reversing the direction of flow of water
passing air through the filter
scraping off top layers of sand and admitting water
passing a solution of alum and lime through the filter
Discuss in Comment
"Scientists dream about doing great things. Engineers do them."
PSC Advertisement ⏩ | Federal PSC | Bagmati PSC | PSC Karnali | PSC Lumbini | PSC Sudurpaschim | PSC Gandaki | PSC State 1.