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1.
Water Res ; 83: 293-302, 2015 Oct 15.
Article in English | MEDLINE | ID: mdl-26164801

ABSTRACT

Hospital wastewater represents a significant input of pharmaceuticals into municipal wastewater. As Moving Bed Biofilm Reactors (MBBRs) appear to remove organic micro-pollutants, hospital wastewater was treated with a pilot plant consisting of three MBBRs in series. The removal of pharmaceuticals was studied in two experiments: 1) A batch experiment where pharmaceuticals were spiked to each reactor and 2) a continuous flow experiment at native concentrations. DOC removal, nitrification as well as removal of pharmaceuticals (including X-ray contrast media, ß-blockers, analgesics and antibiotics) occurred mainly in the first reactor. In the batch experiment most of the compounds followed a single first-order kinetics degradation function, giving degradation rate constants ranged from 5.77 × 10(-3) to 4.07 h(-1), from -5.53 × 10(-3) to 9.24 × 10(-1) h(-1) and from 1.83 × 10(-3) to 2.42 × 10(-1) h(-1) for first, second and third reactor respectively. Generally, the highest removal rate constants were found in the first reactor while the lowest were found in the third one. This order was inverted for most compounds, when the removal rate constants were normalized to biomass, indicating that the last tank had the most effective biofilms. In the batch experiment, 21 out of 26 compounds were assessed to be degraded with more than 20% within the MBBR train. In the continuous flow experiment the measured removal rates were lower than those estimated from the batch experiments.


Subject(s)
Bacterial Physiological Phenomena , Biofilms/growth & development , Environmental Restoration and Remediation/methods , Pharmaceutical Preparations/metabolism , Water Pollutants, Chemical/metabolism , Biodegradation, Environmental , Bioreactors , Denmark , Hospitals , Pilot Projects , Wastewater/analysis
2.
Sci Total Environ ; 530-531: 383-392, 2015 Oct 15.
Article in English | MEDLINE | ID: mdl-26057543

ABSTRACT

Hospital wastewater contributes a significant input of pharmaceuticals into municipal wastewater. The combination of suspended activated sludge and biofilm processes, as stand-alone or as hybrid process (hybrid biofilm and activated sludge system (Hybas™)) has been suggested as a possible solution for hospital wastewater treatment. To investigate the potential of such a hybrid system for the removal of pharmaceuticals in hospital wastewater a pilot plant consisting of a series of one activated sludge reactor, two Hybas™ reactors and one moving bed biofilm reactor (MBBR) has been established and adapted during 10 months of continuous operation. After this adaption phase batch and continuous experiments were performed for the determination of degradation of pharmaceuticals. Removal of organic matter and nitrification mainly occurred in the first reactor. Most pharmaceuticals were removed significantly. The removal of pharmaceuticals (including X-ray contrast media, ß-blockers, analgesics and antibiotics) was fitted to a single first-order kinetics degradation function, giving degradation rate constants from 0 to 1.49 h(-1), from 0 to 7.78 × 10(-1)h(-1), from 0 to 7.86 × 10(-1)h(-1) and from 0 to 1.07 × 10(-1)h(-1) for first, second, third and fourth reactors respectively. Generally, the highest removal rate constants were found in the first and third reactors while the lowest were found in the second one. When the removal rate constants were normalized to biomass amount, the last reactor (biofilm only) appeared to have the most effective biomass in respect to removing pharmaceuticals. In the batch experiment, out of 26 compounds, 16 were assessed to degrade more than 20% of the respective pharmaceutical within the Hybas™ train. In the continuous flow experiments, the measured removals were similar to those estimated from the batch experiments, but the concentrations of a few pharmaceuticals appeared to increase during the first treatment step. Such increase could be attributed to de-conjugation or formation from other metabolites.


Subject(s)
Pharmaceutical Preparations/analysis , Waste Disposal, Fluid/methods , Wastewater/microbiology , Water Pollutants, Chemical/metabolism , Biodegradation, Environmental , Biofilms/growth & development , Hospitals , Wastewater/chemistry , Water Pollutants, Chemical/analysis
3.
Sci Total Environ ; 520: 96-105, 2015 Jul 01.
Article in English | MEDLINE | ID: mdl-25804876

ABSTRACT

Formation of disinfection by-products (DBPs) during experimental UV treatment of pool water has previously been reported with little concurrence between laboratory studies, field studies and research groups. In the current study, changes in concentration of seven out of eleven investigated volatile DBPs were observed in experiments using medium pressure UV treatment, with and without chlorine and after post-UV chlorination. Results showed that post-UV chlorine consumption increased, dose-dependently, with UV treatment dose. A clear absence of trihalomethane formation by UV and UV with chlorine was observed, while small yet statistically significant increases in dichloroacetonitrile and dichloropropanone concentrations were detected. Results indicate that post-UV chlorination clearly induced secondary formation of several DBPs. However, the formation of total trihalomethanes was no greater than what could be replicated by performing the DBP formation assay with higher chlorine concentrations to simulate extended chlorination. Post-UV chlorination of water from a swimming pool that continuously uses UV treatment to control combined chlorine could not induce secondary formation for most DBPs. Concurrence for induction of trihalomethanes was identified between post-UV chlorination treatments and simulated extended chlorination time treatment. Trihalomethanes could not be induced by UV treatment of water from a continuously UV treated pool. This indicates that literature reports of experimentally induced trihalomethane formation by UV may be a result of kinetic increase in formation by UV. However, this does not imply that higher trihalomethane concentrations would occur in pools that apply continuous UV treatment. The bromine fraction of halogens in formed trihalomethanes increased with UV dose. This indicates that UV removes bromine atoms from larger molecules that participate in trihalomethane production during post-UV chlorination. Additionally, no significant effect on DBP formation was observed due to photo-inducible radical forming molecules NO3- (potentially present in high concentrations in pool water) and H2O2 (added as part of commercially employed DBP reducing practices).


