scholarly journals Model Parameters for Aerobic Biological Sulfide Oxidation in Sewer Wastewater

Water ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 981
Author(s):  
Asbjørn Haaning Nielsen ◽  
Jes Vollertsen
Keyword(s):  
Elemental Sulfur ◽  
Oxygen Uptake Rate ◽  
Sulfide Oxidation ◽  
Oxygen Demand ◽  
Model Parameters ◽  
Important Process ◽  
Model Concept ◽  
Average Growth Rate ◽  
Average Growth ◽  
Sewer Networks

Sulfide related odor and corrosion are two of the major problems associated with the operation and maintenance of sewer networks. The extent of the problems is governed by several complex and interrelated processes. Sulfide oxidation is typically the most important process for sulfide removal in wastewater from aerobic gravity sewers. Despite the significance of the process, little is known about the significance of the growth of sulfide oxidizing bacteria (SOB) during the transport of wastewater. Biological sulfide oxidation in wastewater from sewers was investigated in a series of oxygen uptake rate (OUR) experiments. The experiments showed that, for oxygen nonlimiting conditions, sulfate was produced, with elemental sulfur as an intermediate. During each experiment, the activity of the sulfide oxidizing bacteria increased significantly. This was interpreted as the result of bacterial growth related to the oxidation of intermediately stored elemental sulfur. A model concept describing biological sulfide oxidation, with intermediary storage of elemental sulfur and associated growth, was developed. The model was calibrated against the experimental results. The observed average growth rate and yield constant for the SOB were determined at 1.98 d−1 and 0.17 g Chemical Oxygen Demand (COD) per g sulfur, respectively. These values correspond to reported values for mixed cultures of autotrophic SOB.

Coupled anaerobic/aerobic treatment of high-sulfate wastewater with sulfate reduction and biological sulfide oxidation

1996 ◽  
Vol 34 (5-6) ◽  
pp. 359-366 ◽  
Author(s):  
Peter Fox ◽  
Venkatraghavan Venkatasubbiah
Keyword(s):  
Elemental Sulfur ◽  
Sulfide Oxidation ◽  
Oxygen Demand ◽  
Major Product ◽  
Pharmaceutical Wastewater ◽  
Anaerobic Baffled Reactor ◽  
Isopropyl Acetate ◽  
Sulfide Inhibition ◽  
Wastewater Stream ◽  
High Sulfate

A pharmaceutical wastewater with a chemical oxygen demand (COD) concentration of 40,000 mg/l and a sulfate concentration of 5,000 mg/l was treated in a anaerobic baffled reactor. Treatment of the wastewater at 10% dilution was effective but at higher influent concentrations sulfide inhibition reduced efficacy of both COD conversion and sulfate conversion. A recycle line with an attached-film biological reactor was inserted into the anaerobic baffled reactor to facilitate biological sulfide oxidation. Recycling anaerobic effluent through a sulfide oxidizing biological system reduced inhibition in the anaerobic reactor by both reducing inhibitory sulfide concentrations within the reactor and by diluting the influent. The major product of the biological oxidation of sulfide by a Thiobacillus species appeared to be elemental sulfur. At an influent wastewater concentration of 40% and a HRT of 1 day, COD removal efficiencies were greater than 50% and the conversion of influent sulfate was greater than 95% with effluent sulfide concentrations of less than 20 mg/l. The major product observed from degradation of isopropyl acetate was acetic acid. Coupled anaerobic/aerobic provided removal of sulfur from the wastewater stream and helped to stabilize the pH in the reactor system.

Simulation of sulfide buildup in wastewater and atmosphere of sewer networks

2005 ◽  
Vol 52 (3) ◽  
pp. 201-208 ◽  
Author(s):  
A.H. Nielsen ◽  
C. Yongsiri ◽  
T. Hvitved-Jacobsen ◽  
J. Vollertsen
Keyword(s):  
Hydrogen Sulfide ◽  
Sulfide Oxidation ◽  
Sulfur Cycle ◽  
Model Concept ◽  
Concrete Corrosion ◽  
Sulfide Production ◽  
Oxidation Of Hydrogen ◽  
Sulfide Precipitation ◽  
Further Development ◽  
Sewer Networks

