[en] The PIBA (BArros Irradiation Plant), a sewage irradiation plant has being built at Tucuman (Argentina) the National Commission of Atomic Energy. It is designed for insure an absorbed dose of 2 kGy (3 kGy without oxygenation) to 140 m³/day of sludge by gamma irradiation from ⁶⁰ Co sources. To guarantee that almost all the volume of the irradiate sludge had absorbed at least the fixed dose is more important that its volume uniformity since the desired effect of the treatment is to produce a harmless sewage in respect to the risk diseases. The objective of this work is the calculation if the absorbed dose related to the irradiation time, the operation time and the sources geometry and activity. Mathematical models are developed for obtaining the volume distribution of the absorbed dose. An absorbed dose ≥ 2 kGy is required for the 99.8% of the irradiated sludge volume. Achieving the threshold dose depends upon the total activity which determines the daily time of operation. A numerical set of the major interrelated parameters is given for the efficient operation of the PIBA. (author). 5 refs., 3 figs., 1 tab

[en] Biological hydrogen production potential of a defined microbial consortium consisting of three facultative anaerobes, Enterobacter cloacae IIT-BT 08, Citrobacter freundii IIT-BT L139 and Bacillus coagulans IIT-BT S1 was studied. In this investigation their individual and combinatorial H₂ production capabilities have been studied on defined media and pretreated sewage sludge. Defined medium, MYG (1% w/v Malt extract, 0.4% w/v yeast extract and 1% w/v glucose) with glucose as limiting substrate has been found to be most suitable for hydrogen production. Individually E. cloacae clearly gave higher yield (276 ml H₂/ g COD reduced) using defined medium than the other two strains. There was no considerable difference in maximal yield of hydrogen from individual and combinatorial (1:1:1 consortium) modes suggesting that E. cloacae dominated in the consortia on defined medium. Contradictorily, B. coagulans gave better bio-hydrogen yield (37.16 ml H₂/g COD consumed) than the other two strains when activated sewage sludge was used as substrate. The pretreatment of sludge included sterilization, (15% v/v) dilution and supplementation with 0.5%w/v glucose which was found to be essential to screen out the hydrogen consuming bacteria and ameliorate the hydrogenation. Considering (1:1:1) consortium as inoculum, interestingly yield of hydrogen was recorded to increase to 41.23 ml H₂/ g COD reduced inferring that in consortium, the substrate utilization was significantly higher. The hydrogen yield from pretreated sludge obtained in this study (35.54 ml H₂ g sludge) has been found to be distinctively higher than the earlier reports (8.1 - 16.9 ml H₂/g sludge). However it was lower compared to the yield obtained from co-digestion of (83:17) food waste and sewage sludge (122 ml H₂/g carbohydrate COD). Employing formulated microbial consortia for bio-hydrogen production from sewage sludge was an attempt to augment the hydrogen yield from sludge. (authors)

[en] A parallel, bench-scale study was undertaken to study the effect of grinding/blending biological solids followed by subsequent aeration for 24-hours on overall sludge production. This was compared to a completely-mixed system from which solids were wasted directly back to the aeration basin. In essence, both treatment trains employed total recycle of the waste biological solids, except that the solids from Train 2 were ground and aerated prior to re-introduction. The bench-scale reactors were continuously operated from November through December 2000 and from January through April 2001. Temperature of the wastewater during the first and second runs was maintained at 14^o C and 25^o C, respectively. Each parallel train was fed synthetic wastewater at a flow rate of approximately 2.25 gallons per day resulting in a hydraulic detention time of approximately 13 hours. Samples of the influent, effluent, and mixed liquor were collected weekly and the following analyses were performed: COD, pH, temperature, total solids, suspended solids, volatile suspended solids, dissolved solids, and oxygen uptake rate (OUR). Results of the study indicate that the system in which the solids were ground and re-aerated produced less sludge than the conventional system. Substrate removal rates were the same for both systems. Statistical analyses using the analysis of variance indicated the results were significant at the 95 % confidence level. (author)

