Changes in water quality of treated sewage effluents by their receiving environments in Tablas de Daimiel National Park,Spain

The Tablas de Daimiel National Park (TDNP), a floodplain wetland located in the Upper Guadiana Basin (central Spain), receives pollution from wastewater treatment plants (WWTPs) discharging their treated sewage effluents (TSEs) to tributary channels to the wetland. The TSEs suffer transformations on their way to the TDNP, but the water quality is controlled only at the point of discharge. In this work, we analyse the change in water quality of the TSE from four urban WWTPs in the surroundings of the TDNP (Alcázar de San Juan, Daimiel, Manzanares and Villarrubia de los Ojos towns). The water samples were taken at the outlet of the plants and in the receiving environments, to analyse the water quality transformation of the TSE. The different discharge configurations of each WWTP have been related with the water quality transformation of their TSE, to interpret the influence of the hydro-geomorphology in the improvement or deterioration of the water quality of TSE. We found that the discharge of TSE into slow flow channels with macrophyte vegetation facilitates water self-purification but, with time, the accumulation of sludge in the beds of the effluents tends to be the cause of the deterioration of the water quality.     

Migration of polycyclic aromatic hydrocarbons (PAHs) in urban treatment sludge to the air during PAH removal applications

In the present study, the amounts of polycylic aromatic hydrocarbons (PAHs) penetrating into air during PAH removal applications from the urban treatment sludge were investigated. The effects of the temperature, photocatalyst type, and dose on the PAH removal efficiencies and PAH evaporation were explained. The sludge samples were taken from an urban wastewater treatment plant located in the city of Bursa, with 585,000 equivalent population. The ultraviolet C (UV-C) light of 254 nm wavelength was used within the UV applications performed on a specially designed setup. Internal air of the setup was vacuumed through polyurethane foam (PUF) columns in order to collect the evaporated PAHs from the sludge during the PAH removal applications. All experiments were performed with three repetitions. The PAH concentrations were measured by gas chromatography–mass spectrometry (GC-MS). It was observed that the amounts of PAHs penetrating into the air were increased with increase of temperature, and more than 80% of PAHs migrated to the air consisted of 3-ring compounds during the UV and UV-diethylamine (DEA) experiments at 38 and 53 °C. It was determined that 40% decrease was ensured in Σ₁₂ (total of 12) PAH amounts with UV application and 13% of PAHs in sludge penetrated into the air. In the UV-TiO₂ applications, a maximum 80% of Σ₁₂ PAH removal was obtained by adding 0.5% TiO₂ of dry weight of sludge. The quantity of PAH penetrating into air did not exceed 15%. UV-TiO₂ applications ensured high levels of PAH removal in the sludge and also reduced the quantity of PAH penetrating into the air. Within the scope of the samples added with DEA, there was no increase in PAH removal efficiencies and the penetration of PAHs into air was not decreased. In light of these data, it was concluded that UV-TiO₂ application is the most suitable PAH removal alternative that restricts the convection of PAH pollution.

Implications: Polycyclic aromatic hydrocarbon (PAH) evaporation rates from sludge samples obtained from an urban wastewater treatment plant were investigated here for the first time by employing removal applications. TiO₂ and diethylamine were used as photocatalysts in this study. A special device was designed and successfully used in this study. Treatment sludge can be a significant source of PAHs for the atmosphere. The data highlight the need for removal of PAHs in treatment sludge via methods limiting their evaporation to the air. It was observed that UV-TiO₂ application was the most suitable PAH removal alternative that restricts the convection of PAH pollution.     

