Fate of effluent organic matter (EfOM) and natural organic matter (NOM) through riverbank filtration.

Understanding the fate of effluent organic matter (EfOM) and natural organic matter (NOM) through riverbank filtration is essential to assess the impact of wastewater effluent on the post treatment requirements of riverbank filtrates. Furthermore, their fate during drinking water treatment can significantly determine the process design. The objective of this study was to characterise bulk organic matter which consists of EfOM and NOM during riverbank filtration using a suite of innovative analytical tools. Wastewater effluent-derived surface water and surface water were used as source waters in experiments with soil columns. Results showed the preferential removal of non-humic substances (i.e. biopolymers) from wastewater effluent-derived surface water. The bulk organic matter characteristics of wastewater effluent-derived surface water and surface water were similar after 5 m soil passage in laboratory column experiment. Humic-like organic matter in surface water and wastewater effluent-derived surface water persisted through the soil passage. More than 50% of total dissolved organic carbon (DOC) removal with significant reduction of dissolved oxygen (DO) was observed in the top 50 cm of the soil columns for both surface water and wastewater effluent-derived surface water. This was due to biodegradation by soil biomass which was determined by adenosine triphosphate (ATP) concentrations and heterotrophic plate counts. High concentrations of ATP in the first few centimeters of infiltration surface reflect the highest microbial activity which correlates with the extent of DOC reduction. Good correlation of DOC removal with DO and biomass development was observed in the soil columns.     

The application of bioremediation: reduction of metal concentrations in river water and COD in distillery effluent.

The major aim of this study was to evaluate and develop artificial bioremediation systems to reduce or remove metal pollutants from contaminated river water and to decrease the chemical oxygen demand (COD) in distillery effluent. Metals were extracted using the nitric acid digestion method, and the concentrations determined using inductively coupled plasma-atomic emission spectrometry. A decrease in metal concentrations was observed for most of the metals analysed in the river water after being pumped through the bioreactor system for approximately two weeks, e.g. Al concentration decreased from 0.75mg.l(-1) to 0.18mg.l(-) and for Ni, from 0.19mg.l(-1) to 0 mg.l(-l). In addition, the COD counts decreased from 2255 mg.l(-1) to a final value of < 150 mg.l(-1) in the distillery effluent. It could thus be concluded that the bioreactor system decreased the COD and metal concentrations in the distillery effluent as well as the river water, respectively. A bioreactor is being evaluated on-site at a wine cellar to reduce COD and will be constructed at a site along the Plankenbrug River.     

Differentiation of wastewater effluent organic matter (EfOM) from natural organic matter (NOM) using multiple analytical techniques.

Using three analytical techniques of size exclusion chromatography (SEC), fluorescence excitation-emission matrix (EEM), and dissolved organic nitrogen (DON) measurement, differentiating characteristics of effluent organic matter (EfOM) from natural organic matter (NOM) have been investigated. SEC reveals a wide range of molecular weight (MW) for EfOM and high amount of high MW polysaccharides, and low MW organic acids compared to NOM. Clear protein-like peaks using fluorescence EEM were a major feature of EfOM distinguishing it from NOM. Fluorescence index (FI), an indicator to distinguish autochthonous origin from allochthonous origin, differentiated EfOM from NOM by exhibiting higher values, indicating a microbial origin. In EfOM samples, DON present in higher amounts than NOM.     

Effect of an industrial waste water on the nitrification in fixed-bed biofilm reactors--use of fluorescence in-situ hybridization (FISH).

The influence of an industrial waste water containing partly toxic and poorly biodegradable substances on an autotrophic biocenosis was investigated. Nitrifying bacteria were identified using fluorescently-labeled oligonucleotide probes and epifluorescence microscopy. Industrial waste water was used untreated and after ozonation to simulate the effects of indirect discharge to municipal waste water treatment plants. Results were compared to those obtained with acetate as a non-toxic and easily biodegradable substance and a mixture of acetate and pyruvate. The degradation of ammonium and the formation of nitrite and nitrate were measured and compared with the results obtained by fluorescence in-situ hybridization (FISH). The untreated waste water, containing higher amounts of refractory substances, disturbed nitrification, which was restored after reaching higher elimination of the organic substances. However, it showed only minor effects on the bacterial composition. These findings were similar to those reached by the addition of acetate and pyruvate. On the other hand, the ozonated waste water, showing higher toxicity than the untreated waste water, caused a stabilization in nitrification, but the composition of the population of ammonium-oxidizing bacteria changed significantly. In all cases, nitrite-oxidizing bacteria were only little affected both in activity and abundance.     

