Threshold Odor Number Research Articles

A comparative assessment of biomethane potential of fresh fecal matter and fecal sludge and its correlation with malodor.

Comprehensive and proper management of fecal sludge (FS) is an ongoing concern in many nations.Decentralizedfecal sludge treatment plants (FSTPs) are effective in this regard; however, many have experienced strong public opposition based partly on suspicion of malodor. Fecal sludge and freshly generated fecal matter (FM) samples from various FSTPs were collected, characterized, and investigated for biomethane potential. The homogenized samples were anaerobically digested for 28days. Digestion successfully reduced total suspended solids, biochemical oxygen demand, and threshold odor number values of 97,350-97,420mg/l, 43,230-43,260mg/l, and 130-150 for FM, to 49,500-49,650mg/l, 23,760-23,850mg/l, and 3338, respectively, for FS samples. The comprehensive gas yield from Bhongir, Boduppal, and Shadnagar FS samples was 40, 55, and 31ml, respectively. In contrast, cumulative gas generation from the FM was 26,361ml. Digestion of FS samples also reduced concentrations of volatile solids and coliforms by 66-72% and 99%, respectively. Characterization of gas samples revealed methane and carbon dioxide concentrations as 56% and 22% for FM, and 0.4% and 61% for FS samples, respectively. Hydrogen sulfide and ammonia gas were absent in FS samples, dispelling common societal misconceptions of FSTPs being associated with malodor.

Assessment of Rainwater Quality Regarding its Use in The Roztocze National Park (Poland)—Case Study

The aim of this study was to determine the quality of rainwater and the possibility of using it for various purposes in the Roztocze National Park (RNP), Poland. This study was carried out in 2021–2022. Samples of rainwater that drained from the roofs of farm buildings in the RNP were tested for their organoleptic, physicochemical and microbiological qualities. The organoleptic tests were run to evaluate the water for a foreign odour and the threshold odour number. The physical and chemical tests included turbidity; colour; pH; conductivity; concentrations of ammonium ions, nitrates, nitrites, manganese, iron and chlorides; and general hardness. The microbiological tests included total microbial counts at 36 °C and 22 °C, coliform bacteria, Escherichia coli, intestinal enterococci and Pseudomonas aeruginosa. The rainwater quality results were compared with the quality parameters of surface water collected from the River Świerszcz, as well as with the Polish drinking water standards. The findings indicated that rainwater collected in the RNP had good organoleptic, physicochemical and microbiological properties, which, in some cases, complied with the standards for potable water. Exceedances of the permissible limits, mainly for ammonium ions and microbiological indicators, were periodically observed in the tested rainwater. This was probably due to contamination of roof surfaces with bird droppings. However, these exceedances did not exclude the use of the rainwater for economic purposes, e.g., flushing toilets, washing vehicles or watering plants, which may significantly reduce the abstraction of high-quality groundwater. The rainwater that is planned to be used as drinking water for the Polish konik horses living in the park will have to be pre-treated via filtration and disinfection processes (e.g., with a UV lamp).

A combined deodorization reflux system and tidal flow constructed wetland for sewage treatment performance

The biggest problem in the treatment of septic tank wastewater of scattered farmers is the high concentration of chemical oxygen demand (COD), ammonia nitrogen (NH4+-N), total phosphorus (TP), and odor (threshold odor number, TON). A combined process of reflux deodorization and tidal flow constructed wetland was developed, and its removal efficiencies of COD, NH4+-N, TP, sulfide (S2-), and TON were evaluated. The effect of reflux ratio on system pollutant removal is significant. The removal efficiencies of COD, NH4+-N, S2-, and TON increased as R increased. When R is 150%, the system achieves the optimal operation effect. By analyzing the microbial community and functional bacteria in the system, it was found that Thiobacillus could conduct simultaneous denitrification and deodorization in the deodorization pool. The effects of ρ(NO3--N)/ρ(S2-) and ρ(COD)/ρ(NO3--N) on the denitrification and deodorization of the deodorization pool were studied to further reveal the mechanism and law of denitrification and deodorization in the deodorization pool. It was found that with the increase of ρ(NO3--N)/ρ(S2-), the denitrification effect of the deodorizing pool decreased and the deodorization effect increased. When ρ(NO3--N)/ρ(S2-) is 0.8, good denitrification and deodorization effect can be achieved in the deodorization pool. With the increase of ρ(COD)/ρ(NO3--N), the denitrification effect of the deodorizer was enhanced, but the deodorization effect was weakened. When ρ(COD)/ρ(NO3--N) is 4, good denitrification and deodorization effect can be achieved in the deodorization pool.