[en] Pharmaceuticals can enter the soil environment when animal slurries and sewage sludge are applied to land as a fertiliser or during irrigation with contaminated water. These pharmaceuticals may then be taken up by soil organisms possibly resulting in toxic effects and/or exposure of organisms higher up the food chain. This study investigated the influence of soil properties on the uptake and depuration of pharmaceuticals (carbamazepine, diclofenac, fluoxetine and orlistat) in the earthworm Eisenia fetida. The uptake and accumulation of pharmaceuticals into E. fetida changed depending on soil type. Orlistat exhibited the highest pore water based bioconcentration factors (BCFs) and displayed the largest differences between soil types with BCFs ranging between 30.5 and 115.9. For carbamazepine, diclofenac and fluoxetine BCFs ranged between 1.1 and 1.6, 7.0 and 69.6 and 14.1 and 20.4 respectively. Additional analysis demonstrated that in certain treatments the presence of these chemicals in the soil matrices changed the soil pH over time, with a statistically significant pH difference to control samples. The internal pH of E. fetida also changed as a result of incubation in pharmaceutically spiked soil, in comparison to the control earthworms. These results demonstrate that a combination of soil properties and pharmaceutical physico-chemical properties are important in terms of predicting pharmaceutical uptake in terrestrial systems and that pharmaceuticals can modify soil and internal earthworm chemistry which may hold wider implications for risk assessment. - Highlights: • Uptake of pharmaceuticals into earthworms is influenced by soil parameters. • Presence of pharmaceuticals in the terrestrial environment influences soil pH. • Uptake of pharmaceuticals by earthworms changes internal earthworm pH. - The uptake of pharmaceuticals into soil invertebrates is dependent on the complex interplay between pharmaceutical physico-chemical properties and soil parameters.

[en] Assessment of doses due to radionuclides in sewage sludge for different scenarios of its use was made for sewage plant storage in Visaginas, Rimses district, Karlu village. Calculations of individual and collective doses were made on the basis of results of measurements. Two potential exposure pathways from radionuclides in sewage sludge were considered and two scenarios descriptions were made. The first scenario is when the sludge is using for fertilization, and the second one - the sludge is covered with soil. Using program Environ-Calc made by American Chemical Society the number of samples needed to be sampled was optimized. 38 sewage samples were collected for gamma spectrometrical measurements and 10 samples - for measurements of tritium activity. Results of measurements pointed out that the sludge has no higher activity of tritium that background ones. The only two man made radionuclides ⁶⁰Co and ¹³⁷Cs were found by gamma spectrometry in the sludge. Average activity for the fresh weight in the samples of ⁶⁰Co was 42 Bq/kg, ¹³⁷Cs - 10 Bq/kg. Concentration of natural radionuclides was in the same range as in any soil samples from Lithuania. The dose for the first scenario for 1 years child will be 12 μSv, for adult - 9,4 μSv. In another scenario doses for the workers in sewage plant were estimated as 0,76 mSv. Collective dose in case of use of sewage sludge for fertilizers will be 4,4*10^-3 man Sv. The lowest doses will be when the sewage storage is covered using soil. (author)

[en] Biological hydrogen production potential of a defined microbial consortium consisting of three facultative anaerobes, Enterobacter cloacae IIT-BT 08, Citrobacter freundii IIT-BT L139 and Bacillus coagulans IIT-BT S1 was studied. In this investigation their individual and combinatorial H₂ production capabilities have been studied on defined media and pretreated sewage sludge. Defined medium, MYG (1% w/v Malt extract, 0.4% w/v yeast extract and 1% w/v glucose) with glucose as limiting substrate has been found to be most suitable for hydrogen production. Individually E. cloacae clearly gave higher yield (276 ml H₂/ g COD reduced) using defined medium than the other two strains. There was no considerable difference in maximal yield of hydrogen from individual and combinatorial (1:1:1 consortium) modes suggesting that E. cloacae dominated in the consortia on defined medium. Contradictorily, B. coagulans gave better bio-hydrogen yield (37.16 ml H₂/ g COD consumed) than the other two strains when activated sewage sludge was used as substrate. The pretreatment of sludge included sterilization, (15% v/v) dilution and supplementation with 0.5% w/v glucose which was found to be essential to screen out the hydrogen consuming bacteria and ameliorate the hydrogenation. Considering (1:1:1) consortium as inoculum, interestingly yield of hydrogen was recorded to increase to 41.23 ml H₂/ g COD reduced inferring that in consortium, the substrate utilization was significantly higher. The hydrogen yield from pretreated sludge obtained in this study (35.54 ml H₂/ g sludge) has been found to be distinctively higher than the earlier reports (8.1 - 16.9 ml H₂ / g sludge). However it was lower compared to the yield obtained from co-digestion of (83:17) food waste and sewage sludge (122 ml H₂/ g carbohydrate COD). Employing formulated microbial consortia for bio-hydrogen production from sewage sludge was an attempt to augment the hydrogen yield from sludge. (authors)

