A study of pollutant flows was carried out at a wastewater treatment plant in Nancy, France, which used activated-sludge treatment. To carry out observation of hourly flow variation, a sampling strategy needs to be defined. A comparison between two methods of sampling was conducted: dip samples every 2 h over a period of 24 h and one 24-h composite sample were taken from raw and treated wastewater and then analyzed for enteroviruses, fecal coliforms, chemical oxygen demand, biochemical oxygen demand, and suspended solids. The results showed that the hourly variations of these pollutants in the effluents are in good agreement with expectations based upon the customers' usage and the characteristics of the wastewater network. Significant correlations were found between all tested parameters and enteroviruses in raw wastewater. After biological treatment, no correlation remained in treated wastewater between viruses and other parameters. As for the two sampling methods, a rather good representation of the daily load was given by the composite mode of sampling as concerns physicochemical and microbiological parameters. Biological treatment removed an average of 83% of viruses.
Currently, biological method has been utilized in the treatment of wastewater -containing synthetic dyes used by textile industries in Iraq. The present work was devoted to study the operating feasibility using reverse osmosis (RO) and nanofiltration (NF) membrane systems as an alternative treatment method of wastewater discharged from Iraqi textile mills. Acid red, reactive black and reactive blue dyes were selected, based on the usage rate in Iraq. Effects of dye concentration, pH of solution, feed temperature, dissolved salts and operating pressure on permeate flux and dye rejection were studied. Results at operating conditions of dye concentration = 65 mg/L, feed temperature = 39°C and pressure = 8 bar showed the final dye removal with RO membrane as 97.2%, 99.58% and 99.9% for acid red, reactive black and reactive blue dyes, respectively. With NF membrane, the final dye removal were as 93.77%, 95.67%, and 97% for red, black and blue dyes, respectively. The presence of salt (particularly NaCl) in the dye solution resulted in a higher color removal with a permeate flux decline. It was confirmed that pH of solution had a positive impact on dye removal while feed temperature showed a different image. A comparison was made between the results of dye removal in biological and membrane methods. The results showed that membrane method had higher removal potential with lower effective cost. The present study indicates that the use of NF membrane in dye removal from the effluent of Iraqi textile mills is promising.
Membrane separation; Synthetic dyes; Reverse osmosis; Nanofiltration; Wastewater reuse
High salinity (1–10% w/v) of tannery wastewater makes it difficult to be treated by conventional biological treatment. Salt tolerant microbes can adapt to these saline conditions and degrade the organics in saline wastewater.
Four salt tolerant bacterial strains isolated from marine and tannery saline wastewater samples were identified as Pseudomonas aeruginosa, Bacillus flexus, Exiguobacterium homiense and Staphylococcus aureus. Growth factors of the identified strains were optimized. Tannery saline wastewater obtained from a Common Effluent Treatment Plant (CETP) near Chennai (southern India) was treated with pure and mixed consortia of four salt tolerant bacterial strains. Experiments with optimized conditions and varying salt content (between 2 and 10% (w/v) were conducted. Salt inhibition effects on COD removal rate were noted. Comparative analysis was made by treating the tannery saline wastewater with activated sludge obtained from CETP and with natural habitat microbes present in raw tannery saline wastewater.
Salt tolerant bacterial mixed consortia showed appreciable biodegradation at all saline concentrations (2%, 4%, 6%, 8% and 10% w/v) with 80% COD reduction in particular at 8% salinity level the consortia could be used as suitable working cultures for tannery saline wastewater treatment.
There are increasing concerns over the presence and implications of pharmaceutical agents in water. In 2002, California banned pharmaceutical use of lindane because of concerns about water quality, as lindane treatment for head lice and scabies was found to be a significant factor adversely affecting wastewater quality.
In this article we describe the effects the ban has had on wastewater quality, unintentional exposures, and clinical practice. This is the first time that a pharmaceutical has been outlawed to protect water quality. As such, this ban provides a rare opportunity to evaluate the possible or potential outcomes of future public health interventions aimed at reducing pharmaceutical water contamination.