Distribution of perfluorinated compounds in surface water from Hanjiang River in Wuhan,China

This study provided the first spatial distribution of perfluorinated compounds (PFCs) in Hanjiang River in Wuhan, China (HR). Surface water samples, collected from 23 sites in HR were analyzed for eight PFCs. The total concentrations of PFCs ranged from 8.90 to 568 ng L⁻¹, while perfluoropentanoic acid (PFOA, <LOQ − 256 ng L⁻¹) and perfluorooctane sulfonate (PFOS, <LOQ − 88.9 ng L⁻¹) dominated. All data were found to be normally distributed in the river. Similar spatial distribution tendencies were found among perfluorocarboxylates (PFCAs) and significant correlations were observed among PFCAs, while no significant correlations were found between PFOS and PFCAs. The distributions of PFCs were highly influenced by the industrial discharge and urban activities. The flux of PFCs from HR to the Yangtze River was estimated in the range of 16.9–127 kg yr⁻¹. More than a half of the samples studied could not meet the drinking water standards and avian wildlife values, suggesting further studies of characterizing PFCs and their potential risk to human were needed.     

Perfluorochemicals in wastewater treatment plants and sediments in Hong Kong

The study reported in this paper examined the concentrations of nineteen perfluorochemicals (PFCs), including perfluoroalkyl sulfonates, carboxylates, and sulfonamides in samples collected from Hong Kong wastewater treatment plants (WWTPs) and sediments. The study was the first to use an external isolator column to assist in the quantification of PFCs in environmental samples without having to make internal modifications to a liquid chromatography system. Perfluorooctanesulfonate was found to be the dominant PFC pollutant in Hong Kong, and the WWTP sludge was the major sink of PFCs discharged from the urban areas. Compared to discharge influenced by industrial activities, much less perfluorooctanoate was found in waste streams. The significantly lower level of perfluorodecanesulfonate in WWTP sludge reflects the important influence of consumer products on PFC distribution. The dominance of even-chain length perfluoroalkyl carboxylates in all of the WWTP sludge samples investigated further suggests the strong aerobic degradation of fluorotelomer alcohols in WWTPs.     

Levels, profile and pattern of PCDDs and PCDFs in samples related to the production and use of chlorine

Analyses of sludge from graphite electrodes used in the chloralkali process show total levels of PCDFs as high as 650000 pg/g sludge. The levels of tetra-, penta-and hexaCDFs were found to be approximately the same. The levels for the corresponding PCDDs were below the detection level. The dominating congeners within each group are the toxic 2,3,7,8-substituted PCDFs at levels of 340000 pg/g, This typical pattern, called the “chloralkali pattern” can also be found in soil samples taken at another chloralkali plant. The typical pattern can also be identified in a solution of ferric chloride. Traces of “chloralkali pattern” are identified in a sludge sample from the drinking water purification plant, the source for PCDFs in the sludge is unknown.     

The concentrations and distribution of polycyclic musks in a typical cosmetic plant

Polycyclic musks [cashmeran (DPMI), celestolide (ADBI), phantolide (AHMI), traseolide (ATII), tonalide (AHTN) and galaxolide (HHCB)] in the air, wastewater, sludge samples of a typical cosmetic plant were analyzed. DPMI, ADBI, HHCB and AHTN were found in all samples, and ATII was not found in any sample. HHCB and AHTN were the major components in all samples. The polycyclic musk concentrations were very high in the air of the cosmetic plant, and polycyclic musks were mostly contained in the gas phase at the percentage of 86.35-97.70%. Average polycyclic musk concentrations in effluent were high, and ranged from 0.62 to 32.06 microgl-1. The removal efficiency during the active sludge wastewater treatment was also high, resulting from the adsorption of those compounds into the sludge. So the polycyclic musk concentrations were very high in the primary sludge and second sludge, and ranged from 1.78 to 92.45 mgkg-1 (dry), and from 2.87 to 65.67 mgkg-1 (dry), respectively. Results suggested that the sludge needed to be further treated to make polycyclic musks less influence to the environment.     

