A compressible biomass carrier for use in fluid treatment systems is disclosed. The biomass carrier includes an extruded circumferential mesh-like structure and elongated elements positioned in a space confined by the circumferential mesh-like structure and at least some of the elongated elements are joined to an inner portion of the mesh-like structure.

Described herein are strength characteristics and biodegradation of articles produced using one or more petrochemical-based polymers and one or more carbohydrate-based polymers. A compatibilizer can optionally be included in the article. In some cases, the article can include a film or bag.