INTRODUCTION

Infiltration is the rate at which water enters a soil and percolation is the rate at which water moves through a soil . Percolation is the ability of soil to absorb water. The amount of water absorbed by any soil at any given time is known as the percolation rate and plays a major role to determine filter field design and site suitability for an on-site wastewater treatment facility. Different soil has different percolation rates as the rate of percolation depends on soil type.

The particle size plays a vital role in the percolation rate of that particular soil. As the particle size reduces the surface area of the soil grain increases which slow down the rate of percolation. Similarly for larger grain sizes percolation is faster. Along with the size of the particle another factor which affects the rate of percolation is the shape of the particles. The round shaped particles provide easy access to water movement compared to irregular ones. Another factor affecting the percolation is surface texture of particles: smooth surfaced particles show higher percolation rate than the rough particles.

For experimental purposes the percolation rate is determined by measuring the amount of water passing through the test hole in any given period of time. Generally Percolation rate is highest in sandy soil and least in clayey soil. Which is also an indicator that the percolation rate also depends on particle size. The major drawback with the test is that it does not take into account the capillary action. Unit of Percolation rate = Amount of water (mL)percolation time (mins) Q. ( till this point)

Percolation rate test is used to determine the water absorption capacity of the soil and plays a major role to determine filter field design and site suitability for an on-site wastewater treatment facility. The major drawback with the test is that it does not take into account the capillary action.

Equation