An international survey of decabromodiphenyl ethane (deBDethane) and decabromodiphenyl ether (decaBDE) in sewage sludge samples

Decabromodiphenyl ethane (deBDethane) is an additive flame retardant marketed as a replacement for decabromodiphenyl ether (decaBDE). The structures of the two chemicals are similar, and hence deBDethane may also become an environmental contaminant of concern. Environmental data on deBDethane are scarce. Since sewage sludge is an early indicator of leakage of these chemicals into the environment, an international survey of deBDethane and decaBDE levels in sludge was conducted. Samples were collected from 42 WWTPs in 12 different countries and analyzed with GC/LRMS. DeBDethane was present in sludge from all countries and may therefore be a worldwide concern. The levels of deBDethane in sludge samples from the Ruhr area of Germany were the highest so far reported in the literature (216 ng g⁻¹ d.wt.). The [deBDethane]/[decaBDE] quotient for the whole data set ranged from 0.0018 to 0.83. High ratios were found in and around Germany where deBDethane imports are known to have been high and substitution of decaBDE with deBDethane is likely to have occurred. Low ratios were found in the USA and the UK, countries that have traditionally been large users of decaBDE. An estimate of the flux of deBDEthane from the technosphere via WWTPs to the environment within the European Union gave 1.7 ± 0.34 mg annually per person. The corresponding value for decaBDE was 41 ± 22 mg annually per person.     

深圳笔架山水厂优化节水的实验研究

针对目前我国城镇需水量大、原水费用高的问题,大多数水厂通过降低自用水量的方式节约水资源。经过在笔架山水厂进行的生产性实验,优化耗水工艺的运行条件,挖潜了该水厂的节水空间,自用水量降低。优化后,全处理系统可节约水资源76.83万m3/a,耗水率由原来的2.08%下降到1.49%,同时水厂的经济效益也得到了显著提高,优化后可在原来的基础上节约运行成本近60万元/a。     

Formation of PFOA from 8:2 FTOH in closed-bottle experiments with brackish water

The formation of perfluorooctanoate (PFOA) from 1H,1H,2H,2H-perfluorodecanol (8:2 FTOH) was studied for the first time in laboratory experiments with brackish water. The water samples were collected from the Baltic Sea, which is one of the largest brackish water areas in the world and is polluted with PFOA and other perfluorinated compounds. The formation of PFOA was studied in closed-bottle experiments at different water temperatures. As a reference experiment, a modified OECD 310 test was conducted with sludge from a wastewater treatment plant and with brackish water. The PFOA and 8:2 FTOH were concentrated from water samples by solid-phase extraction (SPE) and were analysed using liquid chromatography–mass spectrometry. The effect of oxygen concentration on the formation of PFOA was studied using surface water samples with high and low oxygen contents. Other experiments were performed with oxygen-rich surface water and oxygen-deficient bottom water. The formation of PFOA was observed in all experiments; it was higher in the trial performed with brackish water than in the reference test carried out with sludge. Clear temperature dependence was observed in the formation of PFOA in brackish water tests; after a 30-day test period, a sixfold increase was observed in the amount of PFOA in surface water between the temperatures of 15 and 20 °C. Microbes were suggested as the major cause of the formation of PFOA, but other environmental characteristics, such as oxygen, could also affect the formation potential of PFOA.     

The contribution of azo dyes to the mutagenic activity of the Cristais River

To verify whether dyes emitted within the discharge of a dye processing plant were contributing to the mutagenicity repeatedly found in the Cristais River, Sao Paulo, Brazil, we chemically characterized the following mutagenic samples: the treated industrial effluent, raw and treated water, and the sludge produced by a Drinking Water Treatment Plant (DWTP) located approximately 6 km from the industrial discharge. Considering that 20% of the dyes used for coloring activities might be lost to wastewaters and knowing that several dyes have mutagenic activity, we decided to analyze the samples for the presence of dyes. Thin layer chromatographic analysis indicated the presence of three prevalent dyes in all samples, except for the drinking water. This combination of dyes corresponded to a commercial product used by the industry, and it tested positive in the Salmonella assay. The structures of the dye components were determined using proton magnetic resonance and mass spectrometric (MS) methods, and the dyes were tested for mutagenicity. The blue component was identified as the C.I. Disperse Blue 373, the violet as C.I. Disperse Violet 93, and the orange as C.I. Disperse Orange 37. The dyes showed mutagenic responses of 6300, 4600, and 280 revertants/microg for YG1041 with S9 respectively. A bioassay-directed fractionation/chemical analysis showed that the C.I. Disperse Blue 373 contributed 55% of the mutagenic activity of the DWTP sludge. We showed that these dyes contributed to the mutagenic activity found in the Cristais River environmental samples analyzed and are indirectly affecting the quality of the related drinking water. Therefore, we believe that this type of discharge should be more thoroughly characterized chemically and toxicologically. Additionally, human and ecological risks associated with the release of dye processing plant effluents should be more fully investigated, especially where the resultant water is taken for human consumption.     

