Biochemical Oxygen Demand Parameters Research Articles

Analisis daya tampung beban pencemaran sungai bedadung Jember menggunakan software wasp

The distribution of pollution sources from domestic, agricultural, and industrial activities has the potential to reduce the water quality of the Bedadung River, thereby negatively impacting its self-purification. The aim of this research is to model the parameters, specifically the values of Biochemical Oxygen Demand (BOD) and Total Suspended Solid (TSS), and to determine the river's capacity to carry the pollution load using the Water Quality Analysis Simulation Program (WASP). The input parameters for this study include BOD, TSS, and water discharge data collected at 21 monitoring points along the Bedadung River, with the river water sampling technique employing the grab sampling method. The output validation of the modeling is assessed using the Root Mean Square Error (RSME) equation, and the research results indicate that the water quality modeling with WASP software effectively reflects the dynamics of BOD and TSS parameters in the Bedadung River, as supported by an average output validation value of 9%. The pollution load capacity values for the Bedadung River in the Patrang - Ajung segment are found to be 361.48 kg/day for BOD and 5368.31 kg/day for TSS. The positive values suggest that the Bedadung River still has the capacity to naturally degrade organic pollutants.

Modelling of Pollutant Transport in Yamuna River from the Najafgarh Drain, NCT Delhi Using Matlab Software

When the river Yamuna leaves the National Capital Territory of Delhi, its situation further deteriorates. Despite accounting for only 1% of the river’s overall catchment area, this region is responsible for more than half of the pollutants discovered in the Yamuna. The river Yamuna, on the other hand, is Delhi’s only natural resource for maintaining all forms of life. The Yamuna River is currently experiencing a significant level of pollution problem, and in order to control pollution in the Yamuna River, continual analysis is essential. The Yamuna River is contaminated by the discharge of untreated municipal sewage and industrial effluent through seven major drains: Najafgarh, Yamunapur, Sen Nursing Home, Barathpula, Maharani Bagh, Kalkaji, and Tuglakabad. In terms of people and chemicals, continuous sampling takes time and money. The primary objective of this study is to analyse the wastewater samples collected by sub-drains and STP’s to predict the pollutant transportation in river Yamuna from Najafgarh Drain. The study focusses on the only pollutant, i.e., Biochemical Oxygen Demand from the starting point to after the confluence of Najafgarh Drain into river Yamuna. The prediction is to be done by using MATLAB software. This study would help to identify the main sources of sub-drains which are polluting Najafgarh Drain and eventually the river Yamuna. This shows how MATLAB may be used to calculate the pollution load caused by organic waste in the Yamuna River as it flows through Delhi, India’s National Capital Territory. The model numerically solves a series of differential equations to simulate the dissolved oxygen and biochemical oxygen demand parameters in two dimensions. MATLAB is an interactive programming language that may be used to develop algorithms, graphics, and user interfaces in other computer languages. MATLAB helps estimate future water quality using present data, which saves time, labour, and other costs associated with the continuous study. There are various software programmes available in the market for predicting river water quality, however, MATLAB GUI provides an accessible and convenient user interface (Graphical User Interface).

EFEKTIVITAS ARANG AKTIF CANGKANG KEMIRI (Aleuritas molaccanu) UNTUK PENGOLAHAN LIMBAH TEMPE

This study aims to determine the effect of giving candlenut shell activated charcoal using the parameters BOD (Biochemical Oxygen Demand), TSS (Total Suspended Solid), and pH (power of hydrogen) in tempe waste. The research uses quantitative methods, the type of research is experimental and laboratory observation. The research sample consisted of tempe waste and candlenut shell activatedcharcoal. The data analysis technique consisted of calculating the effectiveness and efficiency of removal, as well as the Kruskal-Wallis statistical test. The results showed that activated charcoal of candlenut shells could reduce BOD and TSS levels in tempe waste. In addition, it can increase the pH of tempe wastewater to normal (pH = 7). Overall, the BOD parameters are still in normal conditionsand have not passed the predetermined threshold. The removal efficiency of activated charcoal from candlenut shells on BOD, TSS, and pH levels in tempe waste as a whole increased. The results of the Kruskal-Wallis H test for the BOD parameter obtained a significant value (Asymp. Sig.) of 0.083 > 0.05. TSS obtained a significant value (Asymp. Sig.) of 0.881 > 0.05. pH obtained a significant value (Asymp. Sig.) of 0.351 > 0.05. Thus, H0 is accepted or there is no significant (significant) difference in the ability of candlenut shell activated charcoal to BOD, TSS, and pH levels in tempe waste. This is because the samples used in laboratory tests on tempeh waste are still small, only repeated twice, the weight of the candlenut shell activated charcoal is only 5 grams and 10 grams, respectively.The conclusion shows that there is a decrease caused by giving candlenut shell activated charcoal using BOD (Biochemical Oxygen Demand) and TSS (Total Suspended Solid) parameters, as well as making the pH (power of hydrogen) neutral (pH 7) in tempe waste.

