Identification and chemical characterization of specific organic constituents of petrochemical effluents

Based on extensive GC/MS screening analyses, the molecular diversity of petrochemical effluents discharged to a river in North Rhine-Westphalia was characterised. Within a wide spectrum of organic wastewater constituents, specific compounds that might act as source indicators have been determined. This differentiation was based on (i) the individual molecular structures, (ii) the quantitative appearance of organic compounds in treated effluents and (iii) the information on their general occurrence in the technosphere and hydrosphere. Principally, site-specific indicators have been distinguished from candidates to act as general petrochemical indicators. Further on, monitoring the environmental behaviour of target organic contaminants in an aquatic system shortly after their release into the river allowed a first evaluation of the impact of the petrogenic emission in terms of the quantity and spatial distribution.The identification of petrogenic contaminants was not restricted to constituents of the effluents only, but comprised the compounds circulating in the wastewater systems within a petrochemical plant. A number of environmentally relevant and structurally specific substances that are normally eliminated by wastewater treatment facilities were identified. Insufficient wastewater treatment, careless waste handling or accidents at industrial complexes are potential sources for a single release of the pollutants.This study demonstrates the relevance of source specific organic indicators to be an important tool for comprehensive assessment of the potential impact of petrochemical activities to the contamination of an aquatic environment.     

Screening of plant species for the phytotreatment of wastewater containing sulphonated anthraquinones

Sulphonated anthraquinones are known to be recalcitrant to biodegradation and are not eliminated by traditional wastewater treatment plants, leading to their accumulation in fresh water. Due to the high cost and limited efficiency of existing physical-chemical treatments, alternative cheaper processes are required to remove these compounds from industrial effluents. Four plant species were tested under hydroponic conditions for their ability to treat model effluents contaminated with mono- and disulphonated anthraquinones. Among them, Rheum rabarbarum (rhubarb) showed the most promising results and was chosen for further investigation. The apparent transpiration stream concentration factor obtained with this plant species reached up to 2.5, indicating a strong phytotreatment potential that should be further explored then exploited.     

Identification of organic compounds and ecotoxicological assessment of sewage treatment plants (STP) effluents

An integrated approach combining chemistry and biological methods was conducted to assess the toxicity of seven sewage treatment plant effluents. Solid phase concentration procedures were applied to facilitate the study of organic micro pollutants. A chemical analysis was performed by GC/MS. Organic fraction toxicity was determined by using bioassays such as Daphnia magna and Chlorella vulgaris tests and sub-lethal effects were also evaluated by using Salmonella typhimurium Test (mutagenicity), recombinant yeast screen (estrogenicity), and Oryzias latipes embryo-larval test. More than 49 compounds were detected in the organic fraction due to the various inputs of each effluents. The most frequently detected compounds in the effluents were bisphenol A (BPA), octylphenol (OP), 1,2-benzenedicarboxylic acid, bis(2-ethylhexyl) ester (DEHP) and 1,2-benzenedicarboxylic acid, bis(methylpropyl) ester (DBP). Biological assays showed toxicity effects on D. magna tests in all samples, whereas toxicity on C. vulgaris or S. typhimurium tests were not observed. Estrogenicity and teratogenicity were observed in several samples. The cause-effect relationship could not be established given the high chemical complexity of the effluents and the lack of information available on 70% of the detected compounds subsequent to reviewing various data bases. Nevertheless, due to the high chemical variability revealed by STP effluents, bioassay sets may provide a very useful amount of information for detecting potential toxicity risks.     

Use of a chemical sensor array for detecting pollutants in domestic wastewater

A chemical sensor array (consisting of 8 conducting polymers) was used to continuously monitor for the presence or absence of industrial pollutants in the headspace of wastewater generated from an on-line flow-cell. A domestic wastewater (Cranfield University sewage works) was dosed with diesel to stimulate the presence of an intermittent discharge in a wastewater influent. Response patterns between the sensors were used to detect for the presence of organic compounds in the wastewater. Correlations between the sensor response patterns or fingerprints were also analysed using principal component analysis. The results clearly demonstrate that a chemical sensor array can rapidly identify the presence of organic compounds (such as diesel) in a wastewater matrix and could be further developed to monitor for industrial pollutants at the inlet of a sewage works.     

