The Experts below are selected from a list of 249 Experts worldwide ranked by ideXlab platform

Dara S.m. Ghasimi - One of the best experts on this subject based on the ideXlab platform.

  • comparative analysis of the digestibility of sewage fine sieved fraction and hygiene Paper produced from virgin fibers and recycled fibers
    Waste Management, 2016
    Co-Authors: Dara S.m. Ghasimi, Marcel H Zandvoo, Michiel Adriaanse, Jules Van Lie, Merle De Kreuk
    Abstract:

    Sewage fine sieved fraction (FSF) is a heterogeneous substrate consisting of mainly Toilet Paper fibers sequestered from municipal raw sewage by a fine screen. In earlier studies, a maximum biodegradation of 62% and 57% of the sewage FSF was found under thermophilic (55 °C) and mesophilic (35 °C) conditions, respectively. In order to research this limited biodegradability of sewage FSF, this study investigates the biodegradation of different types of cellulosic fibers-based hygiene Papers including virgin fibers based Toilet Paper (VTP), recycled fiber based Toilet Paper (RTP), virgin pulp for Paper production (VPPP) as a raw material, as well as microcrystalline cellulose (MCC) as a kind of fiberless reference material. The anaerobic biodegradation or digestibility tests were conducted under thermophilic and mesophilic conditions. Results of the experiments showed different biomethane potential (BMP) values for each tested cellulose fiber-based substrate, which might be associated with the physical characteristics of the fibers, type of pulping, presence of lignin encrusted fibers, and/or the presence of additive chemicals and refractory compounds. Higher hydrolysis rates (Kh), higher specific methane production rates (SMPR) and shorter required incubation times to achieve 90% of the BMP (t90%CH4), were achieved under thermophilic conditions for all examined substrates compared to the mesophilic ones. Furthermore, the biodegradability of all employed cellulose fiber-based substrates was in the same range, 38–45%, under both conditions and less than the observed FSF biodegradability, i.e. 57–62%. MCC achieved the highest BMP and biodegradability, 86–91%, among all cellulosic substrates.

  • high rate thermophilic bio methanation of the fine sieved fraction from dutch municipal raw sewage cost effective potentials for on site energy recovery
    Applied Energy, 2016
    Co-Authors: Dara S.m. Ghasimi, Merle De Kreuk, Myriam H.w.m. Van Zandvoort, Sung Kyu Maeng, Jules B Van Lier
    Abstract:

    Sieving of Dutch raw sewage over a 350μm screen, produces a cake layer called fine sieved fraction (FSF), an energy-rich material that contains mainly cellulosic fibers originating from Toilet Paper. The FSF biomethane potential (BMP) was studied under both mesophilic (35°C) and thermophilic (55°C) conditions, whereas the stability of the fed-batch digesters at both 35°C and 55°C was researched by varying the inoculum to substrate ratios (RI/S: 0.5–15). Results clearly showed advantages of thermophilic conditions over mesophilic conditions at all tested RI/S. Stable digestion was even possible at an RI/S of 0.5 at 55°C.

  • digester performance and microbial community changes in thermophilic and mesophilic sequencing batch reactors fed with the fine sieved fraction of municipal sewage
    Water Research, 2015
    Co-Authors: Dara S.m. Ghasimi, Merle De Kreuk, Ben Abbas, Myriam H.w.m. Van Zandvoort, Jules B.van Lier
    Abstract:

    Abstract This study investigates the start-up and operation of bench-scale mesophilic (35 °C) and thermophilic (55 °C) anaerobic sequencing batch reactor (SBR) digesters treating the fine sieved fraction (FSF) from raw municipal sewage. FSF was sequestered from raw municipal wastewater, in the Netherlands, using a rotating belt filter equipped with a 350 micron mesh. For the given wastewater, the major component of FSF was Toilet Paper, which is estimated to be 10–14 kg per year per average person in the western European countries. A seven months adaptation time was allowed for the thermophilic and mesophilic digesters in order to adapt to FSF as the sole substrate with varying dry solids content of 10–25%. Different SBR cycle durations (14, 9 and 2 days) were applied for both temperature conditions to study methane production rates, volatile fatty acids (VFAs) dynamics, lag phases, as well as changes in microbial communities. The prevailing sludge in the two digesters consisted of very different bacterial and archaeal communities, with OP9 lineage and Methanothermobacter being pre-dominant in the thermophilic digester and Bacteroides and Methanosaeta dominating the mesophilic one. Eventually, decreasing the SBR cycle period, thus increasing the FSF load, resulted in improved digester performances, particularly with regard to the thermophilic digester, i.e. shortened lag phases following the batch feedings, and reduced VFA peaks. Over time, the thermophilic digester outperformed the mesophilic one with 15% increased volatile solids (VS) destruction, irrespective to lower species diversity found at high temperature.

