Biological Oxygen Demand Values Research Articles

THE APPLICATION OF THE MATHEMATICAL MODEL FOR PREDICTING THE THRESHOLD CONCENTRATIONS OF THE INFLUENCE OF PESTICIDES ON THE SANITARY STATUS OF WATERS

Introduction. The rapid growth in the production and use of pesticides poses a real risk of the possible contamination of water bodies, which determines the urgency of the improving the methods of hygienic rating of pesticide preparations in water bodies, as well as the search for screening methods for establishing threshold concentrations.The issues of the need to improve the methodological approaches to the hygienic regulation of pesticide products in water of water bodies are considered, the need for further scientific study of this issue is shown. Material and methods. There are presented results of ourselves laboratory studies on the effect of herbicides of the sulfonylurea class on the processes of self-purification of reservoirs according to the Biological Oxygen Demand (BOD) index. In the work there were used substances of the sulfonylureas derivatives with a multi-directional mechanism of action that exerts both a stimulating and inhibitory effect on the course of processes of the biochemical oxygen consumption. With the use of the formula (Gotovtsev A.V., 2016), the total biochemical oxygen consumption for sulfonylurea derivatives was calculated from the two experimentally measured BOD values. Results. The data of biochemical oxygen consumption for two substances, obtained as a result of experimental studies, are presented. Selected substances have a multi-directional effect on the course of biochemical processes: stimulation - deviation of BOD from the control (%); inhibition - deviation of BOD from the control (%). There was made an estimation of the possible use of the formula for calculating the total biochemical oxygen consumption obtained in the solution of the modified Streeter-Phelps equation system for pesticides of the sulfonylurea class. The formula was applied as a mathematical model for the predictive assessment of the establishment of threshold concentrations of pesticides on the effect on the sanitary regime of water bodies (accordingly to BOD index). Discussion. In the paper, experimental and calculated values of biochemical oxygen consumption were compared, which shows the possibility of using this mathematical method for predicting the effect of pesticidal preparations of this class on the processes of self-purification of water reservoirs. Conclusion. There was shown the possibility of using mathematical modeling methods, in particular, the modified Streeter-Phelps system of equations in the practice of sanitary and hygienic investigations.

Seasonal variations of chemical properties of water of the Kaptai lake, Rangamati, Bangladesh

The chemical properties are the most important factors in the aquatic environment. The present study was carried out to analyze the chemical properties of the water of the Kaptai lake, Rangamati. The investigation was done from December, 2007 to November, 2008, during four seasons in two sites and three sub-sites. The main aim of the present research was to analyze the water quality of the Kaptai lake. Chemical properties of the water of this lake were determined by different standard methods. The chemical properties of water varied in different sites and seasons. The value of pH and dissolved oxygen (DO) was higher in undisturbed (UD) area than in less disturbed (LD) and disturbed (D) area (UD>LD>D). The nitrate (NO3) value was higher in disturbed area than undisturbed and less disturbed area (D>UD>LD). The phosphate (PO4) value was higher in less disturbed area than disturbed and undisturbed area (LD>D>UD). The electrical conductivity (EC), biological oxygen demand (BOD) chemical oxygen demand (COD) were higher in disturbed area than less disturbed and undisturbed area (D>LD>UD). The potassium (K) value was LD>UD>D. The pH value was higher in winter (W) than in late monsoon (LM), early monsoon (EM) and monsoon (M) (W>LM>EM>M). The NO3 -1 value was EM>M>LM>W>EM. The PO4 -2 value was LM>M>W>EM. The EC value was W>LM>M>EM. The biological oxygen demand (BOD) value was EM> W>LM>M. The DO value was higher in monsoon than late monsoon, early monsoon, and winter (M>LM>EM>W). The COD was EM>M>W>LM. The K value was EM>W>M>LM. The highest value of pH, K, NO3 and BOD were recorded in the Kaptai hydroelectricity project area (site –A) and the highest value of the DO, EC and COD were recorded in the Longudu area (site-B). This study is the first initiative to assess the detail chemical properties of water of the Kaptai lake.Jahangirnagar University J. Biol. Sci. 6(2): 11-17, 2017 (December)

