Hún sagði að við hefðum átt að flokka þetta sorp strax, en að það væri samt ekki of seint að endurnýta hluta af því.

It means we should have sorted or we were supposed to have sorted.

The key pattern is:

• eiga að + infinitive = should / be supposed to
• hafa átt að + infinitive = should have / was supposed to have

So:

• við áttum að flokka = we were supposed to sort
• við hefðum átt að flokka = we should have sorted

In this sentence, it implies that the sorting did not happen when it should have.

Hefðum is the past subjunctive form of hafa for við.

In this sentence, it appears in the expression hefðum átt að, which is a very common way to express a missed obligation: should have.

It is also helped by the fact that the whole idea is being reported after Hún sagði að... (She said that...). In reported speech, Icelandic often uses the subjunctive, especially when relaying someone’s statement or viewpoint rather than presenting it as a plain independent fact.

So við hefðum átt að flokka is a natural reported-speech way to say we should have sorted.

Væri is the past subjunctive of vera (to be).

Here again, the clause is part of reported speech after Hún sagði að..., so the subjunctive is very natural:

• að það væri samt ekki of seint...

This corresponds to something like:

• that it was / would still not be too late...

If you imagine the direct version, it might have been:

• Það er samt ekki of seint... = It is still not too late...

When reported from a past perspective, Icelandic often shifts this to væri.

Because both parts are subordinate clauses depending on sagði.

Structure:

• Hún sagði [að við hefðum átt að flokka þetta sorp strax]
• en [að það væri samt ekki of seint að endurnýta hluta af því]

So the second að basically means but that...

Repeating að is very normal and helps make the structure clear. English sometimes does the same:

• She said that we should have sorted this trash right away, but that it still wasn’t too late...

Samt here means still, nevertheless, or all the same.

So:

• það væri samt ekki of seint = it still would not be too late / it nevertheless was not too late

It adds a contrast:

• We should have sorted it immediately,
• but still, it is not too late to do something useful with part of it.

This is an important vocabulary point.

• endurnýta = reuse, repurpose, use again
• endurvinna = recycle

So að endurnýta hluta af því means to reuse part of it, not necessarily to recycle it through a formal recycling process.

That fits nicely with the first part of the sentence, which talks about sorting trash, and the second part, which says that some of it might still be reusable.

This phrase means part of it.

Breakdown:

• hluta = accusative singular of hluti (part), because it is the object of endurnýta
• af = of / from, and this preposition takes the dative
• því = dative singular of það

So:

• hluta af því = part of it

A learner often notices that því is not the form they expected. The reason is simply that af requires the dative.

Þetta sorp means this trash / this rubbish.

A few useful things are happening here:

• sorp is a neuter noun
• þetta is the neuter singular form of this
• the phrase is in the accusative, but for neuter singular many forms look the same as the nominative

So þetta correctly agrees with sorp.

Using þetta makes it specific: not trash in general, but this particular trash.

It works just like it in English it is not too late.

This það is not really referring to a concrete object. It is a kind of dummy or formal subject used in impersonal expressions.

So:

• það væri ekki of seint = it would not be too late

This is very similar to English structure.

It works very much like English not too late to + verb.

So:

• ekki of seint að endurnýta hluta af því
• not too late to reuse part of it

Pattern:

• of + adjective = too + adjective
• að + infinitive = to + verb

Examples:

• of erfitt að skilja = too difficult to understand
• ekki of seint að byrja = not too late to begin

The sentence is easier to understand if you split it into parts:

• Hún sagði
• að við hefðum átt að flokka þetta sorp strax
• en að það væri samt ekki of seint að endurnýta hluta af því

A useful rule is that after a subordinating að, Icelandic does not follow the normal main-clause verb-second pattern. So the order is more like:

• að + subject + finite verb + rest

That is why you get:

• að við hefðum...
• að það væri...

Also notice where samt goes:

• að það væri samt ekki...

Adverbs like samt often come after the finite verb in this kind of subordinate clause.

So the sentence structure is very standard Icelandic subordinate-clause word order.