Avaliação do desempenho de um reator anaeróbico compartimentado no tratamento de soro de queijo

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Desempenho de reator anaeróbio de fluxo ascendente alimentado com lodo de estação de tratamento de água e esgoto sanitário

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Caracterização e estudo do comportamento térmico de lodo proveniente da indústria sucroalcooleira

Pós-graduação em Química - IBILCE

Process optimization of an aerobic upflow sludge blanket reactor system

Response of an aerobic upflow sludge blanket (AUSB) reactor system to the changes in operating conditions was investigated by varying two principle operating variables: the oxygenation pressure and the flow recirculation rate. The oxygenation pressure was varied between 0 and 25 psig (relative), while flow recirculation rates were between 1,300 and 600% correspondingly. The AUSB reactor system was able to handle a volumetric loading of as high as 3.8 kg total organic carbon (TOC)/m(3) day, with a removal efficiency of 92%. The rate of TOC removal by AUSB was highest at a pressure of 20 psig and it decreased when the pressure was increased to 25 psig and the flow recirculation rate was reduced to 600%. The TOC removal rate also decreased when the operating pressure was reduced to 0 and 15 psig, with corresponding increase in flow recirculation rates to 1,300 and 1,000%, respectively. Maintenance of a high dissolved oxygen level and a high flow recirculation rate was found to improve the substrate removal capacity of the AUSB system. The AUSB system was extremely effective in retaining the produced biomass despite a high upflow velocity and the overall sludge yield was only 0.24-0.32 g VSS/g TOC removed. However, the effluent TOC was relatively high due to the system's operation at a high organic loading.