[en] Thermophilic processes digest sludge at high temperatures to produce Class A biosolids.Recent research work revealed that digestion temperature is the predominant factor affecting dewaterability of thermophilic biosolids. This paper presents findings of a laboratory study that investigated how various digestion temperatures affect dewaterability of digested biosolids, studied the phase partition of the substances affecting dewaterability in digested biosolids, and tested the role of cellular polymeric substances in affecting dewaterability.Secondary sludges were digested at 40-70^oC or 22^oC for up to 12 days. Centrate from thermophilically digested biosolids were treated with protease and boiling. This study found that, during the first few hours of digestion, higher temperatures resulted in more rapid and more significant deterioration in dewaterability than lower digestion temperatures. Continued digestion resulted in either improved (60^oC or 70^oC), or unchanged (40^oC or 50^oC), or gradually deteriorated dewaterability (22^oC). The substances affecting dewaterability were primarily located in the liquid phase of thermophilically digested biosolids. Boiling treatment did not result in significant changes in dewaterability. Protease treatment of the liquid phase of thermophilic biosolids improved dewaterability by 13-19%. Such an improvement confirmed the role of proteins in affecting dewaterability. (author)

[en] The goal of COPS is to couple a program of regular observations to numerical models, through techniques of data assimilation, in order to provide a predictive capability for the US coastal ocean including the Great Lakes, estuaries, and the entire Exclusive Economic Zone (EEZ). The objectives of the program include: determining the predictability of the coastal ocean and the processes that govern the predictability; developing efficient prediction systems for the coastal ocean based on the assimilation of real-time observations into numerical models; and coupling the predictive systems for the physical behavior of the coastal ocean to predictive systems for biological, chemical, and geological processes to achieve an interdisciplinary capability. COPS will provide the basis for effective monitoring and prediction of coastal ocean conditions by optimizing the use of increased scientific understanding, improved observations, advanced computer models, and computer graphics to make the best possible estimates of sea level, currents, temperatures, salinities, and other properties of entire coastal regions

[en] Full text: The Sludge Irradiation Plant (PIBA) was designed for the disinfection with ⁶⁰Co gamma radiation of the urban sewage effluents already treated in a conventional plant. A facility is under construction in Tucuman, and is expected to be in operation shortly. The actual treatment of sewage effluents ends with the sludge classified in open air pools where it dries by evaporation and by filtering to the underground and to the river. When PIBA will be incorporated to the treatment process, the classified sludge will be irradiated before entering the dry beds. Tucuman province, and all the rest of the Argentine Northwest, is a region affected by frequent summer gastritis, hepatitis, meningitis, etc., caused by microorganisms living in the water and which reproduce in the human digestive apparatus and in some warm blood animals.The evaluation of ulterior irradiation effects is being studied covering different aspects. For the information of users and public in general, a massive diffusion booklet is available, which was presented in a previous publication (1). For the dialogue with specialists in particular areas, such as social health and environment, the effects are analyzed within a multidisciplinary scientific frame, where the concept of life quality changes is formalized in a quantitative way.The concept of ecological niche in biology is integrated with the concept of state number in a system of thermodynamic statistics, in order to suggest a mathematical model which will allow the condition of a life quality change as a change in entropy. This model is applied to the PIBA case with fecal coliforms in classified sludge, without irradiation and irradiated with doses of 1, 2, 3 and 4 kGy (2). It is shown that the diminishing number of fecal coliforms in dry beds corresponds to an improvement of the human life quality that is evaluated through a negative entropy change. The objective of this work is to contribute to the number of scientific arguments available for the difficult, but important dialogue in society, about the influence of nuclear applications on human life improvements and the conservation of environment

[en] The aim of this work was to assess the differences among soil available P, the use by the plants of sludge P, and of a water soluble fertilizer (Ca(H₂PO₄)₂ ) P, using isotopic exchange kinetics methods. The sludge was provided by the Sewage Sludge Treatment Plant of Tucuman City, Argentina. The isotopic exchange kinetics experiment, in which the fate of carrier free ³²PO₄ added to the soil solution at a steady state was studied, gives information on soil P exchangeability. The experiment was carried out in the laboratory, where sewage sludge and water soluble fertilizer were added to soil samples taken at a depth of 0-25 and 25-40 cm. Changes in the soil P isotopically exchangeable within 1 minute measurements in the soil with sludge and in the soil with water soluble fertilizer showed that the 0-25 cm deep soil samples had a low P sorption capacity (r1 /R values were low). The sludge had high total and organic P, but the P in the soil solution was lower than the P provided by the water soluble fertilizer. Therefore, despite its higher total P content, this sludge contained slow available forms of P