Perfluorooctanoic acid and perfluorooctane sulfonate released from a waste water treatment plant in Bavaria, Germany

Purpose

Perfluorooctanoate (PFOA), perfluorooctane sulfonate (PFOS), and precursors and derivatives thereof have been employed as surfactants and anti-adhesives. PFOA and PFOS are environmentally persistent and the discharge of municipal waste waters is one of the principal routes of these compounds into the aquatic environment. In a previous study, the concentrations of PFOA and PFOS in grab samples collected from the waste water treatment plant (WWTP) of Bayreuth, a city of 72,000 inhabitants in Bavaria, Germany, during two periods showed considerable variability. For a better estimate of average mass flows, the surfactants were monitored (five samplings) from 16 March to 18 May 2007. In a second campaign, river water receiving the WWTP effluent was sampled twice a day for five consecutive days.

Methods

Quantitative analysis was done by stable-isotope dilution, pre-cleaning, and pre-concentration by solid-phase extraction, and liquid chromatography followed by electrospray ionization/tandem mass spectrometry.

Results

The mass flows of PFOA and PFOS through the WWTP were determined. PFOA is fully discharged into the river, while about half of PFOS is retained in the sewage sludge. The average daily mass load of the river Roter Main by the WWTP of Bayreuth is about 1.2?±?0.5 g PFOA and 5?±?2 g PFOS, with variations of up to 140% within one day.

Conclusion

Overall, the total annual release to the rivers of Germany may be in the range of several hundred kilograms of PFOA and several tons of PFOS.     

Detection of veterinary drug residues in surface waters collected nearby farming areas in Galicia,North of Spain

The occurrence of pharmaceuticals in the aquatic environment has become a matter of concern in the last decade due to potential risks posed to non-target organisms and the potential for unintended human exposure via food chain. This concern has been driven by a high detection frequency for drugs in environmental samples; these substances are produced in large quantities and are used in both veterinary and human medicine, leading to deposition and potential effects in the environment. However, few studies have focused on the presence of pharmaceuticals in rural areas associated with farming activities in comparison to urban areas. The aim of this study is to investigate the occurrence of pharmaceutically active compounds in surface waters collected from urban and rural areas in northwestern Spain. A monitoring study was conducted with 312 river water samples analysed by high-performance liquid chromatography coupled to tandem mass spectrometry. Positive detection of pharmaceuticals was made for 51 % of the samples. Decoquinate, sulfamethazine, sulfamethoxypyridazine and trimethoprim were the drugs most frequently detected, being present in more than 10 % of the samples. The sampling sites located downstream of the discharge points for wastewater treatment plants yielded the highest number of positive samples, 13 % of the positive samples were detected in these sites and 38 % of the samples collected near the collection point of a drinking water treatment plant were positive.     

Perfluorooctane surfactants in waste waters, the major source of river pollution

Perfluorooctanoate (PFOA) and perfluorooctane sulfonate (PFOS) are persistent and widely distributed in the environment. Recently, the discharge of municipal waste water has been shown to be an important route of such perfluoroalkyl surfactants into the aquatic environment. The aim of this study was to assess the mass flow of PFOA and PFOS from typical waste water treatment plants (WWTPs) into surface waters. Samples were collected at different stages of treatment of four WWTPs in Northern Bavaria, Germany, and from the rivers receiving the treated waste waters (WW). The outflow of PFOA from the WWTPs to the rivers was 20-fold higher than the inflow to the plants; about a tenth was removed with the sludge. For PFOS, the increase from inlet to outlet was about 3-fold; almost half of it was retained in the sludge. Both surfactants were released into river water from the WWTP of a medium-sized city with domestic, industrial and commercial waste waters; in domestic waste waters the surfactants were found at much lower levels.     

