Desain Kolom Adsorpsi Granular Activated Carbon Untuk Mereduksi Zat Organik (KMnO4) Efluen IPAL Laundry Koperasi Desa Sukadanau = Design of Adsorption Column using Granular Activated Carbon to Reduce Organic Material (KMnO4) of the Effluent of Laundry Sewerage Treatment Plant, Koperasi Desa Sukadanau