We compiled data on lindane in wastewater treatment plant effluent for several large plants in California and one outside of California. Data on exposures to lindane were obtained from records of the California Poison Control System. We assessed the impact on clinical practice via a survey of 400 pediatricians
Wastewater treatment plant monitoring showed that lindane declined in California after the ban. Similarly, unintentional exposure calls declined. Most physicians were aware of the ban (81%) and had used lindane previously (61%), but they did not notice any difficulties with the ban (78%).
The California experience suggests that elimination of pharmaceutical lindane produced environmental benefits, was associated with a reduction in reported unintentional exposures, and did not adversely affect head lice and scabies treatment. This ban serves as a model for governing bodies considering limits on the use of lindane or other pharmaceuticals.
contamination; head lice; lindane; persistent organic pollutant; pharmaceutical; physician survey; scabies; unintentional ingestions; wastewater
Naturally occurring and synthetic estrogens and other molecules from industrial sources strongly contribute to the endocrine disruption of urban wastewater. Because of the presence of these molecules in low but effective concentrations in wastewaters, these endocrine disruptors (EDs) are only partially removed after most wastewater treatments, reflecting the presence of these molecules in rivers in urban areas. The development of a two-phase partitioning bioreactor (TPPB) might be an effective strategy for the removal of EDs from wastewater plant effluents. Here, we describe the establishment of three ED-degrading microbial enrichment cultures adapted to a solid-liquid two-phase partitioning system using Hytrel as the immiscible water phase and loaded with estrone, estradiol, estriol, ethynylestradiol, nonylphenol, and bisphenol A. All molecules except ethynylestradiol were degraded in the enrichment cultures. The bacterial composition of the three enrichment cultures was determined using 16S rRNA gene sequencing and showed sequences affiliated with bacteria associated with the degradation of these compounds, such as Sphingomonadales. One Rhodococcus isolate capable of degrading estrone, estradiol, and estriol was isolated from one enrichment culture. These results highlight the great potential for the development of TPPB for the degradation of highly diluted EDs in water effluents.
Data were collected at a wastewater treatment plant (WWTP)
Vermont, USA, (serving 30,000 people) to assess the relative contribution
of CSO (combined sewer overflow) bypass flows and treated wastewater
effluent to the load of steroid hormones and other wastewater micropollutants
(WMPs) from a WWTP to a lake. Flow-weighted composite samples were
collected over a 13 month period at this WWTP from CSO bypass flows
or plant influent flows (n = 28) and treated effluent
discharges (n = 22). Although CSO discharges represent
10% of the total annual water discharge (CSO plus treated plant effluent
discharges) from the WWTP, CSO discharges contribute 40–90%
of the annual load for hormones and WMPs with high (>90%) wastewater
treatment removal efficiency. By contrast, compounds with low removal
efficiencies (<90%) have less than 10% of annual load contributed
by CSO discharges. Concentrations of estrogens, androgens, and WMPs
generally are 10 times higher in CSO discharges compared to treated
wastewater discharges. Compound concentrations in samples of CSO discharges
generally decrease with increasing flow because of wastewater dilution
by rainfall runoff. By contrast, concentrations of hormones and many
WMPs in samples from treated discharges can increase with increasing
flow due to decreasing removal efficiency.
Constructed wetland (CW) with monoculture of Arundo donax L. was investigated for the posttreatment of anaerobic bioreactor (ABR) treating combined industrial wastewater. Different dilutions of combined industrial wastewater (20, 40, 60, and 80) and original wastewater were fed into the ABR and then posttreated by the laboratory scale CW. The respective removal efficiencies of COD, BOD, TSS, nitrates, and ammonia were 80%, 78–82%, 91.7%, 88–92%, and 100% for original industrial wastewater treated in ABR. ABR was efficient in the removal of Ni, Pb, and Cd with removal efficiencies in the order of Cd (2.7%) > Ni (79%) > Pb (85%). Posttreatment of the ABR treated effluent was carried out in lab scale CW containing A. donax L. CW was effective in the removal of COD and various heavy metals present in ABR effluents. The posttreatment in CW resulted in reducing the metal concentrations to 1.95 mg/L, 0 mg/L, and 0.004 mg/L for Ni, Pb, and Cd which were within the permissible water quality standards for industrial effluents. The treatment strategy was effective and sustainable for the treatment of combined industrial wastewater.
