Variations In Wastewater Composition Research Articles

Mathematical Modeling of a Domestic Wastewater Treatment System Combining a Septic Tank, an Up Flow Anaerobic Filter, and a Constructed Wetland

Systems combining anaerobic bioreactors with constructed wetlands (CW) have proven to be adequate and efficient for wastewater treatment. Detailed knowledge of removal dynamics of contaminants can ensure positive results for engineering and design. Mathematical modeling is a useful approach to studying the dynamics of contaminant removal in wastewater. In this study, water quality monitoring was performed in a system composed of a septic tank (ST), an up flow anaerobic filter (UAF), and a horizontal flow constructed wetland (HFCW). Biological oxygen demand (BOD5), chemical oxygen demand (COD), total Kjeldahl nitrogen (TKN), NH3, organic nitrogen (ON), total suspended solids (TSS), NO2−, and NO3− were measured biweekly during a 3-month period. First-order kinetics, multiple linear regression, and mass balance models were applied for data adjustment. First-order models were useful to predict the outlet concentration of pollutants (R2 > 0.87). Relevant multiple linear regression models were found, which could be applied to facilitate the system’s monitoring and provide valuable information to control and improve biological and physical processes necessary for wastewater treatment. Finally, the values of important parameters (μmax, Ks, and Yx/s) in mass-balance models were determined with the aid of a differential neural network (DNN) and an optimization algorithm. The estimated parameters indicated the high robustness of the treatment system since performance stability was found despite variations in wastewater composition.

Microalgae production in wastewater treatment systems, anaerobic digestion and modelling using ADM1

An integrated microalgae-based system for urban wastewater treatment, microalgae production and bioenergy generation through anaerobic digestion was evaluated over a period of one year. The pilot HRAP was effective at removing COD (~80%) and ammonium (~95%) and robust, despite common variations in wastewater composition and weather conditions in the Mediterranean region. Biomass production showed a strong seasonality, reaching an annual average of 10gTSS/m2·day and the highest values in spring (23gTSS/m2·day). Conversely, the macromolecular composition was fairly constant (58% proteins, 22% carbohydrates and 20% lipids). Predominant microalgae species varied throughout the year, influencing biogas production. Indeed, the anaerobic biodegradability of harvested biomass was 20–25% in July–October 2012 and May–July 2013 and 25–38% in November 2012–April 2013. Adapting the content of particulate inert COD in Anaerobic Digestion Model No. 1 (ADM1) was crucial for model calibration. After adjustment, ADM1 was able to predict microalgae anaerobic digestion performance, which showed an average methane yield of 0.09LCH4/gCOD at 15days HRT and 0.16LCH4/gCOD at 20days HRT.

Variations in wastewater composition in the water use system of Kovdorskii mining-and-processing integrated works

Variations in wastewater composition in the case of seepage through levees bounding treatment facilities as a function of the composition of dump rock and recirculation water of the concentrating mill. The character and degree of pollutant leaching is established as a function environmental pH. Measures for mitigating the adverse impact of the interaction between disintegrated tailing dumps and rock-forming overburden with the recirculation water of tailing dump on water resources of the area of production activity of the Kovdor Mining-and-Processing Integrated Works (MPIW)

