Avaliação de bactérias nitrificantes em filtros biológicos submersos aerados

This study investigates a new treatment system of wastewater by anaerobic and aerobic biological filters for nitrogen modification. The main objective of this study was evaluate, on a pilot scale, quantitatively and qualitatively the bacterian nitrifying community in a experimental sewage treatment system made by aerobics biological filters in series, in search of figure out the dynamic of nitrogen modification process. It was collected and laboratorial analysed microbiologically, regarding NMP of Nitrosomonas e Nitrobacter, and physical-chemically considering nitrogen sequence. We conclude that: the association in aerobic biological filters under nutrition controlled conditions and oxygen level allows the appearance of bacterian community responsible for the nitrogen modification; the method used, despite its limitations, provided the selection of autotrophic nitrifying microorganisms, allowing the identification of Nitrosomonas and Nitrobacter; the flow direction tested in the experimental unit did not affect the nitrifying bacterial community, certainly because they were kept drowned and did not occur flow speed that could breake the formed biomass; the nitrification process happened in aerated biological filters in all phases of the research, comproved by microbiological tests; in the third phase of the research the increase of the oxygen rate was significant for the nitrificant bacterian community in the aerate biological filters, allowing its growth, occurring relation between the efficiency of nitrification system and the quantity of organisms responsible for this process; the conduit used in aerated biological filters showed satisfactory performance support material to the nitrifying bacteria development

Nitrificação de efluentes de reatores anaeróbicos em filtros submersos aerados

Although the good performance in organic matter and suspended solids removal, the anaerobic reactors are unable to remove ammonia nitrogen from sewage, which makes indispensable to include a step of post-treatment for removal of ammonia or nitrate as necessary. This paper presents the performance of a new variant technology, where the nitrification unit, preceded by anaerobic units, is a submerged aerated biological filter, without continuous sludge discharge in their daily operation. The oxygenation system is very simple and inexpensive, consisting of perforated hoses and compressors. The anaerobic reactors are a septic tank with two chambers followed (8.82 m³) and two parallel anaerobic filters (36 m³ each) filled with ceramic bricks and conics plastic parts. Both followed aerated filters were filled with cut corrugated conduit. The study evaluated the behavior of the system with constant domestic sewage flow (10 m³/d) and different aeration conditions, are these: stage 01, when applied air flow of 0.01 m³ air/min in both aerated filter; stage 02, remained in the initial air flow rate in the second aerated filter and increased at the first to 0.05 m³ air/min; at last, at last, in stage 03, the air flow rate of first aerated filter was 0.10 m³ air/min and on the second remained at 0.01 m³ air/min. The filter FA1 received load of 0.41 kg COD/m³.d, 0.37 kg COD/m³.d and 0.26 kg COD/m³.d on phases 01, 02 and 03, respectively. The FA2 received loads of 0.25 kg COD/m³.d, 0.18 kg COD/m³.d and 0.14 kg COD/m³.d on phases 01, 02 and 03, respectively. During stage 01, were found the following results: 98% removals of BODtotal and 92% of CODtotal, with effluent presenting 9 mg/L of BODtotal final average and 53 mg/L of CODtotal average; suspended solids removals of 93%, with a mean concentration of 10 mg/L in the final effluent; 47% reduction of ammonia of FA2 to FAN 's, presenting average of 28 mg NNH3/ L of ammonia in the effluent with; the dissolved oxygen levels always remained around 2.0 mg/L. During stage 02, were found removals of 97% and 95% to BODtotal and suspended solids, respectively, with average final concentrations of 8 and 7 mg/L, respectively; was removed 60% of ammonia, whose final concentration was 16.3 mg NNH3/ L, and nitrate was increased to a final average concentration of 16.55 mg N-NO3/L. Finally, the stage 03 provided 6 mg/L of DBOtotal (98% removal) and 23 mg/L of CODtotal (95% removal) of final effluent concentrations average. At this stage was identified the higher ammonia oxidation (86%), with final effluent showing average concentration of 6.1 mg N-NH3/L, reaching a minimum of 1.70 mg N-NH3/L. In some moments, during stage 03, there was a moderate denitrification process in the last aerated filter. The average turbidity in the effluent showed around 1.5 NTU, proving the good biomass physical stability. Therefore, the results demonstrate the submerged biological filters potential, filled with high void ratio material (98%), and aerated with hoses and compressor adoption, in the carbonaceous and nitrogenous matter oxidation, also generating an effluent with low concentration of solids