Subject(s)
Air Pollutants/analysis , Disinfectants/analysis , Swimming Pools , Water Purification/methods , Disinfection/methods , Trihalomethanes/analysis , Ultraviolet Rays , Volatilization
4.
J Water Health ; 11(3): 465-72, 2013 Sep.
Article in English | MEDLINE | ID: mdl-23981875

ABSTRACT

In order to identify the optimal pH range for chlorinated swimming pools, the formation of trihalomethanes, haloacetonitriles and trichloramine was investigated in the pH-range 6.5-7.5 in batch experiments. An artificial body fluid analogue was used to simulate bather load as the precursor for by-products. The chlorine-to-precursor ratio used in the batch experiments influenced the amounts of by-products formed, but regardless of the ratio the same trends in the effect of pH were observed. Trihalomethane formation was reduced by decreasing pH, but haloacetonitrile and trichloramine formation increased. To evaluate the significance of the increase and decrease of the investigated organic by-products at the different pH values, the genotoxicity was calculated based on literature values. The calculated genotoxicity was approximately at the same level in the pH range 6.8-7.5 and increased when pH was 6.7 or lower. An optimal pH range for by-products formation in swimming pools was identified at pH 7.0-7.2. In the wider pH range (pH 6.8-7.5), the effect on by-product formation was negligible. Swimming pools should never be maintained at lower pH than 6.8 since formation of both haloacetonitriles and trichloramine increase significantly below this value.


Subject(s)
Halogenation , Swimming Pools , Water Pollutants, Chemical/analysis , Acetonitriles/chemistry , Chlorides/chemistry , Hydrogen-Ion Concentration , Mutagenicity Tests , Nitrogen Compounds/chemistry , Trihalomethanes/chemistry
5.
Sci Total Environ ; 443: 850-6, 2013 Jan 15.
Article in English | MEDLINE | ID: mdl-23247288

ABSTRACT

Medium pressure UV is used for controlling the concentration of combined chlorine (chloramines) in many public swimming pools. Little is known about the fate of other disinfection by-products (DBPs) in UV treatment. Photolysis by medium pressure UV treatment was investigated for 12 DBPs reported to be found in swimming pool water: chloroform, bromodichloromethane, dibromochloromethane, bromoform, dichloroacetonitrile, bromochloroacetonitrile, dibromoacetronitrile, trichloroacetonitrile, trichloronitromethane, dichloropropanone, trichloropropanone, and chloral hydrate. First order photolysis constants ranged 26-fold from 0.020 min(-1) for chloroform to 0.523 min(-1) for trichloronitromethane. The rate constants generally increased with bromine substitution. Using the UV removal of combined chlorine as an actinometer, the rate constants were recalculated to actual treatment doses of UV applied in a swimming pool. In an investigated public pool the UV dose was equivalent to an applied electrical energy of 1.34 kWh m(-3) d(-1) and the UV dose required to removed 90% of trichloronitromethane was 0.4 kWh m(-3) d(-1), while 2.6 kWh m(-3) d(-1) was required for chloral hydrate and the bromine containing haloacetonitriles and trihalomethanes ranged from 0.6 to 3.1 kWh m(-3) d(-1). It was predicted thus that a beneficial side-effect of applying UV for removing combined chlorine from the pool water could be a significant removal of trichloronitromethane, chloral hydrate and the bromine containing haloacetonitriles and trihalomethanes.


Subject(s)
Chlorine/chemistry , Disinfectants/chemistry , Swimming Pools , Ultraviolet Rays , Photolysis , Pressure
6.
Water Res ; 46(19): 6399-409, 2012 Dec 01.
Article in English | MEDLINE | ID: mdl-23026126

ABSTRACT

This study investigated the formation and predicted toxicity of different groups of disinfection byproducts (DBPs) from human exudates in relation to chlorination of pool water at different pH values. Specifically, the formation of the DBP groups trihalomethanes (THMs), haloacetic acids (HAAs), haloacetonitriles (HANs) and trichloramine (NCl(3)), resulting from the chlorination of body fluid analog, were investigated at 6.0 ≤ pH ≤ 8.0. Either the initial concentration of active chorine or free chlorine was kept constant in the tested pH range. THM formation was reduced by decreasing pH but HAN, and NCl(3) formation increased at decreasing pH whereas the formation of HAAs remained constant. Under our experimental conditions, the formation of NCl(3) (suspected asthma inducing compound) at pH = 6.0 was an order of magnitude higher than at pH = 7.5. Furthermore, the effect of the presence of bromide on DBP formation was investigated and found to follow the same pH dependency as without bromide present, with the overall DBP formation increasing, except for HAAs. Estimation of genotoxicity and cytotoxicity of the chlorinated human exudates showed that among the quantified DBP groups, HAN formation were responsible for the majority of the toxicity from the measured DBPs in both absence and presence of bromide.


