The Experts below are selected from a list of 177 Experts worldwide ranked by ideXlab platform

Nidal Mahmoud - One of the best experts on this subject based on the ideXlab platform.

  • anaerobic sewage treatment in a one stage uasb reactor and a combined uasb digester system
    Water Research, 2004
    Co-Authors: Nidal Mahmoud, G Zeeman, H J Gijzen, G Lettinga
    Abstract:

    The treatment of sewage at 15°C was investigated in a one-stage upflow anaerobic Sludge blanket (UASB) reactor and a UASB-Digester system. The latter consists of a UASB reactor complemented with a digester for mutual sewage treatment and Sludge Stabilisation. The UASB reactor was operated at a hydraulic retention time of 6 h and a controlled temperature of 15°C, the average sewage temperature during wintertime of some Middle East countries. The digester was operated at 35°C. The UASB-Digester system provided significantly (significance level 5%) higher COD removal efficiencies than the one-stage UASB reactor. The achieved removal efficiencies in the UASB-Digester system and the one-stage UASB reactor for total, suspended, colloidal and dissolved COD were 66%, 87%, 44% and 30%, and 44%, 73%, 3% and 5% for both systems, respectively. The stability values of the wasted Sludge from the one-stage UASB reactor and the UASB-Digester system were, respectively, 0.47 and 0.36 g CH4-COD/g COD. Therefore, the anaerobic sewage treatment at low temperature in a UASB-Digester system is promising

  • anaerobic Stabilisation and conversion of biopolymers in primary Sludge effect of temperature and Sludge retention time
    Water Research, 2004
    Co-Authors: Nidal Mahmoud, G Zeeman, H J Gijzen, G Lettinga
    Abstract:

    The effect of Sludge retention time (SRT) and process temperature on the hydrolysis, acidification and methanogenesis of primary Sludge was investigated in completely stirred tank reactors (CSTRs). The CSTRs were operated to maintain SRTs of 10, 15, 20 and 30 days at process temperatures of 25°C and 35°C. The rates of hydrolysis and the biodegradability of primary Sludge were assessed in batch reactors incubated at 15°C, 25°C and 35°C. The results revealed that the major amount of Sludge Stabilisation occurred between 0 and 10 days at 35°C and 10 and 15 days at 25°C. Hydrolysis was found to be the rate limiting-step of the overall digestion process, for the reactors operated at 35°C and 25°C, except for the reactor operated at 10 days and 25°C. At the latter conditions, methanogenesis was the rate-limiting step of the overall digestion process. Proteins hydrolysis was limited to a maximum value of 39% at 30 days and 35°C due to proteins availability in the form of biomass. The biodegradability of primary Sludge was around 60%, and showed no temperature dependency. The hydrolysis of the main biopolymers and overall particulate COD of the primary Sludge digested in CSTRs were well described by first-order kinetics, in case hydrolysis was the rate-limiting step. Similarly, the hydrolysis of the overall particulate COD of the primary Sludge digested in batch reactors were described by first-order kinetics and revealed strong temperature dependency, which follows Arrhenius equation.

  • Anaerobic sewage treatment in a one-stage UASB reactor and a combined UASB-Digester system.
    Water research, 2004
    Co-Authors: Nidal Mahmoud, G Zeeman, H J Gijzen, G Lettinga
    Abstract:

    The treatment of sewage at 15 degrees C was investigated in a one-stage upflow anaerobic Sludge blanket (UASB) reactor and a UASB-Digester system. The latter consists of a UASB reactor complemented with a digester for mutual sewage treatment and Sludge Stabilisation. The UASB reactor was operated at a hydraulic retention time of 6h and a controlled temperature of 15 degrees C, the average sewage temperature during wintertime of some Middle East countries. The digester was operated at 35 degrees C. The UASB-Digester system provided significantly (significance level 5%) higher COD removal efficiencies than the one-stage UASB reactor. The achieved removal efficiencies in the UASB-Digester system and the one-stage UASB reactor for total, suspended, colloidal and dissolved COD were 66%, 87%, 44% and 30%, and 44%, 73%, 3% and 5% for both systems, respectively. The stability values of the wasted Sludge from the one-stage UASB reactor and the UASB-Digester system were, respectively, 0.47 and 0.36g CH(4)-COD/g COD. Therefore, the anaerobic sewage treatment at low temperature in a UASB-Digester system is promising.