Remoção de nitrogênio em biofiltros aerado e anóxico, com alto índice de vazios e sem remoção de lodo

The improper disposal of nitrogen in receiving water courses causes problems such as toxicity to living beings through the consumption of oxygen to meet the nitrogen demand, eutrophication and nitrate contamination of aquifers. For this reason it is often necessary to be carried out complementary treatment of wastewater to eliminate or reduce the concentration of this compound in the wastewater. The objective of this study is to evaluate the biological removal of nitrogen compounds using submerged aerated and anoxic filters as post-treatment of an anaerobic system, with low cost and innovative technology, which in previous studies has shown high removal efficiency of organic matter and great potential biological nitrogen compounds removal. The simple design with perforated hoses for air distribution and filling with plastic parts proved to be very efficient in relation to organic matter removal and nitrification. The system presented, in the best stage, efficiency in converting ammonia to nitrate by 71%, and produced a final effluent concentration below 10 mg / L of NH3-N. In addition, carbon concentration was removed by 77%, producing final effluent with 24 mg/L COD. However, denitrification in anoxic filter was not effective even with the addition of an external carbon source. There was a reduction of up to 56% of nitrogen caused by the process of simultaneous nitrification and denitrification (SND). The high voids space presented by this type of support material coupled with direct aeration of the sludge, allows the respiration of biomass retained between the endogenous phase, increased cell retention time and sludge retention capacity, producing a final effluent with turbidity less than 5 UT and total suspended solids around 5.0 mg/L

A influência da poluição difusa e do regime hidrológico peculiar do semiárido na qualidade da água de um reservatório tropical

In semiarid region of northeast Brazil, the majority of reservoirs used for public supply has suffered degradation of water quality affected by diffuse pollution from agricultural and livestock areas of the watershed and by hydrologic regime peculiar to the region, characterized by a rainy season with higher volumes stored in reservoirs and a dry season with a reduction in water level due to high evaporation and increase of eutrophication. The Dourado reservoir, located in Currais Novos city, semiarid region of Rio Grande do Norte state, is one example of a water supply reservoir that can have degradation of water quality and impracticability of their use, due to the high external input of nutrients from non-point sources of watershed during the rainy season and increasing of eutrophication due to decrease the stored volume during the dry period. This study aimed to investigate and quantify diffuse pollution and the hydrologic regime of semiarid region in order to establish standards regarding the water quality of Dourado reservoir. The study period was between the months of May 2011 to March 2012. The diffuse pollution was quantified in terms of watershed from the mass balance of phosphorus in the reservoir, as in relation to areas under different types of land use within the riparian zone of the reservoir from the assessment of soil chemical properties and losses of phosphorus in each area. The influence of hydrological regime on water quality of the reservoir was evaluated from the monthly monitoring of the morphometric, meteorological and limnological features throughout the study period. The results showed that the reservoir has received a high load of phosphorus coming from the drainage basin and presents itself as a system able to retain some of that load tributary, giving an upward trend of the eutrophication process. Diffuse pollution by nutrients from areas under different types of land use within the riparian zone of the reservoir was higher in areas under the influence of livestock, being this area considered a potential diffuse source of nutrients to the reservoir. Regarding the water regime during the rainy season the reservoir was characterized by high concentrations of nutrients and small algal biomass, while in the dry season the reduction of volume and increase of the water retention time of the reservoir, contributing to the excessive growth algal biomass, favoring an increase in eutrophication and deterioration of water quality. In synthesis the water quality of Dourado reservoir is directed by diffuse pollution coming from the drainage basin and the hydrological regime of the peculiar semiarid region, where the rainy season is characterized by high input of allochthonous compounds from the tributaries and erosion of the soil in the reservoir riparian zone, and the dry season characterized by reducing the storage volume due to high evaporation, high residence time of water and consequent degradation of water quality due to the increase of eutrophication process