Analysis of Water Quality Trends Using the Mann-Kendall Test and Sen’s Estimator of Slope in a Tropical River Basin

Trends in water quality, either increasing or decreasing over the long term, are becoming an essential guide to understanding water quality. This study aims to analyse the trends in water quality in the upstream part of the Bernam River Basin, Malaysia from 1998 to 2018. This study involved the collection of data on water quality from the Department of Environment, Malaysia. Six main parameters of the water quality index (WQI) were chosen, including the dissolved oxygen (DO), biochemical oxygen demand (BOD), chemical oxygen demand (COD), ammoniacal nitrogen (NH3-N), total suspended solids (TSS) and pH. The analysis methods applied are the Mann-Kendall test and Sen’s estimator of slope. The results of the WQI value trend analysis revealed that most stations have decreasing trends. A trend analysis of the parameters found that most stations had increasing trends for the DO, BOD, NH3-N and pH parameters, while decreasing trends for the COD and TSS parameters were observed. An increasing trend indicated that the water quality parameters were getting better, and a decreasing trend indicated the opposite. This study will benefit the parties responsible for planning and monitoring developments to reduce water pollution around the upstream Bernam River Basin. In the upstream of Bernam River Basin, land use changes have occurred rapidly, especially forest areas have been explored for human settlements, agricultural and industrial activities. Thus, the sustainability of the river basin can be maintained and valued by the various parties in the future. The river basin is also important as a domestic water supply for the residents of Selangor and Perak.

Determination of water quality in Universiti Malaysia Sabah (UMS), Kota Kinabalu: The effectiveness of stormwater management systems

Universiti Malaysia Sabah (UMS) campus in Kota Kinabalu consists of a large detention pond that stores the stormwater and limits the outflow rate into Likas' estuary. It is no doubt the detention pond has been designed per the Urban Stormwater Management Manual (USMM) requirement in terms of quantity control, however rapid development and changes in surrounding landscapes may affect the water quality. This study investigates the stormwater quality from the UMS detention pond and drainages within the campus. Water sampling was primarily taken during the dry period to justify worst-case scenarios without dilution from the rainfall season. Then the water quality parameters were tested using standard laboratory procedures mainly for Biochemical Oxygen Demand (BOD), Ammoniacal Nitrogen (AN), and Total Suspended Solids (TSS) with a minimum of a triplicate experimental run at the Environmental Laboratory, Faculty of Engineering, UMS. The determined water quality was compared with the National Water Quality Standards (NWQS) from the Department of Environment Malaysia. Overall the stormwater quality obtained for Dissolved Oxygen (DO), Chemical Oxygen Demand (COD), AN and pH is within Class II to III, which is slightly polluted. However, the TSS from ponds near to main road and construction areas exceeds Class IV, indicating polluted conditions. There is a slight increase for BOD and AN parameters when comparing samples between June 2020 (post-MCO) and January 2017, which was suspected briefly due to fertilizing work for the campus landscapes. Although the TSS value is low, the TSS volume would increase over a period, raising the temperature while reducing the DO concentration and endanger the aquatic species and the ecosystem. Hence, it is recommended for a future study to emphasize TSS value as it would contribute significantly in designing sustainable stormwater management, particularly for the stormwater treatment, such as when optimizing for the utilization of alternative filter media, which reduces the maintenance and increasing the lifespan of the system.

