Even in the largest cities such as Manila in the Philippines, when sewer lines are extended, the septic tanks remain as integral components of the sewerage system, and therefore also require periodic desludging.
Even in the largest cities such as Manila in the Philippines, when sewer lines are extended and homes are connect to the piped sewerage grid, these are usually effluent sewers only. The septic tanks remain as integrel components of the sewerage system, and therefore also require periodic desludging.