Cleaning and scraping of filters in water treatment facilities in FACT- Cochin Division

Cleaning and scraping of filters in water treatment facilities in FACT- Cochin Division

Sand scraping of slow sand filters 1. After getting clearance from the operating personnel ensure that the water level is 15 to 20 cms. below the top of the sand bed. Water level can be brought down by suitably operating the scour valve. 2. Scrape off 0.5 to 1 c.m. of the top layer of sand along with the filter skin. 3. Remove the scraped material outside the filter chamber to the specified location. 4. Clean the side walls and water outlet chamber. 5. Loosen at least 15 cms. of the top sand layer uniformly. After loosening, uniformly level the surface. 6. Thoroughly clean the chamber and channels around the filter bed. 7. Each chamber scraping work to be completed within 10 hours time.

Cleaning of PSF with Alkali washing 1. Open the manhole cover on sand filter top 2. Scrap and remove the top layer of sand by one centimeter. 3. Shuffle the sand upto a depth of one feet. 4. Fill the vessel with water , air scour for ten minutes and give open back wash for 30 minutes. 5. Repeat the above process 3 times. 6. Add 60 litres of caustic soda in the filter and soak the contents overnight. 7. Close the top manhole cover and tight the same leak proof.

Clearing of vegetation near to the Slow sand filters and pressure sand filters in Filter bed area, cleaning of effluent channels, cleaning of substation yard & premises, transporting of various raw materials required for continuous operation in thermal plants such as non-ferric alum, hydrated lime, diesel , various lubricating oils, Chlorine cylinders etc. from one place to another ,as instructed by the Shift in charge of Thermal Plant.