The formation and control of ozonation by-products during drinking water advanced treatment in a pilot-scale study

Ozone has been widely applied during drinking water treatment for organic pollutants removal, however, the ozonation by-products such as bromate, aldehydes, and carboxylic acids could be produced. To investigate the ozonation by-products formation and control efficiency, a continuous pilot-scale system was established including conventional treatment and ozone-biological activated carbon (O3-BAC) treatment processes in a waterworks that receives bromide-bearing source water from the Yellow River in northern China. It was found that ozonation could reduce the threshold odour number and the haloacetic acids formation potential effectively. As 1.8–2.6 mg/L of ozone was applied, the bromate concentration would exceed the standard of 10 μg/L. Simultaneously, ozonation led to a large number of formaldehyde, methylglyoxal and other aldehydes. At the ozone dosage of 3.0 mg/L, the total concentration of aldehydes reached the highest of 45.4 μg/L. Ammonia and hydrogen peroxide (H2O2) addition could inhibit the formation of bromate effectively. The application of H2O2 induced an increase in aldehydes concentration reaching a maximum concentration of 57.6 μg/L. During the BAC treatment, the removal rate of aldehydes would reach 19%–41%. The addition of H2O2 inhibited the formation of bromate but increased the production of aldehydes, thus it is important to search a balance point for controlling bromate and aldehydes simultaneously. The H2O2/O3 (g/g) of 1.0 could be possible to control both bromate and aldehydes concentrations within the standards.

Contaminants migrating from crossed-linked polyethylene pipes and their effect on drinking water odour

The formation potential of contaminants diffusing from cross-linked polyethylene (PE-X) pipes and their impact on the odour of drinking water was determined. Three types of PE-X material, Pe-Xa, PE-Xb and PE-Xc, were extensively assessed by performing migration tests following EN 1420 and EN 12873–1. Migration waters were analysed for their threshold odour number (TON). The same samples were investigated by two gas chromatography-mass spectrometry methods: screening and olfactometry. Most of the PE-X materials failed the German regulation of TON <2 for cold water and TON ≤4 for warm water. PE-Xb material caused the strongest odour and also released the highest amount of contaminants. Metilox, 7,9-di-tert-butyl-1-oxaspiro(4,5)deca-6,9-diene-2,8-dione, 3,5-di-tert-butyl-4-hydroxybenzaldehyde and 2,6-di-tert-butyl-p-benzoquinone (2,6-DtBQ) were the most often detected substances leaching from the tested plastic materials. However, no odour was perceived for most of these substances. Methyl tert-butyl ether (MtBE) and 2-tert-butylphenol are believed to contribute to the sensory problem in the migration water among other substances such as tert-amyl methyl ether, 2,2,2,5-tetramethyltetrahydrofuran, toluene or xylene. In total ten specific descriptions characterized the odour of the individual contaminants: ethereal, fresh, solvent, sweet, fruity, floral, unsavoury, pungent, aromatic and chemical.

Measurement of Odour on Source of Drinking Water Using Threshold Odour Number and Modified Olfactometry

Concerns on odour of water have increased rapidly. However, odour measurement in water for drinking sources has yet to be established in Malaysia. More study is needed for an approach to quantify the odour incidences in water supply, one that is effective and applicable as a guideline towards the early identification of contamination occurrences. Thus, the objective of this study was to identify correlation (if any) between Threshold Odour Number (TON) test with a portable olfactometry plus odour wheel (POPOW) combination method for assessing odour in drinking water. Water samples collected from a drinking water supply system was tested for odour concentration as well as its character based on an odour wheel. Results from the Pearson correlation showed that the TON and POPOW gave the r-value of 0.833 which indicates that both method highly correlate with a level of confidence of 99 percent. Sample water that was taken near the main source of drinking water was given off as earthy smell, indicating geosmin as a likely contaminant. On the other hand, treated water samples taken directly at the treatment plant had a distinctive, chlorinous odour, which was expected from it use of chlorine as a disinfectant. This study has demonstrated the effectiveness of the portable olfactometer and odour wheel combination method for detecting odour in drinking water supply with at par results to the standard TON. More importantly, POPOW would enable the assessment of odour at site and at a shorter test preparation time, traits which are important especially for remotely located sites.