SUVA as control parameter for the effective ozonation of organic pollutants in secondary effluent.

Recent research projects have shown a good suitability of the ozonation process to transform trace concentrations of most pharmaceuticals in wastewater treatment plant (WWTP) effluents. The concentrations of carbamazepine and 17 alpha-ethinylestradiol, for instance, were reduced below their detection limits by use of ozone dosages resulting in a specific ozone consumption of 0.5 mg O3/mg DOC0. At the same time a good disinfection performance was achieved. The given hygienic requirements of the EU bathing water directive (e.g. 2,000 N/100 mL faecal coliforms) are fulfilled without the formation of bromate (<10 microg/L). As technical control parameter of the ozonation process usually the residual ozone in the liquid phase or in the off-gas are used. However, at very low specific ozone consumptions, ozone reacts instantaneously with dissolved compounds and cannot be detected. Hence, alternative parameters should be used for effective operation control. The present paper evaluates the relation between UVA decrease and the removal of different compounds (endocrine disrupting compounds, pharmaceuticals, iodinated X-ray contrast media), microbial parameters and bromate formation. The results can be used as a guideline for the control of the oxidation performance at large scale ozonation units.     

High COD wastewater treatment in an aerobic SBR: treatment of effluent from a small farm goat's cheese dairy.

In France, small goat's cheese dairies using traditional craft methods often have no profitable solution for dealing with the whey byproduct of their cheesemaking activity: it is usually mixed with the cleaning wastewater which, in the absence of other possibilities, is then discharged directly into the environment. The volume of such wastewater is small but it has a high COD of around 12-15 g/L. An aerobic SBR was proposed as a method for treating the mixture of wastewater and whey and the first installation was set up on a farm with 170 goats. Its operations were monitored for 7.5 months, particularly in order to measure any excess volume of sludge and to check that such excess remained within acceptable limits, given the high COD of the effluent requiring treatment. The results obtained show that the treated wastewater was of excellent quality, well within the most rigorous discharge norms. With this type of wastewater, excess sludge was produced in only very low amounts with 0.2 g of SS/g of COD. Moreover, the sludge proved to be quick settling which made it possible to: i) maintain a high level of SS in the reactor (up to 15 g/L); ii) withdraw sludge with concentrations reaching 30 g/L after 2 hours of settling. This resulted in a low volume of excess sludge (less than 5% of treated volume), making such aerobic biological treatment in an SBR competitive when compared to the straightforward spreading of all the wastewater.     

Comparison of total and faecal coliforms as faecal indicator in eutrophicated surface water.

The aim of this study was to evaluate the use of total coliforms (TC) and faecal coliforms (FC) using a membrane filtration method for precise monitoring of faecal pollution in Korean surface water. The samples were collected in Korea from both main rivers and their tributaries. Presumptive TC * FC were enumerated. The ratios of presumptive FC to TC were not constant, but varied widely, and TC were difficult to enumerate because of overgrowth by background colonies. For FC this was not the case. Seven hundred and three purified strains of presumptive TC * FC and their background colonies were biotyped using API 20E. Among 272 presumptive TC, non-faecal related species, Aeromonas hydrophila dominated (34.6%) and E. coli accounted for only 5.1%. In contrast, E. coli made up 89% of the 209 presumptive FC. Furthermore, of 164 background colonies on Endo Agar LES, 54.9% was A. hydrophila, while background colonies on m-FC Agar were few (58 strains), and despite their atypical colony appearance, most of them were biotyped as enteric bacteria. These results reveal that the detection of FC rather than TC using m-FC Agar is more appropriate for faecal pollution monitoring in eutrophicated surface water located in a temperate region.     

The effect of nitrogen supplementation on the efficiency of colour and COD removal by Malaysian white-rot fungi in textile dyeing effluent.

White-rot fungi, namely Coriolus versicolor and Schizophyllum commune, were studied for the biodecolorization of textile dyeing effluent in shaker-flask experiments. The results showed that C. versicolor was able to achieve 68% color removal after 5 days of treatment while that of S. commune was 88% in 9 days. Both fungi achieved the above results in non-sterile condition with diammonium hydrogen phosphate as the nutrient supplement. On the other hand, the best COD removal of 80% was obtained with C. versicolor in 9 days in sterile effluent with yeast extract as nutrient supplement, while S. commune was able to remove 85% COD within 8 days in non-sterile textile effluent supplemented with diammonium hydrogen phosphate.     

