Research On The Application Of Sewage Sludge In Making Geopolymer

Sweage sludge is a kind of sediment produced during the purification process of urban domestic sewage and industrial wastewater,which is a type of hazardous solid waste.The most common sludge resource utilization is to use the sludge incinerated at high-temperature incineration to prepare building materials as admixture.However,although incineration can be used to carbonize organic matters in the sludge,it will produce carcinogenic dioxins during incineration and is always with high operating costs.This topic is devoted to the study of a low-energy-consuming sludge treatment method,starting with the reduction of sludge,using aluminum chloride modified rice husk ash,and then using modified rice husk ash to pretreat the sludge,the purpose of which is to reduce the volume and make it stable.The treated sludge was then prepared in a base-activated state to produce geopolymers.This series of studies is to promote the research of sludge remediation,and integrates the core technology of building materials production with the concept of environmentally friendly waste,which is of great importance for the promotion of research and development of new building materials and technological progress in the field of civil engineering materials.In addition,this project has carried out research on the preparation of geopolymers from unsintered sludge,which is in line with national industry guidance and policy support scope,achieving the goal of reducing environmental pollution,reducing energy waste,and enabling sludge to realize the use in the region of building materials.This kind of sustainable development cycle get the dual benefits of environmental and economic purposes.The results show that rice husk ash has a great effect on the dewatering performance of sludge,and the modification of rice hull ash will intensify this improvement.The use of modified rice husk ash to pretreat can not only reduce the volume sludge,but also reduce the content of organic matter in the sludge,providing a well foundation for the further use of sludge as building materials.The main inorganic components in the sludge are SiO2,Al2O3 and Fe2O3,which let sludge have the potential to make building materials.To facilitate the test,the pretreated sludge was dried at a basic temperature of 300? in order to remove the taste of the sludge and dry the pretreated sludge.Alkaline activator(a mixture of NaOH and Na2 SiO3)was then used to alkali-activate the pretreated sludge to prepare the sludge and rice husk ash-based geopolymer.It was found that the ratio of sludge and rice hull ash,the modulus of alkali activator that means the alkalinity,and liquid-solid ratio all have an effect on the strength of the geopolymer.This geopolymer has a good effect on the consolidation of heavy metals in sludge and will not harm the natural environment and human health.This experiment provides a good solution for the application of sludge and rice hull ash,but there are still some deficiencies,and further researches are needed to transform this method into reality.