  • anaerobic pre treatment of sewage under low temperature 15 degrees c conditions in an integrated uasb digester system
    2002
    Co-Authors: Nidal Mahmoud
    Abstract:

    The main objective of this thesis was to amend the UASB by the means of incorporating a digester for anaerobic sewage treatment in the Middle East region. A literature search of the various parameters that mightaffect the solid liquid separation process by filtration through the Sludge bed of a UASB has been elaborated. The overall output of this study includes, literature review, structuring this field of science and highlighting fields where research is needed. The investigation of sewage characteristics in Palestine revealed that the sewage is of high strength and low temperature during wintertime ca . 15 oC. Accordingly, prediction based on model calculations revealed that the application of the one stage UASB reactor for sewage treatment in Palestine is only possible when designed at a HRT of more than 22 hours. Alternatively, a novel technology consisting of a Digester complementing a UASB, namely UASB-Digester system, was proposed. The results of primary Sludge Stabilisation in CSTRs revealed that the major achievement of Sludge Stabilisation occurred at SRT ³ 10 and 15 days at process temperatures of 35 and 25 oC, respectively. The Sludge dewatering results showed the existence of optimal SRT at 20 and 15 days at process temperatures of 25 and 35 oC, respectively. While, the Sludge settling is not affected by digestion. Running a pilot-scale one stage UASB and a UASB-Digester system on sewage from the village of Bennekom, The Netherlands validated the technical viability of the UASB-Digester system. The UASB reactor was operated at an HRT of 6 hours and temperature of 15 ° C, the wintertime sewage temperature in Palestine, and the digester was operated at 35 ° C. The achieved removal efficiencies of total COD, suspended COD, colloidal COD and dissolved COD of respectively 66, 87, 44 and 30 in the UASB-Digester is significantly higher than the respectively 44, 73, 3 and 5 achieved in the one stage UASB and as high as those reported for tropical countries. The conversion in the UASB of the UASB-Digester system is substantially higher than in the one stage, viz. the percentage methanogenesis of the influent COD were 21 and 44% in the first and second systems, respectively. The Sludge produced from the UASB of the UASB-Digester system is substantially lower and more stable as compared with the Sludge in the one stage UASB reactor. The settleability of the Sludge of the UASB, UASB of the UASB-Digester system and the digester Sludges reveals high settleability with no influence of the digestion conditions. The wasted Sludge from the UASB of the UASB-Digester system is better dewaterable as compared to that of the UASB reactor.

G Lettinga - One of the best experts on this subject based on the ideXlab platform.

  • anaerobic sewage treatment in a one stage uasb reactor and a combined uasb digester system
    Water Research, 2004
    Co-Authors: Nidal Mahmoud, G Zeeman, H J Gijzen, G Lettinga
    Abstract:

    The treatment of sewage at 15°C was investigated in a one-stage upflow anaerobic Sludge blanket (UASB) reactor and a UASB-Digester system. The latter consists of a UASB reactor complemented with a digester for mutual sewage treatment and Sludge Stabilisation. The UASB reactor was operated at a hydraulic retention time of 6 h and a controlled temperature of 15°C, the average sewage temperature during wintertime of some Middle East countries. The digester was operated at 35°C. The UASB-Digester system provided significantly (significance level 5%) higher COD removal efficiencies than the one-stage UASB reactor. The achieved removal efficiencies in the UASB-Digester system and the one-stage UASB reactor for total, suspended, colloidal and dissolved COD were 66%, 87%, 44% and 30%, and 44%, 73%, 3% and 5% for both systems, respectively. The stability values of the wasted Sludge from the one-stage UASB reactor and the UASB-Digester system were, respectively, 0.47 and 0.36 g CH4-COD/g COD. Therefore, the anaerobic sewage treatment at low temperature in a UASB-Digester system is promising

  • Anaerobic sewage treatment in a one-stage UASB reactor and a combined UASB-Digester system.
    Water research, 2004
    Co-Authors: Nidal Mahmoud, G Zeeman, H J Gijzen, G Lettinga
    Abstract:

    The treatment of sewage at 15 degrees C was investigated in a one-stage upflow anaerobic Sludge blanket (UASB) reactor and a UASB-Digester system. The latter consists of a UASB reactor complemented with a digester for mutual sewage treatment and Sludge Stabilisation. The UASB reactor was operated at a hydraulic retention time of 6h and a controlled temperature of 15 degrees C, the average sewage temperature during wintertime of some Middle East countries. The digester was operated at 35 degrees C. The UASB-Digester system provided significantly (significance level 5%) higher COD removal efficiencies than the one-stage UASB reactor. The achieved removal efficiencies in the UASB-Digester system and the one-stage UASB reactor for total, suspended, colloidal and dissolved COD were 66%, 87%, 44% and 30%, and 44%, 73%, 3% and 5% for both systems, respectively. The stability values of the wasted Sludge from the one-stage UASB reactor and the UASB-Digester system were, respectively, 0.47 and 0.36g CH(4)-COD/g COD. Therefore, the anaerobic sewage treatment at low temperature in a UASB-Digester system is promising.

