A Laboratory Study Of Thermophilic Anaerobic Treatment For Hypersaline Dye Wastewater

The reactive dyes-containing effluents from the industries have caused serious environment pollution because the presence of dyes in water is highly visible and noxious. Therefore, effluents containing dyes must be treated before their discharge into the environment. The purpose of the dissertation is the disposal of hypersaline dye wastewater in two similar thermophilic UASB reactors. The experiment was carried out to explore start-up of the UASB reactors, the treatment effect, the characteristics of anaerobic granular sludge, the degradation process of RR2, ect. In order to debate the effect of the choice in auxiliary substrate in the biodegrading RR2 system, two types of auxiliary substrates (glucose/ VFAs-mixture) were fed to two UASB reactors.Experimental results demonstrated: the two reactors were seeded with ambient flocculent digester sludge. After running through warming startup phase, adding salt phase and adding dye phase, when the running conditions were as follows: temperature 55±1℃, HRT 12h, salinity 50000mg/L, influent COD_Cr 1000mg/L, RR2 concentration 100mg /L. The anaerobic granular sludge was found in both reactors in 44 days. The quasi-steady state of the reactor 1 was achieved after 78 running days, the COD_Cr and RR2 removal efficency was about 44% and 90 %, respectively. The quasi-steady state of the reactor 2 was achieved after 93 running days, the COD_Cr and RR2 removal efficency was 20 % and 93 % ,respectively.When anaerobic granular sludge were used as seed, the running conditions did not change, the two reactors were achieved steady state quickly, and the COD_Cr and RR2 removals in the reactor 1 were above 70% and 80% respectively; the COD_Cr and RR2 removals in the reactor 2 were above 35% and 90% respectively. It was shown that anaerobic granular sludge could quickly restart-up the thermophilic UASB reactor.The performance of the two auxiliary substrates which were selected in the two UASB reactor shown that auxiliary substrates didn't affect starting-up and running of the UASB system. The high activity thermophilic anaerobic granular sludge was achieved.HPLC and GC-MS were used to inspect the degradation process of RR2. Thermophilic salt-tolerant anaerobic granular sludge brought about the reductive cleavage of the azo linkage, which resulted in dye decolourisation and production of aromatic amines. Some of the aromatic amines degraded to small molecular metabolites through hydrolysis and oxidation.