Qidiruv

1) stained; frowzy, blurry, dirty, dungy, filthy, frowsy, grubby, impure, mangy, messy, miry, mucky, muddy, piggish, scruffy, sludgy, smeary, smudgy, smutty, sordid, spot

ponds used for biological treatment of sewage. Used independently – for treatment by micro-organisms and algae of sinks, saturated with easily oxidizing organic matters,