Analisis Pengaruh Dosis Klorin dan Waktu Kontak kepada Rasio Bakteri Extended Spectrum Beta-Lactamase Producing Escherichia Coli terhadap Escherichia Coli = Analysis of The Effect of Chlorine Dose and Contact Time towards The Ratio of Extended Spectrum Beta-Lactamase Producing Escherichia Coli Bacteria to Escherichia Coli