Figure 5 The performance of the bioreactor, however, got stable
Related Figures (6)
pecially evident in case of wood and textile fibers, which com- prise elongated and empty cell walls’. Fig. 1. Structure of cellulose (A) B-glucosidic bonds (B) schematic structure of a fibril (Adopted from [2}). Table 2. Composition of carboxymethyl cellulose bearing synthetic feed Fig. 2. Schematic diagram of the aerobic bioreactor treating CMC bearing synthetic wastewater. Chatterjee et al.: Biodegradation study of cellulose bearing synthetic wastewater in activated sludge systen lose (CMC) bearing synthetic feed were prepared as speci- fied in Table 1 and Table 2. The C:N:P ratio in both the feed solutions were kept at 100:5:1. Fig. 4. pH profile for various CMC to dextrose ratios. Fig. 3. COD profile for various CMC to dextrose ratios. Fig. 5. MLSS profile for various CMC to dextrose ratios. with the onset of batch 4, which had cellulose to dextrose ratio of 4. The gradual fall in system pH, as observed from Fig. 4, had to be adjusted every time with 2 N NaHCO, solu- tion. In addition, supplementation of micronutrients (cobalt, nickel, molybdenum, copper, manganese) in suitable amounts had to be done several times in order to counter any pos- sible inhibition. Once the system got stabilized, the pH for the batches from 5 to 8 remained within 7.9 to 8.6, and com- plete acclimation with 100 mL cellulose bearing wastewater was achieved. This is evident from percentage COD removal profile, shown in Fig. 6, which shows degradation of the in- troduced COD reaching an asymptotic pattern from the sixth batch onwards, where cellulose to dextrose ratio was 9. The percentage COD removal for the last set of batch runs (in- cluding those which had not been shown) with cellulose to dextrose ratio => 9 consistently remained above 64%. Not only that, in case of the batch where only 100 mL cellulose bearing synthetic wastewater feed was introduced, 64.7% COD removal was achieved, as noticed in Fig. 6. Fig. 6. Profile of percentage COD removal in various batch runs. References Aerobic biodegradation of a polysaccharide, such as CMC, usually proceeds with hydrolysis of the polysaccha- ride to monosaccharide. This results in the formation of a variety of intermediates including glucose and glycolic acid@". The acclimatization becomes faster and easier, with the for- mation of easily biodegradable intermediates, when carried out with a co-substrate, such as glucose. It is evident from the above shown COD, pH and MLSS profiles, that there was no production of any major bio-stable intermediate, which could have inhibited the acclimation phase. As pointed out in past studies'*:'9:21 | the most likely products of aerobic CMC degradation are alcohols, ketones, acids (including salts and
