Biochemical Oxygen Demand Analysis Research Articles

Biofilm reactor based real-time analysis of biochemical oxygendemand

We reported a biofilm reactor (BFR) based analytical system for real-time biochemical oxygen demand (BOD) monitoring. It does not need a blank solution and other chemical reagents to operate. The initial dissolved oxygen (DO) in sample solution was measured as blank, while DO in the BFR effluent was measured as response. The DO difference obtained before and after the sample solution flowed through the BFR was regarded as an indicator of real-time BOD. The analytical performance of this reagent-free BFR system was equal to the previous BFR system operated using phosphate buffer saline (PBS) and high purity deionized water in reproducibility, accuracy and long-term stability. Besides, this method embraces many notable advantages, such as no secondary pollution. Additionally, the sample solutions are free from temperature controlling and air-saturation before injection. Significantly, this is a real-time BOD analysis method. This method was successfully carried out in a simulated emergency, and the obtained results agreed well with conventional BOD5. These advantages, coupled with simplicity in device, convenience in operation and minimal maintenance, make such a reagent-free BFR analytical system promising for practical BOD real-time warning.

Measurement of biochemical oxygen demand of the leachates

Biochemical oxygen demand (BOD) of the leachates originally from the different types of landfill sites was studied based on the data measured using the two manometric methods. The measurements of BOD using the dilution method were carried out to assess the typical physicochemical and biological characteristics of the leachates together with some other parameters. The linear regression analysis was used to predict rate constants for biochemical reactions and ultimate BOD values of the different leachates. The rate of a biochemical reaction implicated in microbial biodegradation of pollutants depends on the leachate characteristics, mass of contaminant in the leachate, and nature of the leachate. Character of leachate samples for BOD analysis of using the different methods may differ significantly during the experimental period, resulting in different BOD values. This work intends to verify effect of the different dilutions for the manometric method tests on the BOD concentrations of the leachate samples to contribute to the assessment of reaction rate and microbial consumption of oxygen.

BOD biosensors for pulp and paper industry wastewater analysis

Two semi-specific microbial biosensors were constructed for the analysis of biochemical oxygen demand (BOD) in high-cellulose-content pulp and paper industry wastewaters. The biosensors were based on living cells of Bacillus subtilis and Paenibacillus sp. immobilized in an agarose gel matrix. Semi-specific microorganisms were isolated from various samples (decaying sawdust and rabbit manure) and were chosen based on their ability to assimilate cellulose. The biosensors were calibrated with the Organization for Economic Cooperation and Development synthetic wastewater, and measurements with different wastewaters were conducted. The response time of biosensors using the steady-state method was 20-25min, and the service life of immobilized microorganisms was 96days. Detection limit was 5mg/l of BOD(7) while linear ranges extended up to 55 and 50mg/l of the BOD(7) for B. subtilis- and Paenibacillus sp.-based biosensors, respectively. Repeatability and reproducibility of both biosensors were within the limits set by APHA-less than 15.4%. In comparison, both biosensors overestimated the BOD(7) values in paper mill wastewaters and underestimated the BOD(7) in aspen pulp mill wastewater. The semi-specific biosensors are suitable for the estimation of organic pollution derived from cellulose, while the detection of pollution derived from tannins and lignins was minor. Better results in terms of accuracy and repeatability were gained with Paenibacillus sp. biosensor.

Restructuring BOD : COD Ratio of Dairy Milk Industrial Wastewaters in BOD Analysis by Formulating a Specific Microbial Seed

BOD (Biochemical oxygen demand) is the pollution index of any water sample. One of the main factors influencing the estimation of BOD is the nature of microorganisms used as seeding material. In order to meet the variation in wastewater characteristics, one has to be specific in choosing the biological component that is the seeding material. The present study deals with the estimation of BOD of dairy wastewater using a specific microbial consortium and compares of the results with seeding material (BODSEED). Bacterial strains were isolated from 5 different sources and were screened by the conventional BOD method. The selected microbial seed comprises of Enterobacter sp., Pseudomonas sp. BOD : COD (Chemical oxygen demand) ratio using the formulated seed comes in the range of 0.7-0.8 whereas that using BODSEED comes in the ratio of 0.5-0.6. The ultimate BOD (UBOD) was also performed by exceeding the 3-day dilution BOD test. After 90 days, it has been observed that the ratio of BOD : COD increased in case of selected consortium 7 up to 0.91 in comparison to 0.74 by BODSEED. The results were analyzed statistically by t-test and it was observed that selected consortium was more significant than the BODSEED.