N-substituted aromatics are important priority pollutants entering the environment primarily through anthropogenic activities associated with the industrial production of dyes, explosives, pesticides, and pharmaceuticals. Anaerobic treatment of wastewaters discharged by these industries could potentially be problematical as a result of the high toxicity of N-substituted aromatics. The objective of this study was to examine the structure-toxicity relationships of N-substituted aromatic compounds to acetoclastic methanogenic bacteria. The toxicity was assayed in serum flasks by measuring methane production in granular sludge. Unacclimated cultures were used to minimize the biotransformation of the toxic organic chemicals during the test. The nature and the degree of the aromatic substitution were observed to have a profound effect on the toxicity of the test compound. Nitroaromatic compounds were, on the average, over 500-fold more toxic than their corresponding aromatic amines. Considering the facile reduction of nitro groups by anaerobic microorganisms, a dramatic detoxification of nitroaromatics towards methanogens can be expected to occur during anaerobic wastewater treatment. While the toxicity exerted by the N-substituted aromatic compounds was closely correlated with compound apolarity (log P), it was observed that at any given log P, N-substituted phenols had a toxicity that was 2 orders of magnitude higher than that of chlorophenols and alkylphenols. This indicates that toxicity due to the chemical reactivity of nitroaromatics is much more important than partitioning effects in bacterial membranes.
The Pseudomonas aeruginosa-containing wastewater released by hospitals is treated by wastewater treatment plants (WWTPs), generating sludge, which is used as a fertilizer, and effluent, which is discharged into rivers. We evaluated the risk of dissemination of antibiotic-resistant P. aeruginosa (AR-PA) from the hospital to the environment via the wastewater network. Over a 10-week period, we sampled weekly 11 points (hospital and urban wastewater, untreated and treated water, sludge) of the wastewater network and the river upstream and downstream of the WWTP of a city in eastern France. We quantified the P. aeruginosa load by colony counting. We determined the susceptibility to 16 antibiotics of 225 isolates, which we sorted into three categories (wild-type, antibiotic-resistant and multidrug-resistant). Extended-spectrum β-lactamases (ESBLs) and metallo-β-lactamases (MBLs) were identified by gene sequencing. All non-wild-type isolates (n = 56) and a similar number of wild-type isolates (n = 54) were genotyped by pulsed-field gel electrophoresis and multilocus sequence typing. Almost all the samples (105/110, 95.5%) contained P. aeruginosa, with high loads in hospital wastewater and sludge (≥3×106 CFU/l or/kg). Most of the multidrug-resistant isolates belonged to ST235, CC111 and ST395. They were found in hospital wastewater and some produced ESBLs such as PER-1 and MBLs such as IMP-29. The WWTP greatly reduced P. aeruginosa counts in effluent, but the P. aeruginosa load in the river was nonetheless higher downstream than upstream from the WWTP. We conclude that the antibiotic-resistant P. aeruginosa released by hospitals is found in the water downstream from the WWTP and in sludge, constituting a potential risk of environmental contamination.
