Nanofiltration of a Landfill Leachate Containing Pharmaceutical Intermediates from Vitamin C Production

The main landfill of the city of Zagreb generates several hundreds of cubic meters of heavily contaminated leachate per day. The organic composition of the leachate is particularly peculiar because, besides common macromolecular humus-like dissolved organic carbon,it encompasses a number of specific compounds of pharmaceutical origin, including a suite of by-products deriving from the production of vitamin C. Since both macromolecular humic organic matter and vitamin C intermediates are rather resistant to microbial degradation, leachate treatment procedures using simple retention lagoons or conventional bioreactors are not very effective in reducing their levels before the discharge into the receiving waters. An attractive alternative is the application of membrane technology. The efficiencies of three different types of nanofilters for the purification of leachates from the Jakuševec landfill were examined. It was shown that both complex humic-like dissolved organic matter and anthropogenic compounds of pharmaceutical origin can be eliminated at high efficiencies, mostly above 90 %

Nanofiltration of a Landfill Leachate Containing Pharmaceutical Intermediates from Vitamin C Production

The main landfill of the city of Zagreb generates several hundreds of cubic meters of heavily contaminated leachate per day. The organic composition of the leachate is particularly peculiar because, besides common macromolecular humus-like dissolved organic carbon,it encompasses a number of specific compounds of pharmaceutical origin, including a suite of by-products deriving from the production of vitamin C. Since both macromolecular humic organic matter and vitamin C intermediates are rather resistant to microbial degradation, leachate treatment procedures using simple retention lagoons or conventional bioreactors are not very effective in reducing their levels before the discharge into the receiving waters. An attractive alternative is the application of membrane technology. The efficiencies of three different types of nanofilters for the purification of leachates from the Jakuševec landfill were examined. It was shown that both complex humic-like dissolved organic matter and anthropogenic compounds of pharmaceutical origin can be eliminated at high efficiencies, mostly above 90 %

MUNICIPAL WASTEWATER TREATMENT IN A MEMBRANE BIOREACTOR

ABSTRACT A membrane bioreactor (MBR) with a submerged membrane was used for the treatment of municipal wastewater from the city of Zagreb, Croatia, in a continuous mode for 123 days. The MBR was very efficient in organic matter removal (92.3 and 98.5 % for COD and BOD, respectively) for the entire duration of the experiment. Nitrification was established after 20 days remaining stable and efficient with a low concentration of ammonia and nitrite in the effluent. On average, 87% of ammonia was converted to nitrate. Biomass concentration, measured as MLSS, was dependant on the organic loading rate (OLR) and food to microorganism ratio (F/M), and its growth could be stopped or its concentration reduced by setting OLR and F/M to appropriate values, thus reducing the excess sludge production. Throughout the range of hydraulic retention times from 2.6 to 5.9 h, the efficiencies of organic matter removal and nitrification were not affected

Membrane bioreactor (MBR) as an advanced wastewater treatment technology

Persistent organic pollutants released from wastewater discharges into the environment can persist in the environment, bioaccumulate through the food web, enter drinking water production and pose a risk to human health and the environment. Conventional activated sludge (CAS) treatments are usually designed to remove or to decrease the concentrations of pathogens and the loads of the bulk organic but generally they are not designed to remove residues of trace organics. In the present work the presence of pesticides, pharmaceuticals and personal care products, surfactants and other contaminants and their removal in CAS systems are presented and discussed. The capacity to eliminate micropollutants in CAS depends on various factors, including physico-chemical properties, biological persistence of the individual compound and the technology and process conditions (e.g. temperature and seasonal variability, hydraulic and sludge retention time applied). Sludge retention time, though not exclusively, has been revealed as one of the most important process parameters. The relative importance of sorption, more relevant for lipophilic compounds and some hydrophilic compounds (e.g. surfactants), as compared to biodegradation can increase when the residence time in CAS is too short for implementing an efficient degradation. For high polar substances (e.g. most pharmaceuticals) the most important removal process is biological transformation or mineralization by microorganisms. Finally, present levels of knowledge about the degradation pathway in CAS is often not complete and formation of human and natural metabolites should be continuously and carefully monitored as they can be, occasionally, more toxic than the parental compounds

