Estudo da desidratação de tomates em pedaços com pré-tratamento osmótico

Vegetables drying plays an important role in the field of food dehydration, being a very old practice that was originated from sun drying items of food in order to preserve them to be consumed during the periods of scarcity. One of these vegetables is the tomato, that was originally grown in South America. Tomatoes are easily perishable after being picked up from the tree and this makes the process of tomato dehydration a challenge due to the high amount of water (95%) contained in them. The present research work was mainly intended to develop alternative processes for tomato conservation, by drying slices of skinned and unskinned tomatoes in the in natura form or in the osmotically pre-dehydrated form. Firstly, the best conditions of the osmotic pre-dehydration process were defined including temperature, immersion time and concentration of the osmotic solution, based on the results of water loss, solids gain and weigh reduction of the pre-dehydration tomatoes at different processing conditions. The osmotic solution used was made up of NaCl (5 and 10%) and sucrose (25 and 35%) at different combinations. For a fixed conditions of osmotic pre-dehydration, the drying tests of the pre-processed and in natura tomatoes were carried out in a stove with air circulation and a convective dryer with trays, at two levels of temperature. The sensorial analysis of the osmotically pre-treated and unskinned dehydrated tomatoes was carried out as well as a study on the their shelf-live. The results obtained showed that the drying of the tomatoes took place as a result of the internal control of the water transport, and did not show a constant rate, while two distinct periods of the decreasing phase were observed. The osmotic pre treatment substancially reduced the initial amount of humidity in the tomatoes, thus reducing the necessary time for the product to attain levels of intermediate humidity. The impermeability of the tomato skin was identified as well as the unfavorable influence of the pre-treatment on the unskinned tomatoes, whose solid gain brought about a decrease in the water activity with subsequent reduction of the drying rate. Despite the various simplifications carried out during the development of this study, the proposed diffusive model adjusted to the experimental data satisfactorily, thus making it possible to determine the effective coefficients of diffusion, whose results were consistent and compatible with those found in the current literature. Concerning the higher rates of evaporation and the lowest processing time, the best results were obtained in the drying of the unskinned, in natura tomatoes and of the skinned, pre-dehydrated tomatoes, at 60ºC, both processed in the convective drier. The results of the sensorial analysis of the unskinned and pre-treated product did not prove to be satisfactory. Regarding the shelf-live of the tomatoes, for a period of 45 days, no physicochemical or microbiological alteration of the product was noted

Planejamento experimental aplicada a um novo separador líquido-líquido utilizado no tratamento de águas residuais contaminadas com petróleo

The present work had as objective to apply an experimental planning aiming at to improve the efficiency of separation of a new type of mixer-settler applied to treat waste water contaminated with oil. An unity in scale of laboratory, was installed in the Post-graduation Program of Chemical Engineering of UFRN. It was constructed in partnership with Petrobras S.A. This called device Misturador-Decantador a Inversão de Fases (MDIF) , possess features of conventional mixer-settler and spray column type. The equipment is composed of three main parts: mixing chamber; chamber of decantation and chamber of separation. The efficiency of separation is evaluated analyzing the oil concentrations in water in the feed and the output of the device. For the analysis one used the gravimetric method of oil and greases analysis (TOG). The system in study is a water of formation emulsified with oil. The used extractant is a mixture of Turpentine spirit hydro-carbons, supplied for Petrobras. It was applied, for otimization of the efficiency of separation of the equipment, an experimental planning of the composite central type, having as factorial portion fractionary factorial planning 2 5-2, with the magnifying of the type star and five replications in the central point. In this work, the following independents variables were studied: contents of oil in the feed of the device; volumetric ratio (O/A); total flowrate ; agitation in the mixing chamber and height of the organic bed. Minimum and maximum limits for the studied variables had been fixed according previous works. The analysis of variance for the equation of the empirical model, revealed statistically significant and useful results for predictions ends. The variance analysis also presented the distribution of the error as a normal distribution and was observed that as the dispersions do not depend on the levels of the factors, the independence assumption can be verified. The variation around the average is explained by 98.98%, or either, equal to the maximum value, being the smoothing of the model in relation to the experimental points of 0,98981. The results present a strong interaction between the variable oil contents in the feed and agitation in the mixing chamber, having great and positive influence in the separation efficiency. Another variable that presented a great positive influence was the height of the organic bed. The best results of separation efficiency had been obtained for high flowrates when associates the high oil concentrations and high agitation. The results of the present work had shown excellent agreement with the results carried out through previous works with the mixer-settler of phase inversion

Análise dos Processos de Flotação e Oxidação Avançada para o Tratamento de Efluente Modelo da Indústria do Petróleo