The concentrations of Escherichia coli, F-specific RNA bacteriophage (FRNA bacteriophage), and norovirus genogroup I (NoV GI) and norovirus genogroup II (NoV GII) in wastewater were monitored weekly over a 1-year period at a wastewater treatment plant (WWTP) providing secondary wastewater treatment. A total of 49 samples of influent wastewater and wastewater that had been treated by primary and secondary wastewater treatment processes (primary and secondary treated wastewater) were analyzed. Using a real-time reverse transcription-quantitative PCR (RT-qPCR), the mean NoV GI and NoV GII concentrations detected in effluent wastewater were 2.53 and 2.63 log10 virus genome copies 100 ml−1, respectively. The mean NoV concentrations in wastewater during the winter period (January to March) (n = 12) were 0.82 (NoV GI) and 1.41 (NoV GII) log units greater than the mean concentrations for the rest of the year (n = 37). The mean reductions of NoV GI and GII during treatment were 0.80 and 0.92 log units, respectively, with no significant difference detected in the extent of NoV reductions due to season. No seasonal trend was detected in the concentrations of E. coli or FRNA bacteriophage in wastewater influent and showed mean reductions of 1.49 and 2.13 log units, respectively. Mean concentrations of 3.56 and 3.72 log10 virus genome copies 100 ml−1 for NoV GI and GII, respectively, were detected in oysters sampled adjacent to the WWTP discharge. A strong seasonal trend was observed, and the concentrations of NoV GI and GII detected in oysters were correlated with concentrations detected in the wastewater effluent. No seasonal difference was detected in concentrations of E. coli or FRNA bacteriophage detected in oysters.
An extracellular polysaccharide was purified from culture supernatants of Paenibacillus jamilae CP-7, a gram-positive bacillus that was isolated from compost prepared with olive mill wastewaters. The extracellular polysaccharide was produced under aerobic conditions in a medium containing olive mill wastewaters (80% [vol/vol]). This exopolymer had a low level of acute toxicity when it is administered to BALB/c mice by the intraperitoneal route. Interesting immunomodulatory effects were detected when mice were given 10 mg of exopolysaccharide per kg of body weight; the proliferative responses of splenocytes to B-cell and T-cell mitogens were suppressed, the in vitro levels of production of gamma interferon and granulocyte-macrophage colony-stimulating factor by unstimulated and lipopolysaccharide-stimulated splenocytes were enhanced, and the levels of resistance to the intracellular pathogen Listeria monocytogenes was increased in mice. Also, the exopolysaccharide was able to induce lymphocyte proliferation in vitro. We conclude that P. jamilae produces an exopolysaccharide with interesting immunomodulatory properties.
In this work, treatment of textile dye wastewater was carried in a batch reactor using Ganoderma lucidum. The characteristics of textile dye wastewater were studied. The effect of process parameters like pH, temperature, agitation speed and dye wastewater concentration on dye decolourization and degradation were studied. These parameters were optimized using response surface methodology (RSM). From the results, the optimized conditions were: pH 6.6, temperature 26.5 °C, agitation speed 200 rpm and dye wastewater concentration 1:2. At these optimized conditions, the maximum decolourization and COD reduction were found to be 81.4 and 90.3 %. Kinetic studies were carried out using different models like first-order, diffusional and Singh model. From the results, it was found that the degradation follows the first-order reaction model.
Optimization; RSM; Ganoderma lucidum; Dye wastewater; COD
Photocatalytic degradation of olive oil mill wastewater from two-phase continuous centrifugation process was studied. A novel photocatalyst with ferromagnetic properties was characterized and investigated. The degradation capacity of the photocatalytic process of olive oil washing wastewater (OMW) and mixture of olives and olive oil (1 v/v) washing wastewaters (MOMW) was demonstrated. At lab-scale, the %COD removal and residence time (τ) for MOMW and OMW were 58.4% (τ = 2 h) and 21.4% (τ = 3 h), respectively. On the other hand, at pilot scale, 23.4% CODremoval, 19.2% total phenolsremoval, and 28.1% total suspended solidsremoval were registered at the end of the UV/TiO2 process for OMW, whereas 58.3% CODremoval, 27.5% total phenolsremoval, and 25.0% total suspended solidsremoval for MOMW. Also, before the UV/TiO2 reaction, a pH-T flocculation operation as pretreatment was realized. The overall efficiency of the treatment process for MOMW was up to 91% of CODremoval, in contrast with 33.2% of CODremoval for OMW.
