En lugar de mezclar basura, separamos el residuo orgánico.

It means instead of.

So En lugar de mezclar basura means Instead of mixing rubbish/waste.

A very similar expression is en vez de, which also means instead of:

• En lugar de mezclar basura...
• En vez de mezclar basura...

Both are common. En lugar de can sound a little more formal or neutral.

Because after en lugar de, Spanish uses a noun or an infinitive.

Here, mezclar is an infinitive, so en lugar de mezclar literally means instead of mixing.

You cannot use a fully conjugated verb directly after de here:

• Correct: en lugar de mezclar
• Incorrect: en lugar de mezclamos

This is similar to English:

• instead of mixing not
• instead of we mix

Separamos is the present indicative form of separar for nosotros (we).

The sentence is structured like this:

• En lugar de mezclar basura = instead of mixing rubbish
• separamos el residuo orgánico = we separate the organic waste

So the first part uses an infinitive (mezclar) after en lugar de, and the main action uses a normal conjugated verb (separamos).

Because Spanish usually leaves out subject pronouns when the verb ending already makes the subject clear.

Separamos already tells you the subject is we.

So:

• Separamos el residuo orgánico = We separate organic waste
• Nosotros separamos el residuo orgánico is also possible, but it adds emphasis or contrast

Spanish often omits pronouns unless they are needed for clarity or emphasis.

In Spanish, basura is often treated as an uncountable or collective noun, like trash or rubbish in English.

So mezclar basura means to mix trash/waste, not necessarily one piece of trash.

This is normal:

• Sacar la basura = to take out the trash
• Hay basura en la calle = there is trash in the street

Even though English sometimes uses plural ideas like different kinds of waste, Spanish often uses singular basura for the general concept.

They are related, but not exactly the same.

• Basura is the more everyday word: trash, rubbish
• Residuo is a bit more technical, formal, or administrative: waste, residue

In this sentence, the contrast makes sense:

• mezclar basura sounds like a general everyday action
• el residuo orgánico sounds more specific, like the category used in recycling or waste sorting

In Spain, this kind of wording is very common in public information about recycling.

Because singular can be used in Spanish to talk about a category in a general sense.

So el residuo orgánico here means organic waste as a type/category.

This is similar to English expressions like:

• The elephant is a large animal
  meaning elephants as a species, not one specific elephant.

Spanish often uses the singular article this way:

• el plástico
• el papel
• el vidrio
• el residuo orgánico

You could also hear plural forms in real life, depending on context:

• separamos los residuos orgánicos

Both can work, but the singular sounds very natural when talking about waste categories.

Not exactly.

In waste and recycling contexts, residuo orgánico usually means organic waste in the sense of biodegradable material, such as:

• food scraps
• fruit and vegetable peels
• garden waste

So here orgánico is about the type of waste, not necessarily about organic produce from a supermarket.

Context is very important.

Yes, you could.

La basura orgánica is more everyday and very understandable.
El residuo orgánico sounds a little more official, technical, or institutional.

So:

• separamos la basura orgánica = natural, everyday
• separamos el residuo orgánico = also natural, but a bit more formal/public-information style

In Spain, both are possible, especially in recycling contexts.

Here it means to mix waste together instead of sorting it.

It does not usually mean physically stirring rubbish around. It means putting different kinds of waste in the same place instead of separating them by type.

So the sentence is talking about sorting waste properly:

• not mixing everything together
• separating the organic waste

That is why separamos is the opposite action.

The comma separates the introductory phrase from the main clause:

• En lugar de mezclar basura, = introductory contrast
• separamos el residuo orgánico. = main statement

It helps readability and makes the sentence easier to process.

In short:

• first, the sentence presents what is not done
• then, after the comma, it gives what is done instead

It would be understood throughout the Spanish-speaking world.

That said, the wording el residuo orgánico sounds especially compatible with the kind of recycling language often seen in Spain, where waste sorting categories are very visible in public life.

A speaker from another country might be more likely to say something like:

• la basura orgánica
• los desechos orgánicos

But your original sentence is perfectly good Spanish and very natural in a Spain context.