The effects of pH and suspended solids in the removal of organics from waters and wastewaters by the activated carbon adsorption process

The effects of pH, inorganic suspended solids and organic suspended solids on the adsorption of organics by activated carbon were investigated using sewage effluents and selected organic compounds of varying size, structure, molecular weight and properties in model solutions. It was found that suspended solids, and in particular organic suspended solids, could interfere with the adsorption process, both in terms of adsorption capacity and adsorption rate; the effect of the solids diminished as the size of the adsorbate increased. The effect of pH variation became more significant as the acidity or basicity of the adsorbate in solution increased. Adsorption of organics from biologically treated sewage effluents was somewhat more effective in the acid and alkaline pH regions than in the neutral pH region.     

Mercury in feathers of wild birds from the mercury - polluted area along the shore of the Shiranui Sea, Japan

Total mercury content in the feathers of 95 stuffed, wild birds collected all over the shore of the Shiranui Sea (where Minamata disease occurred in many towns and villages in the 1960's) was measured. They were collected over 25 years, from 1955 to 1980. They showed relatively high mercury levels till the late 1970's, although drainage of waste water containing methylmercury from the Chisso Corporation's Minamata Factory was stopped in 1968. In addition, a strong correlation between feeding habits and mercury content was observed; thus the five groups in order of diminishing mercury content were: fish-eating sea birds (mean ± SD = 7.1 ± 3.7 ppm, N = 14), omnivorous water fowl (5.5 ± 5.6 ppm, N = 17), predatory birds (3.6 ± 2.9 ppm, N = 16), omnivorous terrestrial birds (1.5 ± 1.2 ppm, N = 31), and herbivorous water fowl (0.9 ± 0.4 ppm, N = 17). Mercury content of the feathers of omnivorous terrestrial birds in the Shiranui Sea was exceedingly high compared with those in China and Korea. The findings in the present study suggest that stuffed, wild birds may be a good index of past environmental pollution.     

Measurements of alkyllead compounds in the gas and aerosol phase in urban and rural atmospheres

Alkyllead compounds in the gas and aerosol phase were determined simultaneously in urban and rural atmospheres using gas chromatography--atomic absorption spectroscopy and wet chemical (iodine monochloride) methods. The difference in results between the two methods suggests the presence of vapour-phase tri- (and/or di-)alkyllead in both urban and rural air. Concentrations of 0.06-1.6 and 16-205 ng Pb m-3 were found for vapour-phase organolead compounds other than tetraalkyllead in rural and kerbside urban air, respectively. Tetraalkyllead and trialkyllead compounds were identified in atmospheric aerosols at both sites, but these were found to be present at concentrations less than 1.2% of the total gas-phase alkyllead.     

Lead content of small mammals at a roadside site in relation to the pathways of exposure

Concentrations of lead have been determined in three species of small mammal, Sorex araneus, Clethrionomys glareolus and Apodemus sylvaticus at roadside and control sites. The results are considered in relation to the lead content of the diet and the air, and it is concluded that the diet provides far the major pathway for lead exposure, even at the roadside site. Bone lead concentrations are found to be consistent with estimated lead exposure and metabolism.     

Activity of benzo[a]pyrene monooxygenase in fish from the Sava River, Yugoslavia: correlation with pollution

Benzo[a]pyrene monooxygenase (B[a]PMO) activity in non-migratory fish from a given river segment is highly correlated to the recent pollutional history of that part of the river. The enzyme activity level can serve as a relevant measure for the harmful pollutant potential in aquatic ecosystems. Caged experimental fish exposed for about 10 days in river segments show BaPMO activity changes with the same predictive validity as that of the natural population.     