Merle De Kreuk - One of the best experts on this subject based on the ideXlab platform.

  • comparative analysis of the digestibility of sewage fine sieved fraction and hygiene Paper produced from virgin fibers and recycled fibers
    Waste Management, 2016
    Co-Authors: Dara S.m. Ghasimi, Marcel H Zandvoo, Michiel Adriaanse, Jules Van Lie, Merle De Kreuk
    Abstract:

    Sewage fine sieved fraction (FSF) is a heterogeneous substrate consisting of mainly Toilet Paper fibers sequestered from municipal raw sewage by a fine screen. In earlier studies, a maximum biodegradation of 62% and 57% of the sewage FSF was found under thermophilic (55 °C) and mesophilic (35 °C) conditions, respectively. In order to research this limited biodegradability of sewage FSF, this study investigates the biodegradation of different types of cellulosic fibers-based hygiene Papers including virgin fibers based Toilet Paper (VTP), recycled fiber based Toilet Paper (RTP), virgin pulp for Paper production (VPPP) as a raw material, as well as microcrystalline cellulose (MCC) as a kind of fiberless reference material. The anaerobic biodegradation or digestibility tests were conducted under thermophilic and mesophilic conditions. Results of the experiments showed different biomethane potential (BMP) values for each tested cellulose fiber-based substrate, which might be associated with the physical characteristics of the fibers, type of pulping, presence of lignin encrusted fibers, and/or the presence of additive chemicals and refractory compounds. Higher hydrolysis rates (Kh), higher specific methane production rates (SMPR) and shorter required incubation times to achieve 90% of the BMP (t90%CH4), were achieved under thermophilic conditions for all examined substrates compared to the mesophilic ones. Furthermore, the biodegradability of all employed cellulose fiber-based substrates was in the same range, 38–45%, under both conditions and less than the observed FSF biodegradability, i.e. 57–62%. MCC achieved the highest BMP and biodegradability, 86–91%, among all cellulosic substrates.

  • high rate thermophilic bio methanation of the fine sieved fraction from dutch municipal raw sewage cost effective potentials for on site energy recovery
    Applied Energy, 2016
    Co-Authors: Dara S.m. Ghasimi, Merle De Kreuk, Myriam H.w.m. Van Zandvoort, Sung Kyu Maeng, Jules B Van Lier
    Abstract:

    Sieving of Dutch raw sewage over a 350μm screen, produces a cake layer called fine sieved fraction (FSF), an energy-rich material that contains mainly cellulosic fibers originating from Toilet Paper. The FSF biomethane potential (BMP) was studied under both mesophilic (35°C) and thermophilic (55°C) conditions, whereas the stability of the fed-batch digesters at both 35°C and 55°C was researched by varying the inoculum to substrate ratios (RI/S: 0.5–15). Results clearly showed advantages of thermophilic conditions over mesophilic conditions at all tested RI/S. Stable digestion was even possible at an RI/S of 0.5 at 55°C.

  • digester performance and microbial community changes in thermophilic and mesophilic sequencing batch reactors fed with the fine sieved fraction of municipal sewage
    Water Research, 2015
    Co-Authors: Dara S.m. Ghasimi, Merle De Kreuk, Ben Abbas, Myriam H.w.m. Van Zandvoort, Jules B.van Lier
    Abstract:

    Abstract This study investigates the start-up and operation of bench-scale mesophilic (35 °C) and thermophilic (55 °C) anaerobic sequencing batch reactor (SBR) digesters treating the fine sieved fraction (FSF) from raw municipal sewage. FSF was sequestered from raw municipal wastewater, in the Netherlands, using a rotating belt filter equipped with a 350 micron mesh. For the given wastewater, the major component of FSF was Toilet Paper, which is estimated to be 10–14 kg per year per average person in the western European countries. A seven months adaptation time was allowed for the thermophilic and mesophilic digesters in order to adapt to FSF as the sole substrate with varying dry solids content of 10–25%. Different SBR cycle durations (14, 9 and 2 days) were applied for both temperature conditions to study methane production rates, volatile fatty acids (VFAs) dynamics, lag phases, as well as changes in microbial communities. The prevailing sludge in the two digesters consisted of very different bacterial and archaeal communities, with OP9 lineage and Methanothermobacter being pre-dominant in the thermophilic digester and Bacteroides and Methanosaeta dominating the mesophilic one. Eventually, decreasing the SBR cycle period, thus increasing the FSF load, resulted in improved digester performances, particularly with regard to the thermophilic digester, i.e. shortened lag phases following the batch feedings, and reduced VFA peaks. Over time, the thermophilic digester outperformed the mesophilic one with 15% increased volatile solids (VS) destruction, irrespective to lower species diversity found at high temperature.