Biological assessment of contaminated land using earthworm biomarkers in support of chemical analysis

Biological indicators can be used to assess polluted sites but their success depends on the availability of suitable assays. The aim of this study was to investigate the performance of two earthworm biomarkers, lysosomal membrane stability measured using the neutral red retention assay (NRR-T) and the total immune activity (TIA) assay, that have previously been established as responsive to chemical exposure. Responses of the two assays were measured following in situ exposure to complexly contaminated field soils at three industrial sites as well as urban and rural controls. The industrial sites were contaminated with a range of metal (cadmium, copper, lead, zinc, nickel and cobalt) and organic (including polycyclic aromatic hydrocarbons) contaminants, but at concentrations below the 'New Dutch List' Intervention concentrations. Exposed earthworms accumulated both metals and organic compounds at the contaminated sites, indicating that there was significant exposure. No effect on earthworm survival was found at any of the sites. Biomarker measurements, however, indicated significant effects, with lower NRR-T and TIA found in the contaminated soils when compared to the two controls. The results demonstrate that a comparison of soil pollutant concentrations with guideline values would not have unequivocally identified chemical exposure and toxic effect for soil organisms living in these soils. However, the earthworm biomarkers successfully identified significant exposure and biological effects caused by the mixture of chemicals present.     

The microcoulometric determination of extractable organic halogen in surface water; Application to surface waters of The Netherlands

In this paper an analytical method is described for the microcoulometric determination of extractable organic halogen, especially chlorine, in surface waters and sediments. The minimum detectable amounts of chlorine are respectivelly 1.0 μg/l (ppb) in water and 0.5 mg/kg (ppm) in sediments. The results of a monitoring program in the river Rhine and several Dutch surface waters with respect to this parameter are presented. The results cover the period January 1973 to December 1975.In 1973, 1974 and 1975 the average daily loads of organic halogen calculated as chlorine in the river Rhine at Lobith were 3300, 3410 and 2050 kg, respectively.The parameter “Extractable Organic Chlorine” (EOCl) is suggested as a useful general indicator for chemical pollution in surface waters and in effluents from industrial plants.     

Indicator compounds for assessment of wastewater effluent contributions to flow and water quality

Numerous studies have reported the presence of trace (i.e., ng/L) organic chemicals in municipal wastewater effluents, but it is unclear which compounds will be useful to evaluate the contribution of effluent to overall river flow or the attenuation processes that occur in receiving streams. This paper presents a new approach that uses a suite of common trace organic chemicals as indicators to assess the degree of impact and attenuation of trace organic chemicals in receiving streams. The utility of the approach was validated by effluent monitoring at ten wastewater treatment plants and two effluent-impacted rivers with short retention times (<17 h). A total of 56 compounds were particularly well suited as potential indicators, occurring frequently in effluent samples at concentrations that were at least five times higher than their limit of quantification. Monitoring data from two effluent-impacted rivers indicated that biotransformation was not important for these two river stretches, whereas photolysis attenuation was possibly important for the shallow river. The application of this approach to receiving waters and water reclamation and reuse systems will allow for more effective allocation of resources in future monitoring programs.     

Study of catalyzed ozonation for advanced treatment of pulp and paper mill effluents