Recalcitrant COD degradation by an integrated system of ozonation and membrane bioreactor.

In order to treat wastewater to a low residual COD-concentration such as 125 mg/L, classical biological treatment is not sufficient for many types of industry. This research focused on the integrated treatment of the wastewater of the paper industry, with a membrane bioreactor (MBR) and an oxidation step. The optimal configuration was examined. Screening tests with different types of oxidation showed that ozonation after biological treatment could reduce the COD with 40% with an ozone dose of 0.4-0.8g O3/g COD. BOD/COD ratio could be increased up to 0.19. Neither combination of ozone with UV and/or hydrogen peroxide nor the process H2O2/UV or (photo-)Fenton reagents gave any improvement in COD reduction or BOD increase, unless the doses were very high. Based on these results, an integrated system MBR-ozonation was designed, with recirculation of MBR effluent over ozonation. This test showed that reduction of COD up to 125 mg/L immediately behind the MBR required a lot of ozone. A technically feasible solution was to discharge the water after an extra ozonation step, which resulted in a high total ozone dosage. The alternative, the consecutive treatment activated sludge-ozonation-activated sludge, did not give a better COD-removal with the same ozone dose as the integrated concept. The economic evaluation proves that the integrated chemical and biological treatment is expensive for the paper industry if a low discharge limit of COD has to be complied with.     

Electron-optical characterization of nano- and micro-particles in raw and treated waters: an overview.

State-of-the-art information is presented on the analysis, by transmission electron microscopy (TEM), of aquatic colloidal particles in the size range of 3 to 500 nm least dimension, with a focus on nanoparticles (1-100 nm). Case studies include selections from both natural waters and waters undergoing treatment. The "species" of nano-particles receiving the greatest attention are: humic substances, polysaccharide fibrils, hydrous iron oxides, viruses, clay minerals, refractory cell debris, and heavy metal agglomerates on biological surfaces. Artifacts and how to both detect and minimize them are outlined. Correlative use of TEM with other imaging techniques is emphasized, along with associated spectroscopy. Noted is the potential of computerized image analysis for quantifying colloids on a "per colloid species" basis, using water samples centrifuged onto electron microscope grids.     

Aeration tank odour by dimethyl sulphoxide (DMSO) waste in sewage.

Sewage plants can experience dimethyl sulphide (DMS) odour problems by at least one mg/L dimethylsulphoxide (DMSO) waste residue in plant influent, through a DMSO/DMS reduction mechanism. This bench-scale batch study simulates in bottles the role of poor aeration in wastewater treatment on the DMSO/DMS and sulphate/H2S reduction. The study compares headspace concentrations of sulphide odorants developed by activated sludge (closed bottles, half full) after six hours under anoxic versus anaerobic conditions, with 0 versus 2 mg/L DMSO addition. Anoxic sludge (0.1 - 2 mg/L dissolved oxygen, DO) with DMSO resulted in about 50 ppmv DMS and no other sulphide, while DMSO-free sludge was free of detectable sulphides. Anaerobic sludge (no measurable DO to the point of sulphate reduction) with DMSO resulted in 22/4/37 ppmv of H2S/methanethiol (MT)/DMS, while DMSO-free sludge resulted in 44/8/2 ppmv of H2S/MT/DMS. It is concluded that common "anoxic" aeration tank zones with measurable DO in bulk water but immeasurable DO inside sludge flocs (nitrate reducing) experience DMSO reduction to DMS that is oxidation resistant and becomes the most important odorant. Under anaerobic conditions, H2S from sulphate reduction becomes an additional important odorant. A strategy is developed that allows operators to determine from the quantity of different sulphides whether the DMSO/DMS mechanism is important at their wastewater plant.     

Monitoring of the process of composting of kitchen waste in an institutional scale worm farm.

