Modern wastewater plants are effective at processing organic solids into fertilizer products (known as biosolids), with advanced facilities also capturing methane for energy production.

In October 2011, scientists found using spectroscopy that cosmic dust contains complex organic matter (specifically, aromatic-aliphatic organic solids) that could be created naturally, and rapidly, by stars.

Alternatively, the sand could also have come from organic solids produced by photochemical reactions in Titan's atmosphere.

Anaerobic digestion is the biological treatment of liquid animal waste using bacteria in an area absent of air, which promotes the decomposition of organic solids.

Examples of organic solids include wood, paraffin wax, naphthalene and a wide variety of polymers and plastics.

A plastic material is any of a wide range of synthetic or semi-synthetic organic solids that are moldable.

Almost all organic solids are insulators.

If stored, it must be used within a very short time or it will begin to putrefy due to the organic solids in the water.

Many organic solids are like this...it's actually quite common.

As for the sand itself, Titan's grains are most likely bits of water ice or organic solids, not silicates like the sand on Earth.