SEWAGE DEPARTMENT TRAINING PROGRAM
How to Build a Free Access Gravity Sandfilter
Over the aggregate, place and level a minimum of 24 inches of sand.
The sand shall have an effective size of between 0.3 and 0.6 mm and a uniformity coefficient of 3.5 or less with less than 4% passing the #100 sieve. The sieve analysis shall be conducted in accordance with Department of Transportation PTM #616 and the uniformity coefficient shall be determined by Department of Transportation PTM # 149. Furthermore, the sand may not contain more than 15% deleterious material as determined using Department of Transportation PTM #149.
