ADP-ribose glycohydrolase that hydrolyzes ADP-ribose and acts on different substrates, such as proteins ADP-ribosylated on glutamate and O-acetyl-ADP-D-ribose (PubMed:21849506, PubMed:23474714, PubMed:23481255). Specifically acts as a glutamate mono-ADP-ribosylhydrolase by mediating the removal of mono-ADP-ribose attached to glutamate residues on proteins (PubMed:23474714, PubMed:23481255). Does not act on poly-ADP-ribosylated proteins: the poly-ADP-ribose chain of poly-ADP-ribosylated glutamate residues must by hydrolyzed into mono-ADP-ribosylated glutamate by PARG to become a substrate for OARD1 (PubMed:23481255). Deacetylates O-acetyl-ADP ribose, a signaling molecule generated by the deacetylation of acetylated lysine residues in histones and other proteins (PubMed:21849506). Catalyzes the deacylation of O-acetyl-ADP-ribose, O-propionyl-ADP-ribose and O-butyryl-ADP-ribose, yielding ADP-ribose plus acetate, propionate and butyrate, respectively (PubMed:21849506).