The performance of isolated designed consortia comprising Bacillus pumilus, Brevibacterium sp, and Pseudomonas aeruginosa for the treatment of sewage wastewater in terms of reduction in COD (chemical oxygen demand), BOD (biochemical oxygen demand) MLSS (mixed liquor suspended solids), and TSS (total suspended solids) was studied. Different parameters were optimized (inoculum size, agitation, and temperature) to achieve effective results in less period of time. The results obtained indicated that consortium in the ratio of 1 : 2 (effluent : biomass) at 200 rpm, 35°C is capable of effectively reducing the pollutional load of the sewage wastewaters, in terms of COD, BOD, TSS, and MLSS within the desired discharge limits, that is, 32 mg/L, 8 mg/L, 162 mg/L, and 190 mg/L. The use of such specific consortia can overcome the inefficiencies of the conventional biological treatment facilities currently operational in sewage treatment plants.
Six mercury-resistant environmental proteobacterial isolates and one genetically modified mercury-resistant Pseudomonas putida strain were analyzed for physiological traits of adaptive relevance in an environment of packed-bed bioreactors designed for the decontamination of mercury-polluted chlor-alkali wastewater. The strains displayed characteristic differences in each trait (i.e., biofilm formation capability, growth rate in mercury contaminated wastewaters, and mercury reduction efficiency). Subsequently, they were immobilized either as a monoculture or as a mixed culture on porous carrier material in packed-bed bioreactors through which different batches of filter-sterilized industrial chlor-alkali wastewater were pumped. In monospecies bioreactors, the mercury retention efficiency was sensitive to rapidly increasing mercury concentrations in the wastewater. Mixed culture biofilms displayed a high mercury retention efficiency that was not affected by rapid increases in mercury or continuously high mercury concentrations. The dynamic in the community composition of the mixed culture bioreactors was determined by ribosomal intergenic spacer polymorphism analysis. Mercury-mediated selective pressure decreased the number of prevalent strains. Microbial diversity was completely restored after easing of the selective pressure. Microbial diversity provides a reservoir of strains with complementary ecological niches that results in a superior bioreactor performance under changing environmental conditions.
Of 6634 registered industries in Pakistan, 1228 are considered to be highly polluting. The major industries include textile, pharmaceutical, chemicals (organic and inorganic), food industries, ceramics, steel, oil mills and leather tanning which spread all over four provinces, with the larger number located in Sindh and Punjab, with smaller number in North Western Frontier Province (NWFP) and Baluchistan. Hattar Industrial Estate extending over 700 acres located in Haripur district of NWFP is a new industrial estate, which has been developed with proper planning for management of industrial effluents. The major industries located in Hattar are ghee industry, chemical (sulfuric acid, synthetic fiber) industry, textile industry and pharmaceuticals industry. These industries, although developed with proper planning are discharging their effluents in the nearby natural drains and ultimately collected in a big drain near Wah. The farmers in the vicinity are using these effluents for growing vegetables and cereal crops due to shortage of water. In view of this discussion, there is a dire need to determine if these effluents are hazardous for soil and plant growth. So, effluents from different industries, sewage and normal tap water samples were collected and analysed for pH, electrical conductivity (EC), total soluble salts (TSS), biological oxygen demand (BOD), chemical oxygen demand (COD), total nitrogen, cations and anions and heavy metals. The effluents of ghee and textile industries are highly alkaline. EC and TSS loads of ghee and textile industries are also above the National Environmental Quality Standards (NEQS), Pakistan. All the effluents had residual sodium carbonates (RSCs), carbonates and bicarbonates in amounts that cannot be used for irrigation. Total toxic metals load in all the effluents is also above the limit i.e. 2.0 mg/L. Copper in effluents of textile and sewage, manganese in ghee industry effluents and iron contents in all the effluents were higher than NEQS. BOD and COD values of all the industries are also above the NEQS. On the whole, these effluents cannot be used for irrigation without proper treatment otherwise that may cause toxicity to soil, plants and animals as well add to the problems of salinity and sododicity. Similarly, these effluents cannot be used for fish farming.