Biological Oxygen Demand in Soils and Litters

Biological oxygen demand (BOD) in mineral and organic horizons of soddy-podzolic soils in the forest-park belt of Moscow as an indicator of their microbial respiration and potential biodestruction function has been studied. The BOD of soil samples has been estimated with a portable electrochemical analyzer after incubation in closed flasks under optimum hydrothermal conditions. A universal gradation scale of this parameter from very low ( 140 g O2/(m3 h)) has been proposed for mineral and organic horizons of soil. A physically substantiated model has been developed for the vertical distribution of BOD in the soil, which combines the diffusion transport of oxygen from the atmosphere and its biogenic uptake in the soil by the first-order reaction. An analytical solution of the model in the stationary state has been obtained; from it, the soil oxygen diffusivity and the kinetic constants of O2 uptake have been estimated, and the profile-integrated total BOD value has been calculated (0.4–1.8 g O2/(m2 h)), which is theoretically identical to the potential oxygen flux from the soil surface due to soil respiration. All model parameters reflect the recreation load on the soil cover by the decrease in their values against the control.

Water quality assessment of shallow and deep boreholes in Ekpan community, Effurun, Delta State, Nigeria

Twelve (12) groundwater samples (six from shallow and six from deep boreholes) were randomly collected in Ekpan community and environs, Delta State, Nigeria, for water quality/safety assessment. All samples were collected in replicates and transferred to the laboratory within 24 h of collection. Soil samples were collected in well-labelled sterilised polythene bags. The samples were subjected to laboratory analysis. Descriptive statistics was used to explore data, while Pearson correlation (r) was used to determine the relationships of the physicochemical and microbial parameters. The test of homogeneity in mean variance of the parameters (with the single-factor analysis of variance ANOVA) was used to determine possible differences between the shallow and deep groundwater sources. pH, temperature and biological oxygen demand (BOD) varied from 6.00 to 6.66 (6.22 ± 0.04), 24.00 to 25.10 (24.50 ± 0.09) mg/l and 2.50 to 5.82 (4.15 ± 0.21) mg/l, respectively. Salinity and total hardness varied from 3.00 to 79.40 (32.24 ± 5.74) % and 4.50 to 97.69 (37.84 ± 7.20) mg/l, while NO3− and SO42− varied from 0.03 to 1.35 (0.67 ± 0.11) and 1.80 to 71.35 (13.97 ± 4.03) mg/l. The heavy metals Pb, Cd, Cr, Mn and Hg ranged from 0.01 to 0.15 (0.07 ± 0.01), 0.01 to 0.64 (0.25 ± 0.05), 0.02 to 0.11 (0.08 ± 0.01), 0.04 to 0.16 (0.10 ± 0.01) and 0.0001 to 0.00039 (0.0002 ± 0.00001) mg/l, respectively, while total coliform counts ranged from 1.90 × 105 to 4.90 × 105 cfu/ml. pH correlated significantly with Cd, Ni, Mn and As, with Pearson correlation r > 0.43, while total coliform counts were influenced by temperature, electrical conductivity EC, total dissolved solids TDS, BOD, K, Mg, SO42− and NO3−, with Pearson correlation r > 0.7. While Hg is averagely at contaminant level, Pb, Cd, Mn, Cr, BOD and total coliform values exceeded the recommended values of World Health Organization WHO guidelines for drinking water quality, and thus constitute pollutants. Relative water quality (and hence water safety) averagely increases with depth of the boreholes (and by implication, the depth to the aquiferous units). The major contributors to heavy metal load are essentially surface/near-surface-based geologic and anthropogenic activities. The predominant effect of natural filtration (during infiltration/recharge through precipitation) is evident and is most likely enhanced by appreciable presence of fines (clay and silt) at variable horizons.

Study of the Gas Hydrate Antiagglomerant Performance of a Series of Mono- and Bis-amine Oxides: Dual Antiagglomerant and Kinetic Hydrate Inhibition Behavior

