Biological Oxygen Demand Measurements Research Articles

Biodegradable Polyurethane Foams Based on Polyols Obtained from Cellulose and Its Hydroxypropyl Derivative

Three methods of cellulose-derived polyol synthesis were elaborated. The suitable substrates were (hydroxypropyl)cellulose or cellulose, which were hydroxyalkylated in reactions with glycidol and ethylene carbonate in triethylene glycol or in water. The products were characterized by IR, 1H NMR, and MALDI ToF spectroscopies. For all polyols, IR spectra showed strong bands at 1060 cm−1 from the ether group formed upon the ring opening of GL and EC. The polyol obtained from (hydroxypropyl)cellulose in the triethylene glycol solvent was accompanied by oligomeric products of glycol hydroxyalkylation and oligomeric glycidol. The polyol obtained by the hydroxyalkylation of cellulose with glycidol and ethylene carbonate in the water contained units of hydroxyalkylated cellulose and products of hydroxyalkylation of water. The physical properties of the obtained polyols, like density, viscosity, and surface tension, were determined. The polyols were then used to obtain rigid polyurethane foams. The foams have apparent density, water uptake, and polymerization shrinkage similar to classic rigid PUFs. The foams showed advantageous thermal resistance in comparison with classic ones. After thermal exposure, their compressive strength improved. The biodegradation of the obtained materials was tested by a respirometric method in standard soil conditions by the measurement of biological oxygen demand and also using the cellulases or the enzymes responsible for cellulose degradation. It has been found that polyols are totally biodegradable within one month of exposure, while the foams obtained thereof are at least 50% biodegraded in the same conditions. The enzymatic biodegradation of the PUFs by the action of microbial cellulase was confirmed.

On-line biological oxygen demand (BOD) monitoring using a microbial membrane reactor

An on-line biological oxygen demand (BOD) monitoring instrument, utilizing an in-situ microbial membrane reactor, automates membrane cultivation, calibration, and rapid BOD detection, eliminating reagent pollution is presented. The core instrument used was an STM32F103RCT6 microcontroller embedded in the FreeRTOS real-time operating system. A series of practical application tests were carried out by the instrument. The results demonstrate that the instrument provides good stability and accuracy in detecting multiple concentrations of glucose and glutamic acid (GGA) standards, with a relative error range and relative standard deviation range from −3.01 to 11.88% and 4.19 to 6.69%, respectively. The tested water samples had a relative error range from −4.93 to 13.37%. The on-line monitoring instrument for BOD has been tested for almost three months and has shown stable performance, high accuracy, and real-time, in-situ, and on-line BOD detection. In the past three months of application testing, the on-line biological oxygen demand monitoring instrument has shown stable performance, good accuracy, and real-time, in-situ, and on-line BOD measurements. This device has significant environmental benefits for continuous water quality monitoring and the timely monitoring of water pollution.

Dynamic-chance-constrained-based Fuzzy Programming Approach for Optimizing Wastewater Facultative Ponds for Multi-period Case

In this article, a novel optimization model that was specifically designed as a dynamic-chance-constrained fuzzy uncertain programming framework is introduced. This model serves the purpose of optimizing the efficiency of facultative ponds utilized in domestic wastewater treatment. The primary focus of this study was maximizing the amount of the wastewater treated in the facility subject to quality requirements via the assessment of wastewater quality through the measurement of Biological Oxygen Demand (BOD). The model's development was grounded in a real-world scenario, where decision-makers encountered uncertainties in various parameters, such as the rate of BOD degradation and the incoming wastewater load, both characterized by fuzzy membership functions. In light of this uncertainty, the decision-maker aimed to maximize the wastewater treatment capacity while maintaining a suitable safety margin for both objective and constraint functions, employing policies founded on probability and chance. A case study was carried out at the Bantul domestic wastewater treatment plant, situated in Yogyakarta, Indonesia. The study successfully identified optimal decisions regarding wastewater flow rates and processing times. As a result, it can be concluded that the proposed model effectively resolved the problem at hand, making it a valuable tool for decision-makers in similar contexts.

