Papers by Keyword: Anaerobic Sludge

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Authors: A. Arora, S. Saxena
Abstract: Sludge, a natural, uncalled for byproduct of aerobic/ anaerobic biological digestion of organic matter present in wastewaters, also known as biosolids, is a thick, black and viscous substance comprising of dead and degraded microbial cells that digested the influents. This dead microbial material, accumulates on the bottom of anaerobic lagoons/ reactors, is organic in nature and rich in plant nutrients such as nitrogen, phosphorus and essential trace elements. It must be removed periodically. Therefore, the objective is to use the sludge as a fertilizer on agricultural land. It is an environmentally acceptable and economical method of sludge disposal. The application of organic wastes to farmland has increased over the years as it contributes to the preservation of the environment and results in an improvement of chemical, biochemical and physical properties of soil, although there is an increased risk of soil and ground water being contaminated by pollutants. Sewage sludge may contain heavy metals whose presence in soil may reduce enzyme activities and affect microbial communities in soil. They accumulate in soil and are taken up by crop plants thus posing health hazard. The study was conducted to characterize anaerobic sludge and quantify the concentration of heavy metals in it, to determine the suitability of the sludge as fertilizer for crops. Physicochemical and biochemical analyses showed that anaerobic sludge produced at Upflow Anaerobic Sludge Blanket (UASB) sewage treatment plant at Faridabad (an industrial town), Haryana, India, contained total organic C 15.714 percent, total Kjeldahl N 0.795 percent, available P 8 3g g-1and heavy metals Zn 1500 3g g-1, Ni 226 3g g-1, Fe 3000 3g g-1 and high activity of enzymes like alkaline phosphatase and dehydrogenase in the sludge. These enzymes are important for soil fertility and nutrient cycling. The toxic heavy metals have been accumulated by bacteria from sewage waters. The ideal C/N ratio, P and enzyme activities show its suitability as fertilizer but presence of heavy metals is a matter of concern. Therefore its application as crop fertilizer or onto land has to be carefully managed.
Authors: Jin Wang, Zhen Jia Zhang, Li Na Chi
Abstract: The microbiological structure characteristic and the particle diameter distribution of different sludges (aerobic excess sludge, sludge from sanitary landfill digested for one year, and granular sludge of pilot-scale expanded granular sludge bed (EGSB) reactor after 400 d of operation) were analyzed through scanning electron microscopy (SEM), transmission electron microscopy (TEM) and sieve. SEM of granules showed that the microbiological structure of the sludge from different sources had differences. But TEM proved that granules of EGSB and landfill both had similar kind of bacterial species i.e. Methanosarcina bacteri sp. There were obvious differences in the transformation trend of size distribution between different granular sludges. Three-step Model for the anaerobic granular sludge formation in sanitary landfill was put forward.
Authors: Man Hong Huang, Liang Chen, Dong Hui Chen, Yu Dong Yang
Abstract: Strong anion exchange (SAX) columns and oasis HLB cartridges were combined to extract trace level oxytetracycline(OTC) and high performance liquid chromatography(HPLC) UV-detector were used to measure it in wastewater sample. The effect of mobile phase was investigated. Under the best analysis conditions, linear calibration equations were established for OTC. The linearity were in the range of 0.1-10g/mL, Correlation coefficient (R2) is about 0.9997. The recovery factors ranged from 82-92% with a relative standard deviation of 4.8-6.4%.Lab-scale experiments were conducted to investigate the sorption behavior of OTC by anaerobic sludge. Starch in the mixed liquor can decrease the adsorption capacity of OTC.
Authors: A.I. Khabibrakhmanova, N.A. Yugina, M.V. Shulaev
Abstract: The analysis of processes intensification of biological wastewater treatment in aerobic and anaerobic conditions using a new generation of bio-stimulants was performed. The humic preparation and synthetic Melaphen influence was investigated on the biocenosis sludge. The humic preparation and Melaphen provided different effects on the growth of microorganisms in the sludge. It was shown that effect depends on concentration of bio-stimulants and stage of microorganisms growth. The concentrations 10-1 and 10-3 g /dm3 for humic preparation and Melaphen respectively were intensified microorganisms growth. The results show that using humic preparation 10-3 g /dm3 and Melaphen - 10-6 mg/dm3 the most effective for the treatment of wastewater in aerobic conditions, but using humic preparation 10-1 g/dm3 and Melaphen - 10-6 mg/dm3 in anaerobic conditions.
Authors: Toshiyuki Nomura, Hideaki Asano, Toshiyuki Takayama, Azusa Naimen, Hayato Tokumoto, Yasuhiro Konishi
Abstract: Highly efficient hydrogen-producing anaerobic microflora was enriched from anaerobic sludge obtained from a methane fermentation plant, with soluble starch as substrate. The effect of culture medium pH on hydrogen production capacity and microbial community was investigated using a batch reactor equipped with a pH controller. The optimal pH was 5.0, the hydrogen yield was 2.59 mol/mol-glucose, and the maximum hydrogen production rate was 123 mL/L-culture/h. Partial 16S rDNA sequencing placed the isolated strain within the Clostridiaceae family. When the isolated strain adhered to polymer resin, the change in free energy of interaction was negative, indicating that the bacteria-resin interaction is thermodynamically favorable, and that the strain will readily immobilize on the resin.
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