Effect of granular activated carbon particle sizes and depths in slow sand filter on water purification

Kamorudeen Olaniyi Yusuf ,S T Yusuff,I B Sadiku ,S A Bukoye

doi:10.48198/njpas/20.a12

Abstract

Most rural dwellers in Nigeria depend on contaminated water from ponds, streams and wells for drinking water. Every household needs simple water purification device like Slow Sand Filter (SSF) to prevent water-borne diseases. This study was conducted to determine the effect of Granular Activated Carbon (GAC) particle sizes and depths in SSF on the purification of water. Two sets of SSF were fabricated using 6 inches (15.24cm) diameter PVC pipe, fine sand (0.25 mm grain size) with 35 cm depth. GAC for the first set SSFs (particle sizes 10 mm, 14 mm with 15 cm depth) and GAC for the second set of the SSFs has 15 and 25 cm depths with particle size 10 mm. The SSF has 50 litres storage tank from which raw water flows into the filter chamber (15.25 diameter and 110 cm long PVC). The filter was kept moist for 21 days for schmutzdecke to fully develop which is effective in trapping bacteria. Raw water was poured into the SSF, water samples were collected and analyzed using standard methods. The SSF has a capacity of producing 35 litres/h clean water. Percentage reduction of Lead, Manganese, Copper, Iron, Turbidity and Total Coliform Counts of the filtered water compared with the control were 91.35-99.88%, 90.00-98.33%, 42.00-100.00%, 46.67-100.00%, 13.04-99.15% and 16.67-57.69%, respectively. The SSF increased pH and Calcium by 7.14-27.71% and 83.65-98.21%, respectively. SSF with 10 mm and 25 cm depths GAC reduced the pollutants than the other two filters and it is recommended for purifying pond water.

Highlights

Many people in rural areas of Nigeria do not have access to tap water and they depend mainly on pond, spring, stream, lake and well water for drinking water and for other domestic uses (Yusuf and Murtala, 2020)
Whered is the mean of the difference from the data x1 and x2, Σd is the summation of d, n is the number of observations, δ is the standard deviation, δEr is the standard error and tcal is the calculated value of t at α = 5 % but 2.5 % for paired t-test (α = 0.05/2 = 0.025)
Well water from 3 sources that are used for drinking were used in this study for the performance evaluation of the Slow Sand Filter (SSF) having Granular Activated Carbon (GAC) with different particle sizes and depths

Summary

Introduction

Many people in rural areas of Nigeria do not have access to tap water (potable water) and they depend mainly on pond, spring, stream, lake and well water for drinking water and for other domestic uses (Yusuf and Murtala, 2020) Water from those sources are normally polluted with some chemicals and pathogens that are harmful to human health (Hammer and Hammer, 2012). SSF could be used effectively in rural areas for water purification because it is cheap, easy to operate, does not require electricity for its operation and could be fabricated from locally available materials (Yusuf et al, 2019). GAC has ability to remove physicochemical and organic compounds from contaminated water while sand medium traps pathogens from water. Water flows from the raw water storage tank (50 litres capacity) through 12.7 mm (0.5 inch) PVC pipe to the filter chamber. Page | 3884 Table 1: Bill of Engineering Measurement and Evaluation for the SSF as at May - June, 2019

14 Labour cost Pipe fittings 1

Results and Discussion

Conclusions