Release Of Organic Substance From Hydrolysis And Acidification Of Excess Sludge And The Influencing Factors

The excess sludge yield is growing along with the urbanizationaccelerates and the Waste Water Treatment Plant scale increasing.There are a great mount of organics in the excess sludge, which canhydrolyzed to Volatile Fatty Acids (VFA). The VFAs can be combined tokinds of useful materials. At present, the research object mainly is themixture of primary sludge and excess sludge and nobody researchesthe excess sludge at the pilot scale experiment.The experiment proposed a process with two sections: the firstsection is lab experiment that the excess sludge hydrolyzed to VFAsthen treat the effluent with the exisiting processes. The second section ispilot experiment at point, debugging the processes which cancombine the PHAs and writing the operation book, which focus on thedifferent Sludge Retention Time(SRT) to the VFAs yield. The researchresults as follows:The lab experiment enclosed the factors(MLSS, temperature, SRT) ofexcess sludge hydrolysis and analysized the effect law then we got thebest operation condition: when the MLSS, temperature and SRT are30g/L,50℃,24h the concentration of VFAs is the highest and the sludgereduction is the best. Under this condition, the COD, VFAs concentrationare8394mg/L、2490mg/L, COD/TN=10.3, VFA/COD=30%and the MLSSreduction22.5%. cation (NH4+) static exchange capacity is7mg/gwhile the dynamic exchange capacity is4.5mg/g when the0.1L/h.when adsorbed ammonia nitrogen, zeolite can desorb. When the regeneration liquor NaOH+NaCl (3/7) zeolite can be regenerated93%and the ammonia nitrogen stripping rate is85%, so we use the NaOH+NaCl (3/7) as the regenrant.As the pilot scale experiment is continuous operation, weresearched the VFAs yield of sludge hydrolysis which based on the labexperiment conclusion. The results suggested that the SRT increasesfrom1d to2d is in favor of the sludge hydrolysis but this won’t besuitable for2d increases to4d. So extention the SRT can increase theVFA concentration and the best is2d, and the VFA is1843mg/L whilethe VFA/COD.