English to Italian Tech/Engineering Engineering (general)

Flat sheet membrane (for water treatment)

Removal of foreign substance
The pipe appendages, cement residuals, leaves, woods and other foreign substances in the MBR tank and other tanks must be removed in advance.
Clean the tank, fill the tank with clean water and then throw out the clean water along the foreign substances.
Make sure that the foreign substances are completely removed.

Premetto che il testo è scritto male, da coreani.
Non capisco la frase, in particolare "throw out" ed "along" in questo contesto.
La traduzione letterale sarebbe: "...fare fuoriuscire l'acqua pulita lungo le sostanze estranee." Che senso ha? Forse con "along" si intende "along with" (assieme). In tal caso ..."fare fuoriuscire l'acqua pulita assieme alle sostanze estranee"??