H J Gijzen - One of the best experts on this subject based on the ideXlab platform.

  • anaerobic sewage treatment in a one stage uasb reactor and a combined uasb digester system
    Water Research, 2004
    Co-Authors: Nidal Mahmoud, G Zeeman, H J Gijzen, G Lettinga
    Abstract:

    The treatment of sewage at 15°C was investigated in a one-stage upflow anaerobic Sludge blanket (UASB) reactor and a UASB-Digester system. The latter consists of a UASB reactor complemented with a digester for mutual sewage treatment and Sludge Stabilisation. The UASB reactor was operated at a hydraulic retention time of 6 h and a controlled temperature of 15°C, the average sewage temperature during wintertime of some Middle East countries. The digester was operated at 35°C. The UASB-Digester system provided significantly (significance level 5%) higher COD removal efficiencies than the one-stage UASB reactor. The achieved removal efficiencies in the UASB-Digester system and the one-stage UASB reactor for total, suspended, colloidal and dissolved COD were 66%, 87%, 44% and 30%, and 44%, 73%, 3% and 5% for both systems, respectively. The stability values of the wasted Sludge from the one-stage UASB reactor and the UASB-Digester system were, respectively, 0.47 and 0.36 g CH4-COD/g COD. Therefore, the anaerobic sewage treatment at low temperature in a UASB-Digester system is promising

  • Anaerobic sewage treatment in a one-stage UASB reactor and a combined UASB-Digester system.
    Water research, 2004
    Co-Authors: Nidal Mahmoud, G Zeeman, H J Gijzen, G Lettinga
    Abstract:

    The treatment of sewage at 15 degrees C was investigated in a one-stage upflow anaerobic Sludge blanket (UASB) reactor and a UASB-Digester system. The latter consists of a UASB reactor complemented with a digester for mutual sewage treatment and Sludge Stabilisation. The UASB reactor was operated at a hydraulic retention time of 6h and a controlled temperature of 15 degrees C, the average sewage temperature during wintertime of some Middle East countries. The digester was operated at 35 degrees C. The UASB-Digester system provided significantly (significance level 5%) higher COD removal efficiencies than the one-stage UASB reactor. The achieved removal efficiencies in the UASB-Digester system and the one-stage UASB reactor for total, suspended, colloidal and dissolved COD were 66%, 87%, 44% and 30%, and 44%, 73%, 3% and 5% for both systems, respectively. The stability values of the wasted Sludge from the one-stage UASB reactor and the UASB-Digester system were, respectively, 0.47 and 0.36g CH(4)-COD/g COD. Therefore, the anaerobic sewage treatment at low temperature in a UASB-Digester system is promising.

G Zeeman - One of the best experts on this subject based on the ideXlab platform.

  • anaerobic sewage treatment in a one stage uasb reactor and a combined uasb digester system
    Water Research, 2004
    Co-Authors: Nidal Mahmoud, G Zeeman, H J Gijzen, G Lettinga
    Abstract:

    The treatment of sewage at 15°C was investigated in a one-stage upflow anaerobic Sludge blanket (UASB) reactor and a UASB-Digester system. The latter consists of a UASB reactor complemented with a digester for mutual sewage treatment and Sludge Stabilisation. The UASB reactor was operated at a hydraulic retention time of 6 h and a controlled temperature of 15°C, the average sewage temperature during wintertime of some Middle East countries. The digester was operated at 35°C. The UASB-Digester system provided significantly (significance level 5%) higher COD removal efficiencies than the one-stage UASB reactor. The achieved removal efficiencies in the UASB-Digester system and the one-stage UASB reactor for total, suspended, colloidal and dissolved COD were 66%, 87%, 44% and 30%, and 44%, 73%, 3% and 5% for both systems, respectively. The stability values of the wasted Sludge from the one-stage UASB reactor and the UASB-Digester system were, respectively, 0.47 and 0.36 g CH4-COD/g COD. Therefore, the anaerobic sewage treatment at low temperature in a UASB-Digester system is promising

