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PubMed2004

Evaluation of electrochemically generated ozone for the disinfection of water and wastewater.

Effective wastewater treatment is critical to public health and well-being. This is especially true in developing countries, where disinfection of wastewater is frequently inadequate. People who live in these areas may benefit from wastewater disinfection using ozone. This study evaluated the ability of a new electrochemical process of ozone generation, which produced ozone continuously at high pressure and concentration by the electrolysis of water, to disinfect tap water and secondarily treated wastewater. Inactivation of Klebsiella terrigena, Escherichia coli, MS2 bacteriophage and poliovirus 1 was evaluated first in reverse osmosis (RO) treated water. Inactivation of K. terrigena (6-log), E. coli (6-log), MS2 (6-log) and poliovirus 1 (>3-log) was observed after 1 min of ozonation in a 1 L batch reactor. Experiments were then performed to assess the microbiological impact of disinfection using ozone on secondarily treated municipal wastewater. The effect of ozonation on wastewater was determined for total and faecal coliforms, bacteriophages and heterotrophic plate count (HPC) bacteria. Electrochemical ozone generators provided an effective, rapid and low-cost method of wastewater disinfection. Based on the results of this research, electrochemically generated ozone would be well suited to remote, small-scale, disinfection operations and may provide a feasible means of wastewater disinfection in developing countries.

Developing Countries↗
PubMed2004

Salt reduction in municipal sewage allocated for reuse: the outcome of a new policy in Israel.

Israel is presently reusing about 70% of its sewage and the buildup of salts in soils has been detected in some areas of the country. Prevention of sewage salt enrichment is one of the most immediately available solutions. The discharge of brines to municipal sewers is now prohibited and they are discharged to the sea. Discharge of brines to the sea has increased from 580,000 m3 in 1999 to more than 700,000 m3 in 2002. These salts are thus definitively taken out of the reuse cycle, year after year. The concentration of salts in industrial effluents is presently limited by the national water law and a unique regulation limiting the Boron and Sodium content in detergents has been implemented. Israeli industry has undergone a radical change in recent years. Many factories and all the hospitals have adopted K or Ca for softening and neutralization, while others have shifted to reverse osmosis. The concentration of Cl and Na in the sewage reaching treatment plants is declining. The addition of Cl to sewage has dropped from 120 mg/l to 70 mg/l. The average Boron concentration in sewage has dropped from 0.6 mg/l to 0.3 mg/l and should reach 0.2 mg/l by 2008.

Conservation of Natural Resources↗
PubMed2004

Treatment techniques for the recycling of bottle washing water in the soft drinks industry.

The soft drink production is an important sector in the manufacturing industry of Mexico. Water is the main source in the production of soft drinks. Wastewater from bottle washing is almost 50% of the total wastewater generated by this industry. In order to reduce the consumption of water, the water of the last bottle rinse can be reused in to the bottle pre-rinse and pre-washing cycles. This work presents the characterization of the final bottle washing rinse discharge and the treatability study for the most appropriate treatment system for recycling. Average characteristics of the final bottle wash rinse were as follows: Turbidity 40.46 NTU, COD 47.7 mg/L, TSS 56 mg/L, TS 693.6 mg/L, electrical conductivity 1,194 microS/cm. The results of the treatability tests showed that the final rinse water can be used in the pre-rinse and pre-washing after removing the totality of the suspended solids, 80% of the COD and 75% of the dissolved solids. This can be done using the following treatment systems: filtration-adsorption-reverse osmosis, or filtration-adsorption-ion exchange. The installation of these treatment techniques in the soft drink industry would decrease bottle washing water consumption by 50%.

Carbonated Beverages↗
PubMed2004

Microbiological water quality in a large in-building, water recycling facility.