Assessment of water quality in coastal estuaries under the impact of an industrial zone in Hai Phong, Vietnam

The purpose of this study was to apply numerical modeling to assess the water quality in Nam Trieu and Lach Tray coastal estuaries. The wind reanalysis data from the Weather Research and Forecasting (WRF) Model were used to simulate waves and hydrodynamic regimes with a definition of 14 km within the longitude range from 105oE to 120oE and latitude range from 5° to 22° in the study area. The calibration and validation results for the wind–wave, hydrodynamic regimes showed that the performance of the 2D hydrodynamic model is extremely good, with a Nash coefficient ranging from 0.89 to 0.92, a root–mean–square error (RMSE) observation standard deviation ratio (RSR) varying from 0.25 to 3.6, and a percent bias (PBIAS) from −4.2% to 0.2%. The calibrated 2D hydrodynamic model was combined with the Ecolab model to evaluate and simulate the spreading of water quality parameters (biochemical oxygen demand (BOD), NH4+-N, and total suspended solids (TSS)). The water quality parameters BOD (16.5–22.5 mg/l), NH4+-N (0.003–0.009 mg/l), and TSS (29.63–40.8 mg/l) were smaller than the parameters of the national technical regulation on coastal water quality and surface water quality in March and August. The assessment results of water quality an industrial zone can help in management, planning, and decision–making to reduce wastewater discharge.

Spatial Analysis of Water Pollution using Multitemporal Satellite Imagery (Case Study: River Lamong Estuary, Surabaya)

Water is a natural resource that has a very important function for human life and promotes the welfare of humanity itself. Water is also the important component of the environment for the survival and life of humans and other living beings. It’s necessary to manage and control water pollution wisely by considering the ecological balance. On the border of the Surabaya and Gresik, there’s an industrial center located on the north coast of Surabaya. River Lamong is estimated to have water quality degradation problems due to growing numbers of industries in River Lamong and factory wastes flowing downstream. By looking at the condition, it’s suspected that there is pollution in River Lamong. Conditions of water pollution can be indicated through several parameters such as the physical parameter, chemical parameter, and biological parameter. Physical parameters that can be observed include temperature, dissolve residue, and suspended residue (TSS). As for the chemical parameters such as pH, BOD (Biochemical Oxygen Demand), (COD) Chemical Oxygen Demand (COD), and other metal content. The result of this study indicates that there are polluted points based on BOD parameters at 4 points.

Effect of Monsoon Flood to Groundwater Quality in Kuala Krai, Kelantan, Malaysia

Evaluation of water sources quality plays an important role during floods especially the groundwater. This study aimed to assess the effect of floods on the quality of groundwater in Kuala Krai. Six sampling stations were selected involving six main parameters, namely dissolved oxygen (DO), pH, biochemical oxygen demand (BOD), chemical oxygen demand (COD), total suspended solids (TSS) and ammonia nitrogen (NH3N). The assessment was conducted according to the Interim National Water Quality Standards Malaysia (INWQS) and the water quality index (WQI) classification, which has been established by the Department of Environment (DOE). The study found that flooding could affect groundwater quality, especially the DO, pH and BOD parameters. Based on WQI classification, most of well water stations are in Class III which is moderately polluted except the T6 station which is in Class II with clean status. This condition shows that the quality of groundwater in Kuala Krai is in the moderately polluted category and a full treatment is required for drinking water supply, especially during flooding events.

Kondisi Fisika Kimia Air Sungai Yang Bermuara di Teluk Sawaibu Kabupaten Manokwari

Penelitian ini dilakukan di tiga sungai kecil (Momo, Sahara dan Konto) yang bermuara di Teluk Sawaibu Kabupaten Manokwari. Pengambilan sampel air untuk ketiga stasiun pengamatan dilakukan untuk pengukuran parameter fisik yaitu suhu, TDS, TSS dan kekeruhan, dan parameter kimia pH, DO, COD, BOD, Nitrat (NO3), Fosfat (PO4) dan Amonia. Tujuan dari penelitian ini adalah mengetahui kualitas fisik kimia air sungai dari lokasi penelitian, dan dibandingkan dengan baku mutu kualitas air berdasarkan Peraturan Pemerintah nomor 82 tahun 2001 tentang pengelolaan kualitas air dan pengendalian pencemaran air. Hasil pengukuran parameter fisik dan kimia adalah kisaran suhu dari tiga stasiun pengamatan berkisar antara 26,6 - 31°C, kekeruhan berkisar 0,17-49,7 NTU. Padatan Terlarut Total (TDS) 134 - 317 mg/l. Padatan Tersuspensi Total 14 – 96 mg/l. pH berkisar antara 6,69 – 7,78. DO (Dissolved Oxygen) 0,03–6,22 mg/l. COD (Chemical Oxygen Demand) <4,99 – 27,75 mg/l, BOD (Biochemical Oxygen Demand) 0,60 – 6,31 mg/l, Nitrat (NO3-N) 0,013 – 0,251 mg/l, Fosfat (PO4) 0,013 – 0,243 mg/l dan Amonia (NH3) 0,051 – 0,346 mg/l.

