Effect of lime addition during sewage sludge treatment on characteristics of resulting SSA when it is used in cementitious materials

Abstract

Final disposal of sewage sludge is important not only in terms of satisfying the regulations, but the aspect of choosing the optimal wastewater treatment technology, including the sludge treatment. In most EU countries, significant amounts of stabilized and dewatered sludge are incinerated, and sewage sludge ash (SSA) is generated as a by product. At the same time, lime is one of the commonly used additives in the sewage sludge treatment primarily to stabilize the sludge. In doing so, the question arose how desirable is such addition of lime if the sludge is subsequently incinerated, and the generated ash is further used in the production of cementitious materials. A series of mortars were prepared where 10-20% of the cement fraction was replaced by SSA. Since all three types of analyzed SSA (without lime, with lime added during sludge stabilization and with extra lime added during sludge incineration) yielded nearly same results, it can be concluded that if sludge incineration is accepted solution, lime addition during sludge treatment is unnecessary even from the standpoint of preserving the pozzolanic properties of the resulting SSA. Results of the research carried out on cement mortars point to the great possibilities of using SSA in concrete industry.

Novel approach on reduction in GHG emissions from sludge lime stabilization as an emergent and regional treatment in China

“…In practice, most serious bottleneck is subsequent recycling of limed sludge. If it was incinerated, then lime pretreatment of sludge is unnecessary 12 . If it was bio-treated by aerobic compost or anaerobic digestion, the essential microbial groups had been inactivated by the heat released in lime stabilization and its strong alkalinity.…”

“…Subsequent difficulty should be faced again that how to dispose lime stabilized sludge reasonably and how to choose its options among incineration, bio-treatment (such as aerobic compost) and landfill. The outlet of lime stabilized sludge seems to be some problems 2 , 11 , for instance, incremental results shown that if sludge incineration is accepted solution, but lime addition prior to incineration is unnecessary 12 . All the same, sludge lime treatment is widely used, particularly in developing countries.…”

Agricultural and non-agricultural directions of bio-based sewage sludge valorization by chemical conditioning

“…Due to the presence of Al, Ca, Si and Fe and pozzolanic properties, SSA can be applied in concrete production as a filler (replacement for fine aggregate) or as cement material. Vouk et al ( 2017 ) prepared mortars in which cement was replaced by SSA (10–20% fraction). They used ashes without lime and ashes where lime was added during stabilization or combustion of sewage sludge.…”

“…Increasing the combustion temperature of sewage sludge is not recommended (up to 1000 °C) because the material’s mechanical properties deteriorate. Sludge conditioning with lime is also unnecessary because it does not significantly affect the quality of the material and causes nitrogen losses (Vouk et al 2017 ).…”

Unconventional Materials from Sewage Sludge with a Potential Application in a Road Construction

“…Economic and environmental aspects confirm the advisability of research concerning the production of alternative materials with the use of sewage sludge [51]. 11. sewage sludge ash production of ceramics materials Suzuki et al [46] 12. sewage sludge production of lightweight clay ceramic Joan and Cecilia [27] 13. sewage sludge ash production of glass-ceramic material Zhikun et al [57] 14. waste paper sludge as an additive in the production of cement Karada and Awchar [29] 15. sewage sludge ash as an additive in the production of cement material Vouk et al [52] Characteristics of materials…”