O efeito do regime hidrológico do semiárido na composição de espécies durante dominância de cianobactérias em um reservatório tropical

The potentially toxic cyanobacterial blooms in water bodies are spread across the globe, resulting in the loss of water quality and adverse effects on human health. In arid and semiarid regions, the hydrologic regime characterized by an annual cycle of drought and rain, change the volume and the retention time of the reservoir. Such changes affect the limnological characteristics and causing changes in composition and biomass community of cyanobacteria. The reservoir Cruzeta (Zmax = 8.7 m) is a eutrophic water supply source located in the semiarid tropical (Northeast Brazil). Raised the hypothesis that the hydrological regime of semi-arid tropical is a determining factor in the availability of resources in eutrophic water sources, which influences the composition of dominant species of cyanobacteria. The aim of this study was to analyze the changes in biomass and species composition of cyanobacteria for two annual hydrological cycles and evaluate factors drivers. The study was divided into five distinct periods (dry 2010, rain 2011, dry 2011, rain 2012, dry 2012). The dominant group found in all periods was Cyanobacteria (99% of total biomass), which contributed to the low diversity. The filamentous species Cylindrospermopsis raciborskii was present at both points in almost every study. The colonial species Microcystis panniformis and Sphaerocavum brasiliensis dominated only in periods with lower volumes of water. The diatoms contribute more to the biomass during the period of severe drought. The point near the dam (P1) had phytoplankton biomass larger than the point near the tributary (P2). The dominant species of colonial cyanobacteria lasted until the overflow in P1, and P2 this dominance was until the first rains. The redundancy analysis indicated that physical factors such as light availability and water level were the main factors driving the seasonal succession of phytoplankton. The composition of phytoplankton in spring was alternated by species of filamentous cyanobacteria in conditions of poor stability of the water column, such as Cylindrospermopsis raciborskii, and colonial species under conditions of high stability of the water column, such as Microcystis panniformis and Sphaerocavum brasiliensis. The extremes of torrential rains and severe droughts, governed by the hydrological regime of the semi-arid region led to the availability of resources in the watershed, directing the spatial and temporal dynamics of phytoplankton in the reservoir Cruzeta

Avaliação da flotação por ar dissolvido no polimento de efluentes de lagoa de estabilização

Experience in the use of stabilization ponds shows that this is a system with low cost, easy operation and maintenance and suitable for tropical countries. One of its disadvantages is due to high concentrations of suspended solids, mainly due to algal biomass in the effluents. Accordingly, the dissolved air flotation has been shown to be an efficient post-treatment technology. However, the efficiency of this process is related to coagulation and flocculation steps, as well as the adjustment of the involved variables in the process. The objective of this work was to evaluate the algae removal efficiency from wastewater stabilization ponds and the influence of the factors involved in the process using dissolved air flotation. For this, we used primary facultative and maturation effluents of ETE Ponta Negra in Natal. We did tests of coagulation, flocculation and flotation with the samples, using the equipment flotatest. In this process were tested coagulants aluminum sulfate and ferric chloride, and varied the factors pH, coagulant concentration, polymer concentration and rate of recirculation. At the end of the experiments were analyzed turbidity, suspended solids, color, COD and chlorophyll "a". These results were submitted to descriptive statistics to verify the efficiency of the process in general, and regression analysis to identify models that describe the process and demonstrate the factors that have greater influence on flotation. After step methodology, high values were found removal efficiency of suspended solids, reaching values greater than 90% in the best cases. It was concluded that flotation is more efficient in the facultative pond effluent using ferric chloride, and the variability of algae may negatively influence the process. Regression analyzes showed that pH is the most influential variable in the coagulation-flocculation-flotation, and its optimal value among the tested is 5.5 for both coagulants

O que controla o crescimento do Fitoplâncton em lagoas costeiras tropicais? um modelo para a lagoa de Extremoz (RN)

