| Sludge is a byproduct after sewage treatment, which is a kind of organic debris, bacteria, inorganic particles, colloids and other components of the non-homogeneous complex. Solid waste fly ash emissions from coal-fired power plant, if mismanaged, will not only cause secondary pollution to the environment, but also a serious waste of resources. At present, the main applications of fly ash is used directly as building material or sintering ceramsite used as construction aggregate. Sludge disposal includes landfill, land use, burning and sludge drying. Made of recycled ceramic wastewater treatment by BAF becomes the focus of research in recent years. Adding tourmaline to wastewater treatment can effectively promote microbial activity and increase startup time. Therefore, the research and development of sludge volume to meet the BAF ceramsite filter requirements is imperative.In this study, ceramsite was made from fly ash sludge and tourmaline. Fly ash and sludge was the main ingredient and tourmaline was the catalyst. Technololgical process of preparation of fly as was as follows: firstly, mixdation; secondly, balling; lastly, calcinations. Impacts of calcination temperature, soaking time and proportion of tourmaline on the performance of ceramsite were studied respectively. And then, we determined the best technological condition for the preparation of fly ash ceramsite. At last, fly ash ceramsites produced under the best technololgical condition were used as filter material of Biological Aerated Filter(BAF) reactor in the experiment of treating domestic sewage. By the study of removal efficiency of typical pollutants, performance of wastewater biological treatment utilization of fly ash ceramsite was researched. Density, piled density, apparent density, specific surface area, void fraction, silt carrying capacity, solubility in hydrochloric acid, sum of braking and ware rate were mearesurement cretieria of performance of ceramsite according to national standard Artifical Ceramsite Filter Material for Water Treatment- IV-(CJ/T299-2008).By the combination of singal-factor and orthogonal test, the best techno logical condition was determined as follows: calcination temperature was 1050℃, soaking time was 10 min and proportion of coal gangue was 50%. P erformance indices of ceramsite produced under the best technological condi tion were as follows: density was 2.1273g/cm3, piled density was 0.9886g/c m3, apparent density was 1.6927g/cm3, specific surface area was 1.6012×104cm2/g, void fraction was 42.13%, silt carrying capacity was 0.25%, solubilit y in hydrochloric acid was 1.46%, sum of braking and ware rate was 2.96%. Analysis by SEM showed that fly ash ceramsite had rough surface, abun dant pore structures and a large number of pores with large diameters, whic h was very suitable for the survival of micro-organnisms. So, it could be sa id that fly ash ceramsite was an excellent filter material for Biological Aera ted Filter(BAF).At last, fly ash ceramsites prepared under the best techno lolgical condition were used as filter material of Biological Aerated Filter(BAF) to treat domestic sewage. Inculation of biofilm was used as the method of the start-up of reactor, which need only 11 days. The removal efficiency of pollutants such as COD, NH3-N, SS and total porsphrus were studied during both the start-up and steady operation period. During the start-up period, COD in effluent decreased as its removal rate increased progressively; total phorsphorus in effluent increased and its remova l rate decreased progressively; NH3-N concentration in effluent decreased and its removal rate increased progressively, then both of them kept steady.Finally, the comparison of the physical properties of the ceramic tourmaline ceramic and control and application performance in biological wastewater treatment. After the cost-effectiveness analysis of tourmaline ceramic, the use of waste heat fired thermal power plants, energy conservation, greatly reducing costs. Analysis showed that sludge, fly ash and raw materials for the preparation of ceramic tourmaline can achieve good economic, social and environmental benefits. |
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