Ozonation effects for excess sludge reduction on bacterial communities composition in a full-scale activated sludge plant for domestic wastewater treatment.

Activated sludge process is the most widely diffused system to treat wastewater to control the discharge of pollutants into the environment. Microorganisms are responsible for the removal of organic matter, nitrogen, phosphorous and other emerging contaminants. The environmental conditions of biological reactors significantly affects the ecology of the microbial community and, therefore, the performance of the treatment process. In the last years, ozone has been used to reduce excess sludge production by wastewater treatment plants (WWTPs), whose disposal represents one of the most relevant operational costs. The ozonation process has demonstrated to be a viable method to allow a consistent reduction in excess sludge. This study was carried out in a full-scale plant treating municipal wastewater in two parallel lines, one ozonated in the digestion tank and another used as a control. Bacterial communities of samples collected from both lines of digestion thanks were then compared to assess differences related to the ozonation treatment. Data were then analysed with terminal restriction fragment length polymorphism (T-RFLP) analysis on 16S rRNA gene. Differences between bacterial communities of both treated and untreated line appeared 2 weeks after the beginning of the treatment. Results demonstrated that ozonation treatment significantly affected the activated sludge in WWTP.

Environmental Life Cycle Assessment of Hydrothermal Carbonization of Sewage Sludge and Its Products Valorization Pathways.

Abstract: This study is aimed at evaluating through Life Cycle Assessment (LCA) the environmental performances of an integrated system of an existing Water Resources Recovery Facility (WRRF) and a hypothetical hydrothermal carbonization (HTC) plant applied to the generated sewage sludge (SS). Beside the valorisation of the solid product (hydrochar, HC) as a fuel substituting lignite, the possibility to valorize also the liquid fraction (process water, PW) derived by the HTC, by anaerobic digestion to produce biogas, is here proposed and analysed. Additionally, phosphorus recovery from HC, prior its use, by acid leaching with nitric acid is also suggested and evaluated. Thus, four integrated scenarios, based on SS carbonization, are proposed and compared with the current SS treatment, based on composting outside of the WRRF (Benchmark scenario). The proposed scenarios, based on HTC, show improved performances with respect to the benchmark one, for thirteen of sixteen considered impact indicators. For the Climate Change (CC) indicator, the two HTC scenarios are able to reduce the impacts up to - 98%, with respect to the Benchmark. Further, the introduction of anaerobic digestion of PW proves to reduce impacts more than other configurations in eleven on sixteen impact categories. On the contrary, the introduction of phosphorus recovery process negatively affects the values for most of indicators. Thus, possible solutions to improve the integration of this process are outlined (e.g., the use of sulfuric acid instead of nitric one, or the application of a different ratio between solid and acidified solution during acid leaching of HC to recover phosphorus). Supplementary Information: The online version contains supplementary material available at 10.1007/s12649-022-01821-x.

Characterization of tannery wastewater and biomass in a membrane bioreactor using respirometric analysis.

Respirometric techniques and an activated sludge model (ASM) were applied for the characterization of tannery wastewater and biomass in a pilot plant membrane bioreactor (MBR) operating at high sludge age. The traditional respirometric tests and the IWA-ASM1 were modified to take into account the specific operating conditions, the solid-liquid separation technology and the wastewater complexity. As a result the wastewater biodegradable COD was fractionated into four components: readily biodegradable, rapidly hydrolysable, slowly hydrolysable and inorganic (due to the presence of reduced sulphur compounds). The kinetic and stoichiometric parameters of the biomass (heterotrophic and nitrifying) were estimated through the integration of model simulations and respirometric tests results. In particular the ammonium and nitrite-oxidizing biomasses were separately characterized: the growth kinetics of ammonium and nitrite-oxidizing bacteria resulted noticeably lower than the traditional reference values (mu(max,AOB)=0.25d(-1)e mu(max,NOB)=0.23d(-1) at 20 degrees C, respectively). The ASM was finally used to confirm that the results of the wastewater and biomass characterization allow to properly simulate the mixed liquor suspended solids in the MBR pilot plant and the COD concentration in the effluent.

Experimental study on municipal and industrial reclaimed wastewater refinement for agricultural reuse.

The present study is aimed at verifying the possibility of reusing municipal and industrial reclaimed wastewaters for the irrigation of container-grown ornamental shrubs, paying attention to the refinery treatment. The research has been carried out in the district of Pistoia (Central Italy), which represents one of the main nursery areas in Europe. Two experimental sites, each consisting of a refinery treatment pilot plant (filtration and disinfection) and an agronomic area, were set-up. In this paper the attention is focused on the selection of the refinery treatment. The combined process of peracetic acid (PAA) and ultraviolet irradiation (UV) chosen for the disinfection treatment proved to be very effective for the inactivation of microorganisms for both municipal and industrial wastewaters. The high efficiency is recognised as being brought about by the formation of free radicals due to the photolysis of the PAA when in the presence of the UV rays. A preliminary cost analysis has been carried out in order to highlight the most economically advantageous solution which guarantees the compliance to the Italian limits for wastewater reuse in agriculture (Escherichia Coli 10 CFU/100 mL).

