Ultimate Biochemical Oxygen Demand Research Articles

Methane emissions originating from the anaerobic waste stabilization ponds case study: Izmir wastewater treatment system

One of the sources of methane is anaerobic waste stabilization ponds (AWSPs). Anaerobic waste stabilization ponds have been used successfully to treat municipal and industrial wastewaters. Stabilization is brought about by a combination of precipitation and the anaerobic conversion of organic wastes to CO 2, CH 4, other gaseous end products, organic acids, and cell tissues. Methane production rate mainly depends on the temperature. The theoretical amount of methane produced during the anaerobic process is 0.7 m 3 for 1 kg of ultimate biochemical oxygen demand (BOD L) removed.

Biochemical oxygen demand and algae: Fractionation of phytoplankton and nonphytoplankton respiration in a large river

Mass balance equations for dissolved oxygen in streams are formulated to account for, among other variables, algal respiration (R), and biochemical oxygen demand (BOD). The oxygen consumption measured in primary productivity‐respiration analyses is not R but is total community oxygen consumption (TCOC), and BOD measurements are complicated by undefined algal components. Ultimate BOD was found to be 0.24 mg of O2 consumed per μg chlorophyll a and carbonaceous BOD was 0.20 per μ‐g chlorophyll a in excess of background BOD. The results were similar for live and dead algae. Phytoplankton respiration was fractionated from nonphytoplankton oxygen consumption (NPOC) by the regression of respiration against chlorophyll a to obtain a y intercept of zero chlorophyll. The intercepts, NPOC, closely matched O2 consumption measured when phytoplankton biomass was very low. Phytoplankton respiration, calculated as the residual of the difference between TCOC and NPOC, ranged from 0.2 to 1.5 (mean = 0.88) mg O2 per mg chlorophyll a per hour, close to the literature value of 1 (in cultures). Depth‐integrated (DI) phytoplankton respiration was 1/4 to 1/3 of DI gross primary productivity and 1–3% of maximum primary productivity. The separation of phytoplankton R and NPOC permitted the demonstration that R probably is not a simple function of productivity.

Biodegradability and Nutritional Value to Zooplankton of Selected Organic Fertilizers

Abstract In laboratory studies we compared the biodegradability and nutritional value to zooplankton of four organic fertilizers. Degradability rates and ultimate biochemical oxygen demand of wheat shorts, cottonseed meal, alfalfa meal, and chicken manure were computed. The nutritional values of the three meals, and of combined trout chow–yeast–CEROPHYL® (TCYC) food, were compared by ability of Ceriodaphnia dubia and Daphnia magna to survive and reproduce in culture media prepared from them. Decomposition rates and decomposable organic matter for the three meals were similar. Chicken manure oxidized more rapidly than the vegetable meals, but contained less decomposable organic matter. Both C. dubia and D. magna survived better and produced more neonates in cultures with alfalfa meal than in those with wheat shorts or cottonseed meal. Daphnia magna in cultures with wheat shorts or cottonseed meal did not reproduce. Daphnia magna reproduced about 19 h earlier in the alfalfa meal culture than in the TCYC med...

The oxygen uptake rate approach for analysing respirometric biochemical oxygen demand data—I. method development

When electrolytic and other continuous respirometers are used for monitoring the progression of a Biochemical Oxygen Demand (BOD) curve, cumulative data are acquired. The structure of these data limits the reliable application of existing methodologies for estimating typical BOD parameters such as the rate constant and the ultimate BOD value. In this case, it is proposed that the Oxygen Uptake Rate (OUR) should rather be used as the data source for further analysis, instead of the cumulative form. To model the OUR data trend, 1st and 2nd-order models are proposed. Theoretical examination of the properties of these OUR models indicates that they are likely to have improved nonlinear behaviour, and that their parameters will have more reliable confidence interval estimates. Furthermore, the optimal duration of an experiment performed to estimate OUR-BOD parameters is shorter, compared to that required for estimating similar parameters, in the case of cumulative data.

Stochastic models for first-order kinetics of biochemical oxygen demand with random initial conditions, inputs, and coefficients

Biochemical oxygen demand (BOD) is a parameter of prime importance in surface water pollution studies and in the design and operation of waste-water treatment plants. A general, stochastic analytical model (denoted S1) is developed for the temporal expectation and (heteroscedastic) variance of first-order BOD kinetics. The model is obtained by integrating the moment equation, which is derived from the mathematical theory of stochastic differential equations. This model takes into account random initial conditions, random inputs, and random coefficients, which appear in the model formulation as initial condition ( σ O 2), input ( σ l 2), and coefficient ( σ c 2) variance parameters, respectively. By constraining these three variance parameters to either vanish or to be nonnegative, model S1 is allowed (under appropriate combinations of the constraints) to split into six stochastic “submodels” (denoted S2 to S7), with each of these submodels being a particular case of the general model. Model S1 also degenerates to the deterministic model (denoted D) when each of the variance parameters vanish. The deterministic parameters (i.e., the rate coefficient and the ultimate BOD) and the stochastic variance parameters of the seven models are estimated on sets of replicated BOD data using the maximum likelihood principle. In this study, two (S5 and S7) of these seven stochastic models are found to be appropriate for BOD. The stochastic input (S5) model (i.e., null initial condition and coefficient variance parameters) shows the best prediction capabilities, while the next best is the stochastic initial condition (S7) model (i.e., null input and coefficient variance parameters).

