nir-vana innovation network

⦁ Filter Type There are two types of filtration devices: 1) Pore Control Fibre (PCF) filters by pressure 2) Gravity Flow Fibre Filter (GFF) filters by gravity. ⦁ Filtration Process The PCF filtration system consists of a perforated cylindrical strainer surrounded by flexible fibre bundles. Unlike traditional sand filtration, it does not need flocculation nor sedimentation, but instant coagulation* (1sec), then direct microfibre filtration (3min). During filtration process, the fibres are tightened upward, compressing the air gap. As a result, this removes impurities and suspended solids (SS) through narrow pores* and 15cm deep-pressure filtration. During the backwashing process, the fibres are loosened to make wider pores that enable water and air to vigorously shake off and eliminate SS. This process takes a short time and requires only 5% of raw water. *Coagulation: Coagulation is a chemical process in which a chemical compound, a 'coagulant', is added to the water to destabilise the suspended particles and promote the creation of flocs. *Pores: air gaps between particles The GFF filtration system is similar in principle to the PCF system but relies on gravity. It utilises a 30cm water level difference and a 1cm compressed microfibre layer filter, requiring no additional filtering power beyond gravity. Filtered water flows into backwashing water, eliminating the need for a pump and reducing power costs. Additionally, the use of lighter fibres with a shorter filtration depth than sand filter can further reduce backwashing costs. ⦁ Application 1) Wastewater / Sewage Treatment Plant (WWTP/ STP) The system is effective in removing SS, BOD and T-P from sewage and wastewater. It is especially useful for treating sewage water for reuse purposes. Compared with Dissolved Air Flotation (DAF) wastewater treatment, Hydraulic Residence Time (HRT) is 1/8, The amount of coagulant is 1/3 and the HRT of the accelerator sedimentation basin is 1/6. 2) Tap Water Treatment Plant (DWTP) Compared with Rapid Sand Filtration (RSF) system, Hydraulic Residence Time (HRT) is 1/60, Construction and operating cost are below 1/3, but it can remove turbidity up to 99.9% (300 → 0.3 NTU). Further, this system can treat less than 0.1 NTU with 1 NTU sedimentation water. So this system can be an efficient alternative to RSF. 3) Pretreatment of Reverse Osmosis Plant for Desalination (RO PTP) This system is used for pretreatment in Reverse Osmosis Plants. Compared with Ultrafiltration (UF) and Dual Media Filter (DMF), Hydraulic Residence Time (HRT) is 1/12, but it can remove turbidity up to 0.1 NTU. Furthermore, the lifetime of fibre filtration media is longer, and the replacement cost is lower. *SS: Suspended Solids. The dry-weight of suspended particles that are not dissolved in a sample of water that can be trapped by a filter that is analysed using a filtration apparatus. *BOD: Biochemical Oxygen Demand. BOD is an analytical parameter representing the amount of dissolved oxygen consumed by aerobic bacteria growing on the organic material present in a water sample at a specific temperature over a specific time period. *T-P: Total Phosphorus. T-P is a measure of the total amount of phosphorus in water, including both organic and inorganic forms.