Ozonation and catalytic ozonation (TOCCATA process) were used as tertiary treatments of wastewaters from three different pulp and paper mills. Laboratory batch experiments were conducted to assess the efficiency of each oxidation system for removal of organic matter. The investigations measured ozone consumption rate, variations in chemical oxygen demand (COD), total organic carbon (TOC), suspended solids (SS) and molecular weight distribution with contact time. For conventional ozonation, ozone consumption rate was dependent on the nature of the effluent. Organic matter elimination occurred both by oxidation and precipitation. Precipitation played a major role on TOC removal varying with the effluent, and was responsible for production of high final SS concentrations. However, the effluent type did not affect the ozone consumption rate for TOCCATA-catalyzed reactions. Using TOCCATA, it was shown that organic matter was removed through steady conversion of organic carbon to carbon dioxide. Finally the two oxidation systems were compared with respect to their impact on molecular weight distribution. A total removal of the two initial fractions of compounds (high and low molecular weights) was observed with two effluents. With the third effluent, only the initial fraction of low molecular weight compounds was removed by the two oxidizing systems. The results showed that ozonation and TOCCATA-catalyzed ozonation could achieve removals of COD of 36-76%. Depending on the effluent type, the amount of ozone consumed per gram of COD removed was lower for conventional or for catalytic ozonation.     

Economic evaluation of alternative wastewater treatment plant options for pulp and paper industry

Excessive water consumption in pulp and paper industry results in high amount of wastewater. Pollutant characteristics of the wastewater vary depending on the processes used in production and the quality of paper produced. However, in general, high organic material and suspended solid contents are considered as major pollutants of pulp and paper industry effluents. The major pollutant characteristics of pulp and paper industry effluents in Turkey were surveyed and means of major pollutant concentrations, which were grouped in three different pollution grades (low, moderate and high strength effluents), and flow rates within 3000 to 10,000 m³/day range with 1000 m³/day steps were used as design parameters. Ninety-six treatment plants were designed using twelve flow schemes which were combinations of physical treatment, chemical treatment, aerobic and anaerobic biological processes. Detailed comparative cost analysis which includes investment, operation, maintenance and rehabilitation costs was prepared to determine optimum treatment processes for each pollution grade. The most economic and technically optimal treatment processes were found as extended aeration activated sludge process for low strength effluents, extended aeration activated sludge process or UASB followed by an aeration basin for medium strength effluents, and UASB followed by an aeration basin or UASB followed by the conventional activated sludge process for high strength effluents.     

Reactivity and chemical characterization of effluent organic nitrogen from wastewater treatment plants determined by Fourier transform ion cyclotron resonance mass spectrometry

In advanced wastewater treatment plants that achieve high levels of nitrogen (N) removal, up to one-third of the N in effluent is organic, herein referred to as effluent organic N (EON). While we know that inorganic N is highly labile, it is unclear what fraction of EON is bioavailable. In this study, we demonstrate the utility of a method that can be used to examine the reactivity of EON in natural receiving waters to better understand both the ecosystem response and the potential bioavailability of EON. The technique is suitable for analyzing polar organic matter in natural waters; electrospray ionization coupled with Fourier transform mass spectrometry. Bioassays were performed on samples collected at the end of the biological process from two wastewater treatment plants achieving advanced N removal. The samples were concentrated, and then added to natural water samples collected from the oligohaline James River, a major tributary of the Chesapeake Bay. Our results demonstrate that while the lignin-like fraction of the effluent dissolved organic matter (some of which contains N) was conserved, a large portion of aliphatic and aromatic compounds containing N was removed (79-100%) during incubations, while other compounds were produced. Furthermore, the two effluents exhibited differences in the degree of degradation and type of degradation, which can be related both to the various processes employed in the two WWTPs and the dramatic differences in the type of influent they received. These findings suggest that EON is highly reactive in the natural environment and that simple assays examining net consumption or production of bulk dissolved organic N pools are inadequate for assessing the bioavailability of EON.     

Anthropogenic organic contaminants in sediments of the Lippe river, Germany

Sediment samples of the Lippe river (Germany) taken between August 1999 and March 2001 were investigated by GC-MS-analyses. These analyses were performed as non-target-screening approaches in order to identify a wide range of anthropogenic organic contaminants. Unknown contaminants like 3,6-dichlorocarbazole and bis(4-octylphenyl)amine as well as anthropogenic molecular marker compounds were selected for quantification. The obtained qualitative and quantitative analytical results were interpreted in order to visualize the anthropogenic contamination of the Lippe river including spatial distribution, input effects and time dependent occurrence. Anthropogenic molecular markers derived from municipal sources like polycyclic musks, 4-oxoisophorone and methyltriclosan as well as from agricultural sources (hexachlorobenzene) were gathered. In addition molecular markers derived from effluents of three different industrial branches, e.g. halogenated organics, tetrachlorobenzyltoluenes and tetrabutyltin, were identified. While municipal and agricultural contaminations were ubiquitous and diffusive, industrial emission sources were spatially isolated. Specific seasonal trends of distribution patterns were not observed.     