Soft Measurement Modeling Based on Chaos Theory for Biochemical Oxygen Demand (BOD)

The precision of soft measurement for biochemical oxygen demand (BOD) is always restricted due to various factors in the wastewater treatment plant (WWTP). To solve this problem, a new soft measurement modeling method based on chaos theory is proposed and is applied to BOD measurement in this paper. Phase space reconstruction (PSR) based on Takens embedding theorem is used to extract more information from the limited datasets of the chaotic system. The WWTP is first testified as a chaotic system by the correlation dimension (D), the largest Lyapunov exponents (λ1), the Kolmogorov entropy (K) of the BOD and other water quality parameters time series. Multivariate chaotic time series modeling method with principal component analysis (PCA) and artificial neural network (ANN) is then adopted to estimate the value of the effluent BOD. Simulation results show that the proposed approach has higher accuracy and better prediction ability than the corresponding modeling approaches not based on chaos theory.

Fractal, predictability index and variability in trends analysis of river-water dynamics

ABSTRACTStatistical modelling, analysis of physico-chemical parameters chemical oxygen demand (COD), biochemical oxygen demand (BOD), dissolved oxygen (DO), water temperature (WT), free ammonia (AMM), total Kjeldahl nitrogen (TKN), total coliform (TC), fecal coliform (FC) and potential of hydrogen (pH) monitored at the Hathnikund barrage (Haryana) sample site of river Yamuna in India have been studied. It has been observed that water-quality parameters such as COD-BOD, AMM-TKN, WT-pH and TC-FC are positively correlated whereas COD-DO, BOD-DO, TKN-FC and DO-WT are negatively correlated. For water-quality parameters such as pH, AMM, TC and FC no seasonal pattern is observed. Parameters such as COD, BOD, TKN, DO and WT follow a six-month seasonal pattern. All the parameters except DO and WT follow a positive trend for monthly and annual variations. BOD, AMM and TKN have anti-persistence behaviour for both monthly and yearly variations. For parameters COD (+27.83%), BOD (+42.36%), AMM (+49.63%), TKN (+22.71%), TC (+141.80%) and FC (+42.89%) the future trend remains positive with high variability. WT (−7.47%) follows a negative trend with low variation and DO (−17.12%) has a negative trend with lofty variation. Using fractal, predictability index and variability in trend analysis, it is concluded that all parameters, except pH and WT, cross the prescribed limits of WHO/EPA and if the same trend should be followed, then in the future the quality of water shall continuously deteriorate and water may not be fit for drinking, agriculture and industrial use.

Evaluation of the efficiency of selected wastewater treatment plant

This paper is focused on primary, secondary, and total efficiency evaluation of the wastewater treatment process for chosen small wastewater treatment plant (WWTP) located near the Moravian Karst. Eight wastewater samples were taken during one year in three sampling profiles of WWTP: biochemical oxygen demand (BOD), chemical oxygen demand (COD), suspended solids (SS), pH, ammonia nitrogen (N-NH4), nitrite nitrogen (N-NO2), nitrate nitrogen (N-NO3), inorganic nitrogen (Ninorg), total phosphorus (Ptotal). Treatment efficiency by reduction was calculated for all laboratory analyzed indicators and average values were determined for the whole period. Calculated treatment efficiency of indicators BOD, COD and suspended solids was compared with the permissible minimum treatment efficiency of discharged waste water by Government Regulation No. 61/2003 Coll., for the WWTP from 500 to 2 000 PE. Permissible minimum treatment efficiency is not legislatively determined for the primary and secondary level. The results of the work will be used especially to compare results with other similar works.Analyzed values ​​of parameters BOD, COD, suspended solids, N-NH4 at the outflow from wastewater treatment plant were compared with the permissible maximum values at the outflow of the WWTP which the municipality has an obligation to respect according to the decision issued by the District Environment Authority.

