Enqubweni yokukhiqiza ukudla nesiphuzo, uketshezi oluningi lwempahla eluhlaza, okuhlanganisa ijusi, ujusi wamaberry, imikhiqizo yobisi, utshwala, njll., ludinga ukucutshungulwa.Okuqinile okulengisiwe, i-sediment, kanye ne-micro-organisms ngokuvamile kuqukethwe oketshezini lwempahla.Uma ukuhlunga okusebenzayo kungenziwanga ngokuphelele, kuzothinta ikhwalithi nokunambitha kwemikhiqizo.Izinto zokuhlunga zingasusa kahle lokhu kungcola futhi ziqinisekise ukuhlanzeka nokuzinza koketshezi lwempahla eluhlaza.