Study of Municipal Sludge Ash as a Brick Material -A Review

The municipalities produce sludge of different quality and in different quantities. Sludge resulting from municipalities creates problems of disposal. Generally, dewatered sludge’s are disposed of by spreading on the land or by land filling. However, for highly urbanized cities, sludge disposal by land filling might not be appropriate due to land limitation. Incineration might be an alternative solution. However, a substantial amount of ash will be produced after the burning process and must be disposed of by other means. This paper presents the results of the utilization of sludge ash as brick making materials.  The different engineering properties were also studied by conducting tests on brick specimens of various mix proportions prepared. It was seen that when percentage of sludge was increased, water requirement as well as water absorption of the bricks increased. But at the same time, compressive strength of the brick decreased. But on addition of cement and fly ash the compressive strength increased and the properties of the bricks improved. Further it can be added that other alternatives like sisal fibres, charcoal husk, lime whose addition shall enhance the properties which can be considered as the scope for future research.