Reuse of industrial wastewater for the irrigation of ornamental plants.

This paper describes the results of experimental activities carried out for verifying the possibility of reusing reclaimed wastewater originated from textile (70%) and domestic (30%) activities for the irrigation of container-grown ornamental shrubs. Aspects that concern the refinery treatment of reclaimed wastewater and the effect of irrigation on some ornamental plant species were investigated. An experimental site consisting of a refinery treatment pilot plant (filtration and disinfection) and an agronomic experimental area was set-up. The combined treatment of PAA and UV, used for the disinfection, showed to be very effective for inactivation of E. coli with most of PAA and UV dose combinations able to assure total inactivation. The plants (Buxus, Photinia, Pistacia and Viburnum), sprinkle and drip irrigated with well water (WW), reclaimed wastewater (RW) and a water mixed (MW) between reclaimed wastewater and well water (1:1 by vol), showed interesting results. A similar growth among different treatments was achieved for Buxus and Pistacia, while Viburnum and Photinia plants showed a higher sensibility to MW and RW. Photinia, in particular, turned out to be very sensitive to sprinkle irrigation with the reclaimed water, while the drip irrigation had no such bad effects, as reported in previous works.

Catalytic mechanisms and reaction intermediates along the hydrolytic pathway of a plant beta-D-glucan glucohydrolase.

BACKGROUND: Barley beta-D-glucan glucohydrolases represent family 3 glycoside hydrolases that catalyze the hydrolytic removal of nonreducing glucosyl residues from beta-D-glucans and beta-D-glucooligosaccharides. After hydrolysis is completed, glucose remains bound in the active site. RESULTS: When conduritol B epoxide and 2', 4'-dinitrophenyl 2-deoxy-2-fluoro-beta-D-glucopyranoside are diffused into enzyme crystals, they displace the bound glucose and form covalent glycosyl-enzyme complexes through the Odelta1 of D285, which is thereby identified as the catalytic nucleophile. A nonhydrolyzable S-glycosyl analog, 4(I), 4(III), 4(V)-S-trithiocellohexaose, also diffuses into the active site, and a S-cellobioside moiety positions itself at the -1 and +1 subsites. The glycosidic S atom of the S-cellobioside moiety forms a short contact (2.75 A) with the Oepsilon2 of E491, which is likely to be the catalytic acid/base. The glucopyranosyl residues of the S-cellobioside moiety are not distorted from the low-energy 4C(1) conformation, but the glucopyranosyl ring at the +1 subsite is rotated and translated about the linkage. CONCLUSIONS: X-ray crystallography is used to define the three key intermediates during catalysis by beta-D-glucan glucohydrolase. Before a new hydrolytic event begins, the bound product (glucose) from the previous catalytic reaction is displaced by the incoming substrate, and a new enzyme-substrate complex is formed. The second stage of the hydrolytic pathway involves glycosidic bond cleavage, which proceeds through a double-displacement reaction mechanism. The crystallographic analysis of the S-cellobioside-enzyme complex with quantum mechanical modeling suggests that the complex might mimic the oxonium intermediate rather than the enzyme-substrate complex.

Membrane bio-reactor for textile wastewater treatment plant upgrading.

Textile industries carry out several fiber treatments using variable quantities of water, from five to forty times the fiber weight, and consequently generate large volumes of wastewater to be disposed of. Membrane Bio-reactors (MBRs) combine membrane technology with biological reactors for the treatment of wastewater: micro or ultrafiltration membranes are used for solid-liquid separation replacing the secondary settling of the traditional activated sludge system. This paper deals with the possibility of realizing a new section of one existing WWTP (activated sludge + clariflocculation + ozonation) for the treatment of treating textile wastewater to be recycled, equipped with an MBR (76 l/s as design capacity) and running in parallel with the existing one. During a 4-month experimental period, a pilot-scale MBR proved to be very effective for wastewater reclamation. On average, removal efficiency of the pilot plant (93% for COD, and over 99% for total suspended solids) was higher than the WWTP ones. Color was removed as in the WWTP. Anionic surfactants removal of pilot plant was lower than that of the WWTP (90.5 and 93.2% respectively), while the BiAS removal was higher in the pilot plant (98.2 vs. 97.1). At the end cost analysis of the proposed upgrade is reported.

Isolation of the new antigen receptor from wobbegong sharks, and use as a scaffold for the display of protein loop libraries.