净水厂生产废水回用对供水水质的影响

通过研究生产废水回用对水质的影响,认为生产废水含固率是影响回用效果的重要评价指标,回用澄清池排泥水和滤池反冲洗水,对水质的影响规律相似.改善混凝条件的最佳含固率范围也是回用对水质影响最小的含固率范围.当含固率小于1%时,回用不会对水质造成影响,当含固率大于1%时,回用较无回用时的水质变差,但不会超过水质标准.回用生产废水可以提高有机物的去除率,主要是因为生产废水中含有的Al(OH)3沉淀物的物理吸附和卷扫絮凝功能.     

Measuring the flux at the interface of coal-tar impacted sediment and river water near a former MGP site

Determining water movement through contaminated sediment is critical for characterizing transport of chemicals from the sediment to the overlying water. Field studies to characterize the water flow across the sediment-water interface within a river adjacent to a former manufactured gas plant site were conducted. For this purpose, a new design of an interfacial flow meter was developed and tested. The in situ components of the system consisted of: a cylinder with an interfacial area of 2342 cm2; a dome attached to the cylinder; and a flow tube that allows water to flow from inside the dome to the river at the rate equal to the specific discharge across the sediment-water boundary. A 'heat-pulse' method was used to measure flow by heating the center of the flow tube for a brief time period and measuring the temperature profile within the tube over time. The system was calibrated to measure volumetric flux in the range 1.5-4.0 cm d(-1), however using a flow-addition method, the measurement of lower velocities also was accomplished, and calibration at higher fluxes is possible. From the groundwater flow at the interface of the coal-tar impacted sediment and information on the sediment pore water concentrations of several PAHs (poly-cyclic aromatic hydrocarbons), the mass flux of these PAHs to the river were estimated. Information on PAH mass flux at the sediment-water interface is useful for site assessment, including the evaluation of remediation alternatives and longer term site characterization.     

PCBs,PCNs, PCDD/Fs,PAHs and Cl-PAHs in air and water particulate samples--patterns and variations

Methodology for the determination of biologically active polychlorinated biphenyls (PCBs), non-ortho PCBs, polychlorinated naphthalenes (PCNs), polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), polycyclic aromatic hydrocarbons (PAHs) was used to investigate concentrations and patterns of certain chlorinated PAH (Cl-PAH) in source related samples using synthetic reference mixtures. Thus, in addition to the above mentioned compounds, mono-heptachlorosubstituted fluorenes, phenanthrenes/anthracenes and pyrenes/fluoranthenes (Cl-PAHs) were measured in vapour and particulate air samples from urban road tunnels, samples of settling particulate matter (SPM), and in bottom sediment samples from two point source locations (pulp and paper, and Mg-plant/Fe-Mn-smelter/chlor-alkali) and in the Baltic Sea. Concentrations in air samples followed: PAHs>PCBs>PCNs>non-ortho PCBs or Cl-PAHs>PCDD/Fs. SPM samples collected at increasing distance to the urban area of Stockholm showed: PAHs>PCBs>PCNs>PCDD/Fs>non-ortho PCBs or Cl-PAHs. For all compound groups there was a tenfold (Cl-PAHs fivefold) concentration decrease in SPM samples from highest levels in the urban water area to lowest levels at a distance of 26 km from city centre. PCB profiles of SPM showed similarities with combined profiles of Aroclor 1242 and 1254. PCN profiles of SPM showed similarities with combined profiles of Halowax 1099 and 1014. A correlation with concentration of all tested Cl-PAH and their corresponding parent PAH was found only for Cl-fluorene.     

北方某城市饮用水中多环芳烃的来源及其在水处理过程中的行为研究

采用固相萃取(SPE)样品富集前处理技术和气相色谱/质联联用(GC/MS)分析方法,对北方某工业城市给水系统中的多环芳烃类化合物的含量水平进行了研究.结果表明,该城市多环芳烃污染水平较高,但总浓度均未超过城市供水水质标准(CJ/T206-2005)中限值(2μg/L).近郊水库由于受到燃料燃烧产生的多环芳烃的污染,成为该市饮用水中多环芳烃污染的主要来源.传统的混凝-砂滤工艺对多环芳烃有较好的去除效果,总去除率可达55.9%.     