An evolutionary robust soft measurement technique via enhanced atom search optimization and outlier robust extreme learning machine for wastewater treatment process

Accurate and prompt measurement of certain key variables occurring during wastewater treatment, especially effluent ammonia nitrogen (NH4-N) and biological oxygen demand (BOD), is of great importance. In this study, a soft measurement model combining random forest (RF), enhanced atomic search optimization (EASO) and online sequential outlier robust extreme learning machine (OSORELM) is proposed for wastewater treatment. First, RF is used to select auxiliary variables with high correlation of NH4-N and BOD as model inputs. Second, a dynamic perturbation strategy and a generalized opposition-based learning are added to ASO to improve the algorithm performance. And EASO is used for model hyperparameter optimization. Then, the optimized OSORELM model is used for soft measurements of NH4-N and BOD. Finally, to verify the stability of the model, 5 %, 10 % and 15 % noise were added for further experiments. The results show that the proposed model has better prediction and stronger robustness in soft measurements of NH4-N and BOD.

Transformation of organic carbon through medium pressure (polychromatic) UV disinfection of wastewater effluent during wet weather events

An observed decrease in total organic carbon (TOC) and dissolved organic carbon (DOC) concentrations following wastewater disinfection with medium pressure (MP, polychromatic) ultraviolet (UV) irradiation during wet weather flows is investigated. When antecedent rainfall in the previous 7-days was >2 in (5 cm), TOC and DOC concentrations decreased dramatically following MP-UV disinfection. Organic carbon surrogate measurements of biological oxygen demand (BOD), TOC, DOC, turbidity, UVA – 254 nm, SUVA (specific UVA), scanning UV–Visible spectra (200–600 nm), fluorescence excitation-emission matrix (EEM) spectra, and light scattering data are presented for wastewater resource recovery facility (WRRF) influent, secondary effluent (pre-UV-disinfection), and MP-UV-disinfected (final effluent) samples. TOC and DOC in wastewater influent and secondary effluent (i.e., pre-UV disinfection) correlated with antecedent rainfall conditions. The percent TOC and DOC removal through secondary treatment (i.e., from influent to effluent pre-UV) and the percent TOC and DOC removal through MP-UV disinfection (i.e., from effluent pre-UV to effluent post-UV) were compared and the latter approached 90 % through MP-UV disinfection during high antecedent rainfall conditions. Spectroscopy (UV, visible, or fluorescence) was performed on samples after filtration through 0.45 μm filters, i.e., the operationally defined DOC fraction of aquatic carbon. Scanning UV–visible spectra indicated transformation of an unidentified wastewater component into light-scattering entities regardless of antecedent rainfall conditions. The types of organic carbon (diagenetic, biogenic, or anthropogenic) and the significance of wet weather are discussed. An organic carbon contribution via infiltration and inflow was attributed as a source-of-interest in this research.

The effect of tablet detergent wastewater using zeolite from rice husk ash on the chemical water quality and the growth of water hyacinth

Abstract The objective of this study is to determine the effect of detergent tablets containing zeolite from rice husk ash as builder on chemical water quality and growth of water hyacinth (Eichhornia crassipes). Water hyacinth is a plant that grows very readily in waters contaminated by detergent effluent, which can lead to eutrophication. Three detergent formulations were studied, differing only in their zeolite content: F1 (zeolite 15%), F2 (zeolite 20%) and F3 (zeolite 25%). The same formulations containing sodium tripolyphosphate (STTP) instead of zeolite were used for comparison: P1 (STTP 15%), P2 (STTP 20%) and P3 (STTP 25%). The effluents contained the respective formulations at five concentrations (0, 25, 50, 75, 100)%. Water hyacinth growth was studied by plant wet weight, plant height, number of leaves and dry weight, and water chemical parameters were determined by chemical oxygen demand (COD), biological oxygen demand (BOD), total suspended solid (TSS) and pH value. The results of the plant growth studies showed that detergent formulations F1 and F2 and comparative detergent formulations P1 and P2 caused plant growth. The measurements of BOD, COD, TSS and pH showed that the detergent formulation with zeolite had a higher value than the formulation of the comparison detergent. The formulation with a zeolite concentration of 25% (F3) is recommended because it is the best formula that has a negative effect on plant growth compared to formulations F1 and F2. This is supported by chemical parameters among which the COD, BOD and pH values still meet the requirements of the quality standards for detergent waste water.