A model concept for prediction of sulfide buildup in sewer networks is presented. The model concept is an extension to – and a further development of – the WATS model (Wastewater Aerobic-anaerobic Transformations in Sewers), which has been developed by Hvitved-Jacobsen and co-workers at Aalborg University. In addition to the sulfur cycle, the WATS model simulates changes in dissolved oxygen and carbon fractions of different biodegradability. The sulfur cycle was introduced via six processes: 1. sulfide production taking place in the biofilm covering the permanently wetted sewer walls; 2. biological sulfide oxidation in the permanently wetted biofilm; 3. chemical and biological sulfide oxidation in the water phase; 4. sulfide precipitation with metals present in the wastewater; 5. emission of hydrogen sulfide to the sewer atmosphere and 6. adsorption and oxidation of hydrogen sulfide on the moist sewer walls where concrete corrosion may take place.

Transplantation of coral fragment, Acropora formosa (Scleractinia)

2014 ◽  
pp. 1
Author(s):  
Hanny Tioho ◽  
Maykel A.J Karauwan
Keyword(s):  
Fragment Size ◽  
Observation Time ◽  
Minimum Size ◽  
Average Growth Rate ◽  
Average Growth ◽  
Significant Difference ◽  
Acropora Formosa ◽  
Survival And Growth ◽  
One Way Anova ◽  
Better Than

The minimum size of coral transplants, Acropora formosa, was assessed to support their survival and growth. For this, 150 coral fragments of different sizes (5, 10, 15 cm) were transplanted close to the donor colony. Their survivorship and growth were observed for 12 months. At the end of the observation time, 90% of 15 cm-transplanted coral fragments survived, while the others (10cm and 5 cm) did 86% and 82% respectively. The average growth rate of 5 cm-coral fragments was 0.860 cm/month, while 10 and 15 cm-fragments were 0.984 cm/month and 1.108 cm/month respectively. One-way ANOVA showed that there was significant difference (p<0.05) among the three (5, 10, 15 cm) transplant initial sizes in which the longest fragment size tended to survive longer than the smaller one.  However, the smaller transplants grew better than the bigger one, 10.318 cm/year (206%) for 5 cm-transplant, 11.803 cm/year (118%) for 10 cm-transplant, and 13.299 cm/year (89%) for 15 cm-transplant, respectively. Ukuran minimal fragmen karang Acropora formosa yang ditransplantasi diduga untuk mendukung ketahanan hidup dan pertumbuhannya. Untuk itu, 150 fragmen karang ditransplantasi ke lokasi yang berdekatan dengan koloni induknya.  Ketahanan hidup dan pertumbuhan semua fragmen karang yang ditransplantasi diamati selama 12 bulan.  Pada akhir pengamatan, 90% dari fragmen karang berukuran 15 cm yang ditransplantasi dapat bertahan hidup, sedangkan yang lainnya (ukuran 10 cm dan 5 cm) masing-masing sebesar 86% dan 82%.  Rata-rata laju pertumbuhan fragmen karang dengan ukuran awal 5 cm adalah 0,860 cm/bulan, sedangkan ukuran fragmen 10 dan 15 cm masing-masing adalah 0,984 cm/bulan and 1,108 cm/bulan. ANOVA satu arah menunjukkan adanya perbedaan yang nyata (p<0.05) antara ketiga ukuran fragmen yang berbeda, di mana ukuran fragmen karang yang lebih panjang cenderung mempunyai ketahanan hidup yang lebih baik. Namun demikian, ukuran transplant yang lebih kecil memiliki pertumbuhan lebih baik dibandingkan dengan ukuran yang lebih besar, yakni10,318 cm/tahun (206%) untuk transplant berukuran 5 cm, 11,803 cm/tahun (118%) untuk 10 cm, dan 13,299 cm/tahun (89%) untuk ukuran 15 cm.

scholarly journals Microbiological Sulfide Removal—From Microorganism Isolation to Treatment of Industrial Effluent

2021 ◽  
Vol 9 (3) ◽  
pp. 611
Author(s):  
Zhendong Yang ◽  
Zhenghua Liu ◽  
Aleksandra Sklodowska ◽  
Marcin Musialowski ◽  
Tomasz Bajda ◽  
...  
Keyword(s):  
Elemental Sulfur ◽  
Synthetic Medium ◽  
Industrial Effluent ◽  
Oxygen Demand ◽  
Growth Yield ◽  
Xrd Analysis ◽  
Sulfide Concentration ◽  
Leachate Treatment ◽  
Metabolic System ◽  
Sulfide Removal