Antiagglomerants (AAs) are surfactants used in the upstream oil industry to prevent gas hydrate plugging in flow lines. Most, if not all, AAs used in the field today are cationic quaternary ammonium surfactants and function using the “hydrate-philic” mechanism. In this study, we have synthesized a series of butylated mono- and bis-amine oxide surfactants with aliphatic tails with chains of 9–17 carbon atoms and either amide or ester spacer groups. Their performance as hydrate-philic AAs has been investigated in a sapphire autoclave and sapphire rocking cells with a Structure II-forming natural gas mixture. There was generally good agreement regarding the performance and relative ranking of the surfactants between the two sets of equipment. The AA performance of the amine oxide surfactants depended on many factors, including the polar head and spacer groups, tail length, subcooling at hydrate onset, salinity, and the composition of the hydrocarbon fluid. Amido amine oxide surfactants performed better than the equivalent ester amine oxide, probably due to the stronger hydrogen-bonding ability of the amide group. The bis-amine oxide surfactants were designed with optimum interamine distance for best Structure II crystal growth inhibition and performed better as AAs than did the mono-amine oxide surfactants. The amido bis-amine oxide surfactants showed reasonable seawater biodegradation rates over 28 days, giving biological oxygen demand values of 25–40%. The bis-amine oxide surfactants in particular also showed a strong kinetic hydrate inhibition effect, which could be very useful for field applications. Thus, these surfactants could be used first as kinetic hydrate inhibitors (KHIs), and if for any reason hydrate formation does occur they could also function as AAs to prevent hydrate blockages under certain conditions.

Facultative Stabilization Pond: Measuring Biological Oxygen Demand using Mathematical Approaches

Pollution is a man-made phenomenon. Some pollutants which discharged directly to the environment could create serious pollution problems. Untreated wastewater will cause contamination and even pollution on the water body. Biological Oxygen Demand (BOD) is the amount of oxygen required for the oxidation by bacteria. The higher the BOD concentration, the greater the organic matter would be. The purpose of this study was to predict the value of BOD contained in wastewater. Mathematical modeling methods were chosen in this study to depict and predict the BOD values contained in facultative wastewater stabilization ponds. Measurements of sampling data were carried out to validate the model. The results of this study indicated that a mathematical approach can be applied to predict the BOD contained in the facultative wastewater stabilization ponds. The model was validated using Absolute Means Error with 10% tolerance limit, and AME for model was 7.38% (< 10%), so the model is valid. Furthermore, a mathematical approach can also be applied to illustrate and predict the contents of wastewater.

Efficiency of temporary storage of geothermal waters in a lake system: Monitoring the changes of water quality and bacterial community structures.

Disposal of used geothermal waters in Hungary often means temporary storage in reservoir lakes to reduce temperature and improve water quality. In this study, the physical and chemical properties and changes in the bacterial community structure of a reservoir lake system in southeast region of Hungary were monitored and compared through 2 years, respectively. The values of biological oxygen demand, concentrations of ammonium ion, total inorganic nitrogen, total phosphorous, and total phenol decreased, whereas oxygen saturation, total organic nitrogen, pH, and conductivity increased during the storage period. Bacterial community structure of water and sediment samples was compared by denaturing gradient gel electrophoresis (DGGE) following the amplification of the 16S rRNA gene. According to the DGGE patterns, greater seasonal than spatial differences of bacterial communities were revealed in both water and sediment of the lakes. Representatives of the genera Arthrospira and Anabaenopsis (cyanobacteria) were identified as permanent and dominant members of the bacterial communities.

Geo-environmental evaluation of Wadi El Raiyan Lakes, Egypt, using remote sensing and trace element techniques

Wadi El Raiyan depression represents a discharge area of excess wastewater from the Faiyum province. It comprises two lakes: the upper lake connects the lower one through a channel. The intensive agriculture in the area hazardously affects both lakes. To assess the status of these lakes, this work studies the change detection using image classification and post-classification comparison, physicochemical parameters, concentration of trace elements, and microbiological contents. The classified images indicate a maintained constant area of the upper lake from 1990 to 2012 and decreased by 1.6% in 2014. The lower lake area increased by 4.8% between 1990 and 2001, then decreased till 2014 and increased again by 8.4% in 2015. The change detection concluded that the lake could be disappeared by 2019 if the exploitation of water from the upper lake continues, or the lake could be rebounded if the government planned to increase the recharge. The factor analysis implies that the total Fe, Mn, Ni, Ba, and As are controlled by pH–Eh relationship, Cu by TDS, Pb by temperature, while Cd is attributed to anthropogenic factor. The upper and lower lake samples exhibit biological oxygen demand (BOD) and chemical oxygen demand (COD) values lower than fish farm samples. The high BOD and COD values were coupled by high nitrate contents in the studied water samples. The cultivated land drains and the fish farms samples have total coliform (TC) and fecal coliform (FC) higher than the samples collected from the upper lake.