Reliability of Biodegradation Measurements for Inhibitive Industrial Wastewaters

Industrial wastewaters may contain toxic or highly inhibitive compounds, which makes the measurement of biological oxygen demand (BOD) challenging. Due to the high concentration of organic compounds within them, industrial wastewater samples must be diluted to perform BOD measurements. This study focused on determining the reliability of wastewater BOD measurement using two different types of industrial wastewater, namely pharmaceutical wastewater containing a total organic carbon (TOC) value of 34,000 mg(C)/L and industrial paper manufacturing wastewater containing a corresponding TOC value of 30 mg(C)/L. Both manometric respirometry and the closed-bottle method were used in the study, and the results were compared. It was found that the dilution wastewaters containing inhibitive compounds affected BOD values, which increased due to the decreased inhibiting effect of wastewater pollutants. Therefore, the correct BOD for effluents should be measured from undiluted samples, while the diluted value is appropriate for determining the maximum value for biodegradable organic material in the effluent. The accuracy of the results from the blank samples was also examined, and it was found that the readings of these were different to those from the samples. Therefore, the blank value that must be subtracted may differ depending on the sample.

Recent trends and advances in microbial electrochemical sensing technologies: An overview

Microbial electrochemical systems utilize the electrochemical interaction between microorganisms and electrode surfaces to convert chemical energy into electrical energy, offering a promise as technologies for wastewater treatment, bioremediation, and biofuel production. Recently, growing research attention has been devoted to the development of microbial electrochemical sensrs as biosensing platforms. Microbial electrochemical sensors are a type of microbial electrochemical technology (MET) capable of sensing through the anodic or the cathodic electroactive microorganisms and/or biofilms. Herein, we review and summarize the recent advances in the design of microbial electrochemical sensing approaches with a specific overview and discussion of anodic and cathodic microbial electrochemical sensor devices, highlighting both the advantages and disadvantages. Particular emphasis is given on the current trends and strategies in the design of low-cost, convenient, efficient, and high performing METs with different biosensing applications, including toxicity monitoring, pathogen detection, corrosion monitoring, as well as measurements of biological oxygen demand, chemical oxygen demand, and dissolved oxygen. The conclusion provides perspectives and an outlook to understand the shortcomings in the design, development status, and sensing applications of microbial electrochemical platforms. Namely, we discuss key challenges that limit the practical implementation of METs for sensing purposes and deliberate potential solutions, necessary developments, and improvements in the field.

Development of a xurographically fabricated miniaturized low-cost, high-performance microbial fuel cell and its application for sensing biological oxygen demand

The rapid quantification of biological oxygen demand (BOD) plays an important role in environmental management, for instance, wastewater treatment. This study used xurographic fabrication technology to rapidly fabricate a low cost miniaturized microbial fuel cell (MFC) and demonstrated its suitability to measure BOD. The miniaturized sensor could be fabricated in 10 min with low cost of $0.5 U.S. per device. The reaction volume was designed to be 1.8 μL to obtain faster response time. The sensor was tested using sodium acetate (NaAc) as a model BOD analyte. It could response to a wide range of BOD concentration between 20 and 490 mg/L which would cover the majority range of wastewater BOD concentration in a wastewater treatment plant. The response time of this microsensor was 1.1 min which was significantly shorter than other conventional methods for BOD measurements (5 days). This study demonstrated that the use of xurographic methods to fabricate MFCs could enable rapid fabrication of microsensors to measure BOD in a rapid manner. This study also identified the potential of the sensor for application in wastewater treatment plants to monitor BOD and provide guidance for controlling treatment processes.

