Firma przetwarza szkło w surowiec wtórny.

Firma is in the nominative singular because it is the subject of the sentence — the thing doing the action.

• firma = the company
• przetwarza = processes

So the basic structure is:

Firma + przetwarza + szkło + w surowiec wtórny

That is a normal subject–verb–object order.

It is the object, and it is in the accusative, but for this noun the nominative and accusative singular look the same.

• nominative: szkło
• accusative: szkło

This is very common with neuter nouns in Polish.

So in the sentence:

• szkło is the direct object
• it is in the accusative
• it just happens to look unchanged

A similar pattern:

• okno → widzę okno
• jajko → jem jajko

That is a very common learner question. W often does mean in, but not always.

With some verbs of change, transformation, or turning one thing into another, w can mean into.

Here:

• przetwarzać coś w coś = to process/transform something into something

So:

• szkło = what is being processed
• w surowiec wtórny = what it is being turned into

Compare the same idea in other examples:

• zamienić wodę w lód = turn water into ice
• przekształcić budynek w muzeum = transform a building into a museum

It is in the accusative singular because it follows w in this into meaning.

In this sentence:

• surowiec is masculine inanimate
• masculine inanimate nouns often have the same nominative and accusative form in the singular

So:

• nominative: surowiec wtórny
• accusative: surowiec wtórny

The adjective wtórny agrees with surowiec in:

• gender
• number
• case

Even though it is accusative here, it still looks the same because of the noun type.

You are right that in Polish, adjectives usually come before the noun. But surowiec wtórny is a fixed technical term.

In formal, technical, scientific, or classification-style expressions, Polish sometimes places the adjective after the noun. That is what happens here.

So:

• surowiec wtórny is the standard established expression
• it means a secondary raw material or recyclable raw material

This word order is not random — it sounds like a set term used in industry/environmental language.

Przetwarza is:

• 3rd person singular
• present tense
• imperfective

Its infinitive is przetwarzać.

Because it is imperfective, it often describes:

• a general fact
• a repeated action
• an ongoing process
• habitual activity

So this sentence sounds like a general statement such as:

• the company processes glass into recycled raw material
• this is what the company does

The perfective partner is przetworzyć.

Compare:

• Firma przetwarza szkło... = the company processes / is processing glass...
• Firma przetworzy szkło... = the company will process glass...

A perfective verb normally does not describe a regular present-time activity.

Yes, you may hear na in similar sentences, and it can also express the idea of turning something into something else.

However, in the sentence you were given, w is a normal and correct pattern with the sense of transform into.

A good learner rule is:

• przetwarzać coś w coś = a safe pattern to learn from this sentence

You may also encounter na in related contexts, especially in more everyday wording or with other transformation verbs. But for this exact sentence, w is fully natural and correct.

Because Polish does not have articles like English a/an/the.

So firma can mean:

• a company
• the company

And szkło can mean:

• glass
• the glass

The exact meaning depends on context.

If Polish wants to be more specific, it can add words such as:

• ta firma = this/the company
• jakaś firma = some company
• to szkło = this/the glass

But in many cases, no article is needed at all.

Yes. Polish word order is more flexible than English because case endings show grammatical roles.

The neutral order here is:

Firma przetwarza szkło w surowiec wtórny.

But other orders are possible for emphasis, for example:

• Szkło firma przetwarza w surowiec wtórny.
• W surowiec wtórny firma przetwarza szkło.

These alternatives are grammatical, but they sound more marked and depend on context.

For a learner, the original order is the safest and most natural default.

Yes, firma is a feminine noun.

It matters for agreement in some parts of Polish, especially:

• past tense verbs
• adjectives
• pronouns

But in this present-tense sentence, przetwarza does not show gender.

So in the present:

• firma przetwarza
• kobieta przetwarza
• mężczyzna przetwarza

all use the same verb form.

You would see the feminine gender more clearly in the past tense:

• Firma przetwarzała szkło... = The company was processing / processed glass...

Here przetwarzała shows feminine singular agreement.