The new antigen receptor (NAR) from nurse sharks consists of an immunoglobulin variable domain attached to five constant domains, and is hypothesised to function as an antigen-binding antibody-like molecule. To determine whether the NAR is present in other species we have isolated a number of new antigen receptor variable domains from the spotted wobbegong shark (Orectolobus maculatus) and compared their structure to that of the nurse shark protein. To determine whether these wNARs can function as antigen-binding proteins, we have used them as scaffolds for the construction of protein libraries in which the CDR3 loop was randomised, and displayed the resulting recombinant domains on the surface of fd bacteriophages. On selection against several protein antigens, the highest affinity wNAR proteins were generated against the Gingipain K protease from Porphyromonas gingivalis. One wNAR protein bound Gingipain K specifically by ELISA and BIAcore analysis and, when expressed in E. coli and purified by affinity chromatography, eluted from an FPLC column as a single peak consistent with folding into a monomeric protein. Naturally occurring nurse shark and wobbegong NAR variable domains exhibit conserved cysteine residues within the CDR1 and CDR3 loops which potentially form disulphide linkages and enhance protein stability; proteins isolated from the in vitro NAR wobbegong library showed similar selection for such paired cysteine residues. Thus, the New Antigen Receptor represents a protein scaffold with possible stability advantages over conventional antibodies when used in in vitro molecular libraries.

Skin contamination and low airborne nickel exposure of electroplaters.

The present study was performed to evaluate the role of hand and facial contamination in the absorption of soluble nickel compounds in 41 male subjects employed in electroplating operations in 25 small factories in the province of Florence (Italy). Personal exposure to airborne nickel ranged from 0.10 to 42 micrograms/m3; the median (range) urine, hands and face nickel levels were 4.2 (0.7-50) micrograms/l, 39 (1.9-547) micrograms, 9.0 (1.0-86) micrograms, respectively. Face nickel values explained the bulk of the variance in urine nickel levels (42%). In stepwise multiple regression analysis all other variables were not significant. The log-linear model can be expressed as: log (urine-Ni) = 0.295 + 0.593 log (face-Ni). Our results suggest that skin contamination, especially facial skin, plays an important role in nickel absorption in exposed workers.

Plasma retinol and alpha-tocopherol concentrations in insulin-dependent diabetes mellitus: their relationship to microvascular complications.

Plasma alpha-tocopherol and retinol, both assayed by an HPLC method, have been evaluated in a group of 60 patients affected by insulin-dependent (type 1) diabetes mellitus, stratified according to the presence of retinopathy and nephropathy diagnosed by an urinary albumin excretion rate ranging between 20 and 200 micrograms/min (microalbuminaria) or > 200 micrograms/min (macroalbuminuria), all of whom were compared with 26 healthy controls strictly matched for age and sex. Plasma lipids and age were positively correlated with plasma retinol and alpha-tocopherol in both diabetic and control subjects. Either plasma retinol or its ratio to cholesterol were significantly and independently reduced in the younger subset of diabetics, as compared to controls, independently from other confounding variables, while plasma alpha-tocopherol was unchanged in diabetic subjects and in healthy controls. Retinopathy was not associated with altered levels of both plasma alpha-tocopherol or retinol. The presence of increased urinary albumin excretion was associated with higher plasma levels of alpha-tocopherol and, only for macroalbuminuria, of retinol. However, after processing the data by a multivariate model, nephropathy was characterized by an increase only in plasma alpha-tocopherol. In conclusion, according to our findings, plasma retinol is significantly decreased in younger insulin-dependent diabetic patients while alpha-tocopherol is significantly altered in diabetic patients with nephropathy.

HIDE: a new hybrid environment for the design of custom-made hip prosthesis.

This technical note describes a new software environment (HIPCOM design environment, HIDE) for the design of custom-made total hip replacements. These devices are frequently designed using general-purpose mechanical computer-aided design (CAD) programs using a set of bone contours extracted from the computer tomography (CT) images as anatomical reference. On the contrary, the HIDE system was developed to let the operator directly design the stem shape onto the CT images in a single-step operation. The operator can directly import CT data in DICOM format or use special functions to reconvert to a digital stack, the CT images printed on a radiological film. Once the stack of CT images is loaded, the operator can design the implant shape by imposing control sections directly on the CT images. The interpolation of these control sections produces the basic 3D shape of the custom-made stem. The shape is then exported to the CAD-computer-aided manufacturing (CAM) program to refine the design and to generate the part program to manufacture the implant with a CNC tooling machine. Using HIDE, the duration of design steps it affected was reduced by more than 50% with respect to the standard method in use at the manufacturer site. HIDE also improved the accuracy and the repeatability of the whole procedure. The learning curve became flat after only ten cases. These good results were achieved because of the integration of the vectorial description of the prosthetic component with the raster description of the CT data that allowed the designer to use all details available in the CT images.