Reduction of BOD and COD of by using stratified filter and constructed wetland for blackwater treatment

Blackwater is a type of domestic wastewater that must be processed before discharge into the river. This study uses gravel, sand, and charcoal as filtration materials which arranged from coarse to fine, and also wetland system using Vetiver grass (Vetiveria zizanioides) and Cattail (Typha angustifolia). The treatment process is obtained by applying different treatments related to the sand thickness and blackwater residence time in the wetland. The focus of observation is emphasized on the measurement of BOD (Biological oxygen demand) and COD (Chemical oxygen demand). Both parameters measured and compared with the standard of water for agricultural purposes (Grade IV) regulated by Indonesian Government. The results showed that stratified filters can reduce the levels of BOD and COD effectively. The final results obtained after blackwater flowed through the wetland tube shows that BOD and COD levels have yet to meet the standard of grade IV water, although the overall result indicated the significant reduction of both parameters. This can be related to the input of organic matter from wetland itself, and it also can be considered an indication that blackwater treatment requires longer residence time.

Online total organic carbon (TOC) monitoring for water and wastewater treatment plants processes and operations optimization

Abstract. Organic measurements, such as biological oxygen demand (BOD) and chemical oxygen demand (COD) were developed decades ago in order to measure organics in water. Today, these time-consuming measurements are still used as parameters to check the water treatment quality; however, the time required to generate a result, ranging from hours to days, does not allow COD or BOD to be useful process control parameters – see (1) Standard Method 5210 B; 5-day BOD Test, 1997, and (2) ASTM D1252; COD Test, 2012. Online organic carbon monitoring allows for effective process control because results are generated every few minutes. Though it does not replace BOD or COD measurements still required for compliance reporting, it allows for smart, data-driven and rapid decision-making to improve process control and optimization or meet compliances. Thanks to the smart interpretation of generated data and the capability to now take real-time actions, municipal drinking water and wastewater treatment facility operators can positively impact their OPEX (operational expenditure) efficiencies and their capabilities to meet regulatory requirements. This paper describes how three municipal wastewater and drinking water plants gained process insights, and determined optimization opportunities thanks to the implementation of online total organic carbon (TOC) monitoring.

Dye Removal From Textile Waste Water Through The Adsorption By Pumice Used In Stone Washing

Abstract Because the waste production is inevitable in almost all industries, the elimination of these wastes is a requirement in terms of environmental regulations and welfare of all the creatures in the future. In this study, the use of the waste pumice stones of a denim washing mill is intended to eliminate the pollutant by a waste material and obtain economic benefits by converting it to the adsorbent. The pollutants in the effluents obtained from three different localisations of waste water treatment system of the same factory were removed through the adsorption. The experimental studies were carried out in three different steps; characterisation of adsorbent before and after adsorption; adsorption isotherm studies and biological oxygen demand (BOD), chemical oxygen demand (COD) measurements. Characterisation studies showed that the waste pumice has almost the same structural properties with unused one except the existence of some organic residues coming from washing process. The results of adsorption studies conducted at the adsorbent concentrations changing from 5 to 35 g/l revealed that the decolourisation was initial dye-concentration dependent. According to the BOD and COD measurements, the supernatants obtained at the end of adsorption could be assumed as somewhat polluted and this result indicates that the organic impurities other than indigo were also removed through the adsorption.

Long‐term variations in the dissolved oxygen budget of an urbanized tidal river: The upper Delaware Estuary

