Texas Wastewater Class B Practice Exam

The recommended depth of sludge drawn to a drying bed is approximately 12 inches, which is optimal for effective dewatering. This depth ensures that the sludge has enough thickness to retain moisture but is not so deep that it compacts excessively, which would hinder water removal. In context, a depth of 5 inches may not provide sufficient material for effective drainage and may result in less efficient drying. A depth of 9 inches could be close but does not align with best practices for maximizing the drying process. A depth of 15 inches would likely lead to compaction and reduced air circulation, making it less effective for drying out the sludge. Therefore, transporting sludge at the recommended depth of around 12 inches strikes the right balance between adequate moisture retention and efficient drying.