The distribution and origin of mutagens in airborne particulates, detected by the salmonella/microsome assay in relation to levels of lead, vanadium and PAH

At three stations in central Copenhagen, Denmark, samples of particulate matter were collected simultaneously with different contributions from automobile exhaust products. Samples were obtained at street level, 22 m above street level and within a hospital zone; 32 samples were analysed for levels of polycyclic aromatic hydrocarbons (PAH) and elements, as well as for mutagenicity towards S. typhimurium TA1538. Two classes of mutagens were quantified: a non-polar extract rich in PAH and, other promutagens, and a polar extract containing direct acting mutagens (not requiring microsomal activation). Covariances between lead and mutagenicity, and the varying distribution of the polar and non-polar mutagens at the stations, indicate that at all stations the mutagenicity of the non-polar extract is dominated by automobile exhaust products. The polar extract is relatively less influenced by primary traffic emissions; a considerable part of the activity of this extract is attributed to secondary emissions, transformed by atmospheric reactions, and primary emissions from stationary sources.     

The speciation of the chemical forms of arsenic in the biological monitoring of exposure to inorganic arsenic

Total As content may be determined in blood and urine by means of an AAS method that involves reduction of As to its volatile hydride and ashing at 600°C with MgO and Mg (NO₃)₂. Separation of inorganic As (InAs), monomethylarsonic acid (MMA) and dimethylarsinic acid (DMAA) by ion-exchange chromatography, followed by direct AAS analysis, allows the determination of each As species in the urine.In a reference population of 148 subjects with only normal environmental exposure to As, total As concentration in the urine averages 17.2 ± 11.1 μg/l. Urinary As consists of 10% each of InAs, MMAA and DMAA, the remaining 70% consisting of other forms of organic As.Blood As concentration averages 5.1 ± 6.9 μg/l and correlates significantly with the urinary concentration of InAs and the sum of its metabolites (InAs + MMAA + DMAA).Inorganic arsenic undergoes methylation in the organism. After ingestion of high quantities of As₂O₃, the time course of excretion of its metabolites indicates that As methylation occurs by a saturable mechanism.In workers exposed to As₂O₃, InAs, MMAA and DMAA are the only chemical forms of As excreted in the urine that are relevant to a study of occupational exposure. Blood As concentration is proportional to exposure and correlates only with urinary DMAA excretion; DMAA seems to be the most appropriate single indicator of exposure. At high levels of exposure (total As excretion above 200 μg/l), As accumulates in the organism and DMAA excretion reflects its accumulation. At low levels of exposure (total As excretion below 50 μg/l) a short-term accumulation does not occur and the best biological indicator of exposure is InAs excretion.Seafood ingestion brings about a marked increase in urinary excretion of total As that lasts for 24–48 h and is not accompanied by any increase in InAs, MMAA or DMAA excretion. Organic As from seafood does not mix with the pool of inorganic As in the organism and may be separately detected in urine. In the biological monitoring of human exposure to As, particularly in the case of high urinary values, the speciation of the chemical forms of As in urine is necessary in order to establish with certainty the source, industrial or alimentary, of exposure.     

An assessment of the contribution from paint flakes to the lead content of some street and household dusts

A method has been developed for estimating crudely the quantity of lead in dusts derived from paint flakes. This involves an assessment of the paint mass in the dust: gravimetrically in the coarse fractions, and by microscopic measurement in the fine fractions. Some street and house dust samples were examined. The street dusts contained up to 20% of lead from paint, and the house dusts up to 15%. However, it was the least lead-polluted dusts that contained the highest proportions of lead from paint. In the samples examined the paint flakes contained only low to moderate amounts of lead (0.07-4.21% w/w) and in the case of high lead paints the contribution from this source could be considerably greater.     

Factors affecting the extraction and analysis of polynuclear aromatic hydrocarbons in water

Factors expected to affect the efficiency of extraction of Polynuclear Aromatic Hydrocarbons (P.A.H.) from environmental water samples have been systematically investigated. Such factors include the initial concentration of P.A.H., the presence of suspended solids and prolonged storage of the sample prior to analysis. Extraction efficiencies between 30 and 85% have been found and these data make possible more accurate measurements of levels of P.A.H. in water. Analyses of environmental water samples have been performed using both Thin layer chromatography (TLC) and Gas-liquid chromatography (GLC). Accuracy of analysis was assessed by addition of P.A.H. to environmental water samples before extraction. Thin layer chromatography was found to be the better procedure for the compounds analysed, and avoided the need for purification of the solvent extract prior to analysis.     