AbstractThe dissolved oxygen budget in the upper Delaware Estuary between 1970 and 2014 was inferred from oxygen concentration measurements using a box model approach. The region was found to be a net biogeochemical sink of oxygen, with net oxygen consumption greater in the tidal fresh portion than in the oligohaline portion. Net oxygen consumption decreased from the 1970s to the 1990s by roughly a factor of 2 before increasing slightly in the 2000s. The dramatic decline in oxygen consumption was presumably due to improvements in wastewater treatment, though a comparison with biological oxygen demand measurements in wastewater was equivocal. Nonalgal oxygen consumption (i.e., oxygen consumption due to heterotrophic respiration and nitrification) was computed as the sum of the estimated net oxygen consumption and historical measurements of primary production. Nonalgal oxygen consumption was found to be highly seasonal and positively correlated with temperature, with Q10 values ranging between 1.4 and 2.3. Annual nonalgal oxygen consumption was found to be several times annual primary production. Exchange with the atmosphere is the main process that balances the net oxygen consumption throughout the study region, with advection also an important process in the tidal fresh portion. Decadal scale variability in oxygen concentration, including the recent decline in the 2000s, appears to be mainly driven by biological, not physical, processes.

BOD monitoring problems

Problems resulting from the disagreement between Russian and World practices in the organization of biological oxygen demand monitoring being in disagreement with the up-to-date theoretical and experimental achievements. Proposals are put forward aimed to improve the implementation of measure-ments of biological oxygen demand in water bodies and the mathematical processing of the measurement results.

Interaction of Ferrocene Mediators with Gluconobacter oxydans Immobilized Whole Cells and Membrane Fractions in Oxidation of Ethanol

AbstractGluconobacter oxydans whole cells and membrane fractions in combination with ferrocene mediators were used to study oxidation of ethanol. The efficiency of mediatorenzyme interaction was assessed by the ratio of maximum current to the apparent Michaelis constant (Imax/KM) for saturating mediator concentrations. The bioelectrocatalytic processes were found to be more efficient with membrane fractions. The highest Imax/KM value of 120 and 3200 µA g/mol for, respectively, cells and fractions was obtained for ferrocene carboxylic acid. In test measurements of biological oxygen demand for rye distillers’ grains, the values obtained by a biosensor based on Gluconobacter membrane fractions and ferrocene were found to correlate with the reference data.

A detailed field-based evaluation of naphthenic acid mobility in groundwater

An anaerobic plume of process-affected groundwater was characterized in a shallow sand aquifer adjacent to an oil sands tailings impoundment. Based on biological oxygen demand measurements, the reductive capacity of the plume is considered minimal. Major dissolved components associated with the plume include HCO 3, Na, Cl, SO 4, and naphthenic acids (NAs). Quantitative and qualitative NA analyses were performed on groundwater samples to investigate NA fate and transport in the subsurface. Despite subsurface residence times exceeding 20 years, significant attenuation of NAs by biodegradation was not observed based on screening techniques developed at the time of the investigation. Relative to conservative tracers (i.e., Cl), overall NA attenuation in the subsurface is limited, which is consistent with batch sorption and microcosm studies performed by other authors. Insignificant biological oxygen demand and low concentrations of dissolved As (< 10 µg L − 1 ) in the plume suggest that the potential for secondary trace metal release, specifically As, via reductive dissolution reactions driven by ingress of process-affected water is minimal. It is also possible that readily leachable As is not present in significant quantities within the sediments of the study area. Thus, for similar plumes of process-affected groundwater in shallow sand aquifers which may occur as oil sands mining expands, a reasonable expectation is for NA persistence, but minimal trace metal mobilization.

Are Oxygen Demands Relevant for Today's Environmental Assessment of Detergents?

AbstractThough oxygen demands are critical measurements for waste water treatment plant operation and water quality management, they are of little relevance to assess or rank the environmental quality of detergents. It is argued that: (1) No accurate measurements of the oxygen demand of bleach detergents can be made, because these products release oxygen during the measurement. (2) When waste water is adequately treated, under normal operating conditions the oxygen demand (organic loading) of the raw sewage has no influence on river quality. (3) Oxygen demand values are narrowly focused on environmental exposure, while they do not take into account the potential for ecotoxicological effects. (4) Short-term biological oxygen demand measurements are useful for the monitoring of ‘average sewage', but they are unreliable to assess the biodegradability of more specific substances or products. Instead of oxygen demands, more holistic evaluations based on risk assessment or on life cycle analysis are scientifically preferred.

