Showing papers in "Environmental Technology in 1991"
TL;DR: In this article, the adsorption of Cu(II, Ni(II), and Cr(VI) ions to activated sludge bacteria obtained from the waste water system of METEKSAN, Turkey was investigated.
Abstract: In this study, the adsorption of Cu(II), Ni(II), and Cr(VI) ions to activated sludge bacteria obtained from the waste water system of METEKSAN, Turkey was investigated. Optimum adsorption temperatu...
105 citations
TL;DR: In this article, a seasonal basis at 13 sampling points covering the most significant agricultural areas as well as types of culture throughout France, the pesticides selected included 19 herbicides, 7 insecticides and 12 fungicides which represented for each category, respectively 88, 50% and 80% of the quantities applied in France in 1987.
Abstract: Thirty eight active substances were determined on a seasonal basis at 13 sampling points covering the most significant agricultural areas as well as types of culture throughout France. The pesticides selected included 19 herbicides, 7 insecticides and 12 fungicides which represented for each category, respectively 88%, 50% and 80% of the quantities applied in France in 1987. The sampling points included 11 ground waters with different depths and geological characteristics; the last two points were sampled from the river Seine and river Marne which account for 40% of the water supply of the Paris area. Seven multiresidue analytical techniques were developed to measure the 38 pesticides at or below the 100 ngl‐1 level of the drinking water EEC directive. Gas chromatography‐mass spectrometry could be used to quantitate 36 substances following solvent extraction (benzene, methylene chloride) or other sample preparation methods (hydrolysis, methylation, oxidation). The remaining substances were analys...
92 citations
TL;DR: A detailed survey of the River Tees estuary in the north east of England has been carried out to determine the levels of total heavy metal concentrations in its bed sediments as discussed by the authors.
Abstract: A detailed survey of the River Tees estuary in the north east of England has been carried out to determine the levels of total heavy metal concentrations in its bed sediments. Samples were collected at 31 locations, 0.5 km apart between the upper dredging limit and the river mouth. Three samples of the surface sediments were taken at each location; from the north and south banks and at mid‐channel. The mean total metal concentrations after acid digestion were found to decrease in the order Zn>Mn, Pb>Cu>Cr>Ni>Cd for the sample locations. Along some locations of the estuary, the maximum and other peak metal concentrations were similar to those found in strongly polluted industrialised rivers.
84 citations
TL;DR: In this article, a bench test of biofilters using soil, carbon and diatomaceous earth as support media for treatment of JP•5 jet fuel and diesel fuel vapors was conducted.
Abstract: Industrial processes and contaminated site remediation projects produce large‐volume air discharges with low concentrations of pollutants. Biofilters can treat such effluents by passing them through a damp porous medium which supports an active community of microorganisms. This paper reports bench testing of biofilters using soil, carbon and diatomaceous earth as support media for treatment of JP‐5 jet fuel and diesel fuel vapors. Activated carbon supported higher biodegradation rates than soil, and diatomaceous earth was least effective. Jet fuel was degraded more rapidly than diesel fuel.
75 citations
TL;DR: In this article, the degradation of 4-nitrophenol by means of hydrogen peroxide photolysis and photo-lysis in the presence of the Fenton reagent (FeCI2/H2O2) was investigated.
Abstract: Degradation of 4‐nitrophenol by means of the hydrogen peroxide photolysis and the Photolysis in the presence of the Fenton reagent (FeCI2/H2O2) was investigated. The results were compared with those of the dark Fenton reaction, reported elsewhere . In all the cases, decomposition of the pollutant was observed. The best results were obtained when the solutions of 4‐nitrophenol, containing the Fenton reagent, were irradiated with the polychromic UV light. The developed method can be successfully applied for the degradation of this hazardous pollutant which is very difficult to decompose by other means.
59 citations
TL;DR: In this article, the authors studied the biodegradability, toxicity/inhibition, operational temperatures, and the options of treating several effluents separately or jointly for sea fish canning.
