**2. Material and methods**

 LF-EMF was produced with the coiled column and the sinusoidal 50 Hz magnetic field was generated by means of a solenoid, obtained with overlapped winding of copper wire with 500 mm of length and 50 mm diameter of column A and 80 mm diameter of column B. The power of 220 V was connected to solenoid coils waveform generator. The current flowing in the exposure devices was monitored by AC current in parallels of coils. In each coil, the number of turns was between 300 and 600 of 1.5 mm copper wire and the total resistance of the system was 1 Ω. The resulting of the whole inductance coil system was in the range of 2–10 mT. The density of magnetic flux was monitored using Tesla meter (BST600 Gauss meter/ Tesla Meter) and field intensity was varied by ±0.05 mT.

 According to previous studies, the method of IDEXX Colilert® 18 has been verified as an acceptable alternative to other test methods for the recovery of *E. coli* from source water, wastewater, and drinking water [51, 52]. The original method using mTEC agar is a standard method, and is recognised by the U.S.EPA as a useful method for monitoring recreational water quality [52, 53]. In this study, the Colilert® 18 method was compared to the original mTEC membrane filter method for enumeration of *E. coli* by parallel testing the water samples. The Colilert® 18 method was determined to be an acceptable alternative to the traditional mTEC standard method for monitoring *E. coli* levels in river water recreational areas based on the results of the study. No significant difference was found between the results of these two methods. Therefore, the Colilert® 18 method was suggested as an efficient and accurate means for testing water samples in this study.

*Removal of Escherichia Coli Using Low-Frequency Electromagnetic Field in Riverbank Filtration DOI: http://dx.doi.org/10.5772/intechopen.85296* 