Vermicomposting provides an alternative method of managing waste that is ecofriendly and cost-effective. The Environmental Technology Centre (ETC) at Murdoch University and St. John of God Hospital (SJOG) signed a Memorandum of Understanding (MOU) to install a vermiculture system in SJOG to treat some of the organic waste generated by the on site kitchen facility. This is an effort made by SJOG to reduce the amount of organic waste sent to landfill each year and to treat the waste on site as part of a recycling/reuse program. The study is aimed at scientifically monitoring vermicomposting process and to understand the optimum management requirements to improve the operation of an institutional scale worm farm. In addition, an experiment was conducted to investigate the suitability of bedding materials: horse manure, cow manure, peat coir, and natural bedding (vermicast). The species of earthworms used in this experiment were Red (Lumbricus rubellus), Tiger (Eisenia fetida), and Blue (Lumbricus excavatus). The pH, temperature, worm population and quality of castings were tested in different beds. Results indicated that vermicast was the best bedding for vermicomposting, and there were no significant difference between the performances of the other three beds. However, it can be concluded that the bedding material of horse manure, cow manure, and peat coir were successfully established well within the experimental period of eight weeks, and cow manure with the lowest C:N ratio produced the best quality bedding. As using vermicast for the initial bedding creates a very high capital cost these organic substrates provide cost-effective alternative. Therefore they would be quite appropriate to initiate an institutional scale worm farm.     

Biofilm control in water by advanced oxidation process (AOP) pre-treatment: effect of natural organic matter (NOM)

The main goal of this study was to examine the influence of natural organic matter (NOM) on the efficiency of H?O?/UV advanced oxidation process (AOP) as a preventive treatment for biofilm control. Pseudomonas aeruginosa PAO1 biofilm-forming bacteria were suspended in water and exposed to various AOP conditions with different NOM concentrations, and compared to natural waters. H?O?/UV prevented biofilm formation: (a) up to 24 h post treatment - when residual H?O? was neutralized; (b) completely (days) - when residual H?O? was maintained. At high NOM concentrations (i.e. 25 mg/L NOM or 12.5 mg/L DOC) an additive biofilm control effect was observed for the combined H?O?/UV system compared to UV irradiation alone, after short biofilm incubation times (<24 h). This effect was H?O? concentration dependent and can be explained by the high organic content of these water samples, whereby an increase in NOM could enhance (?)OH production and promote the formation of additional reactive oxygen species. In addition, maintaining an appropriate ratio of bacterial surviving conc.: residual H?O? conc. post-treatment could prevent bacterial regrowth and biofilm formation.     

原子荧光测定水中砷汞的方法

文章阐述了用原子荧光法同时测定水中重金属砷和汞的原理、溶液的配制、仪器的选择、使用条件及测定的结果作了分析.深入研究了不同种类的酸度对砷汞的影响以及共存离子的干扰、线性范围、检出限、精密度、准确度、回收率等.     

Identification of humic acid-like and fulvic acid-like natural organic matter in river water using fluorescence spectroscopy

Identifying the extent of humic acid (HA)-like and fulvic acid (FA)-like natural organic matter (NOM) present in natural water is important to assess disinfection by-product formation and fouling potential during drinking water treatment applications. However, the unique fluorescence properties related to HA-like NOM is masked by the fluorescence signals of the more abundant FA-like NOM. For this reason, it is not possible to accurately characterize HA-like and FA-like NOM components in a single water sample using direct fluorescence EEM analysis. A relatively simple approach is described here that demonstrates the feasibility of using a fluorescence excitation-emission matrix (EEM) approach for identifying HA-like and FA-like NOM fractions in water when used in combination with a series of pH adjustments and filtration steps. It is demonstrated that the fluorescence EEMS of HA-like and FA-like NOM fractions from the river water sample possessed different spectral properties. Fractionation of HA-like and FA-like NOM prior to fluorescence analysis is therefore proposed as a more reasonable approach.     

Spectral in-situ analysis of NO2, NO3, COD, DOC and TSS in the effluent of a WWTP.

An in-situ UV spectrometer was applied to the effluent of a WWTP in Switzerland and calibrated using a multivariate calibration algorithm based on PLS regression. Except for nitrite, the calibration was based on comparative measurements of the effluent in the plant laboratory. Samples made of stock solution added to three different matrices prepared in the EAWAG laboratory were used for the nitrite calibration because the effluent concentrations were always in the range of 0.06-0.26 mg/l. The results show very good precision for nitrite and nitrate. The measuring range for COD and DOC was not completely covered by the measurements, so the meaningfulness of the results is limited. Nevertheless the precision obtained for soluble COD is high enough for most applications at WWTPs. The accuracy of the TSS measurement is unsatisfactory as regards effluent limits since the spectrometer used does not cover the wavelength region up to 700 nm, which gives better signals for TSS calibration due to its strong correlation with turbidity.     

Treatment of an ECF effluent by combined use of activated sludge and advanced oxidation process.