The phytoplankton growth is dependent of several abiotic (nutrients, temperature) and biotic (predation by zooplankton) variables. In this work, a mathematical model was developed in Stella software to understand the planktonic dynamics of Extremoz Lagoon (RN) and to simulate scenarios of different environmental conditions. Data were collected monthly at two points of the lagoon. The state variables are phytoplankton and zooplankton and forcing variables are nitrogen, phosphorus and temperature. The results show that: a) the model are well coupled, especially when some constants assume different values; b) simulated nutrient concentrations reduction decreases phytoplankton biomass, but the increase of nutrients does not stimulate the growth; c) changes in the temperature does not change the phytoplankton biomass; d) changes in zooplankton biomass affect directly and reduces the phytoplankton, indicating a topdown control mechanism; e) changes in the nutrient concentration modified the biomass of zooplankton suggesting a rapid flow of energy between nutrients, phytoplankton and zooplankton and a ecosystem likely arranged in an inverted pyramid (higher concentration of zooplankton than phytoplankton)

Remoção de Microalgas de efluentes de lagoas de estabilização utilizando biofiltro

This research evaluated the microalgae removal produced in a stabilization pond system using biofilters as post-treatment, besides characterizing the effluents of stabilization ponds and filters in relation to concentrations of algal biomass (chlorophyll a and suspended solids), organic matter (BOD and COD), total phosphorus, orthophosphate, pH and dissolved oxygen, and tried to correlate physicochemical parameters with chlorophyll "a". It was held at the Ponta Negra ETE which is constituted by three stabilization ponds, with a primary facultative pond and two of maturation. For the algae removal were used two submerged bio-filters: the filter FPF (Facultative Pond Filter), fed with facultative pond effluent; and the filter MPF (Maturation Pond Filter), fed with second maturation pond effluent. The filling material of both filters was predominantly gravel no. 2, although it contains portions of gravel no. 1 and no. 3. The filters operating conditions were bad, they were nearly 10 years without maintenance, without cleaning or removal of sludge since the time of its construction, and part of the filling material may be obstruct. Despite poor operating conditions were obtained satisfactory results, in level of posttreatment. Removal efficiencies in relation to BOD and COD were 7 and 25% in FPF and 9 and 19% and in MPF, respectively. In relation to TSS efficiencies in MPF and FPF were 37 and 20%, respectively. As for the chlorophyll "a" removal, the FPF efficiency was 44% and the MPF was 40%. There was 50% of consumption of dissolved oxygen, on average, within the filters. Two profiles were performed in the filters, and it was possible to conclude that variations throughout the day were not statistically significant, and that, regardless of the time of collection, they would have the same representation comparing to the time of data collection (7 am) and the daily average, although individual variations throughout the day have been shown to be significant. Another important observation is that the correlations between Chlorophyll a and TSS were bigger and more significant in the effluent of the filters than in the effluent of the ponds

Estudos in silico da proteína AlkB e prospecção de bactérias alcanotróficas em solos da bacia petrolífera potiguar

Some microorganisms from virgin ecosystems are able to use petroleum it as source of carbon and energy. The knowledge of microbial biodiversity can help to reveal new metabolic systems for utilization alkanes with biotechnological importance. The aim of this study is: i) Accomplish an in silico study of the AlkB protein aimed to understand the probable mechanism involved on selectivity of alkanes in Gram positive and Gram negative bactéria. ii) prospect and analyze the response of the microbial alkanotrophics communities in soil and mangrove sediments of BPP RN and soil of Atlantic forest in the Horto Dois Irmãos Reserve area/PE using the molecular biomarker, gene alkB; with the PCR and PCR-DGGE approach

Distribuição diária das atividades comportamentais dos camarões marinhos Farfantepenaeus subtilis (Pérez Farfante, 1967) e Litopenaeus schmitti (Burkenroad, 1938) em condições laboratoriais