Chemometric data analysis of pollutants in wastewater—a case study

In this study, chemometric techniques such as cluster analysis (CA), discriminant analysis (DA), principal component analysis (PCA) and partial least squares (PLS) were used to analyse the wastewater dataset to identify the factors which affect the composition of sewage of domestic origin, spatial and temporal variations, similarity/dissimilarity among the wastewater characteristics of cis- and trans-drains and discriminating variables. Samples collected from 24 wastewater drains in Lucknow city and from three sites on Gomti river in the month of January/February, May, August and November during the period of 5 years (1994–1999) were characterized for 32 parameters. The multivariate techniques successfully described the similarities/dissimilarities among the sewage drains on the basis of their wastewater characteristics and sources signifying the effect of routine domestic/commercial activities in respective drainage areas. Spatial and seasonal variations in wastewater composition were also determined successfully. CA generated six groups of drains on the basis of similar wastewater characteristic. PCA provided information on seasonal influence and compositional differences in sewage generated by domestic and industrial waste dominated drains and showed that drains influenced by mixed industrial effluents have high organic pollution load. DA rendered six variables (TDS, alkalinity, F, TKN, Cd and Cr) discriminating between cis- and trans-drains. PLS–DA showed dominance of Cd, Cr, NO 3, PO 4 and F in cis-drains wastewater. The results suggest that biological-process based STPs could treat wastewater both from the cis- as well as trans-drains, however, prior removal of toxic metals will be required from the cis-drains sewage. Further, seasonal variations in wastewater composition and pollution load could be the guiding factor for determining the STPs design parameters. The information generated would be useful in selection of process type and in designing of the proposed sewage treatment plants (STPs) for safe disposal of wastewater.

Lab and pilot scale tests as tools for upgrading - comparison with full scale results

Parameters such as hydraulic retention time, organic load, maximum COD removal, sludge characteristics and optimal nutrient dosage can be determined by simulation in small scale models of the chosen process. Laboratory tests are the natural first step when considering upgrading, or designing a new, biological treatment plant. The potential for a biological treatment can be examined at a low cost and within a minimum of time, often through parallel testing of different treatment methods. Once a suitable process configuration has been found, lab scale tests may well be used for optimizing the process and obtaining design data, thus minimizing the need for more expensive tests in larger scale. The principal reason for a pilot plant test is the possibility to investigate natural variations in wastewater composition and the effect this will have on process stability. The use of laboratory and pilot scale tests is here illustrated by the work carried out prior to the upgrading of the treatment plant at Nyboholm paper mill. A description of the upgraded full scale installation consisting of both chemical treatment and a suspended-carrier biofilm process is included and a comparison between results from lab, pilot and full scale treatment is made.

Lab and pilot scale tests as tools for upgrading — Comparison with full scale results

Parameters such as hydraulic retention time, organic load, maximum COD removal, sludge characteristics and optimal nutrient dosage can be determined by simulation in small scale models of the chosen process. Laboratory tests are the natural first step when considering upgrading, or designing a new, biological treatment plant. The potential for a biological treatment can be examined at a low cost and within a minimum of time, often through parallel testing of different treatment methods. Once a suitable process configuration has been found, lab scale tests may well be used for optimizing the process and obtaining design data, thus minimizing the need for more expensive tests in larger scale. The principal reason for a pilot plant test is the possibility to investigate natural variations in wastewater composition and the effect this will have on process stability. The use of laboratory and pilot scale tests is here illustrated by the work carried out prior to the upgrading of the treatment plant at Nyboholm paper mill. A description of the upgraded full scale installation consisting of both chemical treatment and a suspended-carrier biofilm process is included and a comparison between results from lab, pilot and full scale treatment is made.

Early stages in biofilm development in methanogenic fluidized-bed reactors.

Biofilm development in methanogenic fluidized-bed reactors with sand as the carrier was studied on a laboratory scale. The microorganisms present in consecutive layers of the biofilm of mature sludge granules were preliminarily characterized on the basis of their morphology, element composition and adhesion capacity and were compared to bacteria which take part in the initial colonization of sand. The early phase of biofilm development was monitored with reactors receiving waste-waters containing different mixtures of volatile fatty acids and inoculated with fluidized-bed reactor effluent for different lengths of time. The results obtained indicate that facultative anaerobic bacteria abundantly present in the outermost biofilm layers of mature sludge granules are probably the main primary colonizers of the sand. Methanothrix spp. or other methanogens were rarely observed among the primary colonizers. The course of biofilm formation was comparable under the various start-up conditions employed including variations in waste-water composition, inoculation and anaerobicity. However, omission of waste-water and thus of substrate resulted in rapid wash-out of the attached biomass.