Myriam H.w.m. Van Zandvoort - One of the best experts on this subject based on the ideXlab platform.

  • high rate thermophilic bio methanation of the fine sieved fraction from dutch municipal raw sewage cost effective potentials for on site energy recovery
    Applied Energy, 2016
    Co-Authors: Dara S.m. Ghasimi, Merle De Kreuk, Myriam H.w.m. Van Zandvoort, Sung Kyu Maeng, Jules B Van Lier
    Abstract:

    Sieving of Dutch raw sewage over a 350μm screen, produces a cake layer called fine sieved fraction (FSF), an energy-rich material that contains mainly cellulosic fibers originating from Toilet Paper. The FSF biomethane potential (BMP) was studied under both mesophilic (35°C) and thermophilic (55°C) conditions, whereas the stability of the fed-batch digesters at both 35°C and 55°C was researched by varying the inoculum to substrate ratios (RI/S: 0.5–15). Results clearly showed advantages of thermophilic conditions over mesophilic conditions at all tested RI/S. Stable digestion was even possible at an RI/S of 0.5 at 55°C.

  • digester performance and microbial community changes in thermophilic and mesophilic sequencing batch reactors fed with the fine sieved fraction of municipal sewage
    Water Research, 2015
    Co-Authors: Dara S.m. Ghasimi, Merle De Kreuk, Ben Abbas, Myriam H.w.m. Van Zandvoort, Jules B.van Lier
    Abstract:

    Abstract This study investigates the start-up and operation of bench-scale mesophilic (35 °C) and thermophilic (55 °C) anaerobic sequencing batch reactor (SBR) digesters treating the fine sieved fraction (FSF) from raw municipal sewage. FSF was sequestered from raw municipal wastewater, in the Netherlands, using a rotating belt filter equipped with a 350 micron mesh. For the given wastewater, the major component of FSF was Toilet Paper, which is estimated to be 10–14 kg per year per average person in the western European countries. A seven months adaptation time was allowed for the thermophilic and mesophilic digesters in order to adapt to FSF as the sole substrate with varying dry solids content of 10–25%. Different SBR cycle durations (14, 9 and 2 days) were applied for both temperature conditions to study methane production rates, volatile fatty acids (VFAs) dynamics, lag phases, as well as changes in microbial communities. The prevailing sludge in the two digesters consisted of very different bacterial and archaeal communities, with OP9 lineage and Methanothermobacter being pre-dominant in the thermophilic digester and Bacteroides and Methanosaeta dominating the mesophilic one. Eventually, decreasing the SBR cycle period, thus increasing the FSF load, resulted in improved digester performances, particularly with regard to the thermophilic digester, i.e. shortened lag phases following the batch feedings, and reduced VFA peaks. Over time, the thermophilic digester outperformed the mesophilic one with 15% increased volatile solids (VS) destruction, irrespective to lower species diversity found at high temperature.

Sanders Eduard J. - One of the best experts on this subject based on the ideXlab platform.

  • High prevalence of curable sexually transmitted infections among pregnant women in a rural county hospital in Kilifi, Kenya
    Public Library of Science, 2017
    Co-Authors: Masha Simon Chengo, Cools Piet, Crucitti Tania, Wahome Elizabeth, Vaneechoutte Mario, Sanders Eduard J.
    Abstract:

    , from July to September 2015. by culture. Bacterial vaginosis (BV) was defined as a Nugent score of 7–10 of the Gram stain of a vaginal smear in combination with self-reported vaginal discharge. Genital ulcers were observed during collection of vaginal swabs. All women responded to questions on socio-demographics and sexual health and clinical symptoms of STIs. Predictors for curable STIs were assessed in multivariable logistic regression. (95% CI:4.2–12.0), 19.3% for BV (95% CI: 14.1–25.4) and 2.5% for genital ulcers (95% CI: 0.8–5.7). Predictors for infection with curable STIs included women with a genital ulcer (adjusted odds ratio (AOR) = 35.0, 95% CI: 2.7–461.6) compared to women without a genital ulcer, women who used water for cleaning after visiting the Toilet compared to those who used Toilet Paper or other solid means (AOR = 4.1, 95% CI:1.5–11.3), women who reported having sexual debut ≤ 17 years compared to women having sexual debut ≥18 years (AOR = 2.7, 95% CI:1.1–6.6), and BV-positive women (AOR = 2.7, 95% CI:1.1–6.6) compared to BV-negative women.One in five women attending ANC had a curable STI. These infections were associated with genital ulcers, hygiene practices, early sexual debut and bacterial vaginosis