Methods for controlling stored urine odor in resource-oriented sanitation

Urine odor is a major challenge in the development of resource-oriented sanitation (ROS). One common solution to overcome odor issues is to use energy-consuming ventilation practices. However, historically ancient Koreans practiced separation of urine and feces, followed by the collection and utilization of gathered sanitary matters. Furthermore, ancient Persians developed solutions to urine odor issues. This study investigates the role of NH3 concentration on odor production in stored urine using the standard threshold odor number (TON) measurement. Trends in pH and NH3 production, as well as their interactions with TON, were investigated by simulating ancient Korean practices that stored urine under anaerobic conditions at different temperatures. The results show a direct relationship between the concentrations of NH3 and TON. Storing urine under anaerobic conditions leads to the production of NH3, which intensifies as temperature increases. The effect of pH and NH3 concentrations on the TON of stored urine explains the ancient Persian approach, given that additives, such as acetic acid and sodium bicarbonate, are effective for removing urine odor. Such approaches can be successfully applied to ROS systems.

Control of urine odor in different sanitation practices and its implication on water saving

To avoid odor in sanitation systems, urine is usually diluted with water (flushed), which leads to high water consumption. The smell may remain in sanitation systems if the systems are not well managed, or if the urine is flushed with insufficient amounts of water. In this study, using the standard threshold odor number (TON) measurement as an indicator of urine odor, the effects of the pH and temperature of the diluting water regarding the amount of water:urine dilution ratio were studied. The effects of temperature and pH of the diluting water on TON when the dilution ratio was constant were investigated. Results show that lowering the pH and temperature of the diluting water can reduce the minimum dilution ratio needed to achieve TON = 0. At constant dilution ratio, reducing pH seemed to be more efficient, sustainable, and economical in comparison to adjusting the temperature of the diluting water. It was found that, based on the specific pH and temperature of the diluting water, there is a minimum dilution ratio required to avoid urine odor. Therefore, in sanitation systems, the amount of flushing should be adjusted based on the characteristics of the flushing water as well as on the amount of urination.

Total Intensity of Odor: A New Method to Evaluate Odors

Unpleasant odors in drinking water can have a negative effect on consumer confidence. In fact, consumers often perceive that if their water smells bad, then it must be bad and unsafe to drink. Compliance for odor aesthetics of drinking water in the United States is based on a secondary standard using the threshold odor number (TON) method, a dilution‐to‐threshold test. However, this test has been subject to criticism in the drinking water community for being a poor measure of consumer acceptance. As a result, many utilities have turned to flavor profile analysis (FPA) to better predict consumer acceptance. However, FPA requires a trained panel, and TON remains the recommended procedure for regulatory compliance. The Metropolitan Water District of Southern California, in collaboration with Tufts University, developed a new, robust odor testing method called total intensity of odor, which offers a valid alternative for compliance purposes.

Odor removal by powdered activated carbon (PAC) in low turbidity drinking water

The potential of powdered activated carbon (PAC) adsorption for odor removal in low turbidity drinking water was investigated. The batch experiments were conducted under various conditions including PAC species, dosage, contact time and dosing point. The effects of pre-chlorination and PAC dosage on turbidity were also studied. Results showed that adsorption was quite vulnerable to initial threshold odor number (TON), and higher influent TON required a larger dosage. Both PAC species (derived from coal and wood) presented excellent adsorption capacity for odorants. The adsorption process versus time had three steps and the adsorption kinetics were well fitted by the second order model. Pre-chlorination had an adverse effect on both raw water TON and odor removal. PAC adsorption was enhanced by dosing during coagulation and could, in turn, save coagulant dosage.

Odor Events in Surface and Treated Water: The Case of 1,3-Dioxane Related Compounds.

A study has been carried out to identify the origin of the odorous compounds at trace levels detected in surface waters and in Barcelona's tap water (NE Spain) which caused consumer complaints. The malodorous compounds were 2,5,5-trimethyl-1,3-dioxane (TMD) and 2-ethyl-5,5-dimethyl-1,3-dioxane (2EDD) which impart a distinctive sickening or olive-oil odor to drinking water at low ng/L levels. Flavor profile analysis (FPA) or threshold odor number (TON) were used for organoleptic purposes. Levels up to 749 ng/L for TMD and 658 ng/L for 2EDD were measured at the entrance of the drinking water treatment plant. Three wastewater treatment plants (WWTPs) using industrial byproducts coming from resin manufacturing plants to promote codigestion were found to be the origin of the event. Corrective measures were applied, including the prohibition to use these byproducts for codigestion in the WWTPs involved. A similar event was already recorded in the same area 20 years ago.

