Removal of recalcitrant organic matter of landfill leachate by adsorption onto biochar from sewage sludge: A quali-quantitative analysis.

Sewage sludge is a byproduct of sewage treatment, whereas landfill leachate is a complex wastewater generated by the decomposition of solid waste. These byproducts require adequate management, and one option for the sludge is the thermal treatment by pyrolysis to produce biochar. The resulting biosolid can be used as an adsorbent to treat landfill leachate. The main objective of this research was to remove recalcitrant organic matter from landfill leachate by adsorption onto biochar produced from sewage sludge. Aerobic and anaerobic sludges were pyrolyzed at 450, 650 and 850 °C, under residence times of 60, 90 and 120 min. Temperature had a positive and more significant impact on the characteristics of the biochars produced, and consequently on the adsorption of recalcitrant organic matter. However, the impact of residence time was less intense and, in some cases negative. Biochars produced from both aerobic and anaerobic sludge pyrolyzed at 850 °C for 120 and 60 min, respectively, showed higher specific surface areas (114.4 m2g-1 and 104.2 m2g-1, respectively) compared with those pyrolyzed at 450 °C and 650 °C. The biochar from anaerobic sludge produced at 850 °C and 60 min showed the best performance regarding the adsorption process, with chemical oxygen demand (COD), dissolved organic carbon (DOC), and color removals from the leachate of 32%, 36%, and 41%, respectively. The results of adsorption capacity for this biochar from anaerobic sludge were 26.1 mg g-1 for COD and 7.9 mg g-1 for DOC. The adsorption of recalcitrant organic matter from leachate was evidenced by the decrease in the UV-Vis absorbances and fluorescence intensities. It indicates that recalcitrant and humic substances were removed mainly by biochars pyrolyzed at 850 °C. Thus, the results allow to stress that the pyrolysis of sewage sludge to produce biochar is a promising alternative to sludge treatment, and the biochar may be applied as a pre-treatment of landfill leachate since it successfully removed the recalcitrant organic matter.

The importance of organic carbon as a coadjutant in the transport of pollutants.

Dissolved organic carbon (DOC) is a physicochemical parameter widely used in the evaluation of surface water quality; however, its role as an agent of transport and transference of pollutants sometimes is still disregarded. The heterogeneous composition of DOC, predominantly composed of humin, humic and fulvic acids, renders it an inherent capacity to bind to organic and inorganic pollutants. This is an important feature when the knowledge of present and future conditions of aquatic environments is of concern. Some authors concluded that DOC is a controlling agent of mobility of metals, phosphorus, herbicides, and pesticides, among others. Nevertheless, some physical and chemical conditions in the water column and in the sediment can immobilize the contaminants and make the DOC less soluble, which will hamper the formation of DOC-pollutant complexes. This mini review is intended to present the importance of DOC quantification and some information on its association with water contaminants, which could render them unavailable for uptake.

Scaling-up of the adsorption process of ammonia nitrogen onto expanded vermiculite using fixed-bed columns.

Expanded vermiculite was used as an adsorbent to remove ammonia nitrogen from landfill leachate. Bench and pilot-scale adsorption experiments were performed with leachate collected from a closed sanitary landfill located in Curitiba, southern Brazil. At the bench-scale, two different heights of vermiculite and three different flow rates were tested using a fixed-bed column. These tests produced an average uptake capacity of 33.4 mg g-1 for the ammonia nitrogen concentration of 2,560 mg L-1. The Yan model was used to determine the breakthrough and the exhaustion times due to the best fit of the data to this model. At the pilot-scale, the flow rate was determined from the shortest length of the mass transfer zone obtained from bench-scale experiments. Tests were performed using one stainless-steel column filled with 26.2 kg of expanded vermiculite, which resulted in a bed height of 1.6 m. A leachate flow rate of approximately 350 L d-1 was applied to achieve the required contact time of 8.3 h. At this scale, an average uptake capacity of 18.1 mg g-1 was obtained for the ammonia nitrogen concentration of 1,193 mg L-1. It is worth mentioning that the flow rate and the concentration of the adsorbate in the feeding solution are fundamental to improve the operational time of the fixed-bed column. The main goal of this research was the determination of operating conditions to scale-up the adsorption process of ammonia nitrogen onto expanded vermiculite. The contact time was a key parameter to reach this goal.

Evaluation of the start-up of hydraulic conditions of a fluidised bed system.