  • High prevalence of curable sexually transmitted infections among pregnant women in a rural county hospital in Kilifi, Kenya
    'Public Library of Science (PLoS)', 2017
    Co-Authors: Masha Simon, Cools Piet, Crucitti Tania, Wahome Elizabeth, Vaneechoutte Mario, Sanders Eduard J.
    Abstract:

    Background : Women attending antenatal care (ANC) in resource-limited countries are frequently screened for syphilis and HIV, but rarely for other sexually transmitted infections (STIs). We assessed the prevalence of curable STIs, defined as infection with either Chlamydia trachomatis or Neisseria gonorrhoeae or Trichomonas vaginalis, from July to September 2015. Methods : In a cross-sectional study, women attending ANC at the Kilifi County Hospital, Kenya, had a urine sample tested for C. trachomatis/N. gonorrhoeae by GeneXpert and a vaginal swab for T. vaginalis by culture. Bacterial vaginosis (BV) was defined as a Nugent score of 7-10 of the Gram stain of a vaginal smear in combination with self-reported vaginal discharge. Genital ulcers were observed during collection of vaginal swabs. All women responded to questions on socio-demographics and sexual health and clinical symptoms of STIs. Predictors for curable STIs were assessed in multivariable logistic regression. Results : A total of 42/202 (20.8%, 95% confidence interval (CI):15.4-27.0) women had a curable STI. The prevalence was 14.9% for C. trachomatis (95% Cl:10.2-20.5), 1.0% for N. gonorrhoeae (95% CI: 0.1-3.5), 7.4% for T. vaginalis (95% CI:4.2-12.0), 19.3% for BV (95% CI: 14.1-25.4) and 2.5% for genital ulcers (95% CI: 0.8-5.7). Predictors for infection with curable STIs included women with a genital ulcer (adjusted odds ratio (AOR) = 35.0, 95% CI: 2.7-461.6) compared to women without a genital ulcer, women who used water for cleaning after visiting the Toilet compared to those who used Toilet Paper or other solid means (AOR = 4.1, 95% CI:1.5-11.3), women who reported having sexual debut = 18 years (AOR = 2.7, 95% Cl:1.1-6.6), and BV-positive women (AOR = 2.7, 95% Cl:1.1-6.6) compared to BV-negative women. Conclusion : One in five women attending ANC had a curable STI. These infections were associated with genital ulcers, hygiene practices, early sexual debut and bacterial vaginosis

Jules B.van Lier - One of the best experts on this subject based on the ideXlab platform.

  • digester performance and microbial community changes in thermophilic and mesophilic sequencing batch reactors fed with the fine sieved fraction of municipal sewage
    Water Research, 2015
    Co-Authors: Dara S.m. Ghasimi, Merle De Kreuk, Ben Abbas, Myriam H.w.m. Van Zandvoort, Jules B.van Lier
    Abstract:

    Abstract This study investigates the start-up and operation of bench-scale mesophilic (35 °C) and thermophilic (55 °C) anaerobic sequencing batch reactor (SBR) digesters treating the fine sieved fraction (FSF) from raw municipal sewage. FSF was sequestered from raw municipal wastewater, in the Netherlands, using a rotating belt filter equipped with a 350 micron mesh. For the given wastewater, the major component of FSF was Toilet Paper, which is estimated to be 10–14 kg per year per average person in the western European countries. A seven months adaptation time was allowed for the thermophilic and mesophilic digesters in order to adapt to FSF as the sole substrate with varying dry solids content of 10–25%. Different SBR cycle durations (14, 9 and 2 days) were applied for both temperature conditions to study methane production rates, volatile fatty acids (VFAs) dynamics, lag phases, as well as changes in microbial communities. The prevailing sludge in the two digesters consisted of very different bacterial and archaeal communities, with OP9 lineage and Methanothermobacter being pre-dominant in the thermophilic digester and Bacteroides and Methanosaeta dominating the mesophilic one. Eventually, decreasing the SBR cycle period, thus increasing the FSF load, resulted in improved digester performances, particularly with regard to the thermophilic digester, i.e. shortened lag phases following the batch feedings, and reduced VFA peaks. Over time, the thermophilic digester outperformed the mesophilic one with 15% increased volatile solids (VS) destruction, irrespective to lower species diversity found at high temperature.