厌氧产氢菌的分离筛选、诱变选育及其产氢特性的研究

本文从四川绵竹酒厂、成都市龙泉长安垃圾填埋场以及四川大学荷花池底的厌氧污泥中先后分离得到63株厌氧产氢菌，其中H-8、H-61、HC-10等16株产氢细菌产氢能力较高，HC-10的产氢能力最高，最大产氢量和最大产氢速率分别达到2840 ml H2/L培养基和25.39 mmol H2/g drycell·h，对HC-10进行生理生化鉴定和分子生物学鉴定，判定其为clostridium sp.，对HC-10的产氢条件进行了研究，结果表明，该菌的最适生长温度为35 ℃，最适生长初始pH为7，以葡萄糖为最佳碳源，以蛋白胨为最佳氮源，不利用无机氮源，其产氢发酵液相产物以乙醇和乙酸为主，其发酵类型属于乙醇型发酵。此外，以酒糟废液作为底物，进行了菌株HC-10的生物强化试验，研究表明，投加了HC-10的强化系统其产氢量比对照高出40.32%。 同时为了获得厌氧产氢菌的高效突变株，分别以产氢菌H-8和H-61为原始菌株进行微波诱变处理，对微波诱变参数进行了优化，考察了突变株的遗传稳定性、产氢特性及耐酸性。菌株H-8经过微波诱变得到5株高产氢突变株HW7、HW33、HW181、HW184、HW195，经多次传代表明HW195是稳定的高产突变株。突变株HW195具有较好的耐酸性，在pH值为2.8时仍能生长。通过间歇发酵实验，其最大产氢量和最大产氢速率分别达到2460 mL/L培养基和27.97 mmol H2/g drycell·h，比原始菌分别提高了50.75%和41.7%。菌株H-61经过微波诱变后选育得到的突变株HW-18，其最大产氢量和最大产氢速率分别达到2190 mL/L培养基和25.86 mmol H2/g drycell·h，比原始菌分别提高了23.03%和31.00%。 为了对比各种诱变方式对产氢菌产氢能力的影响，以厌氧产氢菌H-61为原始菌株，先后经亚硝基胍(NTG)、紫外(UV)诱变，选育得到1株高产突变株HCM-23。在葡萄糖浓度为10 g/L的条件下，其产氢量为3024 mL/L培养基，比原始菌株提高了69.89%；其最大产氢速率为33.19 mmol H2/g drycell·h，比原始菌株提高了68.14%。经过多次传代实验，稳定性良好。其发酵末端产物以乙醇和乙酸为主，属于典型乙醇型发酵。其最适产氢初始pH为6.5，最适生长温度为36 ℃，以蔗糖为最佳碳源。与原始菌株相比，突变株HCM-23的产氢特性发生了改变，如生长延滞期延长，可利用无机氮源等。 From anaerobic activated sludge, 16 strains of hydrogen producing bacteria were newly isolated. One of them named as HC-10 had the highest hydrogen producing capability, under the batch fermentative hydrogen production condition, the maximal hydrogen yield and hydrogen production rate was 2840 mL/L culture and 25.39 mmol H2/g drycell·h. It was identified as clostridium sp.HC-10 by 16S rDNA sequence analysis. Various parameters for hydrogen production, including substrates, initial pH and temperature, have been studied. The optimum condition for hydrogen producing of strain HC-10 were achieved as: initial pH 7.0, temperature 35 ℃, glucose as the favorite substrate, Moreover, using distiller's solubles wastewater as substrate, HC-10 strain was added in the biohydrogen producing system to research the bioaugmentation effection. The results showed that the hydrogen production of bioaugmentation system was 40.32% higher than the noaugmentation system. An anaerobic, hydrogen producing strain H-8 was irradiated by microwave to optimize the microwave mutagenesis condition, and to test the heredity, hydrogen-producing potential and aciduric of the mutants. An aciduric mutant named as HW195 with steady hydrogen-producing capability was obtained, which can grow at pH 2.8. Its capability of hydrogen production was tested in the batch culture experiments. The maximum hydrogen yield and hydrogen production rate was 2460 mL/L culture and 29.97 mmol H2/g drycell·h, which was 50.7% and 41.7% higher than those of the initial strain, respectively. When used the strain H-61 as original strain, a mutant named as HW18 was obtained. The maximum hydrogen yield and hydrogen production rate was 2190 mL/L culture and 25.86 mmol H2/g drycell·h, which was 23.03% and 31.00% higher than those of the initial strain, respectively. The results demonstrated that microwave mutagenesis could be used in the field of hydrogen producing microorganism. The hydrogen producing strain H-61 was used as an original strain which was induced by NTG and UV for increasing and the hydrogen production capability. One of the highest efficient H2-producing mutants was named as HCM-23 with its stable hydrogen production capability. which was tested in the batch culture experiments. With the condition of 10 g/L glucose, its cumulative hydrogen yield and hydrogen production rate was 3024 mL/L culture and 33.19 mmol H2/g drycell·h, 69.89％and 68.14％ higher than that of the original strain, respectively. The terminal liquid product compositions showed that the mutant HCM-23 fermentation was ethanol type, while the original strain H-61 fermentation was butyric acid type. Varieties of parameters of hydrogen production fermentation were studied, including time, carbon source, nitrogen source, glucose concentration, glucose utilization, initial pH and incubation temperature had been studied, indicated the optimum condition of hydrogen production for the mutant HCM-23 as initial pH6.5, temperature 36 ℃, and the favorite substrate was sucrose. The hydrogen production characters of the mutant and the original strain were different, such as, the growth lag phase and the utilization of inorganic nitrogen source, etc. This work shows a good application potential of NTG-UV combined mutation in the biohydrogen production. And the hydrogen production mechanism and metabolic pathway should be explored furthermore.