Rapid monitoring of the biodegradation of phenol-like compounds by the yeast Candida maltosa using BOD measurements

Abstract Since phenol-like compounds can have serious environmental effects, microbiological and biochemical features of their aerobic degradation are of great interest, and monitoring oxygen uptake can give valuable data about the processes involved. It is shown here that the AQUALYTIC® Sensomat System can provide reliable, continuous measurement of biological oxygen demand (BOD), and is suitable for small-scale studies of the degradation of phenol-like compounds by the soil-borne yeast Candida maltosa. It was found that C. maltosa can use phenol and catechol as sole sources of carbon and energy at concentrations up to 1.7 g l −1 and 1.5 g l −1 , respectively, and it is unaffected by resorcinol, even at 2 g l −1 . It can also co-metabolise p-cresol, but cannot utilise benzoate or salicylate. These results may have practical implications for the use of C. maltosa in soil bioremediation, e.g. in bioventing. Enzyme tests were also performed to help interpret the data. Phenol hydroxylase activity reached maximum levels at the beginning of the exponential phase during cultivation on phenol. After the phenol had been completely utilised, the enzyme was slowly degraded.

Conventional, confocal and two-photon fluorescence microscopy investigations of polymer-supported oxygen sensors.

Luminescence-based, polymer-supported oxygen sensors, particularly those based on platinum group complexes, continue to be of analytical importance. Commercial applications range from the macroscopic (e.g. aerodynamic investigations in wind tunnels, monitoring of oxygen concentration during fermentation, and measurement of biological oxygen demand) to the microscopic (e.g. imaging of oxygen in blood, tissue, cells and other biological samples). Problems hindering the design of improved oxygen sensors include non-linear Stern-Volmer calibration plots and the multi-exponentiality of measured lifetime decays, both of which are attributed primarily to heterogeneity of the sensor molecule in the polymer support matrix. Conventional, confocal and two-photon fluorescence microscopy have proven to be invaluable tools with which the microscale heterogeneity and response of luminescence-based oxygen sensors can be investigated and compared to the macroscopic response. Results obtained for three ruthenium(II) alpha-diimine complexes in polydimethylsiloxane polymer supports indicate the presence of unquenched microcrystals within the polymer matrix that probably degrade oxygen quenching sensitivity and linearity of the Stern-Volmer quenching plot. Two-photon fluorescence microscopy proved most useful for imaging microcrystals within sensor films, and conventional microscopy allowed direct comparison between microscopic and macroscopic sensor response. The implications of the results in the rational design and mass production of luminescence-based oxygen sensors are significant.

A Comparison of Manometric and Membrane-Electrode Procedures for Measuring Rates of Leaf Decay

Two instruments were compared for consistency of decay-rate measurements of four leaf types: Lolium perenne, Typha domingenesis, Casuarina cunninghamiana and Eucalyptus polyanthemos, via progressive biological oxygen demand (BOD). The instruments were (a) a dissolved oxygen probe (i.e. an oxygen-selective membrane electrode) used in two different modes: (1) measurements of sacrificial samples that were successively discarded, and (2) repeated measurements of the same sample, and (b) a mercury free manometer. Measurements of D-glucose:glutamic acid standards were similar for both instruments, and corresponded with values expected after five days of decay. During five days decay of the four leaf types, progressive measurements obtained by both applications of the dissolved oxygen probe were similar, and could be related linearly. Progressive leaf-decay measurements obtained by the manometer and dissolved oxygen probe could be related linearly also. Decay measurements obtained by both instruments were nearly identical for C. cunninghamiana and E. polyanthemos, but there were slight differences in the slopes of linear relationships for L. perenne and T. domingenesis. These comparisons indicate the feasibility of using both instruments for obtaining comparable measurements of leaf decay rates. It is also feasible to briefly reopen the same glass bottle to facilitate temporal BOD measurements with the dissolved oxygen probe. However, because slight differences in decay rates were evident in two comparisons, care should be exercised to derive and verify the association of data between instruments.