Abstract: Sea fish canning industries produce effluents with a high load of organic matter. High concentrations of salts and possible production of H, S and NH4 + from the degradation of sulphates and proteins respectively, can cause toxicity/inhibition problems during the treatment of these effluents by anaerobic digestion. Biodegradability, toxicity/inhibition, operational temperatures, and the options of treating several effluents separately or jointly were studied. Anaerobic biodegradability reached up to 90% of soluble COD. Despite the high levels of sodium, ammonia and sulphide present, the results obtained allowus to predict a successful operation when adequate conditions are established. In order to gather more information as to the design of an industrial plant, complementary studies of pretreatment of effluents from fish meal factories and the use of high rate anaerobic digesters are proposed.
56 citations
TL;DR: In this paper, the development and implementation of a treatment program for full-scale bioremediation of a creosote contaminated site is described, following a one year feasibility study investigating physical, chemical and biological methods for treating creosotes-derived polyaromatic hydrocarbons in soil.
Abstract: The development and implementation of a treatment programme for full scale bioremediation of a creosote contaminated site is described. Following a one year feasibility study investigating physical, chemical and biological methods for treating creosote‐derived polyaromatic hydrocarbons in soil, two remedial systems were constructed: (a) an in situ treatment facility handling 15000m3 of contaminated soil, designed to allow building development to take place simultaneously, above ground; (b) separate clean‐up of 3500m3 of excavated soil in an off‐site treatment bed.
55 citations
TL;DR: In this paper, soil columns which had received a range of applications of anaerobically digested sewage sludge were incubated for five months and organically bound metals were extracted with pyrophosphate following incubation.
Abstract: Soil columns which had received a range of applications of anaerobically digested sewage sludge were incubated for five months. The sludge application rates were equivalent to the one year average value and maximum value (equivalent to six years’ addition) permitted by UK guidelines. About 23–26% of total organic matter degraded in the soil columns during incubation. Organically bound metals were extracted with pyrophosphate following incubation. Over half of the cadmium was in the organic phase, compared to less than 20% of the lead. The proportion of lead extractable was unaffected by the rate of sludge addition, whereas for copper percentage extractability decreased with increasing sludge application and for nickel and zinc percentage extractability increased. Organic complexes of copper and cadmium were stronger than for the other metals, and the binding capacity of the organic matter for metals was greatest for copper and nickel.
53 citations
TL;DR: In this article, a new approach to the determination of biodegradable dissolved organic carbon (BDOC) is proposed, specially suited to water industry needs, which uses circulating water continuously pumped over a biofilm attached to sand particles inside a glass column.
Abstract: A new approach to the determination of biodegradable dissolved organic carbon (BDOC) is proposed, specially suited to water industry needs. It is a dynamic approach which uses circulating water continuously pumped over a biofilm attached to sand particles inside a glass column. The BDOC value corresponds to the DOC decrement when inlet and outlet water samples are compared. The time taken by BDOC analysis is less than two hours.
49 citations
TL;DR: In this paper, a method for determining macroalgal standing crops in shallow waters of the Venice Lagoon, populated by macroalgae with different densities and variously distributed over the bottom, was presented.
Abstract: A number of procedures were tested to set up a reliable method for determining macroalgal standing crops in the shallow waters of the Venice Lagoon, populated by macroalgae with different densities and variously distributed over the bottom. Accurate and precise measures of biomass were obtained using a box of 1m2 and a grid sampling scheme. Three areas (15 × 15 m2) characterized by high (5–20 kg m‐2), low (0.1–1.0 kg m‐2) and intermediate (1–10 kg m‐2) biomass densities were studied. Twenty sub‐samples were taken in each area and the results obtained were considered as the best estimate of the true mean of the population in the area. The difference between the best estimate of the total macroalgal population mean (BEM) and the mean of different sets of sub‐samples (SM) divided by the best estimate of the mean: | BEM‐SM |/BEM was proved the most efficient parameter to attain a value which differs by a given percentage ‐at 95% probability‐from the true macroalgal biomass, considering all the possib...