耐酸产甲烷菌的分离及其复合菌剂的研究

本文从成都龙泉垃圾填埋场和宜宾造纸厂分离到耐酸性能优良的高温产甲烷菌RY3和中温产甲烷菌SH4，并将其与实验室现有的利用不同底物的产甲烷菌配伍组合成了复合菌剂。采用活性污泥作为固体附着物，研制出了固体产甲烷菌复合菌剂。 菌株RY3的pH耐受范围为5.5～10.5，最适生长pH 6.0～8.0。菌株RY3为革兰氏阳性，长杆状，多数单生，不运动；菌落浅黄色，形状近圆形；利用H2+CO2或甲酸盐作为唯一碳源生长，不利用乙酸盐，对氯霉素非常敏感。该菌最适生长温度为55℃～65℃，最适NaCl浓度为0～2%。根据形态和生理生化特性及16S rDNA序列分析将其初步定为热自养甲烷热杆菌（Methanothermobacter thermautotrophicus）。添加RY3菌液与仅添加厌氧污泥作为接种物相比一周内可使达到最大产甲烷速率所需时间缩短三分之二，甲烷总产量提高约1.8倍。菌株SH4的生长pH范围5.5～9.5，其对酸碱具有良好的适应性，培养3天后，在初始pH值为6.0～8.0的培养基中甲烷产量相差不大，且基本达到最大产量。SH4革兰氏染色阳性，短杆状，多数单生，不运动；菌落近圆形，微黄；利用H2+CO2或甲酸盐作为唯一碳源生长，不利用乙酸盐，对氯霉素非常敏感。SH4最适生长pH 为7.0，最适生长温度为35℃，最适NaCl浓度为0～1.5%。实验表明，添加SH4菌液与仅添加厌氧污泥作为接种物相比可使产甲烷启动时间缩短三分之一，甲烷总产量亦有大幅提高。从形态和生理生化特征以及16S rDNA序列分析表明SH4为嗜树木甲烷短杆菌（Methanobrevibacter arboriphilus）。 以活性污泥为附着物，与培养基和菌种经搅拌后厌氧发酵可得产甲烷菌固体复合菌剂。固体复合菌剂的pH耐受范围为5.5～9.5，温度耐受范围为15℃～65℃，表明其对环境的适应性较强。以猪粪为底物进行厌氧发酵，接种复合菌剂进行试验，以接种实验室长期富集的产甲烷厌氧污泥作为对照，在20℃时，发酵甲烷浓度与对照基本一致，但每日产气量优于对照，第15天时接种复合菌剂的发酵瓶每日产气量是对照的1.59倍；50℃时达到最大甲烷含量所需时间比对照缩短三分之二，三周内总产气量约为对照的2.7倍，甲烷总产量约为2.8倍。以不加接种物为对照，接种复合菌剂20℃时发酵甲烷含量达到50%约需2周，对照2周内甲烷含量最高仅为4.3%；50℃时接种复合菌剂发酵仅需约1周甲烷含量便可达50%，对照则至少需要2周。 In this paper, high-temperature Methanogen RY3 and middle-temperature SH4 were isolated from Chengdu Longquan refuse landfill and Yibin paper mill. They could be used to make compound inoculum that producing methane with the existing Methanogens utilized different substrate. With using anaerobic activated sludge be solid fixture, the process had been designed to produce solid compound inoculum. Strain RY3 possessed excellent capacity of acid and alkali-tolerant. The pH-tolerant scale of RY3 was 5.5～10.5 and its optimum pH value for growth was 6.0～8.0. RY3 was G+, long-rod shape, monothetic and nonmotile, the colony was pale yellow with suborbicular-shape. Formate or H2+CO2 but not acetate was utilized by RY3 as sole C-source, and it was very sensitive to chloramphenicol. Besides, strain RY3 grew fastest at 55℃～65 and 0℃～2% NaCl. Characteristics of modality and physiology with sequence analysis of the 16s rDNA gene of strain RY3 preliminarily showed that it was Methanothermobacter thermautotrophicus. The experiments indicated that the time which began to produce methane with the highest velocity could be shortened two third by adding RY3 in one week, and the total methane production also was 1.8 times than before. Strain SH4 possessed wide scale of growing pH（5.5～9.5）and excellent ability of acclimatizing itself to acid-alkali. The methane production had no apparent difference among those cultivated in different initial pH（6.0～8.0）after three days and equaled to the maximum production basically. Cells of SH4 were G+, short-rod sharp, monothetic and nonmotile. The colony was pale yellow with suborbicular-shape. Formate or H2+CO2 but not acetate was utilized by SH4 as sole C-source, and it was very sensitive to chloramphenicol. Besides, it grew fastest at pH 7.0，55 ℃～65 and 0℃～2% NaCl concentration. The experiment indicated the time that began to produce methane could be shortening one third by adding SH4. And the total methane production also rose apparently. Characteristic of modality and physiology with sequence analysis of the 16S rDNA gene of strain SH4 demonstrated it was Methanobrevibacter arboriphilus. The activated sludge was utilized as fixture, mixed with culture medium and inocolum, that the solid compound inoculum could be produced by anaerobic fermentation. The compound inoculum could grow between pH 5.5～9.5, 15℃～65. It demonstrated the compound inoculum ha℃ve great ability of adapting to circumstance. In the experiment that making pig manure be substrate and taking the anaerobic sludge producing methane that cultured in long term in laboratory to be comparison, the concentration of methane in fermentation added compound inoculum almost equal to the comparison at 20℃, but the volume of gas production could be a little higher. The gas production everyday inoculated compound inoculum was 1.59 times to comparison. The time that the concentration of methane to maximum could be shortening by two third by adding compound inoculum, and the total gas production was 2.7 times to comprison while the total methane production was 2.8 times. If take the no inoculum be the comprasion, anaerobic fermentation added compound inoculum made the concentration of methane to 50% in 2 weeks but the comparison only to 4.3% at 20℃. The time that the concentration of methane to 50% by adding compound inoculum only need 1 week, but the comparison need 2 weeks at 50℃.