The development of this research was based on the analysis of an anaerobic fluidised bed reactor from the assembly of its components to the sealing of the system and further fluidisation. A hydrometer and a Venturi were used to identify the best means of measuring the flow rate. Results produced by both devices were similar, however, the latter was less effective due to the low flow rates necessary to operate the system. The hydrometer was the most adequate device for flow rate measurements in the range between 0.1 and 1.0 m³/h, whereas the Venturi proved to be an adequate device for the flow in the range between 0.3 and 0.7 m³/h. Sand with grain sizes varying from 357 to 1000 µm was used as support material. It was not observed statistically significant differences between the minimum fluidisation velocities related to the amount of supported material of 20% and 40% (VSM/Vusable) added to the reactor. Forty percent of the usable volume occupied with sand is adequate to reach fluidisation, instead of only the expansion of the bed. The fluidisation velocities for the sand grain size of 357 µm were 8.4 m/h ± 0.25 for 20%, and 8.6 m/h ± 0.30 for 40%, whereas for the 505 µm they were, respectively for 20% and 40%, 9.2 m/h ±0.70 and 10.1 m/h ± 0.37. The hydraulic tests allow to stress that sand grain sizes varying from 357 to 505 µm are recommended to be used in a system with similar characteristics.

Prevalence of GJB2 (connexin-26) and GJB6 (connexin-30) mutations in a cohort of 300 Brazilian hearing-impaired individuals: implications for diagnosis and genetic counseling.

OBJECTIVE: Hereditary nonsyndromic deafness is an autosomal recessive condition in about 80% of cases, and point mutations in the GJB2 gene (connexin 26) and two deletions in the GJB6 gene (connexin 30), del(GJB6-D13S1830) and del(GJB6-D13S1854), are reported to account for 50% of recessive deafness. Aiming at establishing the frequencies of GJB2 mutations and GJB6 deletions in the Brazilian population, we screened 300 unrelated individuals with hearing impairment, who were not affected by known deafness related syndromes. METHODS: We firstly screened the most frequently reported mutations, c.35delG and c.167delT in the GJB2 gene, and del(GJB6-D13S1830) and del(GJB6-D13S1854) in the GJB6 gene, through specific techniques. The detected c.35delG and c.167delT mutations were validated by sequencing. Other mutations in the GJB2 gene were screened by single-strand conformation polymorphism and the coding region was sequenced when abnormal patterns were found. RESULTS: Pathogenic mutations in GJB2 and GJB6 genes were detected in 41 individuals (13.7%), and 80.5% (33/41) presented these mutations in homozygosis or compound heterozygosis, thus explaining their hearing defect. The c.35delG in the GJB2 gene was the most frequent mutation (37/300; 12.4%), detected in 23% familial and 6.2% the sporadic cases. The second most frequent mutation (1%; 3/300) was the del(GJB6-D13S1830), always found associated with the c.35delG mutation. Nineteen different sequence variations were found in the GJB2 gene. In addition to the c.35delG mutation, nine known pathogenic alterations were detected c.167delT, p.Trp24X, p.Val37Ile, c.176_191del16, c.235delC, p.Leu90Pro, p.Arg127His, c.509insA, and p.Arg184Pro. Five substitutions had been previously considered benign polymorphisms: c.-15C>T, p.Val27Ile, p.Met34Thr, p.Ala40Ala, and p.Gly160Ser. Two previously reported mutations of unknown pathogenicity were found (p.Lys168Arg, and c.684C>A), and two novel substitutions, p.Leu81Val (c.G241C) and p.Met195Val (c.A583G), both in heterozygosis without an accompanying mutation in the other allele. None of these latter four variants of undefined status was present in a sample of 100 hearing controls. CONCLUSIONS: The present study demonstrates that mutations in the GJB2 gene and del(GJB6 D13S1830) are important causes of hearing impairment in Brazil, thus justifying their screening in a routine basis. The diversity of variants in our sample reflects the ethnic heterogeneity of the Brazilian population.

Quantification of viable helminth eggs in samples of sewage sludge.

For the application of sewage sludge as fertilizer, it is of fundamental importance the absence of pathogenic organisms, such as viable helminth eggs. Thus, the quantification of these organisms has to be carried out by means of the application of reliable and accurate methodologies. Nevertheless, until the present date, there is no consensus with regard to the adoption of a universal methodology for the detection and quantification of viable helminth eggs. It is therefore necessary to instigate a debate on the different protocols currently in use, as well as to assemble relevant information in order to assist in the development of a more comprehensive and accurate method to quantify viable helminth eggs in samples of sewage sludge and its derivatives.

Mass spectrometric and high performance liquid chromatography profiling of the venom of the Brazilian vermivorous mollusk Conus regius: feeding behavior and identification of one novel conotoxin.

