Can the obligated parent discharge child support arrearages in a bankruptcy once the child reaches the age of 18?

If what you mean is can back owed child support payments be discharged in bankruptcy: NO. Regardless of how old the child is now. on the other hand if you mean to be included in the repayment schedule for a chapter 13 then yes. Child support arrearages can sometimes be included in bankruptcy. This pertains to arrearages only and not to current support due. A bankruptcy petition cannot override a court order of support and if arrearages are allowed to be included in a 13 the arrearages must be paid in full, not a percentage thereof, as is possible with unsecured creditors.