The Thames Water recycling plant at the Millennium Dome, London, reclaimed three sources of water: greywater from the washbasins, rainwater from the Dome roof and groundwater from a borehole on site. These were pre-treated separately, and the mixed stream filtered using ultrafiltration and reverse osmosis membranes. Monitoring for indicator microorganisms was undertaken throughout the plant and in the reclaimed water distribution system, as well as ad-hoc monitoring for the presence of pathogens in the raw waters. Treatment to the level of ultrafiltration was more than adequate to produce a water quality meeting existing worldwide reclaimed water guidelines for toilet flushing. Owing to the excellent quality of the water leaving the plant, no significant microbiological growth was observed in the reclaimed water distribution system during the year. The raw greywater exhibited a higher faecal bacterial load than the rainwater and groundwater, as predicted from more human contact (i.e. hand washing). Environmental strains of Legionella were observed in the three raw greywater samples analysed for pathogens, as was Cryptosporidium, Giardia and faecal enterococci. The rainwater had relatively high levels of faecal bacteria, probably of avian origin. Giardia was detected in one rainwater sample confirming the potential for this water source to contain pathogens.

Conservation of Natural Resources↗
PubMed2004

Technical and sanitary aspects of wastewater disinfection by UV irradiation for landscape irrigation.

Water reuse for landscape irrigation requires the production of high quality virus-free effluents to minimize risk for human health. In order to establish the relevance of MS2 phages as an appropriate biodosimeter for UV design, a pilot plant study has been carried out with different types of wastewater effluents. The two pilot systems tested (low-pressure high output and medium-pressure UV units) were able to achieve 4 and 5 log MS2 reduction in tertiary filtered effluent at high calculated UV doses of 170 _ 10 and 300 mJ/cm2, respectively. UV disinfection was extremely efficient for MS2 inactivation in high quality effluents after reverse osmosis: detention times as low as one second and UV dose of 40 mJ/cm2 were sufficient to reach 5 log inactivation of MS2. UV irradiation also produced rapid inactivation of human pathogens such as poliovirus type 1 and indigenous enteroviruses at UV doses up to 3 times lower that those for MS2 disinfection. It was concluded that accurate UV unit design for a given type of wastewater could be ensured by pilot tests using laboratory-propagated MS2 as biodosimeter and collimated-beam tests as the calibration-check.

Agriculture↗
PubMedDate not supplied

Dialysis water treatment systems and monitoring in Italy: results of a national survey.

BACKGROUND: The risks connected with dialysis fluid contamination are well established. Epidemiological studies have demonstrated just how difficult it is to obtain permanently satisfactory quality standards. Therefore, dialysis centers must have effective and regular quality control programs, particularly with the growing and widespread use of online convective dialysis treatments. Considering this, we conducted a national survey of water treatment systems and monitoring in Italian dialysis centers. METHODS: Two independent questionnaires were prepared and distributed in 1999 and 2001. The questions were designed to acquire information on structural and procedural elements. Responses to similar questions from both questionnaires were analyzed together. RESULTS: Responses to questionnaires were received from 148 centers (17% of dialysis centers in Italy). In accordance with the European Best Practice Guidelines (EBPG) published recently concerning dialysis fluid purity, in the majority of centers (97%) the water treatment system consisted of at least pre-treatment and reverse osmosis (RO) modules. However, only one stage RO module was implemented (71%), there was a water storage tank (65%) and water pipe distribution loop was made of sanitary polyvinyl chloride (85%). Analysis of procedural elements--the timing and type of disinfection procedures used for the waterline system and monitors, the timing and type of water treatment quality control procedures--revealed a striking variability among centers in terms of the types and frequency of checks performed. CONCLUSIONS: Taking into account the EBPG, this survey revealed both bright and dark spots, calling for a national initiative aimed at defining a standard periodicity of loop disinfection, points in the water pipe line to be tested, and the frequency and type of tests.

Disinfection↗
PubMedDate not supplied

[Water quality cuts down the chronic inflammatory risk: how to obtain it and keep it over time].

