Parameters for effective sand filtration of <i>Schistosoma mansoni</i> cercariae from water

Braun, Laura; Sylivester, Yasinta Daniel; Zerefa, Meseret Dessalegne; Maru, Muluwork; Allan, Fiona; Zewge, Feleke; Emery, Aidan M.; Kinung’hi, Safari; Templeton, Michael R.

doi:10.2166/ws.2021.312

Cited by 3 publications

(1 citation statement)

References 20 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The physical characteristics of sand, such as its grain size, shape, and porosity, contribute to trapping the particulate matter, including larvae. The sand filter acts barrier, intercepting larvae directly through void spaces between grains or straining them out if they exceed sand pore sizes, significantly reducing larval concentrations in treated water [18]. Granular activated carbon (GAC) is primarily used to remove various contaminants from water sources by passing water through a bed of activated carbon particles with a high surface area and porosity.…”

Section: Introductionmentioning

confidence: 99%

Comprehensive Solutions to Prevent Larvae Breakout in Water Filtration Systems

Kwon,

Hidayaturrahman,

Koutavarapu

et al. 2023

Sustainability

View full text Add to dashboard Cite

The presence of invertebrates in drinking water distribution systems, particularly Chironomidae larvae, has raised concerns among the general public. This study aimed to comprehensively address the issue of larvae breakout in water filtration systems and provide potential solutions to prevent their escape into the water supply. The research investigated various factors contributing to larvae breakout, including the type of filtration column, sand depth, pretreatment methods, and the effective size and uniformity coefficient of sand media. Experimental results revealed that the GAC column, primarily utilized for adsorption, was ineffective in retaining Chironomidae larvae, leading to their escape within a short period. Similarly, the sand filter column, with a design that is currently widely used with sand specifications of an effective size of 0.7 mm and a uniformity coefficient of 1.7, failed to act as a barrier for larvae. Increasing the height of the sand media and applying a pretreatment method, which was expected to prevent larvae from entering the treated water, yielded unsatisfactory results. Our research results show that reducing the uniformity coefficient to 1.5 while maintaining an effective size of 0.7 mm proved to be important in preventing the release of larvae into treated water. The Sand/GAC and Sand/Anthracite systems, by maintaining adjusted media sand specifications, also succeeded in retaining larvae in the filtration system. Additionally, this study emphasized the importance of following the recommended backwash procedure, consisting of specific steps involving air flow, a combination of air and water flow, and final water flow. This sequence effectively removed contaminants, turbidity, and Chironomidae larvae from the filtration media, ensuring improved water quality and system performance. The findings of this study provide valuable insights and recommendations for water treatment plants to address the issue of larvae breakout and enhance water quality.

show abstract

Section: Introductionmentioning

confidence: 99%

Comprehensive Solutions to Prevent Larvae Breakout in Water Filtration Systems

Kwon,

Hidayaturrahman,

Koutavarapu

et al. 2023

Sustainability

View full text Add to dashboard Cite

show abstract

The lethal effect of soap on Schistosoma mansoni cercariae in water

Zhang,

Pitol,

Kinung’hi

et al. 2024

PLoS Negl Trop Dis

View full text Add to dashboard Cite

Background Schistosomiasis is a parasitic disease which is spread through skin contact with water containing Schistosoma cercariae. Drug treatment has been the main control method, but it does not prevent reinfection. The use of soap can be a complementary measure to reduce transmission. Therefore, this study investigates the quantitative effect of different soaps on the mortality of Schistosoma mansoni cercariae. Methodology Four soaps including two powder soaps (Kleesoft and Omo) and two bar soaps (B29 and Rungu) which are used in a schistosomiasis-endemic Tanzanian village were studied. S. mansoni cercariae were exposed to powder soaps of 0 (control), 10, 50, 75, 100 and 1000 mg/L and to bar soaps of 0 (control), 100, 500 and 1000 mg/L. The highest concentration of 1000 mg/L was selected based on the laboratory-estimated average soap concentration during handwashing. Cercariae were observed under a microscope after 0, 5, 15, 30, 45 and 60 minutes of exposure to determine their survival. Conclusions All four soaps can kill S. mansoni cercariae and this lethal effect was related to soap concentration and exposure time. At the highest concentration of 1000 mg/L, all cercariae were dead at 5 minutes post-exposure with two powder soaps and Rungu, while 100% cercarial death was achieved between 5 minutes to 15 minutes for B29. Almost all cercariae survived after being exposed to 10 mg/L powder soaps and 100 mg/L bar soaps for 60 minutes. Powder soaps were more lethal than bar soaps. Considering the widely varying concentrations of soap during real-world hygiene activities and the necessity for a very high soap concentration to eliminate all cercariae in a short 5-minute exposure, providing the efficacy of soap in preventing schistosomiasis becomes challenging. Future studies should investigate whether soap can influence alternative mechanisms such as creating a barrier to skin, thereby providing protection.

show abstract

Pilot studies on the application of triple media filtration at Morton Jaffray Water Works, Harare, Zimbabwe

Hoko,

Musima,

Mapenzauswa

2024

Water Supply

View full text Add to dashboard Cite

Lake Chivero, Harare's main source of raw water for drinking water, is algae infested thus affecting water treatment processes at Morton Jaffray Water Treatment Works (MJWTW). Consequently, several challenges have been encountered including frequent filter backwashing, leading to a reduced plant output. In this study, the potential of substituting single-media filters (currently used at MJWTW) with triple-media filters was investigated. This was done using pilot filters of a single-media filter (SMF) and a triple-media filter (TMF) and piloted using clarified water from MJWTW. Electrical conductivity (EC), pH, total dissolved solids (TDS), turbidity, and temperature were the water quality parameters that were monitored. Headloss and flow rate were the filter operation parameters that were monitored. Both water quality and operational parameters were monitored at hourly intervals until one filter reached the maximum allowable headloss or turbidity limit. The variation in effluent turbidity, TDS, EC, and pH between the filters was insignificant. Nevertheless, the headloss development for the TMF was significantly slower than that of the SMF resulting in the SMF reaching the maximum headloss earlier. Therefore, the TMF performed better overall. Therefore, the adoption of TMF could result in a longer filter run and improve filtration and water production at MJWTW.

show abstract

Parameters for effective sand filtration of Schistosoma mansoni cercariae from water

Cited by 3 publications

References 20 publications

Comprehensive Solutions to Prevent Larvae Breakout in Water Filtration Systems

Comprehensive Solutions to Prevent Larvae Breakout in Water Filtration Systems

The lethal effect of soap on Schistosoma mansoni cercariae in water

Pilot studies on the application of triple media filtration at Morton Jaffray Water Works, Harare, Zimbabwe

Contact Info

Product

Resources

About