Improvement of the analysis of the biochemical oxygen demand (BOD) of Mediterranean seawater by seeding control

Biochemical oxygen demand (BOD) is a useful parameter for assessing the biodegradability of dissolved organic matter in water. At the same time, this parameter is used to evaluate the efficiency with which certain processes remove biodegradable natural organic matter (NOM). However, the values of BOD in seawater are very low (around 2mgO2L−1) and the methods used for its analysis are poorly developed. The increasing attention given to seawater desalination in the Mediterranean environment, and related phenomena such as reverse osmosis membrane biofouling, have stimulated interest in seawater BOD close to the Spanish coast. In this study the BOD analysis protocol was refined by introduction of a new step in which a critical quantity of autochthonous microorganisms, measured as adenosine triphosphate, is added. For the samples analyzed, this improvement allowed us to obtain reliable and replicable BOD measurements, standardized with solutions of glucose–glutamic acid and acetate. After 7 days of analysis duration, more than 80% of ultimate BOD is achieved, which in the case of easily biodegradable compounds represents nearly a 60% of the theoretical oxygen demand. BOD7 obtained from the Mediterranean Sea found to be 2.0±0.3mgO2L−1 but this value decreased with seawater storage time due to the rapid consumption of labile compounds. No significant differences were found between two samples points located on the Spanish coast, since their organic matter content was similar. Finally, the determination of seawater BOD without the use of inoculum may lead to an underestimation of BOD.

Non-steady response of BOD biosensor for the determination of biochemical oxygen demand in wastewater

A biochemical oxygen demand (BOD) biosensor for effective and expeditious BOD(7) estimations was constructed and the non-steady phase of the output signal was extensively studied. The modelling approach introduced allows response curve reconstruction and a curve fitting procedure of good quality, resulting in parameters indicating the relationship between response and organic substrate concentration and stability properties of the BOD biosensor. Also, the immobilization matrixes of different thicknesses were characterized to determine their suitability for bio-sensing measurements in non-stationary conditions, as well as for the determination of the mechanical durability of the BOD biosensor in time. The non-steady response of the experimental output of the BOD biosensor was fitted according to the developed model that enables to determine the stability of the biosensor output and dependency on biodegradable organic substrate concentration. The calibration range of the studied BOD biosensor in OECD synthetic wastewater was 15-110 mg O(2) L(-1). Repeatability tests showed relative standard deviation (RSD) values of 2.8% and 5.8% for the parameter τ(d), characterizing the transient output of the amperometric oxygen sensor in time, and τ(s), describing the dependency of the transient response of the BOD biosensor on organic substrate concentration, respectively. BOD biosensor experiments for the evaluation of the biochemical oxygen demand of easily degradable and refractory municipal wastewater showed good concurrence with traditional BOD(7) analysis.

Preparation of Biofilm Electrode with Xanthomonas sp. and Carbon Nanotubes and the Application to Rapid Biochemical Oxygen Demand Analysis in High‐Salt Condition

A Xanthomonas sp. was isolated from the sludge on the drain outlet of a pharmaceutical factory. Then, the bacterium and carbon nanotubes (CNTs) were co-attached to an oxygen electrode for rapid analysis of biochemical oxygen demand (BOD). The response current was linear with BOD values in the range 10 to 300 mg/L for standard BOD solution with a response time of 35 seconds (R = 0.9994) and 20 to 580 mg/L for pharmaceutical wastewater with a response time < or =200 seconds (R = 0.9985), which means that this modified electrode might be used for online BOD analysis of pharmaceutical wastewater. Further studies revealed that the modified electrode can be used for BOD measurement in a high-salt condition. Also, the bacterium/CNTs biofilm can maintain its activity and good performance, even after being sealed and stored at 4 degrees C for 50 days.

Ferricyanide‐Mediated Microbial Reactions for Environmental Monitoring

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Ferricyanide-Mediated Microbial Reactions for Environmental Monitoring

The ability of microorganisms to use ferricyanide as an alternative electron acceptor for respiratory processes has been known for nearly 100 years. More recently, the use of ferricyanide-mediated bioreactions for environmental monitoring has received much attention. This paper reviews the recent developments of these mediated microbial processes for rapid biochemical oxygen demand analysis and direct toxicity assessment during the past five years. The ability of eukaryotic microorganisms to use ferricyanide as an alternative electron acceptor for a range of applications is also described.