Industrial effluents; Biological oxygen demand (BOD); Chemical oxygen demand (COD); pH; Residual salts; Lead; Zinc; Copper; Nickel; Manganese; Sewage
Facilities involved in the manufacture of pharmaceutical products are an under-investigated source of pharmaceuticals to the environment. Between 2004 and 2009, 35 to 38 effluent samples were collected from each of three wastewater treatment plants (WWTPs) in New York and analyzed for seven pharmaceuticals including opioids and muscle relaxants. Two WWTPs (NY2 and NY3) receive substantial flows (>20% of plant flow) from pharmaceutical formulation facilities (PFF) and one (NY1) receives no PFF flow. Samples of effluents from 23 WWTPs across the United States were analyzed once for these pharmaceuticals as part of a national survey. Maximum pharmaceutical effluent concentrations for the national survey and NY1 effluent samples were generally <1 μg/L. Four pharmaceuticals (methadone, oxycodone, butalbital, and metaxalone) in samples of NY3 effluent had median concentrations ranging from 3.4 to >400 μg/L. Maximum concentrations of oxycodone (1700 μg/L) and metaxalone (3800 μg/L) in samples from NY3 effluent exceeded 1000 μg/L. Three pharmaceuticals (butalbital, carisoprodol, and oxycodone) in samples of NY2 effluent had median concentrations ranging from 2 to 11 μg/L. These findings suggest that current manufacturing practices at these PFFs can result in pharmaceuticals concentrations from 10 to 1000 times higher than those typically found in WWTP effluents.
Concentrations of pharmaceuticals in two wastewater effluents receiving discharges from pharmaceutical formulation facilities are 10−1000 times higher than concentrations measured in typical wastewater effluents.
Much attention has recently been devoted to the life and behaviour of pharmaceuticals in the water cycle. In this study the behaviour of several pharmaceutical products in different therapeutic categories (analgesics and anti-inflammatory drugs, lipid regulators, antibiotics, etc.) was monitored during treatment of wastewater in a laboratory-scale membrane bioreactor (MBR). The results were compared with removal in a conventional activated-sludge (CAS) process in a wastewater-treatment facility. The performance of an MBR was monitored for approximately two months to investigate the long-term operational stability of the system and possible effects of solids retention time on the efficiency of removal of target compounds. Pharmaceuticals were, in general, removed to a greater extent by the MBR integrated system than during the CAS process. For most of the compounds investigated the performance of MBR treatment was better (removal rates >80%) and effluent concentrations of, e.g., diclofenac, ketoprofen, ranitidine, gemfibrozil, bezafibrate, pravastatin, and ofloxacin were steadier than for the conventional system. Occasionally removal efficiency was very similar, and high, for both treatments (e.g. for ibuprofen, naproxen, acetaminophen, paroxetine, and hydrochlorothiazide). The antiepileptic drug carbamazepine was the most persistent pharmaceutical and it passed through both the MBR and CAS systems untransformed. Because there was no washout of biomass from the reactor, high-quality effluent in terms of chemical oxygen demand (COD), ammonium content (N-NH4), total suspended solids (TSS), and total organic carbon (TOC) was obtained.
