A fast flush is a method of cleaning the UF membrane filter whereby 100% of the water passing across the membrane is wasted. A fast flush should occur every 10-15 minutes, and it lasts for 1 minute.
Free residual chlorine. This is the amount of chlorine available in the purified water. It helps combat secondary contamination (e.g., someone putting his or her dirty hands into the water). Under the SPHERE standards, the FRC should be 0.2-0.5 ppm.
Will water moving at a certain flow rate always have the same feed pressure?
The flow rate and the feed pressure are independent variables. Flow rate depends on the feed pump, which pumps water at 4.4 m3/hour. Feed pressure depends on the amount of resistance that the water encounters.For example, water flowing at 4.4 m3/hour might have a feed pressure of 1 bar going into the sand filter, but 0.5 bar on the way out.
Permeate is the purified water thats been filtered through the UF membrane filter.
Membrane flux is the rate at which water moves through the UF membrane filter.
Raw water is untreated water. It is the input for the water treatment plant.
Daltons are a unit of measurement for molecular weight. Delta P is the change in pressure.
The acronym psi stands for pressure per square inch. 15.4 psi is equal to 1 Bar.
These three measures are independent of each other. The maximum feed pressure is the maximum pressure exerted by the pump to push water through the system.
Backwash pressure is the maximum pressure exerted by the pump during backwashing to push water through the system. The pump operates at a higher feed rate during the backwash.
Transmembrane pressure is the pressure exerted on the water as it moves across a membrane. It is determined by the resistance that the membrane provides to the water.
Optimal pH is around 6.8 8.4
It is a solution prepared by mixing a known concentration of coagulant in water. For example, a 1 % mother solution of alum contains 1 part of alum in 100 parts of water.
This indicates that the water has a lot of suspended solids, measure the amount using the turbidity tube to ascertain the NTU value. If above 500 NTU primary sedimentation should be considered or the use of an alternative source.
This may be a result of a blockage in the pump or down the hose. Turn pump off and check the system to clear any blockage.
A cross flow occurs as water is passing through the UF membrane filter. 90% of the water is allowed to pass through the membranes, while 10% of the water is wasted as reject. This 10% of the water cleans the membrane by removing bacteria and other particulate build-up.
The water pressure will be greater when the water is entering the filter, because it provides resistance to the water, than when the water is exiting the filter. If the difference between the water pressure entering the filter and exiting the filter exceeds the parameters (refer pg 9), then the filter needs to be cleaned with a backwash. The change in water pressure means that turbidity has built up to a great extent and is providing resistance to the water going through the filter.
What is a coagulant? Coagulant is a chemical used to remove turbidity from the water. Turbidity is caused by particulates in the water. The particulate sticks to the coagulant, forming larger particles that are more easily removed in the pressure sand filter. The P4000M uses alum as the coagulant.What does NTU stand for?