Search results for "waste water"

Modelling anaerobic biomass growth kinetics with a substrate threshold concentration.

2004

Abstract Many bacteria have been observed to stop growing below a certain substrate threshold concentration. In this study, a modification of the Monod kinetics expression has been proposed to take into account this substrate threshold concentration observed in bacterial growth. Besides the threshold concentration no additional parameters have been added to the kinetic expression and so, only the substrate threshold concentration and the half-saturation constant have to be estimated for model calibration purposes. Furthermore, for parameter estimation purposes, practical identifiability of this new function has been studied and the results have been satisfactory. The new model has been appl…

Cathodic abatement of Cr(VI) in water by microbial reverse-electrodialysis cells

2015

Abstract For the first time a microbial reverse electrodialysis cell (MRC) was used for the treatment of water contaminated by Cr(VI). It has been recently shown that both inorganic and organic pollutants can be removed by reverse electrodialysis processes (RED) using water with different salinity without the supply of electric energy. However, a high number of membrane pairs is usually necessary for the treatment of wastewater by RED. Here, it was showed that a lower number of membranes can be used by the utilization of a MRC (i.e., a RED cell with a biotic anode) for such purposes. Indeed, the abatement of Cr(VI), chosen as model pollutant, was successfully achieved by cathodic reduction …

Chlorocymenes, cymenenes and other chlorohydrocarbons in pulp mill effluents, sludges and exposed biota

1992

Abstract Polychlorinated cymenes (PCYMS) and cymenenes (PCYMD) were analyzed by GC/LRMS/SIM in effluents and sludges of three different pulp mills and in fish and mussels exposed to pulp mill effluents. The levels of PCYMS+PCYMD were 0.3–4.8 μg/l in total effluents,

Quick assessment of the economic value of olive mill waste water

2016

Background: Olive biophenols are emerging as a valued class of natural products finding practical application in the food, pharmaceutical, beverage, cosmetic and nutraceutical industries due to their powerful biological activity which includes antioxidant and antimicrobial properties. Olive mill waste water (OMWW), a by-product in olive oil manufacturing, is rich in biophenols such as hydroxytyrosol and tyrosol. The amount of biophenols depends on the cultivar, the geographical area of cultivation, and the seasonal conditions. The goal of this study was to develop a straightforward method to assess the economic value of OMWW via quantification of hydroxytyrosol and tyrosol. Results: The amo…

Modelling biological and chemically induced precipitation of calcium phosphate in enhanced biological phosphorus removal systems

2011

The biologically induced precipitation processes can be important in wastewater treatment, in particular treating raw wastewater with high calcium concentration combined with Enhanced Biological Phosphorus Removal. Currently, there is little information and experience in modelling jointly biological and chemical processes. This paper presents a calcium phosphate precipitation model and its inclusion in the Activated Sludge Model No 2d (ASM2d). The proposed precipitation model considers that aqueous phase reactions quickly achieve the chemical equilibrium and that aqueous-solid change is kinetically governed. The model was calibrated using data from four experiments in a Sequencing Batch Rea…

Alkyl polychlorobibenzyls and planar aromatic chlorocompounds in pulp mill products, effluents, sludges and exposed biota

1992

Abstract Aromatic chlorocompounds which interfere in GC/MS analysis of dioxins were studied in samples from three different pulp mills and in fish and mussels exposed to pulp mill effluents. The major interfering compounds were chlorinated alkyl bibenzyls (R-PCBBs; R = C5-alkyl; P = 1–4). In pulp mill samples, levels of C5-PCBBs (10–120 ng/l in effluents, 5–33 ng/g in dried sludges) were orders of magnitude higher than the levels of toxic PCDDs and PCDFs. C5-PCBBs bioaccumulated slightly to the recipient fish (0–2 pg/g in fresh muscles) and to incubated mussels (3–26 ng/g in lipid). In mussels, significant levels (19–73 ng/g in lipid) of other than pulp mill originated toxic hepta- and octa…

Radionuclides in wastewater treatment plants: monitoring of Sicilian plants.

2015

Three Sicilian wastewater treatment plants were monitored to assess the occurrence and the behaviour of radionuclides. Two sampling campaigns (screening and long-term) were carried out during which liquid and solid samples have been analysed. It was found that 131I mostly occurred in the samples analysed during the screening campaign (43% of the analysed samples contained 131I). High 131I specific activity was found in the mixed liquor, recycled sludge and dehydrated sludge samples. This finding was mainly due to the tendency of 131I to be associated with solid particles. During the long-term sampling campaign an influence of the sludge retention time (SRT) on the 131I behaviour was found. …

A microplate version of the SOS/umu-test for rapid detection of genotoxins and genotoxic potentials of environmental samples

1991

Abstract The umu-microtest is a miniaturized automated short-term test version proposed for screening of umuC-dependent mutagenic potentials of chemicals relevant to environmental pollution, river water and industrial waste water. The test is based on the SOS/umu-test and has been modified in order to allow extensive testing of environmental samples. Genetically engineered Salmonella typhimurium (TA1535/pSK1002) are incubated on a microplate rotor in a sloping position for 2 h with the test samples, followed by addition of fresh culture medium to reach a 10-fold dilution of the incubation medium. 2 h later, the activity of the β-galactosidase, which reflects umuC induction, is determined co…

From wastes to resources: citrus hydrolatesas natural biostimulants of soil microorganisms

The hydrolates result from the industrial extraction process of the essential oils through cold pressing of the citrus peels. Today, they are considered a waste to be disposed of. However, due to the presence of water soluble compounds (sugars, polyphenols, acids), hydrolates could be reused instead of being, due to the high economic burden, a problem in the disposal of the same, charged to the company.The aim of this work was to evaluate the effects of citrus hydrolate when directly applied as irrigation water on soil microbial biomass, activity and structure community. The soil used for the experiment was collected from the topsoil (0-10 cm) of a citrus orchard, air-dried and sieved at 2 …

Monitoring of the effects of added carbon by citrus hydrolates waste in a soil.

The hydrolates are the waste to be disposed of are a product of the industrial extraction process of the essential oils through cold pressing of the citrus peels. However, due to the presence of water soluble compounds (sugars, polyphenols, acids), hydrolates could be reused instead of being, due to the high economic burden, a problem in the disposal of the same, charged to the company. The aim of this work was to evaluate the effects of citrus hydrolate when directly applied as irrigation water on soil. Was monitored soil chemical and biochemical property, in particularly effect of the high carbon addition on microbial biomass, activity and structure community and effect on carbon soil sto…