The elimination of sulfur dioxide interference in the low level chemical oxygen demand analysis

Sulfur dioxide is a reduced compound which acts as a positive interference in the chemical oxygen demand (COD) analysis. Significant amounts of sulfur dioxide present in industrial waste samples may therefore result in erroneously high COD values, compared to that of a sample with only the organic portion of the waste. By adding 65 mg l⁻¹ Mn²⁺ to a secondary wastewater sample spiked with 500 mg l⁻¹ sulfur dioxide, and oxygenating the sample for 6 min, sulfur dioxide was oxidized completely to sulfate. This oxidation procedure provides a statistically valid means of removing SO₂ interference in the COD analysis. The procedure provides an efficient means of investigating the organic COD of industrial effluents laden with SO₂ or its dissociation products.     

Organic pollutants in the effluents of large wastewater treatment plants in Sweden

Effluents from the three largest WWTPs in Sweden were analysed for the presence of organic pollutants by GC-MS. From a total of 137 identified compounds only 10 were priority pollutants. A broad spectrum of non-regulated organic pollutants found in the effluents included aromatic hydrocarbons, food and household related compounds, solvents, plasticisers, flame retardants, preservatives, antioxidants and washing and cleaning related compounds. The concentrations of individual compounds in effluents of all three WWTPs were in the range of 0.5–50 μg/l. Rather few point-discharged pollutants from specific industries were present in the effluents. The majority of pollutants detected in the effluents were attributable to the overall usage and discharge of chemical products in modern society. These pollutants originate from diffuse sources and represent “a background chemical pollution load” of the receiving waters through the discharge from WWTPs in large cities.     

Secondary organic aerosol formation from a large number of reactive man-made organic compounds

A photochemical trajectory model has been used to examine the relative propensities of a wide variety of volatile organic compounds (VOCs) emitted by human activities to form secondary organic aerosol (SOA) under one set of highly idealised conditions representing northwest Europe. This study applied a detailed speciated VOC emission inventory and the Master Chemical Mechanism version 3.1 (MCM v3.1) gas phase chemistry, coupled with an optimised representation of gas-aerosol absorptive partitioning of 365 oxygenated chemical reaction product species. In all, SOA formation was estimated from the atmospheric oxidation of 113 emitted VOCs. A number of aromatic compounds, together with some alkanes and terpenes, showed significant propensities to form SOA. When these propensities were folded into a detailed speciated emission inventory, 15 organic compounds together accounted for 97% of the SOA formation potential of UK man made VOC emissions and 30 emission source categories accounted for 87% of this potential. After road transport and the chemical industry, SOA formation was dominated by the solvents sector which accounted for 28% of the SOA formation potential.     

Degradation of industrial waste waters on Fe/C-fabrics. Optimization of the solution parameters during reactor operation

This study addresses the pre-treatment of toxic and recalcitrant compounds found in the waste waters arriving at a treating station for industrial effluents containing chlorinated aromatics and non-aromatic compounds, anilines, phenols, methyl-tert-butyl-ether (MTBE). By reducing the total organic carbon (TOC) of these waste waters the hydraulic load for the further bacterial processing in the secondary biological treatment is decreased. The TOC decrease and discoloration of the waste waters was observed only under light irradiation in the reactor by immobilized Fenton processes on Fe/C-fabrics but not in the dark. The energy of activation for the degradation of the waste waters was of 4.2 kcal/mol. The degradation of the waste waters was studied in the reactor as a function of (a) the amount of oxidant used (H2O2), (b) the recirculation rate, (c) the solution pH and (d) the applied temperature. With these parameters taken as input factors, statistical modeling allows one to estimate the most economic use of the oxidant and electrical energy to degrade these waste waters. The concentration of the most abundant organic pollutants during waste waters degradation was followed by gas chromatography/mass spectrometry (GC-MS). The ratio of the biological oxygen demand to the total organic carbon BOD5/TOC increased significantly due to the Fe/C-fabric catalyzed treatment from an initial value of 2.03 to 2.71 (2 h). The reactor results show that the recirculation rate has no influence on the TOC decrease of the treated waters but affects the BOD increase of these solutions.     