The generation of wastes in most industrial process is inevitable. In the petroleum industry, one of the greatest problems for the environment is the huge amount of produced water generated in the oil fields. This wastewater is a complex mixture and present great amounts. These effluents can be hazardous to the environmental without adequate treatment. This research is focused in the analysis of the efficiencies of the flotation and photo-oxidation processes to remove and decompose the organic compounds present in the produced water. A series of surfactants derivated from the laurilic alcohol was utilized in the flotation to promote the separation. The experiments have been performed with a synthetic wastewater, carefully prepared with xylene. The experimental data obtained using flotation presented a first order kinetic, identified by the quality of the linear data fitting. The best conditions were found at 0.029 g.L-1 for the surfactant EO 7, 0.05 g.L-1 for EO 8, 0.07 g.L-1 for EO 9, 0.045 g.L-1 for EO 10 and 0.08 g.L-1 for EO 23 with the following estimated kinetic constants: 0.1765, 0.1325, 0.1210, 0.1531 and 0.1699 min-1, respectively. For the series studied, the most suitable surfactant was the EO 7 due to the lower reagent onsumption, higher separation rate constant and higher removal efficiency of xylene in the aqueous phase (98%). Similarly to the flotation, the photo-Fenton process shows to be efficient for degradation of xylene and promoting the mineralization of the organic charge around 90% and 100% in 90 min

Caracterização de água produzida na indústria de petróleo para fins de descarte e otimização do processo de separação óleo/água

The oil industry has several segments that can impact the environment. Among these, produced water which has been highlight in the environmental problem because of the great volume generated and its toxic composition. Those waters are the major source of waste in the oil industry. The composition of the produced water is strongly dependent on the production field. A good example is the wastewater produced on a Petrobras operating unit of Rio Grande do Norte and Ceará (UO-RNCE). A single effluent treatment station (ETS) of this unit receives effluent from 48 wells (onshore and offshore), which leads a large fluctuations in the water quality that can become a complicating factor for future treatment processes. The present work aims to realize a diagnosis of a sample of produced water from the OU - RNCE in compliance to certain physical and physico-chemical parameters (chloride concentration, conductivity, dissolved oxygen, pH, TOG (oil & grease), nitrate concentration, turbidity, salinity and temperature). The analysis of the effluent is accomplished by means of a MP TROLL 9500 Multiparameter probe, a TOG/TPH Infracal from Wilks Enterprise Corp. - Model HATR - T (TOG) and a MD-31 condutivimeter of Digimed. Results were analyzed by univariated and multivariated analysis (principal component analysis) associated statistical control charts. The multivariate analysis showed a negative correlation between dissolved oxygen and turbidity (-0.55) and positive correlations between salinity and chloride (1), conductivity, chloride and salinity (0.70). Multivariated analysis showed there are seven principal components which can explain the variability of the parameters. The variables, salinity, conductivity and chloride were the most important variables, with, higher sampling variance. Statistical control charts have helped to establish a general trend between the physical and chemical evaluated parameters

Otimização do processo de flotação de emulsão óleo/água através do planejamento fatorial completo

In recent decades, the generation of solid and liquid waste has increased substantially due to increased industrial activity that is directly linked to economic growth. For that is the most efficient process, it is inevitable generation of such wastes. In the oil industry, a major waste generated in oil exploration is produced water, which due to its complex composition and the large amount generated, has become a challenge, given the restrictions imposed by environmental laws regarding their disposal, making if necessary create alternatives for reuse or treatment in order to reduce the content of contaminants and reduce the harmful effects to the environment. This water can be present in free form or emulsified with the oil, when in the form of an emulsion of oil-water type, it is necessary to use chemicals to promote the separation and flotation is the treatment method which has proved to be more efficient, for it can remove much of the emulsified oil when compared to other methods. In this context, the object of this work was to study the individual effects and interactions of some physicochemical parameters of operations, based on previous work to a flotation cell used in the separation of synthetic emulsion oil / water in order to optimize the efficiency of the separation process through of the 24 full factorial design with center point. The response variables to evaluate the separation efficiency was the percentage of color and turbidity removal. The independent variables were: concentration of de-emulsifying, oil content in water, salinity and pH, these being fixed, minimum and maximum limits. The analysis of variance for the equation of the empirical model, was statistically significant and useful for predictive purposes the separation efficiency of the floater with R2 > 90%. The results showed that the oil content in water and the interaction between the oil content in water and salinity, showed the highest values of the estimated effects among all the factors investigated, having great and positive influence on the separation efficiency. By analyzing the response surface was determined maximum removal efficiency above 90% for both measured for turbidity as a measure of color when in a saline medium (30 g/L), the high oil concentrations (306 ppm) using low concentrations of de-emulsifying (1,1 ppm) and at pH close to neutral