Coagulant recovery from water treatment plant sludge and reuse in post-treatment of UASB reactor effluent treating municipal wastewater

In the present study, feasibility of recovering the coagulant from water treatment plant sludge with sulphuric acid and reusing it in post-treatment of upflow anaerobic sludge blanket (UASB) reactor effluent treating municipal wastewater were studied. The optimum conditions for coagulant recovery from water treatment plant sludge were investigated using response surface methodology (RSM). Sludge obtained from plants that use polyaluminium chloride (PACl) and alum coagulant was utilised for the study. Effect of three variables, pH, solid content and mixing time was studied using a Box–Behnken statistical experimental design. RSM model was developed based on the experimental aluminium recovery, and the response plots were developed. Results of the study showed significant effects of all the three variables and their interactions in the recovery process. The optimum aluminium recovery of 73.26 and 62.73 % from PACl sludge and alum sludge, respectively, was obtained at pH of 2.0, solid content of 0.5 % and mixing time of 30 min. The recovered coagulant solution had elevated concentrations of certain metals and chemical oxygen demand (COD) which raised concern about its reuse potential in water treatment. Hence, the coagulant recovered from PACl sludge was reused as coagulant for post-treatment of UASB reactor effluent treating municipal wastewater. The recovered coagulant gave 71 % COD, 80 % turbidity, 89 % phosphate, 77 % suspended solids and 99.5 % total coliform removal at 25 mg Al/L. Fresh PACl also gave similar performance but at higher dose of 40 mg Al/L. The results suggest that coagulant can be recovered from water treatment plant sludge and can be used to treat UASB reactor effluent treating municipal wastewater which can reduce the consumption of fresh coagulant in wastewater treatment.     

Effect of humification processes on polyaromatic hydrocarbons concentration during wastewater treatment.

The aim of the present work was to compare the concentration changes of polyaromatic hydrocarbons (PAH) and the course of humification processes during wastewater treatment. Studies of samples from a biological-mechanical wastewater treatment plant in Sosnowiec-Zagórze (Poland) were carried out. Determination of PAH was performed both for wastewater sludge and sludge water. Observations of the course of humification processes for humic acid fractions isolated from sludges were conducted. Analysis of PAH extracted from wastewaters and from sludge was performed by means of high-performance liquid chromatography. Investigations of humification processes were conducted by electron paramagnetic resonance and nuclear magnetic resonance methods. The elementary composition changes in the structure of the extracted humic acids were determined. It was found that polyaromatic hydrocarbons appear during the processes of humification. Their content in water decreased only after the process of sludge aeration; however, sludge water leaving the settlers was PAH-enriched.     

Occurrence and fate of heavy metals in the wastewater treatment process

The occurrence and the fate of heavy metals (Cd, Pb, Mn, Cu, Zn, Fe and Ni) during the wastewater treatment process were investigated in the wastewater treatment plant (WTP) of the city of Thessaloniki, northern Greece, operating in the activated sludge mode. For this purpose, wastewater and sludge samples were collected from six different points of the plant, namely, the influent (raw wastewater, RW), the effluent of the primary sedimentation tank (primary sedimentation effluent, PSE), the effluent of the secondary sedimentation tank (secondary sedimentation effluent, SSE), sludge from the primary sedimentation tank (primary sludge, PS), activated sludge from the recirculation stream (activated sludge, AS), and the digested/dewatered sludge (final sludge, FS).

The distribution of metals between the aqueous and the solid phase of wastewater was investigated. Good exponential correlation was found between the metal partition coefficient, logK_p, and the suspended solids concentration. The mass balance of heavy metals in the primary, secondary and the whole treatment process showed good closures for all metal species. The relative distribution of individual heavy metals in the treated effluent and the sludge streams indicated that Mn and Cu are primarily (>70%) accumulated in the sludge, while 47–63% of Cd, Cr, Pb, Fe, Ni and Zn remain in the treated effluent.