Who Smells? Forecasting Taste and Odor in a Drinking Water Reservoir.

Taste and odor problems can impede public trust in drinking water and impose major costs on water utilities. The ability to forecast taste and odor events in source waters, in advance, is shown for the first time in this paper. This could allow water utilities to adapt treatment, and where effective treatment is not available, consumers could be warned. A unique 24-year time series, from an important drinking water reservoir in Saskatchewan, Canada, is used to develop forecasting models of odor using chlorophyll a, turbidity, total phosphorus, temperature, and the following odor producing algae taxa: Anabaena spp., Aphanizemenon spp., Oscillatoria spp., Chlorophyta, Cyclotella spp., and Asterionella spp. We demonstrate, using linear regression and random forest models, that odor events can be forecast at 0-26 week time lags, and that the models are able to capture a significant increase in threshold odor number in the mid-1990 s. Models with a fortnight time-lag show a high predictive capacity (R(2) = 0.71 for random forest; 0.52 for linear regression). Predictive skill declines for time lags from 0 to 15 weeks, then increases again, to R(2) values of 0.61 (random forest) and 0.48 (linear regression) at a 26-week lag. The random forest model is also able to provide accurate forecasting of TON levels requiring treatment 12 weeks in advance-93% true positive rate with a 0% false positive rate. Results of the random forest model demonstrate that phytoplankton taxonomic data outperform chlorophyll a in terms of predictive importance.

The cleaning method selected for new PEX pipe installation can affect short-term drinking water quality.

The influence of four different cleaning methods used for newly installed polyethylene (PEX) pipes on chemical and odor quality was determined. Bench-scale testing of two PEX (type b) pipe brands showed that the California Plumbing Code PEX installation method does not maximize total organic carbon (TOC) removal. TOC concentration and threshold odor number values significantly varied between two pipe brands. Different cleaning methods impacted carbon release, odor, as well the level of drinking water odorant ethyl tert-butyl ether. Both pipes caused odor values up to eight times greater than the US federal drinking water odor limit. Unique to this project was that organic chemicals released by PEX pipe were affected by pipe brand, fill/empty cycle frequency, and the pipe cleaning method selected by the installer.

Sewage Quality Assessment of Various Places in Bilaspur City

The quantity, strength and type of sewage depends upon the population, Life style of people and the existence of different types of industries respectively and the amount of treatment required to be given to sewage depends very much upon the source of disposal. In Bilaspur the source of disposal of municipal as well as industrial waste water is Arpa River (Non perennial) which is known as life line of Bilaspur city. The climatic change has already turned the perennial Arpa River into non Perennial River and at this time the Urbanization, Industrial growth and improved standard of living of people of Bilaspur have increased the strength and quantity of sewage in recent years to a point where dilution alone can no longer be relied upon to prevent the undesirable effect of pollution. Hence it is absolutely necessary to study the characteristics and behavior of sewage, to ensure its safe disposal. This study will help us in determining the degree and type of treatment required to a given sewage according to its characteristics and thus to avoid the pollution of the source of its disposal i.e. Arpa river so that the adverse effect of pollution on human health, aquatic life, animals and plants can be eliminated. For the present study we have selected 4 places in Bilaspur City for collection of sewage hence Sample 1 was collected at Vasant Vihar S.E.C.L. Colony, The sample 2 was collected from M/S Narmada Drinks Pvt. Ltd. Sirgitti, The sample 3 was collected at Pachrighat drain. The sample 4 was collected from Nalla near Bannak Chowk Sirgitti. The Chemical tests namely Suspended Solids, Dissolved Solids, Chloride Content, Chemical Oxygen Demand and Physical tests namely pH value, Temperature, Threshold Odour Number (TON) had been performed and the tests results were compared with Indian standards permissible limits. Priority of this journal is to provide our important and valuable information to all people who show interest. The test results indicated that the Sample-1Vasant Vihar is less polluted, Sample-2 Narmada Drinks only requires neutralization of Chloride Content, Sample-3 Pachrighat was polluted and required treatment in summer season for reducing Solids whereas Sample-4 Bannak Nalla was highly polluted and required throughout treatment of higher degree. Out of the four samples the Sample-4 (Nalla near Bannak Chowk) was found to be most polluted sample in terms of Suspended solids, Chloride content, C.O.D., B.O.D. &amp; T.O.N. and the drain containing this sample is being used by local public and is being discharged untreated into Arpa River. This Wastewater must be treated to prevent the Environment and the water bodies.