Bacterial and chemical pollution level of the river Turag, Gazipur, Bangladesh

The river Turag is the upper tributary of the river Buriganga in Bangladesh. Aerobic heterotrophic bacterial count of the river in nutrient agar (NA) and peptone yeast extract glucose (PYG) agar media ranged from 2.91 × 105 to 27.5 × 105 cfu/ml and from 1.09 × 105 to 19.3 × 105 cfu/ml, respectively. Enteric and related bacterial count on MacConkey agar was between 0.88 × 103 and 20.8 × 103 cfu/ml. Out of 91 isolated bacterial isolates, 30 were selected based on their distinctive colony morphology for detailed study. Among these, 16 were Grampositive (53%) and 14 were Gram-negative (47%). Bacillus was dominant among the Gram-positive isolates (69%). The remaining were Brochothrix thermosphacta (6%), Caryophanon sp. (19%) and Renibacterium salmoninarum (6%). Fourteen Gram-negative, enteric and related isolates were identified as Plesiomonas shigelloides (43%), Alcaligenes denitrificans (22%), E. coli (14%), Proteus (14%) and Citrobacter freundii (7%). Biological oxygen demand (BOD) and chemical oxygen demand (COD) values were about 9 and 5-fold higher than standard values whereas dissolved oxygen (DO) of the river was found to be six times less than the standard value. The maximum average TDS, conductivity and turbidity was recorded during the summer season as 441.75 ± 15.52 mg/l, 858.25 ± 19.57 μS/cm and 79.53 ± 6.49 NTU, respectively. Chemical contents viz. sulphate, chloride and fluoride were found to be satisfactory from pollution point of view. Both BOD and COD values along with the abundance of different heterotrophic and enteric bacteria clearly indicated that the river Turag was polluted with organic, chemical and bacterial pollutants.
 Dhaka Univ. J. Biol. Sci. 26(1): 1-11, 2017 (January)

Physico-Chemical Quality of Selected Drinking Water Sources in Mbarara Municipality, Uganda

The study assessed the physico-chemical quality of selected drinking water sources (springs, boreholes, shallow wells and rainfall) in Mbarara municipality with respect to World Health Organization (WHO) drinking water guidelines and other guidelines in light of the increased anthropogenic activities in the municipality. A total of 70 water samples were collected from purposively selected boreholes, springs, wells and rainwater in Nyamitanga, Kamukuzi and Kakoba divisions of Mbarara municipality with various human activities. The samples were analysed for physico-chemical parameters: Temperature, pH, Dissolved Oxygen (DO), Biological Oxygen Demand (BOD), Total Dissolved Solids (TDS), Electrical Conductivity (EC) and Total hardness using American Public Health Association (APHA) standard methods. The mean temperature and pH ranged between 18.07 °C - 23.45 °C and 5.74 - 7.54, respectively. The mean DO values were found to be between 4.84 and 12.86 mg/l; whereas mean BOD was within the range of 1.83 - 7.71 mg/l. The mean TDS and EC of the water samples ranged, between 33.40 - 569.20 mg/l and 29.30 - 1139.90 μS/cm respectively. Furthermore, the lowest and highest mean total hardness were 70.00 and 264.00 mg/l, respectively. The recorded mean water temperatures for each of the water sources were above the WHO threshold temperature (15 °C) which makes drinking water palatable. Boreholes in Nyamitanga and Shuhaddea Secondary Schools, spring in Kiswahili, well in Kisenyi and rainwater in Mbarara University of Science and Technology (MUST) had mean pH below the WHO minimum guideline value (6.5) hence acidic. Borehole in Nyamitanga secondary school, spring in Kisenyi, shallow well in Nyamitanga and the rainwater in MUST had mean DO values below the WHO range (10 - 12 mg/l). Borehole in Shuhaddea Secondary School and the well in Kisenyi had average BOD values above the range of European Union guideline values (3 - 6 mg/l). TDS and EC of all the water sources were below the WHO maximum guideline limits of 1000 mg/l and 1500 μs/cm respectively. Total hardness was also below the WHO harmless limit of 1000 mg/l. However rainwater in MUST was moderately soft while the other drinking water sources exhibited moderate to full total hardness. The physicochemical parameters of some of the selected water sources in Mbarara municipality have been compromised mainly by the increased human activities especially croplands, latrines, landfills, transportation, animal and municipal wastes at the vicinity of the water sources. Mbarara municipal council should therefore ensure proper sanitation and water safety plans for these drinking water sources to avoid further contamination from the human activities.