42 citations
TL;DR: In this paper, the removal of humic acid components by R. arrhizus was investigated and it was found that the presence of Cd2+ ions and high ionic strength in solution increased the adsorptive capacity of R. arrhizus for HPO•A and HP•N.
Abstract: Humic acid components HFO‐A and HPI‐N were studied for their removal by Rhizopus arrhizus. The removal was stimulated by the presence of sucrose followed by pretreating biomass with formaldehyde or autoclaving. The presence of Cd2+ ions and high ionic strength in solution was found to increase the adsorptive capacity of R. arrhizus for HPO‐A and HPI‐N. The uptake of HPO‐A and HPI‐N by R. arrhizus was biphasic in nature and generally a much slower process than heavy metal biosorption. The first phase was rapid and independent of metabolic energy while the second phase was slow and dependent on metabolic energy. The infrared spectra showed no chemical reaction has occurred between cell walls and adsorbates. Physical adsorption is therefore the main mechanism of humic removal by inactive R. arrhizus.
TL;DR: In this paper, the use of pine needles as a biomonitor of atmospheric mercury has been studied in three different areas (mining, volcanic and urban) and the difficulties and limits of pine as a mercury biomoneter are discussed.
Abstract: Pine was studied as a biomonitor of atmospheric mercury. For this purpose seven species of pine in three different areas (mining, volcanic and urban) were considered. Needles, branches and roots were analyzed for mercury and their metal concentrations studied in relation to those of atmosphere and soil. The relations between the Hg content in the different plant parts and between Hg concentration and the age of needles were studied as well. The difficulties and limits of pine as a mercury biomonitor are discussed.
TL;DR: Foaming and surface tension determinations were carried out on mixed liquors from foaming and non-foaming plants and on pure cultures of the isolated actinomycetes which were identified as Nocardia amarae.
Abstract: Actinomycetes that are implicated in foam formation in activated sludge sewage treatment plants were isolated from plants in Queensland, Australia. Foaming and surface tension determinations were carried out on mixed liquors from foaming and non‐foaming plants and on pure cultures of the isolated actinomycetes which were identified as Nocardia amarae. Foam stability of mixed liquors increased with increasing temperature and concentration of mixed liquor suspended solids. The results showed that a surfactant was released by the organisms and that the bacterial cells were responsible for stabilization of laboratory scale foams. The nitrogen source for growth did not affect the foam or surfactant production, however, the carbon source produced growth form‐dependent changes to the foam but did not affect surfactant production.
TL;DR: Four methods for the enumeration of human parasitic nematodes in treated wastewater were compared in field trials in the northeast of Brazil and the recovery of eggs was found to be consistently higher using the method currently recommended by the World Health organisation.
Abstract: Four methods for the enumeration of human parasitic nematodes in treated wastewater were compared in field trials in the northeast of Brazil. Effluents from a series of waste stabilisation ponds and a physico‐chemical lime treatment plant were used. Comparisons were made on a daily and 24 hour basis. The recovery of eggs was found to be consistently higher using the method currently recommended by the World Health organisation (1) (commonly known as the Bailenger method) but only when 10 1 samples, rather than 11 samples, were processed.
TL;DR: In this paper, a double phase metanization was used for anaerobically treating the whey produced by the cheese industry, and a new operational strategy was proposed, where recirculation of the eflluent of the metanisation reactor produces a dilution of the influent that allows a good stability of the system without the necessity of adding alkalinity.
Abstract: The whey produced by the cheese industries can be anaerobically treated. The main operational limitations for single phase reactors are instability and the necessity of adding alkalinity. A double phase reactor has been used and a new operational strategy is proposed. The recirculation of the eflluent of the metanization reactor produces a dilution of the influent that allows a good stability of the system without the necessity of adding alkalinity. COD removal higher than 99% can be obtained operating with Bv = 30 Kg m‐3 d‐1 in the acidification reactor (t=0.45 d) and Bv= 15 Kg m‐3 d‐1 in the metanization reactor (t =0.75 d).
TL;DR: In this article, the degradation of trihalomethanes (THM) by UV irradiation at 253.7 nm was investigated and the results showed that only the brominated THMs were photolysed.