Bioanalytical and chemical assessment of the disinfection by-product formation potential: Role of organic matter

Disinfection by-products (DBP) formed from natural organic matter and disinfectants like chlorine and chloramine may cause adverse health effects. Here, we evaluate how the quantity and quality of natural organic matter and other precursors influence the formation of DBPs during chlorination and chloramination using a comprehensive approach including chemical analysis of regulated and emerging DBPs, total organic halogen quantification, organic matter characterisation and bioanalytical tools. In vitro bioassays allow us to assess the hazard potential of DBPs early in the chain of cellular events, when the DBPs react with their molecular target(s) and activate stress response and defence mechanisms. Given the reactive properties of known DBPs, a suite of bioassays targeting reactive modes of toxic action including genotoxicity and sensitive early warning endpoints such as protein damage and oxidative stress were evaluated in addition to cytotoxicity. Coagulated surface water was collected from three different drinking water treatment plants, along with reverse osmosis permeate from a desalination plant, and DBP formation potential was assessed after chlorination and chloramination. While effects were low or below the limit of detection before disinfection, the observed effects and DBP levels increased after disinfection and were generally higher after chlorination than after chloramination, indicating that chlorination forms higher concentrations of DBPs or more potent DBPs in the studied waters. Bacterial cytotoxicity, assessed using the bioluminescence inhibition assay, and induction of the oxidative stress response were the most sensitive endpoints, followed by genotoxicity. Source waters with higher dissolved organic carbon levels induced increased DBP formation and caused greater effects in the endpoints related to DNA damage repair, glutathione conjugation/protein damage and the Nrf2 oxidative stress response pathway after disinfection. Fractionation studies indicated that all molecular weight fractions of organic carbon contributed to the DBP formation potential, with the humic rich fractions forming the greatest amount of DBPs, while the low molecular weight fractions formed more brominated DBPs due to the high bromide to organic carbon ratio. The presence of higher bromide concentrations also led to a higher fraction of brominated DBPs as well as proportionally higher effects. This study demonstrates how a suite of analytical and bioanalytical tools can be used to effectively characterise the precursors and formation potential of DBPs.     

Treatment of textile waste effluents by ozonation and chemical coagulation

Ozonation experiments in a multiple reactor system were conducted to investigate the efficiency of this process in reducing the color and chemical oxygen demand of the textile waste effluents. It has been observed that decolorization of those waste effluents can be achieved in less than 10 min in all tested cases. In conjunction with chemical coagulation, the chemical oxygen demand of those waste effluents can be consistently reduced by up to 70% or more. Ozonation is capable of decomposing the highly structured dye molecules into smaller ones which can be easily biodegraded in an activated sludge process. Hence combination of ozonation, chemical coagulation and the activated sludge processes can provide a very effective means for dealing with this particular type of industrial waste effluent.     