Comparison of air dilution sensory test and threshold odor number method for odor evaluation of wastewater and lake water

The object of this study is to investigate the relationship between the air dilution sensory test and the threshold odor number (TON) method for evaluating the odor of domestic wastewater, plating plant wastewater, food plant wastewater and lake water. The dilution factor of raw wastewater evaluated by the air dilution sensory test was in the order of food plant > plating plant > domestic > lake, and that evaluated by the threshold odor number method was in the order of food plant > domestic > plating plant > lake. The same results were obtained when the raw wastewater and lake water were diluted 2 and 5 times with pure water. The relative geometric standard deviation determined from the threshold values of each panel on the air dilution sensory test was much larger than that calculated from results derived from the threshold odor number method. The relative geometric standard deviation obtained from samples with a low dilution factor was greater. There was a very good linear correlation (correlation coefficient = 0.968~1.000) between the air dilution sensory test and the threshold odor number method. But, the reduction in odor intensity (the slopes of regression curves) by dilution was dependent on the types of the odor-emission sources.

Release of drinking water contaminants and odor impacts caused by green building cross-linked polyethylene (PEX) plumbing systems

Green buildings are increasingly being plumbed with crosslinked polyethylene (PEX) potable water pipe. Tap water quality was investigated at a six month old plumbing system and chemical and odor quality impacts of six PEX pipe brands were examined. Eleven PEX related contaminants were found in the plumbing system; one regulated (toluene) and several unregulated: Antioxidant degradation products, resin solvents, initiator degradation products, or manufacturing aides. Water chemical and odor quality was monitored for new PEX-a, -b and -c pipes with (2 mg/L free chlorine) and without disinfectant over 30 days. Odor and total organic carbon (TOC) levels decreased for all pipes, but odor remained greater than the USA's Environmental Protection Agency's (USEPA) secondary maximum contaminant level. Odors were not attributed to known odorants ethyl-tert-butyl ether (ETBE) or methyl-tert-butyl ether (MTBE). Free chlorine caused odor levels for PEX-a1 pipe to increase from 26 to 75 threshold odor number (TON) on day 3 and affected the rate at which TOC changed for each brand over 30 days. As TOC decreased, the ultraviolet absorbance at 254 nm increased. Pipes consumed as much as 0.5 mg/L as Cl2 during each 3 day stagnation period. Sixteen organic chemicals were identified, including toluene, pyridine, methylene trichloroacetate and 2,4-di-tert-butylphenol. Some were also detected during the plumbing system field investigation. Six brands of PEX pipes sold in the USA and a PEX-a green building plumbing system impacted chemical and drinking water odor quality.

Reduction of chlorinous odor by the combination of oxidation and ion-exchange treatments

Research Article| November 04 2013 Reduction of chlorinous odor by the combination of oxidation and ion-exchange treatments S. Echigo; S. Echigo 1Graduate School of Engineering, Kyoto University, C1, Nishikyo, Kyoto 615-8540, Japan E-mail: echigo@urban.env.kyoto-u.ac.jp Search for other works by this author on: This Site PubMed Google Scholar S. Itoh; S. Itoh 1Graduate School of Engineering, Kyoto University, C1, Nishikyo, Kyoto 615-8540, Japan Search for other works by this author on: This Site PubMed Google Scholar S. Ishihara; S. Ishihara 2Kobelco Eco-Solutions Co., Ltd, 1-4-78, Wakihama-cho, Chuo, Kobe 651-0072, Japan Search for other works by this author on: This Site PubMed Google Scholar Y. Aoki; Y. Aoki 3Ajinomoto Co., Inc., 1-1, Suzuki, Kawasaki, Kanagawa 210-8681, Japan Search for other works by this author on: This Site PubMed Google Scholar Y. Hisamoto Y. Hisamoto 4METAWATR Co. Ltd., 1, Fuji-cho, Hino, Tokyo 191-8502, Japan Search for other works by this author on: This Site PubMed Google Scholar Journal of Water Supply: Research and Technology-Aqua (2014) 63 (2): 106–113. https://doi.org/10.2166/aqua.2013.205 Views Icon Views Article contents Figures & tables Video Audio Supplementary Data Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Cite Icon Cite Permissions Search Site Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentAll JournalsThis Journal Search Advanced Search Citation S. Echigo, S. Itoh, S. Ishihara, Y. Aoki, Y. Hisamoto; Reduction of chlorinous odor by the combination of oxidation and ion-exchange treatments. Journal of Water Supply: Research and Technology-Aqua 1 March 2014; 63 (2): 106–113. doi: https://doi.org/10.2166/aqua.2013.205 Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex To better control chlorinous odor in tap water, we assessed the performance of the combination of oxidation (ozonation or advanced oxidation processes, AOP) and ion-exchange treatment. In this process, the hydrophilic neutral fraction (a major dissolved organic matter (DOM) fraction) is converted to ionic species, and these ions and ammonium ion are effectively removed during ion-exchange processes. We found that each treatment process (e.g., oxidation alone or ion exchange alone) was effective for the reduction of chlorinous odor to some extent, but the chlorinous odor formation potential was lower when the oxidation process and ion exchange were applied in series. The combination of AOP (ozone/vacuum ultraviolet treatment) at a high ozone dose and ion exchange (both cation and anion) was most effective, and the chlorinous odor formation potential was reduced to approximately 30 TON (threshold odor number) from more than 100 TON. Also, dissolved organic carbon and ammonium ion were effectively removed with this process. Compared with ozonation, AOP was more effective at a higher ozone dose. The effectiveness of this process was also confirmed in continuous mode by pilot-scale experiment. advanced oxidation, ammonium ion, chlorinous odor, dissolved organic matter, ion exchange, trichloramine This content is only available as a PDF. © IWA Publishing 2014 You do not currently have access to this content.

