Chemical and Biochemical Properties of Oxisols after Sewage Sludge Application for 16 Years

ABSTRACT The large production of sewage sludge (SS), especially in large urban centers, has led to the suggestion of using this waste as fertilizer in agriculture. The economic viability of this action is great and contributes to improve the environment by cycling the nutrients present in this waste, including high contents of organic matter and plant nutrients. This study evaluated the chemical and biochemical properties of Dystrophic and EutroferricLatossolos Vermelhos (Oxisols) under corn and after SS application at different rates for 16 years. The field experiment was carried out in Jaboticabal, São Paulo State, Brazil, using a randomized block design with four treatments and five replications. Treatments consisted of control - T1 (mineral fertilization, without SS application), 5 Mg ha-1 SS - T2, 10 Mg ha-1 SS - T3, and 20 Mg ha-1 SS - T4 (dry weight base). The data were submitted to variance analysis and means were compared by the Duncan test at 5 %. Sewage sludge increased P extracted by resin in both theLatossolos Vermelhos, Dystrophic and Eutroferric, and the organic matter content in the Dystrophic Latossolo Vermelho. The waste at the rate 20 Mg ha-1 on a dry weight basis promoted increases in acid phosphatase activity in Eutroferric Latossolo Vermelho, basal respiration and metabolic quotient in DystrophicLatossolo Vermelho. The rate 20 Mg ha-1 sewage sludge on a dry weight basis did not alter the soil microbial biomass in both the Latossolos Vermelhos; in addition, it improved corn yields without inducing any symptoms of phytotoxicity or nutrient deficiency in the plants.

Carbon and Nitrogen Mineralization in Soil Combining Sewage Sludge and Straw

ABSTRACT The combined incorporation of sewage sludge (SS) and oat straw (OS) to the soil can increase straw carbon mineralization and microbial nitrogen immobilization. This hypothesis was tested in two laboratory experiments, in which SS was incorporated in the soil with and without OS. One treatment in which only straw was incorporated and a control with only soil were also evaluated. The release of CO2 and mineral N in the soil after organic material incorporation was evaluated for 110 days. The cumulative C mineralization reached 30.1 % for SS and 54.7 % for OS. When these organic materials were incorporated together in the soil, straw C mineralization was not altered. About 60 % of organic N in the SS was mineralized after 110 days. This N mineralization index was twice as high as that defined by Resolution 375/2006 of the National Environmental Council. The combined incorporation of SS and OS in the soil caused an immobilization of microbial N of 5.9 kg Mg-1 of OS (mean 3.5 kg Mg-1). The results of this study indicated that SS did not increase straw C mineralization, but the SS rate should be adjusted to compensate for the microbial N immobilization caused by straw.

Organic acids in the rhizosphere and phytoavailability of sewage sludge-borne trace elements

The aim of this work was to quantify low molecular weight organic acids in the rhizosphere of plants grown in a sewage sludge-treated media, and to assess the correlation between the release of the acids and the concentrations of trace-elements in the shoots of the plants. The species utilized in the experiment were cultivated in sand and sewage sludge-treated sand. The acetic, citric, lactic, and oxalic acids, were identified and quantified by high performance liquid chromatography in samples collected from a hydroponics system. Averages obtained from each treatment, concentration of trace elements in shoots and concentration of organic acids in the rhizosphere, were compared by Tukey test, at 5% of probability. Linear correlation analysis was applied to verify an association between the concentrations of organic acids and of trace elements. The average composition of organic acids for all plants was: 43.2, 31.1, 20.4 and 5.3% for acetic, citric, lactic, and oxalic acids, respectively. All organic acids evaluated, except for the citric acid, showed a close statistical agreement with the concentrations of Cd, Cu, Ni, and Zn found in the shoots. There is a positive relationship between organic acids present in the rhizosphere and trace element phytoavailability.

Recent research data on the removal of pharmaceuticals from sewage treatment plants (STP)

Pharmaceutical compounds have been detected in sewage treatment plant (STP) effluents, surface waters and, less frequently, in groundwater and drinking water, all over the world. Different sources are responsible for their appearance in the aquatic environment, however, it is widely accepted that the main sources of this type of pollutant are STP effluents. The adverse effects of pharmaceuticals in the environment include aquatic toxicity, development of resistance in pathogenic bacteria, genotoxicity and endocrine disruption. Thus, the discharge of these compounds to the environment in STP effluents should be minimized.

Evaluation of sample processing methods for the polar contaminant analysis of sewage sludge using liquid chromatography - mass spectrometry (LC/MS)

Monitoring of sewage sludge has proved the presence of many polar anthropogenic pollutants since LC/MS techniques came into routine use. While advanced techniques may improve characterizations, flawed sample processing procedures, however, may disturb or disguise the presence and fate of many target compounds present in this type of complex matrix before analytical process starts. Freeze-drying or oven-drying, in combination with centrifugation or filtration as sample processing techniques were performed followed by visual pattern recognition of target compounds for assessment of pretreatment processes. The results shown that oven-drying affected the sludge characterization, while freeze-drying led to less analytical misinterpretations.