BACKGROUND: Every week, approximately 400 liters of water used for dialysate production come into direct contact, through the semi-permeable membrane of the dialyzer, with the dialysis patient's blood stream. Therefore, submitting municipal water to an adequate depuration process before its use for dialysis becomes necessary. METHODS: Problems related to the implementation, updating and management of a dialysis water treatment system are analyzed. The results of the most recent multicenter studies on dialysis fluids quality are also reviewed. RESULTS: The best approach to plan, implement and manage a dialysis water treatment system, first, consists of defining the standards of chemical and microbiological water quality. The most diffused and commonly accepted standards are those recommended by the Association for Advancement of Medical Instrumentation (AAMI) and the European Pharmacopea (EP), which allow a maximum bacterial growth of, respectively, 200 CFU/ml and 100 CFU/mL and a maximum endotoxin concentration of 2 IU/mL and 0.25 IU/mL. A modern dialysis water treatment system provides a final purification process, mainly by reverse osmosis (RO), together with different pre-treatment levels and a hydraulic distribution circuit. Therefore, as RO produces water of optimal chemical and microbial quality, all efforts in the dialysis unit must be aimed at keeping this quality as constant as possible over time, by carrying out effective maintenance strategies and system disinfection. Nevertheless, several multicenter studies reported that 7-35% of water samples exceed a bacterial growth of 200 CFU/mL and that 44% of them display endotoxin concentrations >5 IU/mL. CONCLUSIONS: The results of multicenter studies indicate that the microbial quality of dialysis fluids is, unfortunately, still an often neglected problem. Evidence of a possible relationship between dialysis fluid contamination and patient morbidity, as well as the availability of systems and machines allowing purity levels that were unimaginable only a few years ago, must be a stimulus for modifying clinical practices and starting the improvement processes aimed at maximally reducing the risk of microbial contamination in the dialysis water, as already done with chemical contamination.

Chronic Disease↗
PubMed2004

Comparison of different culture methods on bacterial recovery in hemodialysis fluids.

To examine the culture method that could provide the highest bacterial recovery, 143 reverse osmosis water samples used in hemodialysis were collected for comparison of the media (Tryptic Soy Agar, TSA vs Reasoner's 2A Agar, R2A), the temperature (20 degrees C vs 37 degrees C), the duration of incubation (48-hour vs 7-day), and the culture technique (membrane filtration vs spread plate methods). The European Best Practice Guideline method, R2A at 20 degrees Cfor 7-day incubation provided higher bacterial recovery than the Association for the Advancement of Medical Instrumentation (AAMI) method, TSA at 37 degrees C for 48-hour incubation. The membrane filtration method gave better yield than the spread plate method. As such, the European Best Practice Guideline method in combination with the membrane filtration technique would be the culture method of choice for hemodialysis fluids.

Agar↗
PubMed2005

[Construction and evaluation of the property of decellular porcine aortic valve].

OBJECTIVE: To construct decellular porcine aortic valve (PAV) and to observe the existence of porcine endogenous retrovirus (PERV) and valve scaffold structure before and after implantation. METHODS: (1) Porcine aortic valve was obtained. The cellular components of PAV were completely removed by using detergent and nucleotidase solution combined with alteration of osmosis. (2) The decellular underwent HE staining and light microscopy and detection of its physical and chemical properties. (3) 20 pieces of decellular PAV were implanted into dogs. On e month later blood samples of the dogs were collected. PCR and RT-PCR were used to detect the PERV expression in 20 samples of pig's peripheral blood, 20 fresh PAVs, cultured pig kidney cells of the PK15 line (as positive control), decellular PAVs implanted into the dogs, and 10 samples of dogs' peripheral blood. (4) Small pieces of decellular PAVs were implanted into the subcutaneous tissues of 6 rabbits at the back, 6 pieces for one rabbit, and then extracted by the ends of the 4th, 6th, 8th and 10th week respectively after implantation to undergo HE staining and light microscopy. RESULTS: (1) Almost all cellular components in the PAVs had been removed after decellularization; the soluble protein contents lost markedly [(0.238 +/- 0.038)% vs. (0.484 +/- 0.116)%]; the water content of the decellular tissues increased significantly [(92.16 +/- 1.48)% vs. (89.2 +/- 1.55)%]; however, the decellular PAVs still maintained their excellent fibrous scaffold structure, and their shrinkage temperature and tension at fracture were not significantly changed [(72.0 +/- 0.7) degrees C vs. (71.2 +/- 0.8) degrees C, and (448.7 +/- 18.65)g/mm2 vs. (540.7 +/- 19.46)g/mm2 respectively]. (2) Agarose gel electrophoresis of all fresh PAVs and porcine peripheral blood samples showed a 219 bp band, which was 90% to 97% homologous with PERV-C gene, and the sequence of which is published in Medline. No 219 bp amplified band was found in all decellular PAVs and the peripheral blood samples of the dogs implanted with decellular PAV one month after the implantation. (3) The PAVs implanted in rabbit body showed very slight tissue reaction. Neutrophil, lymphocyte and plasmacyte infiltration were seen 4 weeks after; such inflammatory cell infiltration decreased markedly and the peripheral portions of the decellular PAVs began to be absorbed by the end of the 6th week after implantation. The decellular PAVs were completely absorbed without fibrosis or scar formation in the implantation area by the end of the 10th week. CONCLUSION: (1) The cellular components of PAV can be completely removed, the excellent fibrous scaffold structure and mechanical strength of aorta valve can be maintained, and the antigenicity is very weak. Subcutaneous implantation investigation shows that decellular PAV is an absorbable and degradable biological material. (2) There is PERV-C in PAV that can be removed after decellularization. PERV-C reaction is negative in the peripheral blood samples of the recipients implanted with decellular PAV.