Abstract: In this study, the degradation of trihalomethanes (THM) by UV irradiation at 253.7 nm was investigated. Experiments were carried out with dilute aqueous solutions of CHCl3, CHCl2Br, CHBr2Cl and CHBr3 (< I0–6 mol 1‐1) at 20°C and pH = 7.5 and with photochemical reactors equipped with a low‐pressure mercury vapour lamp. Under our experimental conditions (irradiation time ≤ 30 minutes), the results showed that only the brominated THMs were photolysed. The quantum yield values for the photolysis of the three brominated THMS which could be determined from the kinetic results were found to be equal to 0.43 ± 0.01 at 253.7 nm and at 20°C. Moreover, ionic chromatography analysis revealed that organic halogen present in CHCl2 Br, CHBr2 Cl and CHBr3 was completely converted into chloride and bromide ions during irradiation.
TL;DR: In this paper, the environmental importance of atmospheric polycyclic aromatic hydrocarbons (PAH) is briefly discussed, and a sampling regime, using filters and Tenax TA adsorbent, is outlined which enables the collection of 18 PAH in air, from both the particulate and gaseous phases.
Abstract: The environmental importance of atmospheric polycyclic aromatic hydrocarbons (PAH) is briefly discussed. A sampling regime, using filters and Tenax TA adsorbent, is outlined which enables the collection of 18 PAH in air, from both the particulate and gaseous phases. An extraction and clean up process is described, which prepares the sample for reversed phase high performance liquid chromatography (HPLC) by transferring the analyte to acetonitrile. Tests on the overall methodology indicate that the procedure provides a sensitive and accurate method for assessing levels of atmospheric PAH. An examination of the differing sampling efficiency between impaction and filtration was undertaken, which indicated the effect of sampling duration and temperature on sample integrity. Evidence of the impact of other gaseous pollutants on measured PAH concentrations was highlighted by stepwise multiple regression.
TL;DR: In this paper, a review of the recent application of passive samplers for the sampling of low concentration organic vapours in indoor and ambient air is presented, and it is suggested the effective cross-sectional area should be employed in calculating the diffusion uptake rate according to DA/L instead of the total crosssectional area.
Abstract: This paper presents a review of the recent application of passive samplers for the sampling of low concentration organic vapours in indoor and ambient air. Theoretical equations describing the operation of various types of passive samplers are summarized. The problems associated with the application of passive samplers for the sampling of organic vapours in indoor and ambient air, and the factors affecting the performance of passive samplers are discussed. It is suggested the effective cross‐sectional area be employed in calculating the diffusion uptake rate according to DA/L instead of the total cross‐sectional area. It is further suggested that suitable passive samplers with a higher uptake rate should be designed (e.g. by reducing the diffusion length), and a new and simple validation procedure should be developed for their application in indoor and ambient air environments.
TL;DR: It was found that the nitrifying organisms formed denser and thinner biofilms and exhibited poorer attachment properties and were more easily detached than the heterotrophic microorganisms.
Abstract: The attachment properties of nitrifying and heterotrophic biofilms developed in laboratory scale rotating biological contactors (RBC) were studied by measuring the development of biofilm thickness, biofilm density, activity, and detachment caused by shear stress. It was found that the nitrifying organisms formed denser and thinner biofilms. They also exhibited poorer attachment properties and were more easily detached than the heterotrophic microorganisms.
TL;DR: Variability of lead in tissue (gills, liver, muscles), in a teleost fish exposed to test water with sublethal concentrations of lead, was evaluated and is presented here.
Abstract: The study of bioconcentration, kinetics of accumulation and tissue distribution of lead, in a teleost fish, Colisa fasciatus was undertaken in a laboratory ecosystem. The system was exposed to test water with sublethal concentrations of lead. Variability of lead in tissue (gills, liver, muscles) was evaluated and is presented here. Measurements of lead contained in individual organs expound high concentrations of lead in gills and muscles, explicating gills and muscles as major sites for concentration. The uptake rate kinetics show an initial rapid phase and later slow phase responsible for net accumulation.