Fontes e distribuição de matéria orgânica sedimentar no complexo estuarino-lagunar de Mundaú-Manguaba/AL, utilizando esterois e alcoóis como indicadores

The origin of the sedimentary organic matter in the Mundaú-Manguaba estuarine system was evaluated through the distribution and composition of sterols, alcohols and ancillary data. The muddy sediments of the lagoons are enriched in organic matter, derived from a mixture of autochthonous and allochthonous inputs. Mundaú exhibited moderate contamination by sewage, with coprostanol concentration as high as 4.4 µg g-1. The channels are characterized by sand and organic matter-poor sediments. The sediments from some rivers in the drainage basin accumulated organic matter derived only from terrestrial vegetation. Stanol/sterol ratios evidenced the preferential diagenesis of the autochthonous fraction of organic matter.

Treated domestic sewage: kinetics of Escherichia coli and total coliform inactivation by oxidation with hydrogen peroxide

Hydrogen peroxide has been used for decades in developed countries as an oxidizing agent in the treatment of water, domestic sewage and industrial effluents. This study evaluated the influence of the concentration of H2O2 and pH on the inactivation of Escherichia coli cells and the disinfection of sewage treated. The results showed that the inactivation rate increased with pH and H2O2. The presence of other contaminants dissolved in the effluent is probably the cause of these differences, because E. coli inactivation in synthetic wastewater was found to be much faster than in the real treated domestic sewage.

Root system distribution of sugarcane irrigated with domestic sewage effluent aplication by subsurface drip system

Irrigation with domestic sewage effluent (DSE) has been recommended by subsurface dripping, as it can obtain a high rate of irrigation efficiency and faster use of salts in comparison with other irrigation methods. The study aimed at evaluating the area, the length and the effective depth of the root system of sugarcane irrigated with DSE by subsurface drip system and with different irrigation rates at depths of 0.00-0.20, 0.20-0.40, 0.40-0.60 and 0.60-0.80m. The experiment was carried out in the municipality of Piracicaba, in the state of São Paulo (SP), Brazil, in a sugarcane area irrigated with DSE in a completely randomized blocks set up in furrows, with three replications and four treatments, which are: one area without irrigation (AWI) and three irrigated areas meeting 50% (T50%), 100% (T100%) and 200% (T200%) of the crop's water need between each round of irrigation. T100% and T200% provided smaller areas and lengths of roots in the two deepest layers, as compared to AWI and T50%, which stimulated the development of deeper roots due to the water stress. TWI, T100% and T200% presented 80% of the roots up to a depth of 0.40m and T50% treatment presented 76.43% of roots total.

Shewhart's control charts and process capability ratio applied to a sewage treatment station

The current study used statistical methods of quality control to evaluate the performance of a sewage treatment station. The concerned station is located in Cascavel city, Paraná State. The evaluated parameters were hydrogenionic potential, settleable solids, total suspended solids, chemical oxygen demand and biochemical oxygen demand in five days. Statistical analysis was performed through Shewhart control charts and process capability ratio. According to Shewhart charts, only the BOD(5.20) variable was under statistical control. Through capability ratios, we observed that except for pH the sewage treatment station is not capable to produce effluents under characteristics that fulfill specifications or standard launching required by environmental legislation.

Irrigation with domestic treated sewage and nitrogen fertilizing in sunflower cultivation

The objective of this study was to evaluate the productive performance of sunflower plants irrigated with different levels of domestic treated sewage and groundwater well with different doses of nitrogen. It was used randomized blocks design in split-split plots with four replications. In the plots, we evaluated the effect of two types of irrigation water, in the subplots we evaluated the five irrigation levels expressed as 25, 50, 75, 100 and 125% of the Class A pan Evaporation (CAE), and in the sub subplots, we evaluated the effect of four different doses of nitrogen (25, 50, 75 and 100 kg ha-1). The irrigation of sunflower with domestic sewage produced greater yield potential of grain and oil. The use of water from treated wastewater can replace up to 50 kg N ha-1 without affecting productivity. It is recommended for the commercial production of sunflower the use of treated sewage water with irrigation depth relative to 100% of CAE (296.64 mm) and nitrogen of 25 kg ha-1.

Wet bulbs from the subsurface drip irrigation with water supply and treated sewage effluent

The use of treated sewage effluent (TSE) combined with the subsurface drip irrigation (SDI) method in agriculture can decrease the costs of agricultural production, in attempts to fertigate crops more efficiently. In this study it was compared the dimensions of the wet bulb formed by the application of TSE and municipal water supply (MWS) in an Oxisoil. We have evaluated the effect of water quality and discharge between drippers used in sugarcane crop. Three trenches were opened and 21 three-rod TDR probes were setup in a mesh and a dripper was buried at 0.30 m, for each constant discharge of 1.0 L h-1and 1.6 L h-1. Comparing results from different wetted soil profiles it was observed that the vertical and horizontal dimensions of the wet bulb are similar for both MWS and TSE, being peculiars according to the discharges used and volume applied. Regardless the water quality, an increase of 60% in discharge decreased the deepest infiltration.