Management of excessive aqueous sulfide is one of the most significant challenges of treating effluent after biological sulfate reduction for metal recovery from hydrometallurgical leachate. The main objective of this study was to characterize and verify the effectiveness of a sulfide-oxidizing bacterial (SOB) consortium isolated from post-mining wastes for sulfide removal from industrial leachate through elemental sulfur production. The isolated SOB has a complete sulfur-oxidizing metabolic system encoded by sox genes and is dominated by the Arcobacter genus. XRD analysis confirmed the presence of elemental sulfur in the collected sediment during cultivation of the SOB in synthetic medium under controlled physicochemical conditions. The growth yield after three days of cultivation reached ~2.34 gprotein/molsulfid, while approximately 84% of sulfide was transformed into elemental sulfur after 5 days of incubation. Verification of isolated SOB on the industrial effluent confirmed that it can be used for effective sulfide concentration reduction (~100% reduced from the initial 75.3 mg/L), but for complete leachate treatment (acceptable for discharged limits), bioaugmentation with other bacteria is required to ensure adequate reduction of chemical oxygen demand (COD).

Survival and growth of understory trees in oak forests of the Hudson Highlands, New York

1981 ◽  
Vol 11 (3) ◽  
pp. 689-695 ◽  
Author(s):  
Craig G. Lorimer
Keyword(s):  
New York ◽  
Growth Rates ◽  
Red Oak ◽  
Northern Red Oak ◽  
Average Growth Rate ◽  
Average Growth ◽  
Red Oaks ◽  
Oak Trees ◽  
Survival And Growth ◽  
Understory Trees

Mortality and growth rates of trees in various crown classes and size classes were analyzed from 40-year permanent plot records of slope and ravine forest dominated by chestnut oak (Quercusprinus L.) and northern red oak (Quercusrubra L.). Average 5-year mortality rates for suppressed trees ≥2.5 cm dbh of chestnut oak and red oak in the slope forest were 26 and 45%, respectively. None of the suppressed red oaks survived the 40-year period, compared with 14% of the chestnut oaks and 33% of the red maples (Acerrubrum L.). Mortality of oak trees in the intermediate crown class was less than half that of suppressed trees, but still much higher than that of maples and birches on the tracts. Survival was reasonably high for oaks as long as the top of the crown was receiving direct sunlight, but the expected 40-year survival rate of red oaks in such a position is only 20%, with an average growth rate of 1.0 mm in diameter per year. Curves and equations expressing average mortality and growth rates at various levels of competition are presented for each species.

Determination of Kinetics and Stoichiometry of Chemical Sulfide Oxidation in Wastewater of Sewer Networks

2003 ◽  
Vol 37 (17) ◽  
pp. 3853-3858 ◽  
Author(s):  
Asbjørn H. Nielsen ◽  
Jes Vollertsen ◽  
Thorkild Hvitved-Jacobsen
Keyword(s):  
Sulfide Oxidation ◽  
Sewer Networks

AN ARTIFICIAL INTELLIGENT APPROACH TO TRAFFIC ACCIDENT ESTIMATION: MODEL DEVELOPMENT AND APPLICATION

Transport ◽  
2009 ◽  
Vol 24 (2) ◽  
pp. 135-142 ◽  
Author(s):  
Ali Payıdar Akgüngör ◽  
Erdem Doğan
Keyword(s):  
Genetic Algorithm ◽  
Model Development ◽  
Back Propagation ◽  
Linear Functions ◽  
Model Parameters ◽  
Ann Model ◽  
Back Propagation Algorithm ◽  
Estimation Model ◽  
Average Growth ◽  
Feed Forward Back Propagation