投加溶胞菌群对剩余污泥消化影响的初步研究

活性污泥法是目前世界上普遍应用的污水生物处理工艺，其在运行过程中产生大量的剩余污泥。由于剩余污泥处理费用巨大及污泥最终处置对环境具有潜在危害问题，污泥的处理和处置已经成为水处理领域关注的焦点。本文利用实验室筛选的溶胞菌群，在好氧消化的同时对污泥进行前处理，促进剩余污泥的破解与溶胞，再通过两相厌氧处理对污泥进行进一步消化，以研究投加溶胞菌对剩余污泥消化的影响。 本研究中溶胞菌污泥减量化技术分为两个部分，第一，污泥在溶胞菌作用下的好氧消化与污泥传统好氧消化的对比研究，利用取自成都三瓦窑污水处理厂剩余污泥，向好氧污泥消化反应器中投加溶胞菌，检测各项污泥指标，并通过同传统好氧污泥消化对比，以研究溶胞菌对污泥好氧消化的影响。第二， 经过溶胞菌处理后好氧消化的剩余污泥进行两相厌氧处理研究。通过建立好氧溶胞联合两相厌氧消化系统的来处理剩余污泥，并与相同条件运行的两相厌氧消化系统做对比，检测运行过程中系统中物质成分变化，研究了其处理能力和运行稳定性，探索了两相厌氧消化系统中的发酵类型差别，验证了好氧溶胞对剩余污泥的破解效果。 研究结果表明：污泥在溶胞菌作用下的好氧消化效果和消化效率均优于传统好氧消化。在溶胞菌群存在的情况下，剩余污泥的TSS和VSS去除率达到40%和53%，远高于传统好氧消化的12%和20%。污泥经过溶胞及好氧消化后，TCOD去除率达到54.4%。经过溶胞菌处理后的剩余污泥再进入两相厌氧处理系统，进入厌氧处理系统的剩余污泥的VSS／TSS比值约为0.62。在两相厌氧处理水力停留时间(HRT)为8d时，溶胞处理污泥厌氧消化后VSS去除率达到55.17%，对照组两相厌氧系统的VSS去除率平均值为18.53%。经过溶胞处理的两相厌氧系统的污泥减量了能力远高于对照组。两相厌氧系统的pH值和碱度说明系统运行较为稳定。产酸相的有机酸中乙酸含量高于丙酸和丁酸，说明发酵末端产物以乙酸为主。在20天的试验周期内，污泥溶胞处理后、两相厌氧系统产甲烷相产气量累积产气量为1.2L，对照组只有375ml。气体中甲烷含量都在55%左右。该研究结果表明，好氧溶胞对污泥有破解能力，溶胞处理对两相厌氧中产酸相水解污泥细胞有明显的促进作用，提高了产酸相的水解酸化能力和效率。该研究对于利用生物溶胞途径提高污泥消化效率具有重要意义。 The actived sludge process has been used more and more extensively, but the procedure will lead to a large quantity of excess sludge. The treatment of Excess activated sludge has becomes a focuses not only for it is a seriously negative effect on environment but also for the costly disposal comes subsequently. The cell lysing bacterium was keeped in our lab to joined in the digestion of the excess activated sludge which was carrying at the same time with pre-processing of sludge to investigated the influence of cell lysing bacterium on excess sludge. There are two part in the method of cell lysing bacterium digesting sludge technology, the first, comparison of excess sludge digestion between anaerobic Cell-lysing Pretreatment and Conventional Aerobic Process. The sludge which was collected from San Wanyao disposal plant in Chengdu was thrown into the aerobic process system with cell-lysing bacterium, then, the indexes were detected to compare the difference between the cell-lysing bacterium in aerobic process and the traditional method to determine the influence of cell-lysing bacterium on aerobic process ; The second, the research on the sludge which was pro-treated with cell-lysing and aerobic digestion in the diphase of anaerobic digestion system. The system of cell-lysing combined with diphase of anaerobic digesting was created to compare to the diphase of anaerobic digested system, the changes of mass constituent was detected to study the ability and steady of disposal. Moreover, the research explored the difference among the types of fermentation. The efficacious of aerobic process was been proved. The result shows that the digesting rate of aerobic process with cell-lysing bacterium was higher than the traditional process. The ratio of sludge is reach to 40%~53%, which was far more effectively than the traditional process rate of 12%~20%. The TCOD of sludge which was treated with cell lysing bacterium and Aerobic Process is reach to 54.4%. Then, the sludge was thrown into the diphase of anaerobic digesting system. VSS／TSS of sludge is 0.62, HRT is 6d, the reduction of VSS is reach to 40.8%. The pH and alkalinity indicate the steady running of the diphase anaerobic digest system. In the acerbity phasing, the content of acetic acid was more than butanoic acid and propanoic acid in organic acid, it is demonstrated that the main composition of final production of fermentation was Acetic Acid. During the 20d of experiment, methylhydride phasing of diphase anaerobic digest system produced 1.2L methylhydride, however, there is only 375ml in CK, the content of methylhydride in all gas phase was around the rate of 55%. The average ratio of VSS was 18.53% in CK diphase anaerobic digest system which was far more unavailable than the mass sludge rate of 55.17%. Results demonstrated that aerobic cell-lysing digested the sludge, the treat of cell-lysing could obviously promoted the hydrolyzeing of sludge cell in the acerbity phasing, which improved the ability and rate of hydrolization and acidification. This study is significant in inhenceing the rate of sludge digestion in the method of cell-lysing bacterium.