New microbial-friendly polyaniline nanoparticles on the base of nitrilotriacetic acid: comparison with PANI prepared by standard techniques

This paper describes the influence of polyaniline (PANI) nanoparticles prepared in the presence of the nitrilotriacetic acid (NTA) in comparison with PANI prepared by standard techniques, on mixed microbial cultures in the form of a biological extract from soil and activated sludge and partially digested sludge, both sourced from a municipal wastewater treatment plant. The presence of PANI prepared by standard techniques in aqueous environment has a negative effect on the activity of mixed microbial cultures in the form of activated sludge, digested sludge (anaerobic conditions), and natural soil. According to biological oxygen demand (BOD) values—respirometric test, the slight inhibiting effect of nanoparticles is attributed to impurities and oligomers from aniline polymerization. The use of NTA in the production of PANI, resulted in nanotubes with channels through which NTA is incorporated into the structure. A sample thus obtained shows higher values of BOD, which is associated with the fact that NTA is released from PANI nanotube channels followed by its biodegradation.

Determination of Shelf Life of Selected Sachet Water in Ogbomoso, Oyo State Nigeria

Water is life and every living thing depends on it for existence. Sachet water has gradually become the most widely consumed liquid in Nigeria with varying qualities. This study investigates the temporal variation in water quality of Sachet water produced in Ogbomoso, Oyo State. Ten (10) brands of sachet water from Ogbomoso South and North Local government area were collected within 24 hours of production and stored at standard room temperature and conditions. Sub-samples were drawn from the stock samples on daily basis for physico-chemical measurements on the water samples Temperature, pH, colour, turbidity, Hardness, Total Alkalinity, Dissolve Oxygen (DO), Biological Oxygen Demand (BOD), Electrical Conductivity (EC) and Nitrate values were determined in accordance with World Health Organization (W.H.O) analytical methods. Temperature, pH and Colour values ranged from (28.3 - 30.5) ̊C, (7.96 - 8.80) and (20-70) Hazen, respectively. The Total hardness EC and DO and BOD values varied from (45-105)mg/l, (11 - 184)µs, (2.83 - 12.24)mg/L and (18.2 - 28.4)mg/l, respectively. Shelf life for the selected sachet water in Ogbomoso is 12 weeks from the date of production under laboratory condition with partial exposure to sunlight.

DECOLOURIZATION OF TRIPHENYLMETHANE DYES AND DYE INDUSTRY EFFLUENT BY STAPHYLOCOCCUS AUREUS ISOLATED FROM DYE CONTAMINATED SITE

<p><strong>Objective: </strong>The objectives of the present study were a) to isolate and screen bacteria for dye removal from synthetic solution b) to optimize various variables such as pH, static/shaking and initial dye concentration on degradation of triphenyl methane dyes namely basic violet 3 and basic green 4 by isolated <em>Staphylococcus aureus</em> c) to analyse enzymes involved in the biodegradation of triphenylmethane dyes d) to treat real leather dyeing wastewater with newly isolated strain of <em>Staphylococcus aureus </em>e) to characterize untreated and treated leather dyeing wastewater f) to study the effects of real and treated effluent on plants and <em>Rhizobium</em>.<strong></strong></p><p><strong>Methods: </strong>Isolation of bacteria from sludge was carried out by spread plate method and the bacteria was identified by morphological and biochemical characterization. The isolated bacterium was screened for dye decolorization potential of triphenylmethane dyes basic violet 3 and basic green 4 The effects of parameters were studied by varying pH (from 3 to 9), temperature (from 15-45 °C), and initial dye concentration (from 10-500 mg/l). The enzyme involved in biodegradation was studied in intracellular extract. Real leather dyeing wastewater was treated with the bacteria and characterized. The treated wastewater was tested on plants and <em>Rhizobium </em>for toxicity. <strong></strong></p><p><strong>Results: </strong>Dye decolorization potential of bacteria <em>Staphylococcus aureus</em> isolated from wastewater for leather dyes basic violet 3 and basic green 4 were evaluated. Dye decolorization using bacteria was found to be dependent on physicochemical parameters (shaking, pH and initial dye concentration). Enzymes NADH-DCIP reductase and MG reductase were found to play dominant role during biodegradation of synthetic dyes. Application oriented studies using growing bacteria in pure cultures were carried out with leather dyeing wastewater collected from DKS prime tanners. Analysis of raw leather dyeing wastewater showed high pollution load in terms of color, Total solids, Total suspended solids, Total dissolved solids and Biological oxygen demand whereas the leather dyeing wastewater treated with pure culture of <em>Staphylococcus aureus</em> showed considerable decrease in Total solids, Total suspended solids, Total dissolved solids and Biological oxygen demand values which were within the permissible limits. Phytotoxicity and microbial toxicity studies confirmed the non-toxic nature of treated leather dyeing wastewater. <strong></strong></p><p><strong>Conclusion: </strong>Our study proved that <em>Staphylococcus aureus</em> can serve as a potential remediation agent for the treatment of leather dyeing wastewater.</p>