Wastewater treatment; Membrane bioreactor; Conventional activated sludge treatment; Pharmaceuticals; Removal efficiency
Data on the content of benzo(a)pyrene (BP) in oil shale industry wastewater, the effectiveness of various effluent treatment processes (evaporation, extraction with butyl acetate, trickling filters, aeration tanks) in reducing the level of BP in oil shale wastewater, the level of BP in various bodies of water of Estonia, and in fish and other water organisms are reviewed. The quantitative determination of BP in concentrated diethyl ether extracts of water samples was carried out by ultraviolet and spectroluminescence procedures by use of the quasi-linear spectra at -196 degrees C in solid paraffins. It has been found that oil shale industry wastewater contains large amounts of BP. The most efficient purification process for removing the BP in oil shale industry phenol water is extraction with butyl acetate. The level of BP in the rivers of the oil shale industry area is comparatively higher than in other bodies of water of the Republic. The concentration of BP in the lakes of the Estonian S.S.R. is on the whole insignificant. Even the maximum concentration found in our lakes is as a rule less than the safety limit for BP in bodies of water (0.005 microgram/l). During water is treated at the waterworks. The effectiveness of the water treatment in reducing the level of BP varies from 11 to 88%. Filtration was found to be the most effective treatment. About 20 samples of fish from nine bodies of water in Estonia have been analyzed for content of BP. The average content of BP in the muscular tissue of various species of fish is as a rule less than 1 microgram/kg. There is no significant difference in the concentration of BP in sea and freshwater fish. There is no important difference in the content of BP in the organs of various fish. Fat fish contain more BP than lean ones. The weight (age) of fish does not influence the content of BP in the muscular tissue of fish.
Due to the presence of non-biodegradable and toxic compounds, textile wastewater is difficult to treat by conventional methods. In the present study, Electrochemical Fenton (EF) and Chemical Fenton (CF) processes were studied and compared for the treatment of real textile wastewater. The effects of electrical current, ferrous ion, hydrogen peroxide concentration and reaction time on the removal efficiencies of COD and color were investigated. All the experiments were carried out at pH = 3.
Both EF and CF processes were mostly efficient within hydrogen peroxide concentration of 1978 mg/L (H2O2: COD ~ 1.1). The highest COD and color removal efficiencies were 70.6% and 72.9% respectively which were obtained through the EF process in 350 mA electrical current, 1978 mg/L hydrogen peroxide and 60 minutes reaction time. Furthermore, the operational costs of EF and CF processes were 17.56 and 8.6 US$ per kilogram of the removed COD respectively.
It was concluded that the electrochemical Fenton process was more efficient than the chemical Fenton process in the degradation of textile wastewater. Likewise, Although EF process imposed higher operational costs than the CF; it dramatically decreased the reaction time to gain the highest degradation efficiency.
Chemical Fenton; Decolorization; Electrochemical Fenton; Textile wastewater
The hydrophobic-grid membrane filter (HGMF) has been proposed as an alternate method to the standard membrane filter (MF) procedure for the detection and enumeration of coliforms from water. Eight samples of nonchlorinated wastewater effluents were analyzed by the HGMF, standard MF, and tube fermentation most-probable-number methods for fecal coliforms, and eight samples each of polluted surface and dosed drinking waters were analyzed by the same methods for total coliforms. The drinking waters were dosed with coliforms and other heterotrophs concentrated from nonchlorinated domestic wastewater and treated with chlorine to reduce the numbers of organisms and simulate stress caused by chlorination. Statistical analyses determined that recoveries of fecal coliforms were significantly higher by the filtration methods for the nonchlorinated domestic wastewaters but not for the other waters. The results also indicated that recoveries of fecal and total coliforms did not differ significantly when either MFs or HGMFs were used. Total coliform results obtained with HGMFs having greater than 100 positive grid cells were significantly more precise than estimates obtained by the standard MF method only for polluted surface waters.
Studies on the occurrence of pharmaceuticals show that the widely used pharmaceuticals ibuprofen and diclofenac are present in relevant concentrations in the environment. A pilot plant treating hospital wastewater with relevant concentrations of these pharmaceuticals was evaluated for its performance to reduce the concentration of the pharmaceuticals. Ibuprofen was completely removed, whereas diclofenac yielded a residual concentration, showing the necessity of posttreatment to remove diclofenac, for example, activated carbon. Successively, detailed laboratory experiments with activated sludge from the same wastewater treatment plant showed bioremediation potential in the treatment plant. The biological degradation pathway was studied and showed a mineralisation of ibuprofen and degradation of diclofenac. The present microbes were further studied in laboratory experiments, and DGGE analyses showed the enrichment and isolation of highly purified cultures that degraded either ibuprofen or diclofenac. This research illuminates the importance of the involved bacteria for the effectiveness of the removal of pharmaceuticals in a wastewater treatment plant. A complete removal of pharmaceuticals from wastewater will stimulate water reuse, addressing the worldwide increasing demand for clean and safe fresh water.