Enantiomeric fraction evaluation of pharmaceuticals in environmentalmatrices by liquid chromatography-tandem mass spectrometry

The interest for environmental fate assessment of chiral pharmaceuticals is increasing and enantioselective analytical methods are mandatory. This study presents an enantioselective analytical method for the quantification of seven pairs of enantiomers of pharmaceuticals and a pair of a metabolite. The selected chiral pharmaceuticals belong to three different therapeutic classes, namely selective serotonin reuptake inhibitors (venlafaxine, fluoxetine and its metabolite norfluoxetine), beta-blockers (alprenolol, bisoprolol, metoprolol, propranolol) and a beta2-adrenergic agonist (salbutamol). The analytical method was based on solid phase extraction followed by liquid chromatography tandem mass spectrometry with a triple quadrupole analyser. Briefly, Oasis® MCX cartridges were used to preconcentrate 250 mL of water samples and the reconstituted extracts were analysed with a Chirobiotic™ V under reversed mode. The effluent of a laboratory-scale aerobic granular sludge sequencing batch reactor (AGS-SBR) was used to validate the method. Linearity (r2 > 0.99), selectivity and sensitivity were achieved in the range of 20–400 ng L−1 for all enantiomers, except for norfluoxetine enantiomers which range covered 30–400 ng L−1. The method detection limits were between 0.65 and 11.5 ng L−1 and the method quantification limits were between 1.98 and 19.7 ng L−1. The identity of all enantiomers was confirmed using two MS/MS transitions and its ion ratios, according to European Commission Decision 2002/657/EC. This method was successfully applied to evaluate effluents of wastewater treatment plants (WWTP) in Portugal. Venlafaxine and fluoxetine were quantified as non-racemic mixtures (enantiomeric fraction ≠ 0.5). The enantioselective validated method was able to monitor chiral pharmaceuticals in WWTP effluents and has potential to assess the enantioselective biodegradation in bioreactors. Further application in environmental matrices as surface and estuarine waters can be exploited.

Biomethanation of syngas: identification of metabolic pathways from CO in a natural anaerobic consortium

Au cours des dernières décennies, l’intérêt pour la gazéification de biomasses a considérablement augmenté, notamment en raison de la grande efficacité de recouvrement énergétique de ce procédé par rapport aux autres procédés de génération de bioénergies. Les composants majoritaires du gaz de synthèse, le monoxyde de carbone (CO) et l’hydrogène (H2) peuvent entre autres servir de substrats à divers microorganismes qui peuvent produire une variété de molécules chimiques d’intérêts, ou encore produire des biocarburants, particulièrement le méthane. Il est donc important d'étudier les consortiums méthanogènes naturels qui, en syntrophie, serait en mesure de convertir le gaz de synthèse en carburants utiles. Cette étude évalue principalement le potentiel de méthanisation du CO par un consortium microbien issu d’un réacteur de type UASB, ainsi que les voies métaboliques impliquées dans cette conversion en conditions mésophiles. Des tests d’activité ont donc été réalisés avec la boue anaérobie du réacteur sous différentes pressions partielles de CO variant de 0.1 à 1,65 atm (0.09 à 1.31 mmol CO/L), en présence ou absence de certains inhibiteurs métaboliques spécifiques. Dès le départ, la boue non acclimatée au CO présente une activité carboxidotrophique relativement intéressante et permet une croissance sur le CO. Les tests effectués avec de l’acide 2- bromoethanesulfonique (BES) ou avec de la vancomycine démontrent que le CO est majoritairement consommé par les bactéries acétogènes avant d’être converti en méthane par les méthanogènes acétotrophes. De plus, un plus grand potentiel de méthanisation a pu être atteint sous une atmosphère constituée uniquement de CO en acclimatant auparavant la boue. Cette adaptation est caractérisée par un changement dans la population microbienne désormais dominée par les méthanogènes hydrogénotrophes. Ceci suggère un potentiel de production à large échelle de biométhane à partir du gaz de synthèse avec l’aide de biofilms anaérobies.