Adsorption Characteristics of Different Adsorbents and Iron(III) Salt for Removing As(V) from Water

The aim of this study is to determine the adsorption performance of three types of adsorbents for removal of As(V) from water: Bayoxide® E33 (granular iron(III) oxide), Titansorb® (granular titanium oxide) and a suspension of precipitated iron(III) hydroxide. Results of As(V) adsorption stoichiometry of two commercial adsorbents and precipitated iron(III) hydroxide in tap and demineralized water were fitted to Freundlich and Langmuir adsorption isotherm equations, from which adsorption constants and adsorption capacity were calculated. The separation factor RL for the three adsorbents ranged from 0.04 to 0.61, indicating effective adsorption. Precipitated iron(III) hydroxide had the greatest, while Titansorb had the lowest capacity to adsorb As(V). Comparison of adsorption from tap or demineralized water showed that Bayoxide and precipitated iron(III) hydroxide had higher adsorption capacity in demineralized water, whereas Titansorb showed a slightly higher capacity in tap water. These results provide mechanistic insights into how commonly used adsorbents remove As(V) from water

Linear and Non-Linear Modelling of Bromate Formation during Ozonation of Surface Water in Drinking Water Production

Bromate formation is a complex process that depends on the properties of water and the ozone used. Due to fluctuations in quality, surface waters require major adjustments to the treatment process. In this work, we investigated how the time of year, ozone dose and duration, and ammonium affect bromides, bromates, absorbance at 254 nm (UV254), near-infrared (NIR) spectra, and fluorescent components (humic-like and tyrosine-like) during surface water ozonation. Linear and non-linear models were used to determine and predict the relationships between input and output variables. Season, ozonation dose and time were correlated with the output variables, while ammonium affected only bromates. All coefficients of determination (R2) for the multiple linear regression models were >0.64, while R2 for the piecewise linear regression models was >0.89. The season had no effect on bromate formation in either model, while ammonium only affected bromides and bromates. Three input variables influenced UV254 in both models. The artificial neural network (ANN) model with the season, ozonation dose and time, ammonium, and NIR spectra was an effective way to describe water ozonation results. The multilayer perception neural network 14-14-5 had the lowest errors and was the best ANN model with R2 values for training, testing, and validation of 0.9916, 0.9826, and 0.9732, respectively

Use of near-infrared spectroscopy on predicting wastewater constituents to facilitate the operation of a membrane bioreactor

The use of near-infrared (NIR) spectroscopy in wastewater treatment has continuously expanded. As an alternative to conventional analytical methods for monitoring constituents in wastewater treatment processes, the use of NIR spectroscopy is considered to be cost-effective and less time-consuming. NIR spectroscopy does not distort the measured sample in any way as no prior treatment is required, making it a waste-free technique. On the negative side, one has to be very well versed with chemometric techniques to interpret the results. In this study, filtered and centrifuged wastewater and sludge samples from a lab-scale membrane bioreactor (MBR) were analysed. Two analytical methods (conventional and NIR spectroscopy) were used to determine and compare major wastewater constituents. Particular attention was paid to soluble microbial products (SMPs) and extracellular polymeric substances (EPSs) known to promote membrane fouling. The parameters measured by NIR spectroscopy were analysed and processed with partial least squares regression (PLSR) and artificial neural networks (ANN) models to assess whether the evaluated wastewater constituents can be monitored by NIR spectroscopy. Very good results were obtained with PLSR models, except for the determination of SMP, making the model qualitative rather than quantitative for their monitoring. ANN showed better performance in terms of correlation of NIR spectra with all measured parameters, resulting in correlation coefficients higher than 0.97 for training, testing, and validation in most cases. Based on the results of this research, the combination of NIR spectra and chemometric modelling offers advantages over conventional analytical methods.BN/Cees Dekker LabBT/Environmental Biotechnolog