Animals↗
PubMed2005

[Assessing the ecological risk of effluents from different advanced treatment units by using a battery of bioassay].

In this paper, effluents from different advanced treatment units, which were reclaimed for Olympic Park, were assessed regarding to the removal efficiencies of the technologies on acute toxicants, Ah-acceptor chemicals and estrogenic substances by using a battery of bioassays. The results showed that advanced treatments using ultra-filtration and activated carbon absorption were suitable for removal of toxic organic substances from STP effluent. Activated carbon absorption was the most effective technology to remove acute toxicants and Ah-acceptor chemicals, and the removal efficiency of Ah-acceptor chemicals reached 98%. Ultra-filtration was suitable for removing nonpolar acute toxicants and polar estrogenic chemicals. Nonpolar fraction extracted from water after ultra-filtration treatment showed 100% percentage survival of cell in the acute toxic assay. E2-TEQ was reduced from 0.13 pmol x L(-1) to 0.04 pmol x L(-1) in the polar fraction extracted from water after ultra-filtration. Treatments with micro-filtration and osmosis did not manifest sufficient efficiencies for removal of toxic organic substances. In complex matrix, interactions may occur among different toxic components to interfere the bioassay results. Therefore fractionation of organic concentrate before bioassay is necessary.

Biological Assay↗
PubMed2004

Contaminants in drinking water and its mitigation using suitable adsorbents: an overview.

Various options are applicable for the removal of water pollutants included reverse osmosis, ion exchange, coagulation, co-precipitation, catalytic reduction, herbal filtration, electrodialysis and adsorption. This paper deals with the sorption phenomena for the removal of pollutants from drinking water. Attempts have been made to use low cost sorbents developed by pretreatment/activation/impregnation with alkalis, acids, iron oxide, manganese dioxide, ferric chloride, alum, lime, aluminum salts with natural products/indigenous minerals viz. activated alumina, activated carbon, groundnut husk, saw dust, chemically coated sand, fly ash, zeolites, clay minerals and other plant products. Application of Freundich and Langmuir isotherms were used to assess the adsorption capacity. Equilibrium isotherms were determined at optimum temperature and pH to characterize the sorption process. Statistical parameters such as mass transfer coefficients, multiple regression analysis were applied to establish the mechanism. It is suggested that the characterization of suitable, and exhausted sorbent through the application of fourier transformed infrared spectroscopy (FTIR), X-ray diffraction (XRD), X-ray fluorescence (XRF) is essential to establish its surface bonding. Scope for safety evaluation and risk assessment to human and biosphere may provide the guideline and predication to the regulatory agencies for its sustainable use and safe disposal The ecotoxicological assessment of the leachates and low cost removal technology are discussed in this paper.