This study proposes an Artificial Neural Network (ANN) model and a Genetic Algorithm (GA) model to estimate the number of accidents (A), fatalities (F) and injuries (I) in Ankara, Turkey, utilizing the data obtained between 1986 and 2005. For model development, the number of vehicles (N), fatalities, injuries, accidents and population (P) were selected as model parameters. In the ANN model, the sigmoid and linear functions were used as activation functions with the feed forward‐back propagation algorithm. In the GA approach, two forms of genetic algorithm models including a linear and an exponential form of mathematical expressions were developed. The results of the GA model showed that the exponential model form was suitable to estimate the number of accidents and fatalities while the linear form was the most appropriate for predicting the number of injuries. The best fit model with the lowest mean absolute errors (MAE) between the observed and estimated values is selected for future estimations. The comparison of the model results indicated that the performance of the ANN model was better than that of the GA model. To investigate the performance of the ANN model for future estimations, a fifteen year period from 2006 to 2020 with two possible scenarios was employed. In the first scenario, the annual average growth rates of population and the number of vehicles are assumed to be 2.0 % and 7.5%, respectively. In the second scenario, the average number of vehicles per capita is assumed to reach 0.60, which represents approximately two and a half‐fold increase in fifteen years. The results obtained from both scenarios reveal the suitability of the current methods for road safety applications.

Final products and kinetics of biochemical and chemical sulfide oxidation under microaerobic conditions

2018 ◽  
Vol 78 (9) ◽  
pp. 1916-1924 ◽  
Author(s):  
Lucie Pokorna-Krayzelova ◽  
Dana Vejmelková ◽  
Lara Selan ◽  
Pavel Jenicek ◽  
Eveline I. P. Volcke ◽  
...  
Keyword(s):  
Mathematical Model ◽  
Oxidation Rate ◽  
Elemental Sulfur ◽  
Sulfide Oxidation ◽  
Cost Effective ◽  
Anaerobic Treatment ◽  
Batch Experiments ◽  
Cost Effective Method ◽  
Microaerobic Conditions ◽  
Kinetics Of

Abstract Hydrogen sulfide is a toxic and usually undesirable by-product of the anaerobic treatment of sulfate-containing wastewater. It can be removed through microaeration, a simple and cost-effective method involving the application of oxygen-limiting conditions (i.e., dissolved oxygen below 0.1 mg L−1). However, the exact transformation pathways of sulfide under microaerobic conditions are still unclear. In this paper, batch experiments were performed to study biochemical and chemical sulfide oxidation under microaerobic conditions. The biochemical experiments were conducted using a strain of Sulfuricurvum kujiense. Under microaerobic conditions, the biochemical sulfide oxidation rate (in mg S L−1 d−1) was approximately 2.5 times faster than the chemical sulfide oxidation rate. Elemental sulfur was the major end-product of both biochemical and chemical sulfide oxidation. During biochemical sulfide oxidation elemental sulfur was in the form of white flakes, while during chemical sulfide oxidation elemental sulfur created a white suspension. Moreover, a mathematical model describing biochemical and chemical sulfide oxidation was developed and calibrated by the experimental results.

scholarly journals POTENSI EKSTRAK DAUN KARUK (Piper sarmentosum) SEBAGAI INSEKTISIDA NABATI HAMA ULAT GRAYAK (Spodoptera litura)

EKOLOGIA ◽  
2020 ◽  
Vol 18 (2) ◽  
pp. 55-62
Author(s):  
Rangga Eka S. P ◽  
Moerfiah . ◽  
Triastinurmiatiningsih .
Keyword(s):  
Spodoptera Litura ◽  
Larval Growth ◽  
Mortality Rates ◽  
Average Growth Rate ◽  
Average Growth ◽  
Extract Concentration ◽  
Randomized Design ◽  
Completely Randomized Design ◽  
Four Levels ◽  
Extent Of Damage

The purpose of this study was to determine the activity of the leaf extract of Piper sarmentosum on mortality and damage levels by pest armyworm (Spodoptera litura). This research was conducted at the Laboratory of Biology, Faculty of Mathematics and Natural Sciences, Pakuan University, Bogor. This study uses a completely randomized design (CRD), with four levels of extract concentration, that is 0% as control, 30%, 40% and 50%.  Each treatment was repeated four times. The variables measured were mortality rates, the extent of damage the leaves, and larval growth. A concentration of EDK 50% showed activity in killing the armyworm by 38%. The lowest level of damage is 5%, with an average growth rate to its lowest larvae by 0.8 cm with the provision of treatment EDK 50%, and the higest level of damage is 75% by a concetration of EDK 30% treatments.

Sign in / Sign up

Export Citation Format

Share Document