Dielectric Properties of Soils Affected by Sewage Waste Pollution

Abstract

In this present era of industrialization and increasing population, environment degradation has become one of the major issues of concern. Due to lack of waste management system, all the dumped waste of cities, industries and agriculture is affecting nearby water bodies and land region [1]. This contaminated water when comes in contact soil nearby or used for irrigation purpose of that region tend to contaminate the respective soil with toxins, salts and heavy metals. Major contaminants added to soil by polluted water are heavy metal ions, plastics, some organic matters and some chemicals like phosphates, salts of sodium, potassium etc. [2]. The products of these soils such as crops and food items become toxic minerals and harmful for human health when consumed [3-4]. Therefore, there is need for system of soil studies which can give idea of contamination of soil other than conventional system of studies which are laborious, error prone and chemically affected. An electromagnetic region based soil studies provides one of the alternative methods for investigating soil properties via remote sensing [5]. These studies are based on dielectric properties of soil and covers larger spatiotemporal region. Since every material has its own dielectric signature so dielectric properties of polluted soil which includes dielectric constant and dielectric loss value of soil can provide idea for type and amount of contaminants in the soil [6]

The present paper represents the effect of sewage pollution in altering dielectric properties of soils in the broadband region of 200MHz to 14GHz using open ended coaxial probe (85070E,Agilent Technologies) coupled with vector network analyser(VNA).Samples are collected from different polluted sites and amount of contamination was evaluated using various geophysical and chemical methods as is shown in Table1. Experimental setup of VNA coupled with Agilent probe is shown below in Fig1. The results showed that value of both dielectric constant and dielectric loss factor of soil decrease with increase in frequency and increase with increase in contamination. The compared results with fertile soil indicates that the values of dielectric factors of contaminated soils deviate largely from that of fertile soils showing in change of composition with the presence of contaminants. The pH studies show that polluted soil confirms its acidic nature. A third order regression equation is generated for dielectric properties of contaminated soil. The present results are helpful in developing an alternate method for studies of effects of sewage pollutants on soil and some sensors can also be designed based on present studies for analysing response of soil.