FM Techie

FILTER FEED PUMPS Filter Feed Pumps are used to draw water from the clarified water sump and pass it through the Pressure Sand Filter (PSF) and Activated Carbon Filter (ACF), which are installed in series to improve water quality. PRESSURE SAND FILTER (PSF) Working Principle: The upper layers of sand perform the actual filtration function, while gravel layers provide physical support. Specialized sand with a specific particle size is used to trap solid impurities present in water. The particles get entrapped in the spaces between sand grains, eventually blocking water flow. When the pressure drops beyond a set limit, the sand is cleaned by backwashing with water. Backwashing reverses the flow, fluidizing the sand bed and removing lighter solid particles as waste. Operation And Maintenance Considerations Filtration is followed by a short backwash sequence. The filter requires backwashing when the pressure drop across the filter reaches 0.5 kg/cm². Best practice: Backwash once per shift,...

CLARIFIER/ SETTLING TANK 1 The sewage inlet pipe brings sewage from the aeration tank. 2 The center-feed well takes this incoming sewage and gently releases it in the settling tank, without causing any disturbance or turbulence. 3 The sludge is only slightly heavier than water; so it takes time to sink. It slides down the steeply sloped walls of the tank toward the center of the bottom. 4 The bacterial flocs7 collect here in high concentration. 5 The sludge delivery pipe delivers the slurry to the pumps (6). 6 There are two identical pumps. Since the flow rate of these pumps is fixed, they need to be turned off periodically to bring down the net flow rate to achieve the desired MLSS ratio. This is a critical operation, because if flocs remain in the settling tank for more than 30 minutes, the microorganisms die due to lack of oxygen. 7 The T-shaped header assemble joins the outlet pipes of both pumps, and delivers the sludge to the aeration tank. 8 The clear water rises to the top of t...

 AERATION TANK The Aeration tank is at the heart of the treatment system. The bulk of the treatment is provided here, employing microbes/bacteria for the process.  The main function of the Aeration tank is to maintain a high population level of microbes. This mixture is called MLSS (Mixed Liquor Suspended Solids). The mixed liquor is passed on to the clarifier tank, where the microbes are made to settle at the bottom.  The settled microbes are recycled back to the aeration tank. Thus they are retained for a long period within the system. 1 The inlet pipe brings sewage from the raw sewage lift pump  2 The baffle wall does not let the incoming sewage and sludge go across the tank toward the outlet pipe (6). The wall forces the mix toward the bottom of the tank;  3 The tank is always filled till this level 4 The Outlet Launder collects the sewage and delivers it to the outlet pipe (6). 5 The net prevents entry of debris in the outlet pipe (6).  6 The outlet pi...

 CONSERVATOR:  This is mounted on top of the oil tank. This should have oil two third of its volume and the remaining filled with air. The conservator is used to accommodate the expanded volume of the transformer oil when ever the oil gets heated up owing to loading of the transformer. Also when the oil cools down, the oil from the conservator will flow into the transformer tank. The oil level in the conservator varies depending upon the temperature of the oil on various load conditions. Whenever the oil level reduces in the conservator, atmospheric air from outside will flow through the breather into the conservator and during this process the silica gel will absorb the moisture from the atmospheric air. When the oil level in the conservator rises, the air from the conservator will go to atmosphere through the breather. The breather will have oil to arrest the suspended impurities from the atmospheric air. BREATHER: The breather is connected through a small pipe line to the c...

Equalization Tank The sewage from the bar screen chamber and oil, grease and grit trap comes to the equalization tank. The equalization tank is the first collection tank in an STP. Its main function is to act as buffer:  To collect the incoming raw sewage that comes at widely fluctuating rates, and pass it on to the rest of the STP at a steady (average) flow rate. During the peak hours, sewage comes at a high rate. The equalization tank stores this sewage, and lets it out during the non-peak time when there is no/little incoming sewage. 1 The inlet pipe  2 The sewage is collected in the tank.  3 The raw sewage lift pumps 4 The delivery pipe takes the sewage to the aeration tank. 5 The coarse bubble diffusers are short length of tubes that have holes at regular spacing. They release large bubbles in the tank to lightly aerate the sewage, and also to agitate the mix continuously. 6 Compressed air comes though this air supply pipeline.  Operation And Maintenance Conside...

Procedure for Breakdown test: 1) 3 to 4 litres of oil needs to be let out before collecting the oil sample.  2) oil sample from Transformer before filtration. 3) The gap between the test electrodes must be 2.5mm.  4) The oil can withstand 40kV for a minute if it is having good dielectric strength. Voltage should be gradually increased from zero.  5) At one point Flash will take place and that point is termed as Bread down Voltage In Oil filtration process, the oil passes through three chambers in the oil filter. They are 1.Paper Filter, 2.Heater, 3.Vacuum Chamber Paper Filter removes carbon particles from the oil. Heater & Vacuum Chamber removes moisture content from the oil. Mainly transformer oil is used for insulation purpose.  When the oil contacts with atmospheric air in the conservator, the air moisturize the oil and reduce its dielectric strength.  So, the transformer oil should be filtered once in a year. This process should repeat at least for 6 to ...

Daily Transformer Inspection Checklist Regular inspection of transformers is essential for their efficient operation and long life. Below is a simple checklist for daily transformer inspection to ensure safety and performance. 1. Check and Record Winding Temperature Monitor the winding temperature and note it down. Abnormal temperature rise may indicate a fault. 2. Check and Record Oil Temperature Measure and record the oil temperature. Overheating of oil can reduce its insulating properties. 3. Check Conservator Tank Oil Level Ensure the oil level in the conservator tank is adequate. A low level may indicate leakage or oil degradation. 4. Check for Oil Leakages Inspect the transformer for any visible oil leaks, which can lead to serious operational issues. 5. Check the Colour of Silica Gel The silica gel in the breather should be pale blue. If it turns pink or white, it needs to be replaced as it has absorbed moisture. 6. Check the Explosion Vent Diaphragm Inspect the explosion vent d...