Impact of temperature and storage duration on the chemical and odor quality of military packaged water in polyethylene terephthalate bottles

The impact of temperature and storage time on military packaged water (MPW) quality was examined at four temperatures (23.0°C to 60.0°C) for 120days. Polyethylene terephthalate (PET) bottles were filled in California and Afghanistan with unbuffered water treated by reverse osmosis. The US military's water pH long-term potability standard was exceeded, and US Food and Drug Administration (USFDA) and US Environmental Protection Agency (USEPA) drinking water pH and odor intensity limits were also exceeded. During a 70day exposure period, Port Hueneme MPW total organic carbon and total trihalomethane levels increased from <0.25mg/L to 2.0±0.0mg/L and <0.05μg/L to 51.5±2.1μg/L, respectively. PET released organic contaminants into MPW and residual disinfectant generated trihalomethane contaminants. After 14days at 37.7°C and 60.0°C, Afghanistan MPW threshold odor number values were 8.0 and 8.6, respectively. Total organic carbon concentration only increased with exposure duration at 60.0°C. Acetaldehyde and formaldehyde contaminants were not detected likely due to the high method detection limits applied in this study. Phthalate contaminants detected and their maximum levels were butylbenzylphthalate (BBP) 0.43μg/L, di-n-butylphthalate (DnBP) 0.38μg/L, di(2-ethylhexyl)phthalate (DEHP) 0.6μg/L, and diethylphthalate (DEP) 0.32μg/L. Antimony was only detected in 60.0°C Afghanistan MPW on Day 28 and beyond, and its maximum concentration was 3.6±0.3μg/L. No antimony was found in bottles exposed to lesser temperatures. Environmental health, PET synthesis and bottle manufacturers, and bottle users can integrate results of this work to improve health protective decisions and doctrine.

Relationship between Threshold Odor Number and BOD of River Water

Relationship between Threshold Odor Number and BOD of River Water

Long-term study of migration of volatile organic compounds from cross-linked polyethylene (PEX) pipes and effects on drinking water quality

The objectives of this study were to investigate migration of volatile organic compounds (VOCs) from cross-linked polyethylene (PEX) pipes used for drinking water produced by different production methods, and to evaluate their potential risk for human health and/or influence on aesthetic drinking water quality. The migration tests were carried out in accordance with EN-1420-1, and VOCs were analysed by gas chromatography-mass spectrometry. The levels of VOC migrating from new PEX pipes were generally low, and decreasing with time of pipe use. No association was found between production method of PEX pipes and concentration of migration products. 2,4-di-tert-butyl phenol and methyl tert-butyl ether (MTBE) were two of the major individual components detected. In three new PEX pipes, MTBE was detected in concentrations above the recommended US EPA taste and odour value for drinking water, but decreased below this value after 5 months in service. However, the threshold odour number (TON) values for two pipes were similar to new pipes even after 1 year in use. For seven chemicals for which conclusions on potential health risk could be drawn, this was considered of no or very low concern. However, odour from some of these pipes could negatively affect drinking water for up to 1 year.