The comparison of different mathematical methods to determine the BOD parameters, a new developed method and impacts of these parameters variations on the design of WWTPs

One of the most common tests for the determination of strength and organic content of wastewater is the biochemical oxygen demand (BOD). This test is widely applied to define organic water pollution and to control the performance of wastewater treatment plants. Generally, BOD is standardized by the measurement of oxygen consumption in 5days (BOD5). But, determination of the ultimate biochemical oxygen demand (BODu), which is taken 28days and the reaction rate constant (k) are necessary to understand the organic strength of the wastewater. In this study, the different mathematical methods in order to determine the BOD parameters (BODu, k) and two different BOD test method (respirometer and dilution method) are investigated comparatively. Also, a new method based on cubic spline method to estimate ultimate BOD values is developed. Moreover, the impacts of BOD parameters on the design of an activated sludge and aerated lagoon systems are analyzed by using a written user-friend program, which is developed for designing WWTPs by the mean of C++ programming language.Analytical results show that there is a satisfactory linear relationship between respirometric and dilution BOD values. Also, the mathematical methods, including new developed method generally provide consistent results with high correlation coefficients. On the other hand, it is found that LOG differences method for respirometric test and the new developed method for dilution test do not give good correlation coefficients. Moreover, activated sludge and aerated lagoons systems’ sizes show significant changing depending on the variations of the BOD parameters. Consequently, BOD parameters show significant changes depending on the different test and mathematical methods. Therefore, the changing of these parameters impact a lot of situation such as ultimate BOD estimation, the wastewater treatment plants design, the dimensions of the plants and cost of the plants.

Wavelet and statistical analysis of river water quality parameters

Statistical and wavelet analysis of water quality parameters COD (chemical oxygen demand), BOD (biochemical oxygen demand), DO (dissolved oxygen), WT (water temperature), AMM (free ammonia), TKN (total kjeldahl nitrogen), TC (total coliform), FC (fecal coliform) and pH (potential of hydrogen) monitored at Nizamuddin bridge-mid stream (Delhi) of Yamuna River in India have been studied. It has been observed that COD is highly correlated with BOD, AMM and TKN. Daubechies wavelet at level 5 (Db5) have been calculated for each water quality parameters as it gives the finer scale approximation and decomposition of each water parameters. Wavelet decomposition and approximation using Db5 of each parameters presented in seven parts namely s, a5, d1, d2, d3, d4 and d5 where “s” represents signal or raw data; low frequency part “a5” gives an approximate of signal at level 5; high frequency parts d1, d2, d3, d4 and d5 contains the detail of “s” at different levels respectively.

Analysis of Water Parameters Using Daubechies Wavelet (Level 5) (Db5)

Statistical analysis of the water quality parameters COD (Chemical Oxygen Demand), BOD (Biochemical Oxygen Demand), DO (Dissolved Oxygen), WT (Water Temperature), AMM (Free Ammonia), TKN (Total Kjeldahl Nitrogen), TC (Total Coliform), FC (Fecal Coliform) and pH (Potential of Hydrogen) monitored at Hathni Kund Dam (Haryana) Yamuna River in India have been studied. It has been observed that water quality parameter have positive correlation between COD-BOD; AMM-TKN; WT-pH; TC-FC; and negatively correlation between COD-DO; BOD-DO; TKN-FC; DO-WT. Discrete wavelet analyses of water quality parameter using Daubechies wavelet at level 5 have been calculated. It has been observed that the values of signal data at five different levels for AMM, BOD, COD, DO, FC, pH, TC, TKN, WT varies between -1 to 1, -2 to 2, -20 to 20, -2 to 2, -5 to 5, -1 to 1, -2 to 2, -5 to 5, -10 to 10 respectively.

Biochemical Oxygen Demand Relationships in Typical Agricultural Effluents

Understanding the variables controlling biochemical oxygen demand (BOD) of effluents from agricultural systems is essential for predicting and managing the water quality risks associated with agricultural production. In this study, short- and long-term oxygen demand behaviors of waters from primarily agricultural sources and their relationships with other parameters were evaluated. A total of 46 water samples were generated from diverse organic sources commonly associated with agricultural activities and analyzed for BOD and other various water quality parameters. Short-term BOD (BOD2 and BOD5) were significantly correlated with total organic carbon (TOC), particulate organic carbon (POC), and dissolved organic carbon (DOC) (R 2 = 0.62–0.77, p < 0.001), likewise to total nitrogen, total Kjeldahl nitrogen, and nitrite–nitrogen (NO2–N) (R 2 = 0.40–0.55, p < 0.001). Long-term BOD (BOD60) was generally poorly correlated with these C and N fractions. Phosphate (PO4–P) exhibited a positive and linear relationship with both short- and long-term BOD, whereas chloride (Cl) tended to inhibit oxygen demand. Multivariate combinations of each of TOC, POC, and DOC with NO2–N, and Cl or PO4–P improved the predictions of both short- and long-term BOD. The ultimate BOD (BODu) derived from the first-order kinetics was highly correlated with BOD60 (R 2 = 0.81, p < 0.001) whereas BOD60 was correlated with BOD5 (R 2 = 0.60, p < 0.001). Overall the results indicated that C and N forms along with PO4–P and Cl were the dominant factors controlling the oxygen demand behaviors of agricultural effluents.