Carnivorous mollusks belonging to the genus Conus paralyze their prey by injecting a rich mixture of biologically active peptides. Conus regius is a vermivorous member of this genus that inhabits Brazilian tropical waters. Inter-, intra-species and individual variations of cone snail venom have been previously reported. In order to investigate intra-specific differences in C. regius venom, its feeding behavior and the correlation between these two factors, animals were pooled according to gender, size and season of collection, and their venom composition was compared by high performance liquid chromatography (HPLC). Both the whole venom and one specific peak were monitored by HPLC. Chromatographic profiles revealed no significant differences in their peak areas, indicating that the venom composition, based solely in the presence or absence of the major peaks, is stable regardless of season, gender and size. Therefore, analysis of one given toxin, eluting in one of the major peaks, is representative among the population. Moreover, this work presents the identification of one novel conotoxin (rg11a), which amino acid sequence was deduced by mass spectrometry.

α -RgIB: A Novel Antagonist Peptide of Neuronal Acetylcholine Receptor Isolated from Conus regius Venom.

Conus venoms are rich sources of biologically active peptides that act specifically on ionic channels and metabotropic receptors present at the neuromuscular junction, efficiently paralyzing the prey. Each species of Conus may have 50 to 200 uncharacterized bioactive peptides with pharmacological interest. Conus regius is a vermivorous species that inhabits Northeastern Brazilian tropical waters. In this work, we characterized one peptide with activity on neuronal acetylcholine receptor (nAChR). Crude venom was purified by reverse-phase HPLC and selected fractions were screened and sequenced by mass spectrometry, MALDI-ToF, and ESI-Q-ToF, respectively. A new peptide was identified, bearing two disulfide bridges. The novel 2,701 Da peptide belongs to the cysteine framework I, corresponding to the cysteine pattern CC-C-C. The biological activity of the purified peptide was tested by intracranial injection in mice, and it was observed that high concentrations induced hyperactivity in the animals, whereas lower doses caused breathing difficulty. The activity of this peptide was assayed in patch-clamp experiments, on nAChR-rich cells, in whole-cell configuration. The peptide blocked slow rise-time neuronal receptors, probably α 3 ß 4 and/or α 3 ß 4 α 5 subtype. According to the nomenclature, the new peptide was designated as α -RgIB.

Desenvolvimento de um modelo de banco de dados para sistematização de programas de gerenciamento integrado de resíduos sólidos em serviços de limpeza pública / Development of a data base model for the systematization of integrated municipal solid waste management

Este estudo foi levado a efeito em 17 municípios do Estado do Paraná, com população de até 250 mil habitantes, escolhidos em função de características peculiares das regiões do Estado em que se localizam. A pesquisa abordou o levantamento de dados em cada um dos municípios em relação aos aspectos físico-ambientais, sócio-econômicos e estruturais, e estendeu-se também aos aspectos administrativos, operacionais e sociais com o objetivo de desenvolver um modelo de banco de dados para sistematizar as operações e serviços de limpeza pública. O desenvolvimento e a organização do banco de dados facilitaram a visualização das informações e a elaboração de um diagnóstico que poderá servir como ferramenta para a tomada de decisões e, também, de apoio à elaboração de projetos de gerenciamento integrado de resíduos sólidos nos âmbitos municipal e estadual.

This research was carried out in 17 municipalities of the State of Parana, Brazil, with population up to 250 thousand inhabitants. The municipalities were chosen based on peculiar characteristics of six different regions of the State. The development of the field research was carried out through data collection of physiographic and environmental, socio-economical and structural aspects of each community. This research also considered administrative, operational and social aspects with the aim to develop a data base model for the systematization of municipal solid waste programmes and services. The resulting data base facilitated both the diagnosis and the visualization of all system input information. It is worth mentioning that the results produced by this research can be used as a managerial tool for decision makers at municipal and state levels with regard to integrated solid waste programmes.

Recurrence risks for isolated cases of nonsyndromic deafness

We present, in this paper, general formulae developed so as to permit the calculation of the recurrence risks for isolated cases of nonsyndromic deafness in the offspring of nonconsanguineous and consanguineous couples. We included, in all analyzed situations, the following factors: (a) a generic degree of parental consanguinity; (b) a variable proportion of environmental (non-genetic) cases of the defect, so that the formulae can be easily applied to populations with any epidemiological profile; (c) a variable number of normal sibs of the propositus. Besides presenting the logic and the detailed derivation of all original formulae, we present tables for immediate use, with the numerical values of the recurrence risks as a function of the variables mentioned above.

Aconselhamento genetico da deficiencia auditiva / Genetic counseling for deafness

Baseando-se em dados por nos coletados e pesquisados na literatura nacional e internacional, fornecemos estimativas de incidencia de surdez infantil nao-sindromica, das frequencias de casos ambientais e geneticos e das frequencias relativas dos tipos de surdez monogenica hereditaria...

Atualizacao em genetica da surdez nao-sindromica / Atualization in genetics of nonsyndromic hereditary deafness

A surdez nao-sindromica e uma condicao altamente heterogenea, com inumeros genes de locos diferentes interferindo no desenvolvimento e na fisiologia da audicao...