Sand Filtration Tipe Slow sand filtration Rapid gravity

Sand Filtration

Tipe: • Slow sand filtration • Rapid (gravity) sand filtration • Rapid (pressure) sand filtration

Pengertian. ? • Sand filtration is a water purification process in which water is passed through a porous bed of filter medium – Slow sand filtration? – Rapid sand filtration?

Parameter desain SSF

Perbedaan? • Slow sand filters are distinguished from rapid sand filters by the biologically active sand medium (including the Biofilm), and slow detention times. • In a mature sand bed, a thin upper sand layer called a Schmutzedecke (Biofilm) forms. The Biofilm consists of biologically active microorganisms that break down organic matter while suspended inorganic matter is removed by straining. • Rapid sand filters utilize primarily a physical removal process, are periodically backwashed for cleaning, and operate with long detention times. • Slow sand filters are cleaned by periodically scraping the existing Biofilm.

RAPID SAND FILTER • Effective size: 0. 35 -0. 50 mm • Uniformity coefficient: >1. 3/1. 7 • Filtration Rate : ~ 5 m 3/m 2. jam SLOW SAND FILTER • Effective size: 0. 15 -0. 35 mm • Uniformity coefficient: 2 -3 • Filtration Rate : 0. 1 -0. 2 m 3/m 2. jam

Operasi

Mekasnisme proses. . 1. Mechanical, Phisical 2. Biological Lapisan Biofilm

Backwash. When is Backwashing Needed? • The head loss is so high that the filter no longer produces water at the desired rate; (Filter Mampet) • Floc starts to break through the filter and the turbidity in the filter effluent increases; (Effluent keruh)

Back. Wash

Expansion area = 20 -50 % dari ketinggian bed filter