Adsorption↗
PubMed1992

[A newly designed salt bridge cap-type, a variable, and non-invasive EEG lead electrode and the analytical power spectrum].

A newly devised, variable EEG cap-style electrode that has an electrical salt bridge with 2% agarose gel and 5% NaCl solution was developed. The number of electrodes can be increased as required. The weight of 15 electrodes is about 100g. The electrode is simple, fast and in a one-touch form for measuring the EEG. An EEG using this electrode system was recorded in a healthy man in a sitting position on a chair, at rest, and with eyes closed. The power spectrum showed different patterns for the power at different concentrations of aqueous solution in the matrix of the salt bridge. The power changed to a pattern of J-type with 20% NaCl solution, to a pattern of U-type with 5% NaCl solution, and to a pattern of L-type with 0.9% NaCl solution, respectively. The matrix of the salt bridge that has a concentration higher than 0.9% NaCl, is a hypertonic solution for the isotonic body liquid. One person felt pain in half of the part of the experiment when a 20% NaCl hypertonic solution was applied to the scalp, so a 20% NaCl solution of the salt bridge was used in experiments concerning osmosis. When a salt bridge of 5% NaCl solution was used, the same results of the wave measurement was obtained 10 times. It was a value close to the expected measurement so it has a high probability of being correct. At this time the power spectrum shows a U-type pattern consistently.

Brain↗
PubMedDate not supplied

[SIN survey on quality control of dialysis water in Italy].

BACKGROUND: The importance of high quality water for dialysis is well established. This study aimed to obtain a picture of the Italian situation to develop national guidelines. METHODS: Questionnaire analysis was used to assess water quality control protocols and types of chemical and microbiological parameters monitored. Regions with responses from at least half the units were considered for the study. RESULTS: Eighteen out of 20 regions fulfilled the inclusion criteria; 297/469 dialysis units answered the questionnaire (5208 dialysis beds, 18213 patients). Eighty-one percent of Italian units follow a regular water quality control program. The reverse osmosis outlet is the sampling point used most for assessing chemical and microbiological parameters. The most common frequency in monitoring is < or =6 months. Fifteen chemical items, suggested by the Italian Farmacopea Ufficiale (FU), are periodically controlled by at least half the units. Aluminum is measured in about 70% of units, chloramines and volatile halogenated hydrocarbons, respectively, in 42 and 30% of units. According to the FU, bacterial counts at 22 degrees C (84%) and endotoxin determinations (60%) are the most common microbiological analyzes. CONCLUSIONS: The survey demonstrated protocol differences among the units, confirming the need for Italian guidelines to ameliorate and standardize dialysis water monitoring. More than half the units are following the FU, but we cannot rule out less strict monitoring only in non-participating units.

Hemodialysis Solutions↗
PubMed2005

Sodium sieving in children.

Sodium sieving is a consequence of dissociation between the amount of water and sodium transported over the peritoneal membrane. This dissociation occurs in the presence of aquaporin-mediated water transport. Sieving of sodium can be used as a rough measure for aquaporin-mediated water transport. Icodextrin contains glucose polymers, inducing ultrafiltration by colloid osmosis. Therefore, aquaporins play a minor role in ultrafiltration, which is confirmed by the absence of sodium sieving. Icodextrin is very suitable for the daytime dwell in children on a nightly intermittent peritoneal dialysis regimen. Ultrafiltration obtained with icodextrin is similar to ultrafiltration obtained with 3.86% glucose after a 12-hour dwell. When using icodextrin in children, it is also confirmed by the absence of sodium sieving that the aquaporins play a minor role in ultrafiltration.

Aquaporins↗
PubMed2005

[Roles of calcium in stress-tolerance of plants and its ecological significance].