Oxygen utilization and biochemical stabilization rate constants for a brewery effluent

Composite samples of brewery effluents were obtained from a brewery in Benin City, Nigeria. They were analysed for their biochemical oxygen demand (BOD) values at 20°C for definite periods in days. From the values obtained, oxygen utilization and biochemical stabilization rate constants, k and K, respectively, were determined. The mean values obtained for them were 0.37 day‐1 and 0.16 day‐1 respectively. The ultimate BOD (Lo) value for the brewery effluent was 757.1 mg/l, and the ratio of the 5‐day BOD (BOD5) to the Ultimate BOD (Lo) (i.e., BOD5/Lo) was found to be 0.85.

Evaluation of 60‐Milliliter BOD Bottle Tests

The nonstandard 60 ml incubation bottle was compared to the standard 300 ml bottle for biochemical oxygen demand tests for 16 pairs of duplicate samples. One test used the 60 ml bottle and the duplicate test used the 300 ml bottle. Statistical tests indicate that 5 day and ultimate biochemical oxygen demand and the specific rate constants were not significantly different for the 16 pairs of tests. The samples were collected from river water influenced by urban and rural runoff, urban drainage, and the effluent of a primary wastewater treatment plant. Factors such as strength and characteristics of the carbonaceous material and bacterial seed may not have been adequately factored into the experiment.

Effect of water hardness on the toxicity of cadmium to micro-organisms

A study was made of the effect of water hardness at different concentrations (viz. 0, 80, 120, 160, 240, 320, 400 and 480 mg l −1 as CaCO 3) on the toxicity of cadmium metal (5 mg 1 −1) as sulphate to saprophytic and nitrifying bacteria, with respect to the rate constant ( K) and ultimate biochemical oxygen demand ( L) which were calculated from BOD data (15 days) using the Thomas Graphical Method. Glucose was used as a source of carbon for micro-organisms. It was observed that the toxicity of cadmium to micro-organisms (both saprophytic and nitrifying) decreased with increasing hardness and reached a maximum at 320 mg 1 −1 as CaCO 3 for nitrifying and 400 mg l −1 as CaCO 3 for saprophytic bacteria. After these hardness levels, the ultimate BOD ( L) and rate constant ( K) showed a decrease. Nitrifying bacteria were found to be more sensitive to the metal as well as to its complexation with calcium or with other ions as they retained their normal activity at a lower hardness level as compared to saprophytic bacteria.

Effects of elevated pressures on the activated sludge process

Results of investigations on the effects of elevated pressures on a pilot scale activated sludge process are reported. Parameters of prime interest were pressure overlying the system, Biochemical Oxygen Demand (BOD) and Mixed Liquor Suspended Solids (MLSS). Variations in responses were described by the reaction rate constant k, of the first order BOD reaction and the ultimate BOD L. It was found that increasing the applied pressure accelarated the BOD reactions.

Microbial uptake of cadmium and its effects on the biochemical oxygen demand at various temperatures

Uptake of cadmium by microbes at different temperatures has been studied at pH 7. Glycine was used as a source of carbon for microorganisms in the BOD bottle at 20, 30, 40 and 50°C with varying concentrations of cadmium: control 0.0437, 0.437, 0.875 and 1.31 mg 1 −1 in each set. The influence of temperatures on the toxic effects of cadmium has been studied with respect to rate constant (k) and ultimate biochemical oxygen demand which were calculated from BOD data using Thomas Graphical method. Consumed cadmium mg 1 −1 was determined after eight days and it varied from 14.04 to 32.40% at four temperatures. Highest consumption of Cd was noted in the set at 30 and 40°C and lowest at 50°C.

Least Squares Estimates of BOD Parameters

In stream water quality surveys and in operational studies of sewage treatment plants, long-term biochemical oxygen demand (BOD) tests are often conducted. The purpose of these tests is to find the ultimate oxygen demand of waste and the first-order rate coefficient for the BOD reaction. This information is mandatory if a water quality model is to be used. This paper presents a technique for finding the least squares estimated for the ultimate BOD and rate coefficient without resorting to complicated computer algorithms or subjective graphical methods.

Effects of treatment and flow on the deoxygenation rate constant

The laboratory bench-scale experiments were conducted to investigate the effects of varying degrees of waste treatment and the flow conditions in the receiving waters on the deoxygenation rate constant (k), and ultimate biochemical oxygen demand (L), and the total O2 utilisation of the receiving waters. Industrial wastewaters were collected from 10 major industrial plants located along the Houston Ship Channel in Texas. Two different degrees of treatment for industrial wastewaters were studied. Three different flow conditions studied were the high, the average and the low flow in the Houston Ship Channel. The k values increased for both further treatment and decreased flow in the reactor runs. The L values were higher for the average flow conditions than for the low flow conditions. The total O2 utilization was found to increase with a decrease in the flow of the receiving waters.