Modeling the BOD of Danube River in Serbia using spatial, temporal, and input variables optimized artificial neural network models.

This paper describes the application of artificial neural network models for the prediction of biological oxygen demand (BOD) levels in the Danube River. Eighteen regularly monitored water quality parameters at 17 stations on the river stretch passing through Serbia were used as input variables. The optimization of the model was performed in three consecutive steps: firstly, the spatial influence of a monitoring station was examined; secondly, the monitoring period necessary to reach satisfactory performance was determined; and lastly, correlation analysis was applied to evaluate the relationship among water quality parameters. Root-mean-square error (RMSE) was used to evaluate model performance in the first two steps, whereas in the last step, multiple statistical indicators of performance were utilized. As a result, two optimized models were developed, a general regression neural network model (labeled GRNN-1) that covers the monitoring stations from the Danube inflow to the city of Novi Sad and a GRNN model (labeled GRNN-2) that covers the stations from the city of Novi Sad to the border with Romania. Both models demonstrated good agreement between the predicted and actually observed BOD values.

Deoxygenation rate, reaeration and potential for self-purification of small tropical urban stream

Mathematical models used to simulate the water quality and the processes of self-purification of water bodies are important tools to support effective water resource management. The objective of this study was to evaluate the impact of organic pollution on water quality and the assimilative capacity of organic matter in the Ribeirao Vermelho stream situated in the city of Lavras in Minas Gerais. The deoxygenation rate (K1) and reaeration (K2) were determined and tested in three segments of the Ribeirao Vermelho over two seasons (summer and winter). The purification process simulation was performed using the Streeter- Phelps model. The highest K1 and K2 values occurred during the winter period which was characterized by lower flows. Simulation of the dissolved oxygen profile and biological oxygen demand fitted the model well, indicating the prevalence of carbonaceous deoxygenation due to nitrification and also demonstrating the importance of natural reaeration as part of the purification process. Different response was observed during the winter, in which the high primary productivity values stood in the reaeration process stream. Biological oxygen demand values did not meet the limits recommended by the Resolution of the Ministry of the Environment 357/2005 throughout the river system and the entire study period. In conclusion, the Ribeirao Vermelho is unable to self-purify along its entire length, and water quality is influenced by effluent discharge which intensifies degradation.

Modelling biological oxygen demand in wastewater of Arak City, Iran

Due to the fact that the laboratory analysis of biological oxygen demand (BOD) is time-consuming and uncertain because of some interferences during analysis, automatic estimation of BOD by modeling methods would be of great importance to researchers. The main aim of this study was to compare the performance of three models for the prediction of BOD in the wastewater of Arak City, Iran. The methods were artificial neural network (ANN with early stopping and ANN with Bayesian regularization), an Ensemble of ANN (EANN), and partial least squares regression. The models trained and were validated on a data set containing 18 parameters sampled periodically from the wastewater of Arak City. The performance of these models was assessed by mean squared error (MSE) and R2 of the test data set besides correlation coefficient of observed and predicted values of BOD for each model. Concerning the Bayesian regularization algorithm, the perfect fitting of the model to both training and test data with correlation coefficients of 0.999 and 0.945 confirmed that this method outperformed the results of other models. Moreover, the results of sensitivity analysis indicated that chemical oxygen demand (COD), next to sulfate and fecal coliforms are the most important parameters in the prediction of BOD by ANN modeling.