Economical and bio-friendly approaches are needed to remediate dye-contaminated wastewater from various industries. In this study, a novel bacterial strain capable of decolorizing triarylmethane dyes was isolated from a textile wastewater treatment plant in Greece. The bacterial isolate was identified as Aeromonas hydrophila and was shown to decolorize three triarylmethane dyes tested within 24 h with color removal in the range of 72% to 96%. Decolorization efficiency of the bacterium was a function of operational parameters (aeration, dye concentration, temperature, and pH) and the optimal operational conditions obtained for decolorization of the dyes were: pH 7-8, 35°C and culture agitation. Effective color removal within 24 h was obtained at a maximum dye concentration of 50 mg/L. Dye decolorization was monitored using a scanning UV/visible spectrophotometer which indicated that decolorization was due to the degradation of dyes into non-colored intermediates. Phytotoxicity studies carried out using Triticum aestivum, Hordeum vulgare, and Lens esculenta revealed the triarylmethane dyes exerted toxic effects on plant growth parameters monitored. However, significant reduction in toxicity was obtained with the decolorized dye metabolites thus, indicating the detoxification of the dyes following degradation by Aeromonas hydrophila.
Over the last decade, research has examined the endocrine-disrupting action of various environmental pollutants, including hormones, pharmaceuticals, and surfactants, in sewage treatment plant effluent. Responding to the growth of concentrated animal feeding operations (CAFOs) and the pollutants present in their wastewater (e.g., nutrients, pharmaceuticals, and hormones), the U.S. Environmental Protection Agency developed a new rule that tightens the regulation of CAFOs. In this study, we collected wild fathead minnows (Pimephales promelas) exposed to feedlot effluent (FLE) and observed significant alterations in their reproductive biology. Male fish were demasculinized (having lower testicular testosterone synthesis, altered head morphometrics, and smaller testis size). Defeminization of females, as evidenced by a decreased estrogen:androgen ratio of in vitro steroid hormone synthesis, was also documented. We did not observe characteristics in either male or female fish indicative of exposure to environmental estrogens. Using cells transfected with the human androgen receptor, we detected potent androgenic responses from the FLE. Taken together, our morphologic, endocrinologic, and in vitro gene activation assay data suggest two hypotheses: a) there are potent androgenic substance(s) in the FLE, and/or b) there is a complex mixture of androgenic and estrogenic substances that alter the hypothalamic-pituitary-gonadal axis, inhibiting the release of gonadotropin-releasing hormone or gonadotropins. This is the first study demonstrating that the endocrine and reproductive systems of wild fish can be adversely affected by FLE. Future studies are needed to further investigate the effects of agricultural runoff and to identify the biologically active agents, whether natural or pharmaceutical in origin.
The removal of enteric and tracer viruses by the overland runoff mode of domestic wastewater treatment was evaluated. Raw and primary and secondary treated wastewaters were sprayed onto grass-covered, 36-m soil plots of fine, sandy loam overlying an impermeable clay subsoil. Tracer bacteriophage f2 was seeded into the applied wastewaters, which were subsequently sampled at several points along the length of the plots. Assay of effluent samples revealed modest tracer virus removals of 30 to 60%. Data from timed experiments indicated that advancement of tracer virus to the bottom of the slopes proceeded at the same rate as wastewater, reaching the plot effluents within 50 to 90 min after application. Indigenous enteric virus levels were reduced by approximately 68 to 85% during migration down the treatment slopes. Soil sampling revealed that, although some f2 virus was found associated with the wastewater-saturated topsoil, little penetration of virus into the soil profile occurred. Laboratory soil adsorption studies revealed that poliovirus I was adsorbed much more readily than f2 virus. Comparison of virus removal characteristics during overland runoff with chemical removal characteristics of wastewater did not reveal any obvious correlations that could be used to predict virus removal.