BOD analysis of industrial effluents: 5 days to 5 min

Abstract Wastewater generation and its subsequent treatment is a major problem for every industry and for the society as well. Prior to treatment, the wastewaters need to be monitored so as to permit their discharge into the local water resources. Amongst all the parameters for which the wastewaters are monitored, biochemical oxygen demand (BOD), is one of the most important and frequently used parameters for estimating the level of water pollution. The control of wastewater treatment plants is very difficult or even impossible using the classical determination method for BOD because of its high time consumption (3–5 days). The need for fast, portable and cost-effective methods for environmental monitoring has stimulated the production of a variety of field analytical tools such as biosensors. Biosensors are device that have several unique features such as compact size, simple to use, one step reagentless analysis, low cost and quick-real time results. The conventional BOD measurement requires 3–5 days, which a microbial BOD biosensor senses within minutes. A number of microbial BOD sensors have been developed nationally and internationally. The drawback of such developed sensors is that they cannot be used for all types of industrial and domestic wastewaters. Our developed BOD biosensor is based on a pre-tested, synergistic formulated microbial consortium. It is capable to sense the BOD load of a wide variety of synthetic as well as industrial wastewaters having low–moderate–high biodegradability within minutes. The sensor BOD values show a good linear relationship with the BOD values obtained using the conventional method upto a GGA concentration of 90 mg/l (r=0.938). BOD values of real wastewater samples from different industries viz, distillery dairy and tannery were analysed using the developed sensor. The BOD sensor results were found to be comparable with those obtained using the conventional 3-day method.

A Series Piezoelectric Quartz Crystal Microbial Sensing Technique Used for Biochemical Oxygen Demand Assay in Environmental Monitoring

A new method for biochemical oxygen demand (BOD) determination, which combines the series piezoelectric quartz crystal (SPQC) technique with the growth of a microorganism is presented in this paper. This method needs no immobilization of bacteria and is simple and convenient. When a calibration technique was used for BOD analysis, the detection time was 2.5 h at 37°C. There was a good linear relationship between the frequency shift and BOD value in the range 2.2–11 mg/L and the regression equation was ΔF = 64.10 + 11.23[BOD]. The proposed method was compared with the conventional BOD5 method. This method was more rapid than the BOD5 method and the results obtained by the former were in good agreement with those obtained by the latter. The experimental conditions are also discussed in detail.

Formulation and standardization of a microbial composition useful for reproducible BOD estimation

A number of microorganisms were isolated from sewage. Biochemical oxygen demand (BOD) analysis was carried out by using these isolated microorganisms as a seed material with glucose‐glutamic acid (GGA) as a reference standard. Based on the BOD values, a defined microbial composition was formulated by using these isolates. This formulated microbial composition was standardized for reproducible BOD estimation by using four synthetic and four industrial samples. The results showed reproducibility of the BOD values within an acceptable limit. The BOD results are comparable with sewage which is used as a seed material in conventional BOD analysis. Storage stability studies of formulated microbial composition at different temperatures showed the maximum stability at 4° C. Such microbial composition offers better opportunity to be used as a standard seed inoculum in the BOD test.

Respirometric analysis of the biodegradation of organic contaminants in soil and water

Client-funded bench-scale investigations concerning the likelihood of successfully applying biological remediation to hazardous wastes must be cost-effective, and they usually need only determine if biodegradation is likely to occur on site. To assess the potential for stimulating biodegradation, biochemical oxygen demand (BOD) was used to continuously monitor bacterial respiration during growth on mixed organic wastes from contaminated water and soil. Continuously collected oxygen-consumption data provided information on the overall metabolic activity of the resident bacterial population and permitted direct observation of the cessation of microbial respiratory activity and, thus, the termination of aerobic degradation. The correlation of biological oxygen utilization with biodegradation was confirmed using independent analytical methods. Continuous, long-term BOD analysis was applied to bench-scale studies to assess the biodegradation of mixed organic wastes from contaminated sites and industrial waste effluents. This information was used to make an initial determination regarding the need to further explore bioremediation as a potential remedial-action technology using on-site, pilot-scale testing.

Biochemical oxygen demands of potential cellulose ethanol waste streams

The effects of potential waste streams resulting from ethanol production by the simultaneous saccharification fermentation (SSF) of cellulose were determined by measuring the biochemical oxygen demand (BOD). A worst-case analysis of BOD from ethanol-containing SSF beer showed an initial value of 1670 mg/l BOD, which is 29% of the expected initial BOD. When ethanol was reduced to 0.1–0.2% w/v, BOD levels were 605 mg/l in the mash and 250 mg/l in the beer. Both values were well below the projected discharge levels.

Numerical Analysis of BOD and DO Profiles

The variation of Biochemical Oxygen Demand (BOD) and Dissolved Oxygen (DO) along a stretch of a polluted natural stream can be represented by two second-order partial differential equations. These equations are similar to the equation representing the conduction of heat in solids, with the exception that the stream equations contain additional lower order terms. Analytical solutions have been obtained for many cases of the heat-conduction problem. However, the presence of the lower order terms and the complexities of many of the boundary conditions make it impossible to obtain analytical solutions to the BOD and DO profile equations for most cases of practical interest. Furthermore, the numerical procedures which have been found to work for the solution of the heat conduction equation are not satisfactory for the BOD and DO equations because of the effects introduced by the lower-order terms. Procedures are presented for the numerical solution of the BOD and DO equations under temporally and spatially varying BOD and DO inputs. The procedures described are confined to the condition of steady, uniform stream flow.