Membrane bio-reactor for advanced textile wastewater treatment and reuse.

Textile wastewater contains slowly- or non-biodegradable organic substances whose removal or transformation calls for advanced tertiary treatments downstream Activated Sludge Treatment Plants (ASTP). This work is focused on the treatment of textile industry wastewater using Membrane Bio-reactor (MBR) technology. An experimental activity was carried out at the Baciacavallo Wastewater Treatment Plant (WWTP) (Prato, Italy) to verify the efficiency of a pilot-scale MBR for the treatment of municipal wastewater, in which textile industry wastewater predominates. In the Baciacavallo WWTP the biological section is followed by a coagulation-flocculation treatment and ozonation. During the 5 months experimental period, the pilot-scale MBR proved to be very effective for wastewater reclamation. On average, removal efficiency of the pilot plant (93% for COD, 96% for ammonium and 99% for total suspended solids) was higher than the WWTP ones. Color was removed as in the WWTP. Anionic surf actants removal of pilot plant and WWTP were very similar (92.5 and 93.3% respectively), while the non-ionic surfactants removal was higher in the pilot plant (99.2 vs. 97.1). In conclusion the MBR technology demonstrated to be effective for textile wastewater reclamation, leading both to an improvement of pollutants removal and to a draw-plate simplification.

Reclaimed municipal wastewater as source of water and nutrients for plant nurseries.

A three year experimental activity was carried out to evaluate the possibility of reusing Reclaimed Wastewater (RWW) in Pistoia's nursery area (Central Italy). The research was aimed at: 1. identifying the best tertiary treatment facilities in order to make the effluent in compliance with the current Italian legislation for RWW reuse, 2. evaluating the effects of RWW irrigation on some ornamental, 3. quantifying fertilizing value and environmental impacts of RWW irrigation. In this paper the results of the last year experimental activity are presented. Experimental results indicated that filtration and disinfection with peracetic acid plus UV were very effective in indicator bacteria removal; as a matter of fact, neither Escherichia coli nor Total Coliforms were detected in any samples of pilot plant effluent. Results of an agronomical experiment indicated the suitability of the tertiary effluent for the irrigation: at the end of the growing season a higher (or equal) total dry mass was detected in RWW irrigated plants than well-water (WW) irrigated ones. Finally, the tertiary effluent can be considered as an important source of fertilizer for container-grown plants. As a matter of fact RWW irrigation showed to be able to replace at least one of the traditional fertilization treatments.

[Measuring and speaking about respiration. Role and ethical function of a psychopathological interview in a medical service]. / Mesurer et dire le souffle. Place et fonction éthique d'un entretien psychopathologique dans un service de médecine.

On the occasion of a respiratory function exploration, it was given to the patient the possibility of evoking, in respect of freely association, the psychical sense assumed by his symptom in his history. The unity of time, place and methodology, clinical psychopathology, defined our "experimental device". When the patient of this study, with SAS, said to the physician "I forget myself" with regard to ther apneas, the symptom, spoken, referred to a construction, "complementary" (Bohr, 1927) to another one described and objectivated by medicine. Each interpretation of the somatic phenomenon is related to the occurrence of speaking in the context of discursive associations and transference coordinates. The symptom is related to psychical reality, conflicts and desire of the patient. By the relations established between the advent of the spoken symptom and other events, the patient considers it as a response to a personal question. Then, he can reach a fragment of his verify, hear himself and hear the effects of his speaking. Without this possibility of reappropriating subjectively and intersubjectively the suffering in its irreducible singularity, he would remain alienated from his suffering, as to a trauma. Our approach gives evidence of the methodological as well as praxeological revision of the psychopathology contribution to the medicine.

Respiratory disorders and lung function impairment in pyrite miners.

A research study was carried out at a pyrite mine in Niccioleta, southern Tuscany, during the period 1980-1983 to investigate the possible effects of gaseous and particulate pollutants on the respiratory function of mine workers. The study was undertaken to fill the gap in recent scientific information in this field and also collect data which could be used for future planning of epidemiological and environmental controls at the mine. For the most exposed underground workers a dust exposure of 1.04 mg/m3 of inhalable dust and 0.60 mg/m3 of respirable dust was found. The average quartz content was less than 1.5% in both types of dust. Median exposures of the most exposed risk group were 6.0 ppm for carbon monoxide (CO), 0.22 ppm for nitrogen dioxide (NO2), 0.09 ppm for sulfur dioxide (SO2). The health effects of gaseous and particulate pollutants were studied by comparing the respiratory symptoms and lung function data of the miners with those of a reference group. A significantly increased prevalence of simple chronic bronchitis was found among underground miners when compared to the reference group. This condition was not associated with functional impairment of obstructive nature. Chest x-rays revealed 14 cases of p type pneumoconiosis.