sand filters for household water purification

Abstract

Removal of pharmaceuticals and personal care products (PPCPs) from drinking water is usually enhanced by advanced oxidation which is not affordable in low income countries. Slow sand filtration has been found to be capable of removing anti-inflammatory compounds, and its low maintenance costs and easy operation make it an attractive technology for treating drinking water in many parts of the world. In addition, slow sand filters can be used at both large and household scales. The biofilm (i.e. schmutzdecke) developed on the top of the sand and within the upper layers of the sand is acknowledged to be responsible for the water purification. However, it is possible that the PPCPs may affect the schmutzdecke development and microbial community within the filters, and consequently the performance of the filter. This study investigated two household slow sand filters (for water purification) operated intermittently with and without contamination by six PPCPs. Eleven parameters were monitored in the affluent and effluent water, including bacterial species present and schmutzdecke biomass development. Results demonstrated that the household slow sand filter performance was not affected by the 2μgL of PPCPs in the water. There was no significant difference between filters for total coliforms and E. coli removal, but there was considerable difference between sampling times. Biomass considerably increased with the number of filtrations in both filters and there was no significant difference between filter biomass. However, it was found that more bacterial species were present in the period with no contamination than during the contamination period. Bacillus anthracis and Exiguobacterium sp. showed to be resistant to the effects of the PPCPs. These suggest there are effects of PPCPs on bacterial species within the filter. However, the effect of the PPCPs on biomass was not conclusive in this study and needs to be further investigated.

Making Fe0-Based Filters a Universal Solution for Safe Drinking Water Provision

“…Thus, existing knowledge from the science of aqueous iron corrosion (Corrosion Science) needs to be effectively translated into practical solutions [27][28][29][30] by designing efficient filtration systems based on metallic iron (Fe 0 filters) for safe drinking water provision. This includes the use of established and recommended efficient slow sand filters (SSFs) and biosand filters (BSFs) [31,32], which can be optimized by amendment with Fe 0 [30,33]. Based on these studies, the long-lasting need for an appropriate, demand-based, affordable, efficient, and sustainable water treatment technology, which is additionally centered on local communities (not only in the developing world) has been scientifically resolved [26][27][28][29][30]33].…”

Contaminant Removal and Optimal Operation of Bio-Slow Sand Filtration Water Treatment Based on Nature-Based Solutions

“…It was predicted that the pathogen reduction efficacy would be reduced during either scenario, with the BSSF making a full recovery to its maximum potential reduction efficacy given sufficient time [30]. There was no significant difference between the filters for total coliforms and E. coli removal, but there was considerable difference between sampling times [31].…”

“…To remove pathogenic microorganisms, 93% of the sand was in the full range of 0.212-0.425 mm grain size, and the main fraction had a grain size of 0.425 mm [6]. The high efficiency of water treatment achieved by BSSF is partly explained by the effective size of the sand (0.1-0.3 mm) [10]. BSSF technology does not require backwashing.…”

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“…At the end of the integration of the treatment technologies, the final pH value was 6.93, which is within the allowed range for disposal (between 5-9) according to Brazilian legislation (Pompei et al, 2017 foi adotada a configuração "expert modeler", com a previsão após o último caso em análise e até cinco passos adiante.…”