Cyanobacteria from coastal lagoons of Southern Brazil: coccoid organisms

Considering the great ecological importance of the cyanobacteria and the need for more detailed information about these organisms in Brazilian waters, this paper provides taxonomic information about the unicellular cyanobacteria flora in lagoon systems along the coastal plains of Rio Grande do Sul State. Sampling was performed in different freshwater bodies along the eastern (Casamento Lake area) and western (near the city of Tapes) banks of the Patos Lagoon (30º40' S-30º10' S and 50º30' W-51º30' W). The samples were collected once in the rainy season and once in the dry season (from May 2003 to December 2003) using a plankton net (25 µm mesh) in pelagic and littoral zones, and by squeezing the submerged parts of aquatic macrophytes. Thirty one species belonging to the families Synechoccocaceae (7 taxa), Merismopediaceae (12 taxa), Chamaesiphonaceae (1 taxon), Microcystaceae (4) and Chroococcaceae (7 taxa) were identified. Among these species, five are reported for the first time in Rio Grande do Sul State: Chamaesiphon amethystinus (Rostafinski) Lemmermann, Chroococcus minimus (Keissler) Lemmermann, Coelomoron pusillum (Van Goor) Komárek, Coelosphaerium kuetzingeanum Naegeli, and Cyanodictyon tubiforme Cronberg.

Cyanobacteria from coastal lagoons in southern Brazil: non-heterocytous filamentous organisms

This study describes and illustrates non-heterocytous filamentous cyanobacteria found in lagoon systems on the coastal plains of Rio Grande do Sul State. Collections were carried out in different freshwater bodies along the eastern (Casamento Lake area) and western (Tapes City area) margins of the Patos Lagoon (UTM 461948-6595095 and 542910-6645535) using a plankton net (25 µm mesh) in pelagic and littoral zones as well as by squeezing submerged parts of aquatic macrophytes, during both the rainy and dry seasons, from May to December/2003. Twenty two species belonging to the families Phormidiaceae (eight taxa), Pseudanabaenaceae (seven taxa), Oscillatoriaceae (six taxa), and Spirulinaceae (one taxon) were identified. Among these species, five are reported for the first time from Rio Grande do Sul State: Leptolyngbya cebennensis, Microcoleus subtorulosus, Oscillatoria cf. anguina, O. curviceps and Phormidium formosum.

Residential characteristics aggravating infestation by Culex quinquefasciatus in a region of Northeastern Brazil

OBJECTIVE: Analyse how basic sanitation conditions, water supply and housing conditions affect the concentration of Culex quinquefasciatus METHODS: Populations of C. quinquefasciatus in 61 houses in the municipality of Olinda, PE, were monitored between October 2009 and October 2010. Observations were carried out in homes without the presence of preferred breeding sites in order to identify characteristics that may be aggravating factors for the development of the mosquito. Five aggravating factors were analysed: vegetation cover surrounding the home, number of residents/home, water storage, sewage drainage and water drainage. These characteristics were analysed in terms of presence or absence and as indicators of the degree of infestation, which was estimated through monitoring the concentration of eggs (oviposition traps - BR-OVT) and adults (CDC light traps). RESULTS: Sewage drainage to a rudimentary septic tank or to the open air was the most frequent aggravating factor in the homes (91.8%), although the presence of vegetation was the only characteristic that significantly influenced the increase in the number of egg rafts (p = 0.02). The BR-OVT achieved positive results in 95.1% of the evaluations, with the presence of at least one egg raft per month. A total of 2,366 adults were caught, with a mosquito/room/night ratio of 32.9. No significant difference was found in the number of mosquitoes caught in the homes. CONCLUSIONS: Although the sanitation and water supply influence the population density of C. quinquefasciatus, residence features that are not usually considered in control measures can be aggravating factors in sustaining the mosquito population.

Vulnerabilities in snakebites in Sao Paulo, Brazil

ABSTRACT OBJECTIVE To describe elements of vulnerability of victims of snakebite. METHODS This qualitative, descriptive, cross-sectional study had, as theoretical framework, the concept of vulnerability in individual, social, and programmatic dimensions. We interviewed 21 patients admitted into a hospital specialized in the care of accidents caused by venomous animals. The interviews were analyzed according to a discourse analysis technique. RESULTS Patients were mainly young men, living in remote countryside areas, where health services frequently have limited resources. We found social and individual conditions of vulnerability, such as precarious schooling, low professional qualification, housing without access to piped water, no sewage treated, and no regular garbage collection, and lack of knowledge on this health problem. Regarding the programmatic dimension, we found limited accessibility to the health services that could affect the prognosis and the frequency of sequelae and deaths. CONCLUSIONS Considering such vulnerabilities evoke the need to improve the program for control the Accidents by Venomous Animals and the training of health workers, we highlight the potential use of the concept of vulnerability, which may amplify the understanding and the recommendations for the practice and education related to snakebites.