Subject(s)
Disinfection/methods , Exudates and Transudates/chemistry , Swimming Pools , Trihalomethanes/toxicity , Acetonitriles/chemistry , Bromides/chemistry , Chlorides/chemistry , Chlorides/toxicity , Chlorine/chemistry , Chlorine/toxicity , Halogenation , Humans , Hydrogen-Ion Concentration , Mutagenicity Tests , Nitrogen Compounds/chemistry , Nitrogen Compounds/toxicity , Toxicity Tests , Trihalomethanes/chemistry , Water Purification/methods
7.
Chemosphere ; 87(3): 241-7, 2012 Apr.
Article in English | MEDLINE | ID: mdl-22285035

ABSTRACT

The formation was investigated for different groups of disinfection byproducts (DBPs) during chlorination of filter particles from swimming pools at different pH-values and the toxicity was estimated. Specifically, the formation of the DBP group trihalomethanes (THMs), which is regulated in many countries, and the non-regulated haloacetic acids (HAAs) and haloacetonitriles (HANs) were investigated at 6.0≤pH≤8.0, under controlled chlorination conditions. The investigated particles were collected from a hot tub with a drum micro filter. In two series of experiments with either constant initial active or initial free chlorine concentrations the particles were chlorinated at different pH-values in the relevant range for swimming pools. THM and HAA formations were reduced by decreasing pH while HAN formation increased with decreasing pH. Based on the organic content the relative DBP formation from the particles was higher than previously reported for body fluid analogue and filling water. The genotoxicity and cytotoxicity estimated from formation of DBPs from the treated particle suspension increased with decreasing pH. Among the quantified DBP groups the HANs were responsible for the majority of the toxicity from the measured DBPs.


Subject(s)
Disinfectants/chemistry , Filtration/instrumentation , Swimming Pools , Water Pollutants, Chemical/chemistry , Disinfectants/analysis , Disinfectants/toxicity , Hydrogen-Ion Concentration , Trihalomethanes/analysis , Trihalomethanes/chemistry , Trihalomethanes/toxicity , Water Pollutants, Chemical/analysis , Water Pollutants, Chemical/toxicity
8.
Environ Toxicol Chem ; 30(2): 413-26, 2011 Feb.
Article in English | MEDLINE | ID: mdl-21038429

ABSTRACT

Industrial and municipal effluents are important sources of endocrine disrupting compounds (EDCs) discharged into the aquatic environment. This study investigated the endocrine potency of wastewater and the cleaning efficiency of two typical urban Danish sewage treatment plants (STPs), using chemical analysis and a battery of bioassays. Influent samples, collected at the first STP grate, and effluent samples, collected after the sewage treatment, were extracted using solid phase extraction. Extracts were analyzed for the content of a range of industrial chemicals with endocrine disrupting properties: phthalate metabolites, parabens, industrial phenols, ultraviolet screens, and natural and synthetic steroid estrogens. The endocrine disrupting bioactivity and toxicity of the extracts were analyzed in cell culture assay for the potency to affect the function of the estrogen, androgen, aryl hydrocarbon, and thyroid receptors as well as the steroid hormone synthesis. The early-life stage (ELS) development was tested in a marine copepod. The concentrations of all analyzed chemicals were reduced in effluents compared with influents, and for some to below the detection limit. Influent as well as effluent samples from both STPs were found to interact with all four receptors and to interfere with the steroid hormone synthesis showing the presence of measured EDCs. Both influent samples and one of the effluent samples inhibited the development of the copepod Acartia tonsa. In conclusion, the presence of EDCs was reduced in the STPs but not eliminated, as verified by the applied bioassays that all responded to the extracts of effluent samples. Our data suggest that the wastewater treatment processes are not efficient enough to prevent contamination of environmental surface waters.


Subject(s)
Endocrine Disruptors/analysis , Endocrine Disruptors/toxicity , Waste Disposal, Fluid , Water Pollutants, Chemical/analysis , Water Pollutants, Chemical/toxicity , Animals , Cell Line, Tumor , Cell Proliferation , Copepoda/growth & development , Denmark , Estrogens/analysis , Fungal Proteins/metabolism , Humans , Parabens/analysis , Phenols/analysis , Phthalic Acids/analysis , Receptors, Androgen/metabolism , Receptors, Estrogen/metabolism , Receptors, Progesterone/metabolism , Steroids/metabolism , Waste Disposal, Fluid/economics , Waste Disposal, Fluid/methods , Yeasts/metabolism
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