Assessment of physico-chemical properties and metal contents of water and sediments of Bodo Creek, Niger Delta, Nigeria

Some physico-chemical properties and the concentrations of the metals Fe, Mn, Ni, Cd, Cr, Co, Cu, Pb, and Zn in water and sediments were examined from September 2011 to January 2012 in Bodo Creek, where oil spills have been recurrent. Temperature, pH, total dissolved solid, conductivity, salinity, dissolved oxygen, biological oxygen demand (BOD), chemical oxygen demand (COD), total hardness, sulfate, nitrate, and phosphate were determined in surface water. Particle size, total organic matter (TOM), and pH were also determined in the sediments. The parameters were within permissible limits except the mean values of BOD, COD, total hardness, and sulfate that exceeded levels permissible for domestic use. The sediments consisted mainly of sand, with TOM ranging from 0.2% to 5.5%. With the exception of cadmium that was below detection limit, metal levels (mg kg−1) in the sediments were 12 (Mn), 1070 (Fe), 10 (Cu), 10 (Zn), 5.3 (Cr), 1.1 (Pb), 1.0 (Ni), and 0.5 (Co) while in water they were 24, 98, 21, 6.9, 4.0, 0.6, 0.18, and 0.16, respectively. The latter were higher than World Health Organization recommended permissible levels for both surface and drinking water.

Gluconobacter sp. cells for manufacturing of effective electrochemical biosensors and biofuel cells

AbstractGluconobacter oxydans bacteria exhibit a unique metabolism for quick and incomplete oxidation of a wide range of different compounds (aldoses, ketoses, mono- and poly-alcohols, etc.). Such biotransformation efficiency with simple biomass production led to the industrial applications of these bacteria in the production of several important commodities. Their respiratory activity can also be successfully studied and used in the field of bioelectrochemistry. The main aim of this review is to present various strategies to improve selectivity of assays using intact/treated cells of G. oxydans, to introduce the application of G. oxydans-based biosensors in selective monitoring of analytes during biotransformation processes and to provide information about utilizable sugars in fermentation media or in biological oxygen demand value determination. The final part of the review describes potential application of G. oxydans cells in the generation of electricity from complex fuels within microbial fuel cells by advanced direct electron transfer route between bacterial cells and electrodes.

Artificial neural network modelling of biological oxygen demand in rivers at the national level with input selection based on Monte Carlo simulations.

Biological oxygen demand (BOD) is the most significant water quality parameter and indicates water pollution with respect to the present biodegradable organic matter content. European countries are therefore obliged to report annual BOD values to Eurostat; however, BOD data at the national level is only available for 28 of 35 listed European countries for the period prior to 2008, among which 46% of data is missing. This paper describes the development of an artificial neural network model for the forecasting of annual BOD values at the national level, using widely available sustainability and economical/industrial parameters as inputs. The initial general regression neural network (GRNN) model was trained, validated and tested utilizing 20 inputs. The number of inputs was reduced to 15 using the Monte Carlo simulation technique as the input selection method. The best results were achieved with the GRNN model utilizing 25% less inputs than the initial model and a comparison with a multiple linear regression model trained and tested using the same input variables using multiple statistical performance indicators confirmed the advantage of the GRNN model. Sensitivity analysis has shown that inputs with the greatest effect on the GRNN model were (in descending order) precipitation, rural population with access to improved water sources, treatment capacity of wastewater treatment plants (urban) and treatment of municipal waste, with the last two having an equal effect. Finally, it was concluded that the developed GRNN model can be useful as a tool to support the decision-making process on sustainable development at a regional, national and international level.

Pollution Status of Balu River due to Industrial Input at Dhaka, Bangladesh

Physical parameters of the water are the main properties indicating the status of water quality. Major physical parameters to evaluate water quality were Electrical Conductivity (EC), pH, Dissolve Oxygen (DO), Biological Oxygen Demand (BOD), Total Dissolve Solids (TDS) and Turbidity. This study reveals variations of water quality of Balu River at Dhaka, Bangladesh during rainy and winter seasons between February’ 2008 to June’ 2008. The samples were collected from ten different sports at two different depth of water (surface and 5m depth). In dry period, the highest average values of EC, Turbidity, DO, BOD and TDS were 715.1 μS/cm, 18.87 NTU, 1.04 mg/l, 8.06 mg/l and 87.3 mg/l respectively. While in rainy period, the highest average values of EC, Turbidity, DO, BOD and TDS were 118.6 μS/cm, 11.13 NTU, 2.77 mg/l, 6.56 mg/l and 69.81 mg/l respectively. The river was found unsuitable for drinking, domestic, irrigation and industrial purposes. Poor river water quality impacts the ecosystem and aesthetic features very negatively.