The effect of pH and hardness metal ions on the competitive interaction between trace metal ions and inorganic and organic complexing agents found in natural waters

The effect of pH and hardness metal ions on the interactions between trace metals and both inorganic and organic complexing agents has been studied under conditions simulating natural aquatic conditions, by employing anodic stripping voltammetric titration techniques. The complexation of Bi(III), Cd(II), Cu(II), Pb(II), and Tl(I) with the hydroxo- and carbonato-ligands found in a carbonate medium has been observed to generally increase with increasing pH. Both labile and nonlabile interactions have been observed. Nonlabile interactions are predominant at low pH and labile interactions generally increase with increasing pH. Neither calcium nor magnesium affects these interactions. The complexation of humic acids with trace metals in a carbonate medium was found to be more intense than metal ion-inorganic complexation. Both labile and nonlabile complexation was found; however, no generalizations can be made concerning the type and extent of complexation because of the individual nature of the interactions of each trace metal. Calcium was found to be more effective than magnesium in inhibiting trace metal-organic complexation. The effect of calcium is to inhibit labile complexation and is most pronounced with the cadmium-humic acid system.     

Aeration as a tool to improve water quality and reduce the growth of hydrilla

Aeration of artificial, model lake systems was studied as a tool to improve water quality and to control the growth of a nuisance aquatic weed, Hydrilla verticillata (L.F.) Royle, which has been recognized as a plant pest since the mid-1960s. Aeration decreased the growth of Hydrilla by 20% fresh weight and 18% dry weight on average after 21 days. The effect was due to the oxygenation of the water and not the mechanical effect of the bubbles, as verified by studies using pure nitrogen. Aeration also affected water quality. Inorganic carbon decreased; nitrate-nitrite-nitrogen decreased, more slowly in test systems than in control systems; dissolved oxygen increased to saturation within 24 h and pH increased 0.5–1.5 unit over the period of study. Phosphate-phosphorus concentration was unaffected. The concentrations of zinc, calcium and iron decreased as well. The effect of aeration upon Hydrilla growth appears to be correlated with a decrease of iron. After 7 days, iron concentrations decreased to less than 20 ppb. Iron toxicity is proposed as the mechanism responsible for creating a limiting condition for Hydrilla growth.     

Chlorine demand in deep sea-water

Samples of deep sea-water were obtained at 25, 250 and 2000 m from the Sargasso Sea. The chlorine demands in these samples at any given contact time decrease with the depth at which the sample was obtained. The dissipation of chlorine occurs in two phases. The consumption rate of chlorine is similar in all three samples during the second phase at about 1 × 10⁻⁴ mg l⁻¹ min⁻¹. The difference in chlorine demand is caused primarily by the decrease in the organic chlorine demand, which occurs during the first phase of reactions, with depth reflecting the decreasing amount and increasing inertness of dissolved organic matter. The organic chlorine demands at 25, 250 and 2000 m are 0.9, 0.5 and 0.4 mg l⁻¹ respectively. These organic chlorine demands are significantly lower than those observed in coastal sea-waters with similar dose of added chlorine of about 5 mg l⁻¹. If sea-waters from various depths are available, deeper sea-water would be preferred as a coolant because of its smaller chlorine demand and lower initial temperature.     

Phosphorus dynamics in hypereutrophic lake sediments

The sediments of two hypereutrophic lakes (Stone Lake, Michigan and Lake Charles East, Indiana) were studied to determine phosphorus sorption and release tendencies as they vary seasonally. Techniques used were chemical extractions of phosphorus forms from core fractions and the incubation of undisturbed cores in the laboratory under ambient conditions of temperature and dissolved oxygen. The uptake of phosphorus during aerobic periods was found to be in accord with previously observed trends in that the amount sorbed was proportional to overlying phosphorus concentration supporting an adsorption type of model. Phosphorus was given off during anoxic periods, however, the specific release rates could not be correlated with the gradient of interstitial phosphorus to overlying phosphorus concentrations as reported by others. Rather, release rates were closely correlated with average interstitial phosphorus concentrations. A diffusion model is presented, applicable to systems similar to those studied, in which soluble interstitial phosphorus varies from a greatly elevated concentration in close proximity to sediment particle surfaces to levels approaching those of overlying phosphorus.     