TL;DR: In this paper, a general scheme of the pathways of butyltin compounds is proposed, the degradation of TBT in sediments being much slower than in overlying waters. Butyltins predominates in marinas or mooring areas but MBT is the most abundant away from pollution sources.
Abstract: Arcachon Bay is a site where TBT levels have been high from 1975 to 1981, but have fallen since then. It is therefore a convenient site for studies on the long term fate of butyltin pollution. Surface sediments throughout the Bay still contain all butyltin species. TBT concentration reaches up to 158 ng.g‐1 (as Sn) in marinas, but is only a few ng.g‐1 in remote areas. Amongst Butyltins, TBT predominates in marinas or mooring areas but MBT is the most abundant away from pollution sources. A general scheme of the pathways of butyltin compounds is proposed, the degradation of TBT in sediments beingmuch slower than in overlying waters.
TL;DR: Which environmental variables are important for the development of each ciliate species and for the whole ciliate population are revealed in stepwise multiple regression analysis.
Abstract: Ciliated protozoa communities and physico‐chemical variables were measured in an activated‐sludge sewage‐treatment plant in order to know the influence of the environmental conditions on the ciliate populations during biological treatment. Data of biological and not biological variables were submitted to stepwise multiple regression analysis, revealing which environmental variables are important for the development of each ciliate species and for the whole ciliate population.
TL;DR: In this article, the metal extraction from two contaminated waste site clay soils by 0.1-0.3 N HCl solutions was tested in three laboratory scale, continuous processes: two stirred tank reactors (CSTR) s in series; a countercurrent sieve plate column fed with flocculated.
Abstract: Extraction of metals from two contaminated waste site clay soils by 0.1–0.3 N HCl solutions was tested in three laboratory scale, continuous processes: two stirred tank reactors (CSTR’ s) in series; a countercurrent sieve‐plate column fed with flocculated. clay soil material; and a combination of tank reactor and column. After extraction clay soil suspension and extractant were separated by means of flocculation and sedimentation. The countercurrent process gave greater efficiencies in removing the metal than the CSTR process but the difference was only small. The following type of cleaning process seemed to be promising: first an extraction in a stirred tank followed by a further second extraction in a countercurrent column. Residence time in the CSTR could be short (15–30 minutes) while it should be as long as possible in the column.
TL;DR: Bacterial colonization of an aerobic fixed bed reactor was studied as a function of reactor height and time and a decreasing gradient of biomass from top to bottom of the reactor was observed.
Abstract: Bacterial colonization of an aerobic fixed bed reactor was studied as a function of reactor height and time. The amount of fixed biomass, its activity and the influence of periodic backwashing was measured. Rapid colonization was achieved during the first five days of pilot operation. A decreasing gradient of biomass from top to bottom of the reactor was observed. This zoning tended to disappear with time. Backwashing operation permitted the removal of 30 % of the fixed biomass, without affecting wastewater treatment efficiency. Removal rates remained stable with time and reached 90 % for total COD, from which 60 to 70 % was obtained in the first part of the reactor.
TL;DR: Anaerobic effluent from thermophilic digestion (55°C) of organic fraction of municipal solid waste (OFMSW) was ultimately treated through a co-composting process as discussed by the authors.
Abstract: Anaerobic effluent from thermophilic digestion (55°C) of organic fraction of municipal solid waste (OFMSW) was ultimately treated through a co‐composting process. OFMSW sorted by an industrial plant was used as bulking agent mixed to the digested effluent in the co‐composting experiment. Compost detoxification of the anaerobic effluent was carried out in a static windrow aerated by blowing air in it. The bio‐oxidative post‐treatment technology adopted allowed the anaerobic effluent mixed with the OFMSW to overcome phytotoxicity and to reach maturity for a possible use as organic amendant in agriculture. Short term composting (5 weeks) proved also to act efficiently in drying and hygienizing the initial waste biomass.
TL;DR: In this paper, the effects of nickel, chromium and substrate concentration on the microbial growth of acclimatized and unacclimatized microbes of sewage origin were studied in batch cultures at a constant temperature of 25 °C, at pH 7.0.