Calcium loss from soil has dramatically increased for decades due to the increase of nitrogen input and/or the extension of acid rain, while calcium input into soil has declined substantially for the replacement of superphosphate by ammonium phosphate in fertilization, which intensified the imbalance of calcium input and output in agro-ecosystems, and needed to be solved in the near future for the sustainability of agriculture in such a country like China where the arable land resource is very limited. In recent years, the intensified soil acidification is mainly attributed to the root proton secretion stimulated by fertilization, and the nitrogen input from precipitation near industrialized regions promotes plant growth but results in other nutrients deficiency, which in turn acidifies soil and causes tree death. One of the most important mechanisms of saline soil bioremediation by sesbania is the activation of soil calcium by sesbania's proton secretion and the increase of soil calcium supply for subsequent crops. The present paper summarized the roles of calcium in plant tolerance to the stresses like acidosis, toxic metals, osmosis, ammonium toxicity, drought, extreme temperature (cold or heat shock), anoxia and pathogen infection, and the measures for maintaining soil calcium fertility. It was suggested that the production of ammonium phosphate should not be a pursued target for China's phosphorus fertilizer industry, and the roles of calcium in plant growth should be taken into account in fertilization experimental designs to make the experiments more accurate.

Acid Rain↗
PubMed2005

Comparison of zinc complexation properties of dissolved organic matter from surface waters and wastewater treatment plant effluents.

Unlike natural organic matter(NOM), wastewater organic matter(WWOM) from wastewater treatment plant effluents has not been extensively studied with respect to complexation reactions with heavy metals such as copper or zinc. In this study, organic matter from surface waters and a wastewater treatment plant effluent were concentrated by reverse osmosis (RO) method. The samples were treated in the laboratory to remove trace metals and major cations. The zinc complexing properties of both NOM and the WWOM were studied by square wave anodic stripping voltammetry(SWASV). Experimental data were compared to predictions using the Windermere Humic Aqueous Model (WHAM) Version VI. We found that the zinc binding of WWOM was much stronger than that of NOM and not well predicted by WHAM. This suggests that in natural water bodies that receive wastewater treatment plant effluents the ratio of WWOM to NOM must be taken into account in order to accurately predict free zinc activities.

Benzopyrans↗
PubMed2005

[Characterization of isolated fractions of NOM from Songhua River].

Natural organic matter (NOM) was concentrated from Songhua River using a reverse osmosis system. The hydrophobic fraction (HyO), hydrophilic fraction (HyI), fulvic acid (FA) and humic acid (HA) were fractionated by the XAD resin, and a commercial humic acid (CHA) was used for comparison. The FA fraction predominant in natural water and account for the large part of DOC, and the aromaticity of these fractions followed the order HA> HyO> FA> HyI. A weak relationship exists between the E4/ E6 and aromaticity. FTIR spectra revealed that the degree of saturation among these fractions was in the order of HyO = FA > HyI > HAM=CHA. Gel chromatograph results showed that the weaker ultraviolet-adsorption fraction of NOM contributed to the most part of molecular weight. Potentiometric titration indicated that the total organic acidity was in the range of 9.84 - 12.15 meq/g, and carboxylic acidity decrease in the order of CHA> HyI > HyO > NOM > FA > HA. 1H NMR spectra demonstrated that NOM and the isolated fractions were predominated by aliphatic functional groups.

Benzopyrans↗
PubMed2005

[Effect of organic acids adsorption on catalytic ozonation with metal oxides].

The effectiveness of ozonation, adsorption and catalytic ozonation with ferric hydroxide (FeOOH) and cerium dioxide (CeO2) as catalysts on removal of several organic acids were investigated. The organic acids selected were benzoic acid (BA), phthalic acid (PA), commercial humic acid (CHA), and humic acid of Songhua River water (SHA) concentrated with reverse osmosis (RO). FeOOH was active in catalytic ozonation of the non-adsorbable BA, with 45% of BA removal higher than ozonation alone. It was inactive in case of ozonation of PA, the adsorption of which on FeOOH caused 5% reduction of its concentration. CeO2 enhanced ozonation of PA that was strongly adsorbed, but not for the non-adsorbed BA. Oxalate ions as product of oxidation of PA were also removed by CeO2 catalytic ozonation. As adsorption of humic acids on CeO2 is stronger than that on FeOOH, its catalytic removal by CeO2 was more than by FeOOH. The activity of catalytic ozonation of humic acids was scavenged in case of competition for adsorption sites on the catalysts by inorganic anions.

Adsorption↗