Disclosed are processes and apparatus for producing a carboxylic acid. The processes employ a concentration section disposed before and/or after a product isolation section, which allows for oxidation byproducts produced in the process to exit the product isolation section with the isolated carboxylic acid product and/or to be combined with the isolated carboxylic acid product downstream of the product isolation section at a rate of at least about 15 percent of the net make rate of the oxidation byproducts in the production process.