Abstract: Effects of nickel, chromium and substrate concentration on the microbial growth of acclimatized and unacclimatized microbes of sewage origin were studied in batch cultures at a constant temperature of 25 °C, at pH 7.0. A synthetic medium supplemented with Ni(II) (5 and 10 mgl‐1) or Cr(VI) (1 and 50 mgl‐1) or with their combinations and at various feed concentrations (650, 975, 1300 mgl‐1) was employed to investigate the effects on the specific growth rate (μm) of the microbial culture. The experimental results were statistically analysed by using multiple regression techniques.
TL;DR: In this article, a comparison of levels of respirable suspended particulates, carbon monoxide, carbon dioxide, nitrogen dioxide, volatile organic compounds and nicotine have been made between indoor and outdoor air in 35 street level shops and 35 offices in Hong Kong.
Abstract: Comparisons of levels of respirable suspended particulates, carbon monoxide, carbon dioxide, nitrogen dioxide, volatile organic compounds and nicotine have been made between indoor and outdoor air in 35 street‐level shops and 35 offices in Hong Kong. Additionally, counts of bacteria and fungi were made indoors. In shops, the study showed that the air quality was principally determined by outdoor air, with highly significant correlations between indoor and outdoor levels of RSP, CO and NO2. The levels of these substances were significantly lower in offices. Measurement of analytes related to tobacco smoking showed extremely low levels of environmental tobacco smoke in both shops and offices, but the overall numbers of smokers in such establishments was small. For offices, occupier complaints regarding drowsiness, headache and symptoms of eye, nose and respiratory tract irritation were positively associated with CO2 levels. NO2, CO, toluene and benzene levels did not show any relationship to occupi...
TL;DR: In this paper, a continuously fed 5L capacity bioreactor using an adapted strain of Thiobacillus ferrooxidans at varying dilution rates and an inlet sludge solids concentration of 30g/l was studied.
Abstract: Microbial leaching of metals from digested municipal sludge was studied in a continuously fed 5L capacity bioreactor using an adapted strain of Thiobacillus ferrooxidans at varying dilution rates and an inlet sludge solids concentration of 30g/l. The pH of the feed sludge was adjusted to 4.0 and leaching was conducted at a temperature of 30°C. Acceptable levels of metals in the sludge were reached with a residence time of 5 days compared to 7–12 days in the batch process. The maximum specific growth rate of 0.038/h was found for individual metals or mixture of metals involved in leaching. Ks values for Zn, Cu, and combined Zn and Cu were found to be 18.5, 43.6, and 61.3 mg/L respectively.
TL;DR: In this article, the effects of Cu(II) on a chemostat containing activated sludge were evaluated in a laboratory-scale completely-mixed-activated sludge unit, without recycle, treating simulated wastewater.
Abstract: The purpose of this study was to evaluate the toxic effects of Cu(II) on a chemostat containing activated sludge. Different concentrations of Cu(II) (0.5, 1.0, 5.0, and 10.0mgL‐1) were maintained in a laboratory‐scale completely mixed activated sludge unit, without recycle, treating simulated wastewater. The feed solution contained 650 mgL‐1 protein (corresponding to 1300 mgL‐1 COD) as a source of carbon. Experimental results indicated that the treatment efficiency was not adversely effected by the presence of Cu(II) up to the concentration of 10.0 mgL‐1. Moreover, some stimulatory effects of Cu(II) on the biokinetic parameters were observed.
TL;DR: A preliminary study on heavy metals contamination in fiddler crabs and hermit crabs was carried out as mentioned in this paper, which showed Pb and Cd concentrations were high whereas Zn and Cu concentrations were within the permissible limits.
Abstract: A preliminary study on heavy metals contamination in fiddler crabs and hermit crabs was carried out. As they are easily found in river mouth areas, they can probably serve as good indicators for heavy metals pollution. The results show Pb and Cd concentrations were high whereas Zn and Cu concentrations were within the permissible limits.