Marine aquaculture has developed in the last decades all over the world, especially related to shrimp management. In Brazil, the introduction of the species Litopenaeus vannamei has contributed to the success of the activity, even if there are problems associated with the management of a exotic species, such as new diseases and ecological pressure on native species. It has been emphasized the need of research for developing new methodology that will allow native species management, being the most important Farfantepenaeus subtilis and Litopenaeus schmitti. Most knowledge obtained from research with those species has generally used a technical approach and mainly focused feeding process. There are no specific behavioral data on their activity pattern which should be of great importance for the use of native species on commercial culture farms. So, it was our objective to study and compare the daily distribution of behavioral activities of the marine shrimp species Litopenaeus schmitti and Farfantepenaeus subtilis. Forty animals of each species, 5 individuals per aquarium, were maintained in aquaria containing 200L of sea water under continuous aeration and filtration. They were marked individually and were observed by the instantaneous focal time sampling, along 10 continuous days, in 6 daily 15 min observation windows, every two hour. In each window, behaviors and location position of the animals in the aquarium were registered at 1 min intervals. Food was offered 3 times a day, representing 10% of each aquarium biomass. Aquaria were maintained in artificial photoperiod, 12hour light/l2 hour dark, 4 aquaria in light cycle equivalent to the environmental one (light from 06:00 to 17:59 h and dark from 18:00 to 05:59 h) and the other 4 in the reverse light cycle (light from 18:00 to 05:59 h and dark from 06:00 to 17:59 h) to allow sequential behavioral observation in both phases of the 24 hour cycle. There was a clear distinction between the distribution of behavioral activities of F. subtilis and L. schmitti in the two phases. The activity pattern of Farfantepenaeus subtilis demonstrates that species has prominently night habits and a burying pattern during the light cycle. Exploration, inactivity and swimming were the most common activities. The behavioral pattern of Litopenaeus schmitti indicates that species is active along both phases of the light cycle, and the most evident behaviors were exploration, inactivity and swimming

Extração e análise da fração lipídica da microalga monoraphidium sp., síntese e caracterização do seu biodiesel

The cultivation of microalgae biomass in order to produce biodiesel arises as an extremely promising aspect, in that the microalgae culture includes short cycle of reproduction, smaller areas for planting and residual biomass rich in protein content. The present dissertation evaluates the performance and features, through spectrometry in the region of infrared with transformed Fourier (FTIR) and spectrometry in the region of UVvisible (UV-Vis), of the extracted lipid material (LM) using different techniques of cell wall disruption (mechanical agitation at low and at high spin and agitation associated with cavitation). The technique of gas chromatography (GC) brought to light the success of alkaline transesterification in the conversion of oil into methyl monoesters (MME), which was also analyzed by spectroscopic techniques (FTIR, proton magnetic resonance (1H NMR) and carbon (13C NMR). Through thermogravimetric analysis (TGA) were analyzed the lipid material (LM), biodiesel and the microalgae biomass. The method which provided the best results concerning the efficiency in extraction of the LP of Monoraphidium sp. (12,51%) was by mechanical agitation at high spin (14 000 rpm), for 2 hours being the ideal time, as shown by the t test. The spectroscopic techniques (1H NMR, 13C NMR and FTIR) confirmed that the structure of methyl monoesters and the chromatographic data (CG) revealed a high content of saturated fatty acid esters (about 70%) being the major constituent eicosanoic acid (33,7%), which justifies the high thermal stability of microalgae biodiesel. The TGA also ratified the conversion rate (96%) of LM into MME, pointing out the quantitative results compatible with the values obtained through GC (about 98%) and confirmed the efficiency of the extraction methods used, showing that may be a good technique to confirm the extraction of these materials. The content of LM microalgae obtained (12,51%) indicates good potential for using such material as a raw material for biodiesel production, when compared to oil content which can be obtained from traditional oil for this use, since the productivity of microalgae per hectare is much larger and requires an extremely reduced period to renew its cultivation

Colêmbolos (arthropoda: hexapoda: collembola) numa área de caatinga do nordeste brasileiro