DO-BOD modeling of River Yamuna for national capital territory, India using STREAM II, a 2D water quality model

The study illustrates the utility of STREAM II as a modeling package to determine the pollution load due to organic matter in the River Yamuna during its course through the National Capital Territory that is Delhi, India. The study was done for a period from 1995-2005. Model simulates the dissolved oxygen and biochemical oxygen demand parameters in a two-dimensional fashion by performing the numerical solution to a set of differential equations representing aquatic life with the help of Crank-Nicholson finite difference method. The model was simulated and calibrated through the field water-quality primary data and the secondary data which were taken from Central Pollution Control Board. The main reasons for the high river pollution is increasing population of Delhi and other states, leading to generation of huge amounts of domestic sewage into the river Yamuna. The model gave a good agreement between calibrated and observed data, thus, actualizing the validity of the model. However, discrepancies noticed during model calibrations were attributed to the assumptions adopted in the model formulation and to lack of field data.

What is SPC?

The purpose of this study was to apply numerical modeling to assess the water quality in Nam Trieu and Lach Tray coastal estuaries. The wind reanalysis data from the Weather Research and Forecasting (WRF) Model were used to simulate waves and hydrodynamic regimes with a definition of 14 km within the longitude range from 105oE to 120oE and latitude range from 5° to 22° in the study area. The calibration and validation results for the wind–wave, hydrodynamic regimes showed that the performance of the 2D hydrodynamic model is extremely good, with a Nash coefficient ranging from 0.89 to 0.92, a root–mean–square error (RMSE) observation standard deviation ratio (RSR) varying from 0.25 to 3.6, and a percent bias (PBIAS) from −4.2% to 0.2%. The calibrated 2D hydrodynamic model was combined with the Ecolab model to evaluate and simulate the spreading of water quality parameters (biochemical oxygen demand (BOD), NH4+-N, and total suspended solids (TSS)). The water quality parameters BOD (16.5–22.5 mg/l), NH4+-N (0.003–0.009 mg/l), and TSS (29.63–40.8 mg/l) were smaller than the parameters of the national technical regulation on coastal water quality and surface water quality in March and August. The assessment results of water quality an industrial zone can help in management, planning, and decision–making to reduce wastewater discharge.

Analysis of metal cations and inorganic anions in olive oil mill waste waters by atomic absorption spectroscopy and ion chromatography. Detection of metals bound mainly to the organic polymeric fraction.

Metal cations were quantitatively detected by atomic absorption spectrometry in samples of olive oil mill waste waters obtained by a pressure process (omww(1)) (K, 17.1; Mg, 2.72; Ca, 2.24; Na, 0.40; Fe, 0.123; Zn, 0.0630; Mn, 0.0147; Cu, 0.00860 g L(-)(1)) and a centrifugation process (omww(2)) (K, 9.80; Mg, 1.65; Ca, 1.35; Na, 0. 162; Fe, 0.0330; Zn, 0.0301; Mn, 0.00910; Cu, 0.00980 g L(-)(1)). The inorganic anions, determined in the same samples by ion chromatography, proved to be Cl(-), H(2)PO(4)(-), F(-), SO(4)(2)(-), and NO(3)(-) (1.61, 1.05, 0.66, 0.52, and 0.023 g L(-)(1), respectively, in omww(1) and 0.61, 0.40, 0.25, 0.20, and 0.0090 g L(-)(1), respectively, in omww(2)). Most of the metal cations were revealed to be bound to the omww organic polymeric fraction (opf), composed of polysaccharides, phenol polymers, and proteins. Opf relative molecular weight was substantially estimated in the range between 1000 and 30000 Da for approximately 75% and in the range from 30000 to 100000 Da for approximately 25%. The free residual cations pool proved to be neutralized by the inorganic counteranions. Finally, the possible exploitation of this material in agriculture and in environmental biotechnology processes is also discussed in the light of its chemical and biochemical oxygen demand parameters.

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.