The combined biological and chemical treatments of the cellulose effluents have been studied aiming to promote a more significant degradation of their recalcitrant compounds and to reduce their toxicity, as compared with the isolated treatments. In this work the effluent from acid stages of the ECF bleaching of Eucalyptus urograndis pulp was treated by using separately activated sludge and UV radiation and its combination. The treatment efficiency was evaluated by colour, total phenol, COD, BOD, UV spectroscopy, molar weight distribution and toxicity. The untreated effluent presented 587 +/- 18 CU, 19.3 +/- 0.6 mg.L(-1) of total phenol, 2246 +/- 137 mgO2.L(-1) of COD and 904 +/- 48 mgO2.L(-1) of BOD. It did not show acute toxicity to Escherichia coli, but presented chronic toxicity to Selenastrum capricornutum (EC50 = 25%). The sludge treatment resulted in a colour increasing of 42% and decreasing of total phenol, COD and BOD of 33%, 64% and 92%, respectively. The UV radiation treatment for 120 min resulted in a decrease of colour, total phenol, BOD and COD of 70%, 43%, 62% and 43%, respectively. The combined treatment promoted an expressive decrease for colour and total phenol. The UV absorption indicated a degradation of the aromatic compounds. The biological treatment did not remove chronic toxicity and after UV radiation treatment, a 10 times improving toxicity was noticed.     

Prevalence of human adenoviruses in raw and treated water.

Human adenoviruses (HAds), of which there are 51 antigenic types, are associated aetiologically with gastrointestinal, respiratory, urinary tract and eye infections. The clinical importance of HAds and the potential health risks constituted by HAds in water environments are widely recognised. This study was conducted to assess the use of an optimised integrated cell culture molecular-based technique to determine the prevalence of HAds in raw and treated drinking-water supplies in South Africa. Selected supplies were monitored weekly for the presence of adenoviruses over a one-year period (July 2001 to June 2002). Drinking-water supplies were derived from acceptable quality surface water sources using treatment processes that conformed to international standards for the production of safe drinking water. Adenoviruses were detected by amplification in cell cultures, followed by amplifying the extracted nucleic acids using molecular techniques (nested PCR). HAds were detected in 29.8% (59/198) of the treated drinking water, 16% (8/50) of dam water and 44% (22/50) of river-water samples tested. The results of this study confirmed the presence of HAds in some raw and treated drinking water supplies in South Africa.     

Removal of nitrogen, phosphorus and other priority (hazardous) substances from WWTP effluent.

More stringent effluent criteria will be required in the near future for the so-called priority substances listed in the Annex of the European Water Framework Directive (WFD) 2000/60/EC. This includes heavy metals, volatile and semi-volatile organic substances, pesticides and polychlorinated biphenyls. The Fraunhofer Institute suggested FHI values for these substances in water. National Dutch legislation, the Vierde Nota WaterHuishouding (NWH) introduced in 1998 'maximum tolerable risk concentrations' (MTR). These include requirements for nutrients: P(tot) < 0.15 mg/l and N(tot) < 2.2 mg/l. The MTR values are being used until the FHI values become effective. Investigation into possible effluent polishing techniques is required in order to reach these objectives. During pilot research with tertiary denitrifying multi-media and biological activated carbon filtration at the WWTP Utrecht in The Netherlands, simultaneous nutrient removal to MTR quality was observed. Furthermore, simultaneous removal of heavy metals, 17beta-estradiol, bisphenol A and nonylphenols to extreme low concentrations by denitrifying activated carbon filtrated is achieved.     

Development of a resource protection and waste strategy for water use by the agricultural sector.

The South African Department of Water Affairs and Forestry (DWAF) has started developing a strategy to regulate activities and water uses by the agricultural sector that could impact on the water resource quality. The aim would not be to over-regulate the sector, but to protect the water resource where necessary. Most of these activities constitute diffuse sources of potential pollution. The strategic process will start with investigative discussions with major stakeholders and determining the strategic context and current situation. The latter will consist of a detailed literature and stakeholder survey, and an evaluation of existing agricultural activities. The next steps of determining a vision and the setting of strategic objectives will be done with active participation by the major players. An action plan will be developed to achieve the set objectives. Important components of the strategy will be to: classify activities according to their risk to the water resource, taking into account the sensitivity of the water resource; set regulatory measures in accordance with the risk posed by the activity (measures could include the promulgation of regulations, general authorisations and/or issuing of licenses); harmonise and link the process with existing relevant processes and guidelines within DWAF and other government departments; review existing guidelines; sign agreements with relevant government departments and the agricultural sector; and provide training, built capacity and raise awareness during and after the process.