O biofiltro funciona com a bomba d'água.

Here, funciona com means works with, operates with, or runs using.

So O biofiltro funciona com a bomba d'água suggests that the biofilter operates by using the water pump, or that the water pump is part of how it works.

It does not usually mean works together with in a social sense, like people working with each other. In this kind of technical sentence, com often means by means of / using / with the help of.

O is the masculine singular definite article, meaning the.

Portuguese uses definite articles more often than English does. So where English might sometimes say just biofilter in a general explanation, Portuguese often says o biofiltro.

Here:

• o = the
• biofiltro = biofilter

So O biofiltro = the biofilter

Because in Portuguese, every noun has a grammatical gender. Biofiltro is treated as a masculine noun, so it takes o.

That is why you get:

• o biofiltro
• um biofiltro

This is grammatical gender, not biological gender. Many object nouns are simply assigned masculine or feminine and must agree with articles and adjectives.

Because bomba is a feminine noun in Portuguese.

So you say:

• a bomba = the pump
• uma bomba = a pump

That feminine gender stays the same even in the full expression bomba d'água.

D'água means of water and corresponds to de água.

So:

• bomba d'água = literally pump of water
• in natural English: water pump

This is a very common way Portuguese forms expressions like this.

The apostrophe shows an elision: de água becomes d'água in certain fixed expressions.

So:

• de água = of water
• d'água = a shortened form used in established expressions

A learner should know that this is common in some set terms, but you cannot automatically replace every de with d'. For example, in an ordinary phrase, you would normally still write garrafa de água, not garrafa d'água.

In bomba d'água, the form with the apostrophe is a conventional, established expression.

A means the, and it is used because the sentence is referring to a specific water pump, or to the pump understood from the context.

So:

• com a bomba d'água = with the water pump
• com uma bomba d'água = with a water pump

That difference matters:

• a = a specific one
• uma = any one / one example of that thing

Yes. Funciona is the third-person singular present form of funcionar.

Conjugation:

• eu funciono = I function
• você/ele/ela funciona = you/he/she functions
• o biofiltro funciona = the biofilter functions / works

It matches the singular subject o biofiltro.

Both are correct, but works is more natural in everyday English.

So:

• O biofiltro funciona... = The biofilter works...
• A more literal translation is The biofilter functions...

In technical writing, functions may sound fine. In normal speech, works is usually the more natural choice.

Not always. Com often literally means with, but the exact meaning depends on context.

In this sentence, com suggests:

• using
• by means of
• with the help of
• in combination with

So the idea is not just physical accompaniment. It is more about the mechanism or setup.

Yes, that is possible. Funciona com can be a little broad.

Depending on context, it could mean:

• the biofilter operates using the water pump
• the biofilter works when connected to the water pump
• the biofilter functions as part of a system that includes the water pump

If you wanted to be more explicit, Portuguese could use other structures, such as:

• O biofiltro é movido pela bomba d'água = the biofilter is powered/driven by the water pump
• O biofiltro funciona graças à bomba d'água = the biofilter works thanks to the water pump

But the original sentence is a normal, neutral way to say it.

A rough English-style approximation is:

BOM-ba DA-gwa

A few notes:

• bom has stress on bom
• bomba sounds like BOM-ba
• d'água is pronounced smoothly, roughly like DA-gwa
• água has the stress on the first syllable: Á-gua

The apostrophe does not create a big pause. Native speech flows through it.

A rough approximation is:

oo byo-FEEL-troo foon-see-OH-na kom a BOM-ba DA-gwa

A few stress points:

• biofiltro → stress on FIL
• funciona → stress on O
• bomba → stress on BOM
• água → stress on Á

This is only an approximation for English speakers, but it can help at the beginning.

In normal Portuguese, that sounds less natural as a full sentence.

Standard, natural phrasing is:

• O biofiltro funciona com a bomba d'água

Dropping articles may happen in:

• titles
• labels
• notes
• very telegraphic technical writing

But in regular sentences, Portuguese usually wants those articles.

Yes.

Compare:

• com a bomba d'água = with the water pump
  This suggests a specific, known pump.
• com uma bomba d'água = with a water pump
  This means any pump of that type, not a specific one.

So the original sentence sounds like the speaker has a particular pump in mind.

Yes. This is the most neutral and standard word order:

• O biofiltro = subject
• funciona = verb
• com a bomba d'água = prepositional phrase

Portuguese often follows this same basic pattern: subject + verb + complement

So the sentence sounds natural and straightforward.