Start-up of horizontal anaerobic reactors with sludge blanket and fixed bed for wastewater treatment from coffee processing by wet method

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Effect of anaerobic digestion and initial pH on metal bioleaching from sewage sludge

The effects of anaerobic digestion and initial pH on the bioleaching of metals from sewage sludge were investigated in shake flask experiments. A strain of Acidithiobacillus thiooxidans was employed in the assays using secondary and anaerobic sludges, which resulted in similar solubilization yields of the metals chromium, copper, lead, nickel, and zinc for both the sludges investigated. The effect of initial pH (7.0 and 4.0) on metal bioleaching was assayed by using the anaerobic sludge inoculated with indigenous sulfur-oxidizing thiobacilli. Although the time required to reach the end of the experiment (final pH close to 1.0) was shortened at initial pH of 4.0, final metal solubilization was not significantly different for both initial pH values, resulting in higher solubilization yields for copper, nickel, and zinc (higher than 80%). Chromium and lead presented solubilization yields close to 50%. The results obtained in this work showed that the metal bioleaching process can be applied to sewage sludge regardless of the type of sludge and without the requirement of pH adjustment.

Anaerobic treatment of wastewater from coffee pulping in upflow anaerobic sludge blanket (UASB) in two stages

In this work, the efficiency of two-stage upflow anaerobic sludge blanket (UASB) reactors was evaluated in bench scale, for treating a liquid effluent from coffee pulping. Hydraulic detention times (HDT) were 4.0; 5.2 and 6.2 days, resulting in organic loading rates (OLR) of 5.8; 3.6 and 3.0g total COD per (L-d) in the first reactor (Rl) and HDT of 2.0; 2.6 and 3.1 days with OLR of 5.8; 0.5 and 0.4 g total COD per (L-d) in the second reactor (R2). The medium values of total COD affluent varied from 15.440 to 23.040 mg O 2/L, and in the effluent to the reactors 1 and 2 were from l.lOO to 11.500 mg 0 2/L and 420 to 9.000 mg O 2/L, respectively. The medium values of removal efficiencies of total COD and TSS varied from 66 to 98% and 93 to 97%, respectively, in the system of treatment with the UASB reactors, in two stages. The content of methane in the biogas varied from 69 to 89% in the Rl and from 52 to 73% in the R2. The maximum volumetric methane production of 0.483 m 3 CH 4per (m 3 reactor d) was obtained with OLR of 3.6 g total COD per (L reactor d) and HDT of 6.2 days in the Rl. The volatile fatty acids concentration was kept below 100mg/L with HDT of 5.2 and 6.2 days in the Rl and HDT of 2.6 and 3.1 days in the R2.

A potential application of sludge-based catalysts for the anaerobic bio-decolorization of tartrazine dye.

Two highly efficient (K2CO3/sludge carbon and ZnCl2/sludge carbon) solids were prepared by chemical addition following carbonization at 800 °C and were tested for anaerobic reduction of tartrazine dye in a continuous upflow packed-bed biological reactor, and their performance was compared to that of commercial activated carbon (CAC). The chemical and structural information of the solids was subjected to various characterizations in order to understand the mechanism for anaerobic decolorization, and efficiency for SBCZN800 and SBCPC800 materials was 87% and 74%, respectively, at a short space time (τ) of 2.0 min. A first-order kinetic model fitted the experimental points and kinetic constants of 0.40, 0.92 and 1.46 min(-1) were obtained for SBCZN800, SBCPC800 and CAC, respectively. The experimental results revealed that performance of solids in the anaerobic reduction of tartrazine dye can depend on several factors including chemical agents, carbonization, microbial population, chemical groups and surface chemistry. The Langmuir and Freundlich models are successfully described in the batch adsorption data. Based on these observations, a cost-effective sludge-based catalyst can be produced from harmful sewage sludge for the treatment of industrial effluents.

Two-phase anaerobic digestion for enhanced stabilization and methanation of sewage sludge /

"ILENR/AE-92/02."