Edaphic ecosystems are the basis for the production of terrestrial biological resources and their dynamics affect not only the natural environment but also society and their economic activities. In Caatinga biome, the semi-arid climate associated with an inadequate soil management has increased the degradation and loss of productive potential of the soil. In this context, the study of soil fauna, including springtails, becomes an important indicator of soil quality. This study aimed to evaluate the fauna of Collembola in an area of Caatinga of Rio Grande do Norte State and the influence of biotic and abiotic factors, such as soil, vegetation and climate characteristics, on the structure of the taxocenosis. The environmental variables which were used were the following ones: granulometry (represented by the proportion of sand), quantity of organic matter and soil pH, richness, density and aerial biomass of the vegetal structure, and necromass. We used pitfall traps intending to collect specimens of the epiedaphic fauna of Collembola in 30 points located on Cauaçu Farm, João Câmara, RN, in July (rainy season) and November (dry season) 2011. We collected 5513 individuals of 15 species distributed in 13 genera and 9 families of Collembola. Five of the recorded species are new to science, confirming the expected high degree of endemism for Caatinga biome, and the highest abundance was recorded in the rainy season, which suggests Collembola sensitivity to low humidity. Four species were more abundant in the dry season, all of them belonged to the Order Entomobryomorpha. Results of statistical analyzes suggest that plant species richness, aerial biomass of vegetal structure, proportion of sand in the soil, pH and humidity are the main influences to the abundance of Collembola in the region studied

Qualidade de água como tema para a socialização do conhecimento científico em região semi-árida brasileira

During the dry and rainy periods, in the Piranhas-Assu river hydrographic basin, variations in bacterioplankton and trophic state indexes were studied in the lotic and lentic environments. The means of total bacterial density wavered in the order of 107 organisms. mL-1 and they were higher in the rainy period. Cocci bacteria were numerically predominant in all sampling points, influencing the total abundance of bacterioplankton. Total bacterial biomass varied from 659 to 1997,3 µgC.L-1 due to the high values of filaments cellular volume. Total phosphorus amounted 108 µg.L-1 and it had a positive correlation with chlorophyll a (r = 0,94; p < 0,05) during dry period, when these variables presented higher concentrations. There wasn t a high spatial variation. The low transparency of water and the phosphorus and chlorophyll concentrations indicated eutrophic or hipereutrophic levels in studied points of reservoir. These variables, associated with high density and biomass values found, alert to the necessity of a constant monitoring of the semi-arid aquatic ecosystems, where the quality of water is affected by dry occurrence

Cultivo de algas marinhas como desenvolvimento de comunidades costeiras

In northeastern Brazil, the extraction of agar has increased considerably in recent decades mainly using macroalgae of the genus Gracilaria. The pressure of the harvest of seaweed of this genus has compromised the sustainability of this natural resource. Given the current framework of decline in production of algae in the state of Rio Grande do Norte, it is necessary the deployment of crops that will assist in the development of coastal areas. This research aimed to develop studies on growth, productivity, efficiency and quality of agar of G. birdiae so as to provide subsidies for crops on commercial scale. The study was carried out in dry and rainy periods using rafts of cultivation. Algal biomass and the physical and chemical parameters of water were measured every fifteen days. In laboratory, the resistance and quality of agar were analyzed. The relative growth rate (TCR) was determined by the formula: RGR = ln (final weight / weight initial). 100 / interval time of sampling. During the study, environmental factors as salinity and temperature remained relatively constant (around 35 PSU and 28°C, respectively). The mean values of biomass ranged around 1952.67 ± 576g in the rainy period and 1925.67 ± 450g in the dry period, and they presented no significant variations. The maximum value of growth (TCR) was recorded in the dry season (7.45%.day-1), with an average over the study of 4.35%.day-1. The yield of agar ranged from 22% to 15%, and its resistance ranged from 850 to 650g. cm². The average obtained for the two periods was approximately 750 g cm². These results demonstrate the great potential of Gracilaria birdiae for mariculture can be used as an sustainable activity for coastal communities

Usos e qualidade da água em região semi-árida do nordeste brasileiro: percepção ambiental de professores e alunos

Density and biomass of bacterioplankton in parts of the Marechal Dutra reservoir were studied in periods of dry and rainy season. The averages of the total bacterial densities oscillated in the order of 107 organisms/ mL of sample. The cocci cells were numerically predominant, influencing considerably the total abundance of the bacterioplankton. The total bacterial biomass, was considered raised and varied from 2.431,82 to 2.739,01 μgC.L-1, in function of the high values of biovolume of the filaments forms, and showed no marked spacial fluctuation. These high values of density and biomass alert for the necessity of a frequent monitoring of aquatic ecosystems of semi-arid region, where the quality of the water is affected by the occurrence of extensive dry periods, influencing considerably the quality of life of its population