EU-wide monitoring survey on emerging polar organic contaminants in wastewater treatment plant effluents

In the year 2010, effluents from 90 European wastewater treatment plants (WWTPs) were analyzed for 156 polar organic chemical contaminants. The analyses were complemented by effect-based monitoring approaches aiming at estrogenicity and dioxin-like toxicity analyzed by in vitro reporter gene bioassays, and yeast and diatom culture acute toxicity optical bioassays. Analyses of organic substances were performed by solid-phase extraction (SPE) or liquid–liquid extraction (LLE) followed by liquid chromatography tandem mass spectrometry (LC-MS-MS) or gas chromatography high-resolution mass spectrometry (GC-HRMS). Target microcontaminants were pharmaceuticals and personal care products (PPCPs), veterinary (antibiotic) drugs, perfluoroalkyl substances (PFASs), organophosphate ester flame retardants, pesticides (and some metabolites), industrial chemicals such as benzotriazoles (corrosion inhibitors), iodinated x-ray contrast agents, and gadolinium magnetic resonance imaging agents; in addition biological endpoints were measured. The obtained results show the presence of 125 substances (80% of the target compounds) in European wastewater effluents, in concentrations ranging from low nanograms to milligrams per liter. These results allow for an estimation to be made of a European median level for the chemicals investigated in WWTP effluents. The most relevant compounds in the effluent waters with the highest median concentration levels were the artificial sweeteners acesulfame and sucralose, benzotriazoles (corrosion inhibitors), several organophosphate ester flame retardants and plasticizers (e.g. tris(2-chloroisopropyl)phosphate; TCPP), pharmaceutical compounds such as carbamazepine, tramadol, telmisartan, venlafaxine, irbesartan, fluconazole, oxazepam, fexofenadine, diclofenac, citalopram, codeine, bisoprolol, eprosartan, the antibiotics trimethoprim, ciprofloxacine, sulfamethoxazole, and clindamycine, the insect repellent N,N′-diethyltoluamide (DEET), the pesticides MCPA and mecoprop, perfluoroalkyl substances (such as PFOS and PFOA), caffeine, and gadolinium.     

Occurrence and suitability of sucralose as an indicator compound of wastewater loading to surface waters in urbanized regions

Urban watersheds are susceptible to numerous pollutant sources and the identification of source-specific indicators can provide a beneficial tool in the identification and control of input loads, often times needed for a water body to achieve designated beneficial uses. Differentiation of wastewater flows from other urban wet weather flows is needed in order to more adequately address such environmental concerns as water body nutrient impairment and potable source water contamination. Anthropogenic compounds previously suggested as potential wastewater indicators include caffeine, carbamazepine, N,N-diethyl-meta-toluamide (DEET), gemfibrozil, primidone, sulfamethoxazole, and TCEP. This paper compares the suitability of a variety of anthropogenic compounds to sucralose, an artificial sweetener, as wastewater indicators by examining occurrence data for 85 trace organic compounds in samples of wastewater effluents, source waters with known wastewater point source inputs, and sources without known wastewater point source inputs. The findings statistically demonstrate the superior performance of sucralose as a potential indicator of domestic wastewater input in the U.S. While several compounds were detected in all of the wastewater effluent samples, only sucralose was consistently detected in the source waters with known wastewater discharges, absent in the sources without wastewater influence, and consistently present in septic samples. All of the other compounds were prone to either false negatives or false positives in the environment.     

Nonylphenol polyethoxylate degradation in aqueous waste by the use of batch and continuous biofilm bioreactors

An aerobic bacterial consortium (Consortium A) was recently obtained from textile wastewater and was capable of degrading 4-nonylphenol and nonylphenol polyethoxylates (NPnEOs). In the perspective of developing a biotechnological process for the treatment of effluents from activated sludge plants fed with NPnEO contaminated wastewater, the capability of Consortium A of biodegrading an industrial mixture of NPnEOs in the physiological condition of immobilized cells was investigated. Two identically configured packed bed reactors were developed by immobilizing the consortium on silica beads or granular activated carbon. Both reactors were tested in batch and continuous mode by feeding them with water supplemented with NPnEOs. The two reactors were monitored through chemical, microbiological and molecular integrated methodology. Active biofilms were generated on both immobilization supports. Both reactors displayed comparable NPnEO mineralization under batch and continuous conditions. FISH analyses evidenced that the biofilms evolved with time by changing the reactor operation mode and the organic load. Taken together, the data collected in this study provide a preliminary strong indication on the feasibility of Consortium A-based biofilm technology for the decontamination of NPnEO containing effluents.