Selection And Preliminary Denitrification Test Of Solid Carbon Sources For Bio-Denitrification

The emergence of low carbon source sewage and the reconstruction of wastewatertreatment plant for rising the criterion all exposed the issue that the inflow carbonsource is insufficient for TN removing.The paper makes a comprehensive elaboration ofmeasures and methods taken by wastewater treatment plant to solve the problem of lowcarbon source sewage for denitrification. Technology of denitrification using solidcarbon source solves the problem of low carbon source sewage with advantage of easyto operate and the released easy to control that can be used as a low carbon sourcesewage treatment method or a new technology for reconstructing of wastewatertreatment plant for rising the criterion. Paper comprehensive analysis the function ofsolid carbon source used in enhanced biological denitrification system. From the Angleof economy applicable principles determine the selection of solid carbon sources,widely chosed8biodegradable materials available for experiment: starch-basedbiodegradable materials（PSM）、copolymer of poly-1，4-butylene adipate glycol andpolybutyleneterephthalate（PBAT）produced by two manufacturers、membrane madefrom PBAT、polylactide（PLA）、poly butylenes succinate（PBS）fibrous meal boxes(FMB) and starchy meal boxes (SMB). Rearched the COD released by solid carbonsource in static condition, the biofilm process of each material. Cultivateddenitrification sludge which can use Macromolecular organic matter as substrate, andstructured biofilm system for denitrification using cultivated denitrification sludge.Studied preliminary about denitrification effect of soild carbon source using effluentafter nitrification. The results show that:①COD release test showed that the COD released by different solid carbon sourcein static condition is quite different. The result related to the composition andmanufacture method of each material, as PBAT particle and PBAT membrane. Fromthe perspective of the COD according to standard of effluent, the COD is a parametershould be tested while chosing bio-degradable polymers as carbon source material fordenitrification.②For the bio-degradable materials usually made of high-molecular polymers thatorganic matter released by bio-degradable materials usually are macromolecule. Paperused macromolecular organics (starch) as sole carbon source to cultivate denitrificationsludge. After30days enhancing cultivate, the ability of using macromolecular organics (starch) is enhanced. Compared to SBR sludge, cultivated sludge denitrification usingmicromolecule organics rate of unit mass is about3.7times of sludge in SBR systemtreatment with wastewater while using micromolecule organics, while the rate ofdenitrification using sodium acetate is about3.5times of sludge in SBR systemtreatment with wastewater. according to the PCR-DGGE profiles, found that themicrobiome composition of cultivated denitrifying sludge is much different fromsludge in SBR system, mainly be seen in the microorganism population diversitydescended, the denitrification microorganism was enriched to be the dominantpopulations. The microorganism that capability of hydrolysis extracellular is able wasincrease, for the reason that cultivated sludge can use micromolecule organics fordenitrification.③Using high concentration of nitrate for denitrification membrane process.Measured the COD and nitrate degradation of membrane process, considering the graphtaken by scanning electron microscope，selected4materials that can be used as solidcarbin source for denitrification: fbrous meal boxes (FMB,5#), starchy meal boxes(SMB,6#), poly butylenes succinate（PBS,7#）, copolymer of poly-1，4-butyleneadipate glycol and polybutyleneterephthalate（PBAT,8#）. Researches show that theCOD released by SMB(6#) can be use by microorganism for denitrification and easy toform biological film on the surface, suggest that SMB (6#) material can be used as asolid carbon source denitrification filter. The COD released by other materials can beuse by microorganism for denitrification, but it is difficult to form biological film on thesurface, suggest that these materials can be used as slow release solid carbon sourcematerial.④Research showed that the rate of starchy meal boxes (SMB，6#) useing fordenitrification is highest, which is25.35mg/L·d. This rate is much higher than brousmeal boxes (FMB,5#) and polybutyleneterephthalate（PBAT,8#）, which rate is12.63mg/L·d and6.23mg/L·d respectively. Synthetically analysised the COD releasedby materials, membrane process of materials, and the denitrification rate of materials, itcan be conceptually considered that starchy meal boxes is a ideal material using assolid carbon source for denitrification.Those research results of this paper provided a affordable method for constructinga biological denitrification system using solid carbon source. While also made analternative approach to sovle the problem of insufficient carbon source caused by lowcarbon source sewage and develop an enhanced denitrification technology in the reconstruction of wastewater treatment plant for rising the criterion.