  • Anaerobic sewage treatment in a one-stage UASB reactor and a combined UASB-Digester system.
    Water research, 2004
    Co-Authors: Nidal Mahmoud, G Zeeman, H J Gijzen, G Lettinga
    Abstract:

    The treatment of sewage at 15 degrees C was investigated in a one-stage upflow anaerobic Sludge blanket (UASB) reactor and a UASB-Digester system. The latter consists of a UASB reactor complemented with a digester for mutual sewage treatment and Sludge Stabilisation. The UASB reactor was operated at a hydraulic retention time of 6h and a controlled temperature of 15 degrees C, the average sewage temperature during wintertime of some Middle East countries. The digester was operated at 35 degrees C. The UASB-Digester system provided significantly (significance level 5%) higher COD removal efficiencies than the one-stage UASB reactor. The achieved removal efficiencies in the UASB-Digester system and the one-stage UASB reactor for total, suspended, colloidal and dissolved COD were 66%, 87%, 44% and 30%, and 44%, 73%, 3% and 5% for both systems, respectively. The stability values of the wasted Sludge from the one-stage UASB reactor and the UASB-Digester system were, respectively, 0.47 and 0.36g CH(4)-COD/g COD. Therefore, the anaerobic sewage treatment at low temperature in a UASB-Digester system is promising.

J L Cortina - One of the best experts on this subject based on the ideXlab platform.

  • Stabilisation of dewatered domestic sewage Sludge by lime addition as raw material for the cement industry understanding process and reactor performance
    Chemical Engineering Journal, 2013
    Co-Authors: Cesar Valderrama, Ricard Granados, J L Cortina
    Abstract:

    Abstract This paper describes the performance and feasibility of the domestic dewatered sewage Sludge (DDSS) stabilised with lime as raw material for the cement industry. The Stabilisation process uses a screw-based plug reactor to provide mixing conditions suitable to reduce the water content of the Sludge to level of 10%a w/w by taking advantage of the exothermic reaction of the hydration of lime to form portlandite, which favours the evaporation of water. The high alkalinity provided by the added lime promotes the reduction of the organic matter content through a transformation of the complex organic structures of the biomass present in the DDSS to simple organic structures and partly to inorganic carbon in a form of the (CaCO3(s)) via a series of exothermic (neutralisation and saponification) and endothermic chemical processes (hydrolysis). The Sludge Stabilisation with lime process was studied at a pre-industrial scale using a pilot plant with a 6 t DDSS/h treatment capacity. The dewatered Sludge and the stabilised product streams were properly characterised to quantify the mass and energy balances. Both balances were used to improve the performance of the process and to quantify the reaction enthalpy (−7914.7 ± 172 kJ/kg DDSS) associated with the mineralisation of the organic matter, using a numerical algorithm. The influence of any biological process was discarded by taking into account the microbiological monitoring data. The low residence time in the reactor (less than 40 min) and the high alkalinity of the reaction mixture provided by the produced Ca(OH)2(s) did not favour substantial biological activity which also requires hydroxyl ions and water, however, CaO(s) will generate hydroxyl ions only after being hydrated.

  • evaluation of a lime mediated sewage Sludge Stabilisation process product characterisation and technological validation for its use in the cement industry
    Waste Management, 2012
    Co-Authors: Husillos N Rodriguez, Ricard Granados, Maria Teresa Blancovarela, J L Cortina, S Martinezramirez, M Marsal, Manel Guillem, Jorge Betancor Puig, E Larrotcha, Juan J Flores
    Abstract:

    Abstract This paper describes an industrial process for stabilising sewage Sludge (SS) with lime and evaluates the viability of the stabilised product, denominated Neutral, as a raw material for the cement industry. Lime not only stabilised the Sludge, raised the temperature of the mix to 80–100 °C, furthering water evaporation, portlandite formation and the partial oxidation of the organic matter present in the Sludge. Process mass and energy balances were determined. Neutral, a white powder consisting of portlandite (49.8%), calcite (16.6%), inorganic oxides (13.4%) and organic matter and moisture (20.2%), proved to be technologically apt for inclusion as a component in cement raw mixes. In this study, it was used instead of limestone in raw mixes clinkerised at 1400, 1450 and 1500 °C. These raw meals exhibited greater reactivity at high temperatures than the limestone product and their calcination at 1500 °C yielded clinker containing over 75% calcium silicates, the key phases in Portland clinker. Finally, the two types of raw meal (Neutral and limestone) were observed to exhibit similar mineralogy and crystal size and distribution.