Study On Producing Media For Wastewater Treatment With Sludge From Water Treatment Plants

A large amount of sludge of complex components is produced in the process of drinking water treatment and wastewater treatment. In case of any secondary pollution and any bad effect on the treating efficiency, the sludge should be treated and disposed properly. Traditional ways of sludge treatment and disposal all have certain drawbacks. Thus searching for an economical and effective way to reuse the sludge has recently become one of the increasingly concerned issues in environmental science. Media is a key factor in the attached-growth process. Its performance should have direct influences on the efficiency of the process. Sludge-made ceramic media is a product of the combination of sludge reusage, pottery firing technic and biofilm process. This dissertation carried out a thorough study on the optimal ratio of raw materials, optimal producing process and the physical and biological characteristics of sludge-made ceramic media. The conclusions are as follows:①Through a multipal-material ratio design experiment, a single-factor experiment and an orthogonal experiment, the optimal ratio of raw materials and the optimal producing process was obtained. A new type of porous light media made of sludge from water treatment plants alone was successfully gained in the end. Compared with ordinary ceramic media, this media has a coarser surface and a larger available pore volume, which anables it to be considered as an ideal media for wastewater treatment.②Three types of sludge-made ceramic media along with ordinary ceramic media were applied in biomass attachment expriments to conduct parallel studies. The result indicates that sludge-made ceramic media archieved a better efficiency than ordinary ceramic media with both higher speed and larger biomass. Sludge-made ceramic media is more preferable for microorganism attachment and reproduction among which the batch marked as No.2 has the best efficiency. The determination of final attached biomass shows that the biomass on No.2 sludge-made ceramic media is 2.5 times of that on ordinary ceramic media, which proves that sludge-made ceramic media is indeed an ideal meida for wastewater treatment.③The results of parallel wastewater treating experiments show that sludge-made ceramic media enjoys an efficiency of 85%, 80% and 60% in respectively COD, NH3-N and TP treatment. During the whole process, all three categories of sludge-made ceramic media see a higher and more steady efficiency than ordinary ceramic media. No.2 sludge-made ceramic media still stands out as the best.④The study on the treatment efficiency reveals that organic pollutant load, HRT and temperature should have significant effects on the treatment efficiency, while DO can also cast notable effects when is in certain range. All three categories of sludge-made ceramic media see a higher and more steady efficiency than ordinary ceramic media in a variable situation. No.2 sludge-made ceramic media still delivers the best performance in all cases.⑤The parallel study of three categories of sludge-made ceramic media reveals that No.2 sludge-made ceramic media is an ideal meida for wastewater treatment. It is produced with a ratio of 3 to 2 of sludge from drinking water plant and sludge from wastewater treatment plant.