Preparation And Application Of Ultra-lightweight Ceramic In Industrial Advanced Wastewater Treatment By Biological Aerated Filter

Dehydrated sewage sludge (DSS) and clay used as raw materials for preparation of novel media-Ultra-lightweight sludge ceramics (ULSC) and ULSC employed in an upflow lab-scale biological aerobic filter (BAF) were investigated for industrial wastewater treatment. Firstly, ULSC was prepared from DSS (JN-sludge) and clay (Zibo-clay), which were obtained from Jinan wastewater treatment plant and Zibo city respectively. Then the characteristics of ULSC were tested, including bulk density, grain density, water absorption, microstructure properties and toxic metal leaching properties. Secondly, ULSC utilized as filler of BAF was studied for soy protein wastewater and pharmaceutical wastewater treatment, and the optimum conditions were determined by national discharge standards, investment and running cost. The conclusions were as follows:(1) ULSC prepared from JN-sludge and Zibo-clay verified to be feasible according to the properties. The bulk density, grain density and water absorption were330.80kg m-3,865.30kg m-3and5.30wt%respectively, which reached the national standard of Ultra-lightweight ceramics. The microstructure analysis showed that ULSC was rough in the surface and porous, and the toxic metal leaching test revealed that all the nine metal contents in lixivium were much lower than the limits of the national standards, therefore, ULSC would not lead to secondary pollution.(2) ULSC utilized as filler of BAF was applied in soy protein advanced wastewater treatment. The optimum operational conditions were media height of80cm, hydraulic retention time (HRT) of4h and air-liquid ratio (A/L) was5:1. Under this condition, the final effluent reached the requirement of national discharge standards (CODCr≤100mg L-1, NH4+-N≤15mg L-1).(3) ULSC applied in pharmaceutical advanced wastewater treatment was also investigated. During the whole investigation, domestic sewage was added to enhance the biodegradability of pharmaceutical wastewater and the optimum operational conditions were the addition of domestic sewage was20wt%, media height of80cm, HRT of6h and A/L of5:1respectively. Under this condition, the final effluent also reached the requirement of national discharge standards. Moreover, the pilot scale test revealed that the optimum conditions were different from the lab scale test, but the final effluent also reached the requirement of national discharge standards.(4) All the results showed that ULSC was feasible filler.