Peningkatan kualitas air mutlak diperlukan apabila air tersebut berasal dari air permukaan sehingga penyebaran penyakit dapat ditekan seminimal mungkin. Sebagian masyarakat Indonesia masih tergantung pada air alam dan air dengan kualitas rendah. Penelitian ini bertujuan untuk mengetahui pengaruh jenis bahan dan ukuran arang aktif. Dalam penelitian ini, arang aktif yang digunakan sebagai filter adalah arang aktif tempurung kelapa dan arang aktif kayu dengan ukuran 5/6 mesh, 6/7 mesh, 7/8 mesh, 8/10 mesh, 10/12 mesh. Proses penjernihan dilakukan sebelum dan setelah backwash. Unsur-unsur yang akan dijerap adalah kekeruhan, besi (Fe), mangan (Mn). Air yang digunakan dalam penelitian ini berasal dari air yang telah dibubuhi senyawa (NH4)2 Fe (SO4)2 6H2O dan KMnO4. Hasil penelitian menunjukkan jenis arang aktif kayu dan tempurung kelapa sebelum backwash berpengaruh nyata sedangkan setelah backwash tidak berpengaruh nyata untuk menurunkan kekeruhan, Fe dan Mn. Ukuran mesh sebelum dan setelah backwash berpengaruh sangat nyata untuk menurunkan kekeruhan, Fe dan Mn. Arang aktif efisiensi tertinggi adalah arang aktif kayu dengan ukuran mesh 10/12 yang sebelum dan setelah backwash dapat menurunkan kekeruhan 68,09% dan 71,83%, Fe 70,84% dan 74,59%, Mn 69,38% dan 74,05%. Waktu penjernihan paling efisien pada 30 menit pertama setelah itu efisiensinya terus menurun dan setelah backwash efisiensinya kembali naik.

Upgrading water quality for human being daily consumption is absolute needed, if the water comes from a bad quality water source so that the spreading of diseases can be minimized. Some of Indonesia societies are still depend on the natural water and the water with low quality. The aims of this research are to know the effect of different material and granular size of activated charcoal on the decrease of turbidity and iron and manganese concentration in water purification process. In this research, the activated charcoals used as filter are the activated coconut shell charcoal and the activated wood charcoal with the sizes of 5/6 (through 5 mesh and on 6 mesh), 6/7, 7/8, 8/10, and 10/12. In this research, purification process was conducted before and after backwash. The parameters to be evaluated are the turbidity and iron (Fe) and manganese (Mn) concentration. The raw water used in this experiment was water which has been added by the substances of (NH4)2 Fe (SO4)2 6H2O and KMnO4. The experimental results show that the activated charcoals of coconut shell and wood before backwash have a significant effect to decrease the turbidity and iron and manganese concentration, while after the backwash; there is no significant effect on them. The size of granules of two different charcoals, before and after backwash have a highly significant effects to decrease turbidity and Fe and Mn concentration. The highest performance (efficiency) of activated charcoal of wood with mesh of 10/12, before and after backwash are the decreasing of turbidity of 68,09% and 71,83%, decreasing of Fe concentration of 70,84% and 74,59%, and decreasing of Mn concentration of 69,38% and 74,05%, respectively. The most efficient purification time is at the fist 30 minute, and afterwards the efficiency is decreasing. After backwashing process, the efficiency is increasing.

Kata Kunci : Butir arang aktif,Kadar kekeruhan,0Besi,Mangan,Proses penjernihan, activated charcoal, turbidity, iron and manganese, backwashing