A model study of ozone-sparged vessels for the removal of organics from water

Ozone-sparged vessels for the oxidation of a model organic compound, methanol, was studied. The parameters under study included superficial gas velocity, the gas phase ozone concentration, the rate of ozonation of methanol and its oxidative products, the residence time, etc. The scale-up method based on the mathematical model developed in this study accurately predicts the superficial gas velocity and the gas phase ozone concentration required for two larger geometrically similar vessels to achieve the same level of total organic carbon removal obtained in a small vessel.     

Determination of metals in fish livers by flameless atomic absorption spectroscopy

The samples are digested in nitric acid and evaporated to near dryness. Hydrogen peroxide is then added for complete oxidation of fat residues. Determination of metals is performed by flameless AAS with graphite furnace and results evaluated by the method of standard addition. The method is suitable for the determination of some non-volatile metals in fish livers in which the amount of available sample is limited; Pb, Cd, Cu and Zn have been determined in such samples.     

Reductions in inactivation rates of bacteriophages by clay minerals in lake water

Differences were noted in the rate of inactivation of bacteriophages in natural lake water, with the sequence of lability being φ11M15 of Staphylococcus aureus RN450, Qβ of Escherichia coli K-38 > 80α of S. aureus RN450 > P1 of E. coli B > T1 of E. coli B. The survival of φ11M15 in lake water was unaffected by autoclaving, filtration, or amendment with particulate humic acids or heat-killed cells of Erwinia herbicola, Sarcina lutea, and Saccharomyces cerevisiae. However, in the presence of attapulgite and vermiculite and, to a lesser extent, montmorillonite and kaolinite, the rate of inactivation of φ11M15 in natural, autoclaved, or filtered lake water was greatly reduced.     

Alternatives to pesticides in Southeastern United States

A critical review of alternatives to the use of pesticides in agricultural practice in the Southeastern United States is presented. The methods, their stage of development and case histories are cited.     

Dye-sensitized-photo-oxidation—a new approach to the treatment of organic matter in sewage effluents

A new approach to the oxidation of organic matter in municipal wastewaters by photosensitization is described. Samples of aerated sewage effluents containing an added dye-sensitizer were exposed to u.v.-lamp or solar radiation. The photochemical oxidation of the sewage caused decreases in the content of the fecal coliform, of the chemical oxygen demand and of the methylene blue-active substances by 100, 67 and 90% of their initial values, respectively. The effluents obtained after the removal of the dye, by precipitation with bentonite clay, were colorless, non-odorous and with the amount of suspended solids considerably reduced.     

Nitrification process in a packed bed reactor with a chemically active bed

A laboratory scale submerged filter filled with crushed marble was used for the nitrification process investigation. The results obtained showed that the alkaline reactor filling material react with the hydrogen ions released during the process course which enables reactor exploitation without any pH value or alkalinity control.     

Estimation of nitrifying biomass and kinetics in wastewater

A technique is proposed for the in situ measurement of nitrifying bacterial kinetics in mixed culture. A direct addition of known quantities of pure nitrifiers to a mixed liquor sample, along with selective inhibition of Nitrosomonas activity allows the estimation of nitrifier populations and maximum specific substrate removal rates. The method demonstrates that nitrification is zero order for substrate and first order with respect to bacterial concentration. The constant rate responses of batch kinetic tests require only a simple analysis and can be adapted to situations where nitrifier concentrations are small. Application of the technique to a carbon removal-nitrification system subjected to a variety of total Kjeldahl nitrogen loadings indicates that for a fixed carbon loading, nitrifier populations are strongly dependent on the nitrogen concentration of the feed.