Caracterização de Efluente Têxtil e Proposta de Tratamento

Textile industry deals with a high diversity of processes and generation of wastewaters with a high content of pollutant material. Before being disposed of in water bodies, a pre-treatment of the effluent is carried out, which is sometimes ineffective. In order to be properly treated, physical and chemical properties of the effluent must be known, as well as the pollutant agents that might be present in it. This has turned out to be a great problem in the textile industry, for there is a variety of processes and the pollutant load is very diversified. The characterization of the effluent allows the identification of most critical points and, as a consequence, the most appropriate treatment procedure to be employed, may be chosen. This study presents the results obtained after characterizing the effluent of a textile industry that comprises knitting, dyeing and apparel sections, processing mainly polyester/cotton articles. In this work, twenty samples of the effluent were collected, and related to the changes in production. From the results, a statistical evaluation was applied, determined in function of the rate of flow. The following properties and pollutants agents were quantitatively analysed: temperature; pH; sulfides; chlorine; alcalinity; chlorides; cianides; phenols; color; COD (Chemical Oxygen Demand); TOC (Total Organic Carbon); oil and grease; total, fixed and volatile solids; dissolved, fixed and volatile solids; suspended, fixed and volatile solids; setteable solids and heavy metals such as cadmium, copper, lead, chromium, tin, iron, zinc and nickel. Analyses were carried out according to ABNT NBR 13402 norm, based upon Standard Methods for the Examination of Water and Wastewater. As a consequence, a global treatment proposal is presented, involving clean production practices as contaminant load reducer, followed by conventional (biological) treatment

Projeto e Operação em Escala Semi-Industrial de um Equipamento para Tratamento de Águas Produzidas na Indústria do Petróleo Utilizando Nova Tecnologia: misturador-decantador à inversão de fases - MDIF

The aim of this work is to use a new technology in the treatment of produced wastewaters from oil industry. An unit for treat produced waters called UTMDIF, was designed, installed and operated in an industrial plant for treatment of effluents from oil industry. This unit operates by means of the method of separation of phase inversion and can become a promising alternative to solve the problem of oil/water separation. This method constitutes the basis of the working of a new design of mixersettler of vertical configuration which occupies small surface area. The last characteristic becomes specially important when there is limitation on the lay-out of the plant, for example, over maritime platforms to explore oil. This equipment in a semi-industrial scale treats produced wastewaters contaminated with oil at low concentrations (ranging from 30 to 150 mg/L) and throughputs of 320 m3/d (47,4 m3 m-2 h-1). Good results were obtained in oil/water separation which leads to the necessary specification to discharge those wastewaters. Besides, the non dependence of the efficiency of separation in spite of the salinity of the medium becomes the equipment an attractive new technology to treat wastewaters containing oil at low concentrations

Uso da tecnologia de troca iônica no tratamento de águas contaminadas com Nitrato do Aqüífero Dunas-Barreiras, Natal/RN-Brasil

The city of Natal comprises an area of about 170 km² (65,63 squares miles). The Dunas-Barreiras Aquifer is the most important reservoir of the coastal basin of RN. It is being responsible for the water supplying of about 70% of the population, however, due to the sewage disposal system by cesspools and drains, it is presently affected in a great extent by nitrates contamination. Thus, the present work proposes to research the utilization of contaminated water by nitrates of this fountainhead and find cost of the potable water through the ionic exchange technology. This technology consists in the removal of mineral salts by the exchange of cations for one ion of hydrogen (H+), through the passage of water by cationic resin bed and, secondly, by the exchange of the anions for hydroxyl ions (OH-) through a anionic resin bed. The obtained results have showed the waters derived from fountains, big water holes and shallow wells were microbiologically contaminated, while the waters derived from deep wells (above 70 m 76,58 yards) were free of contamination. Thus, only these ones are suitable to the use of ionic technology. The experiments were conducted with the resin IMAC-HP-555 such as kinetic, thermodynamic, and adsorption by fixed bed studies, being obtained several project variables for the experimental column, as follow: work temperature of 25oC; resin maximum capacity maximum e mean of adsorption ==0,01692 g NO3-1/g R e 0,0110 g NO3-1/g R, respectively. On the experimental column were performed breakthrough tests which pointed for an average ideal average speed of work of 13.2 m / h, with an average efficiency of 45% of adsorption, an optimal concentration of NaCl desorption of 8%, and an ideal desorption time of 80 minutes for the equilibrium conditions of water from the Dunas-Barreiras aquifer. Scale projection for ion-exchange column for denitrification, for these variables, using a computer modeling programme, to project the column of ion exchange ROREX-420/2000, obtained a cost for the drinking water denitrified by this system of R$ 0,16 / m3

Estudo de técnicas para o tratamento alternativo de efluentes oleosos oriundos da industrialização da castanha de caju

An evaluation project was conducted on the technique of treatment for effluent oil which is the deriving process to improve cashews. During the evaluation the following techniques were developed: advanced processes of humid oxidation, oxidative processes, processes of biological treatment and processes of adsorption. The assays had been carried through in kinetic models, with an evaluation of the quality of the process by means of determining the chemical demand of oxygen (defined as a technique of control by means of comparative study between the available techniques). The results demonstrated that the natural biodegradation of the effluent ones is limited, as result using the present natural flora in the effluent one revealed impracticable for an application in the industrial systems, independent of the evaluation environment (with or without the oxygen presence). The job of specific microorganisms for the oily composite degradation developed the viability technique of this route, the acceptable levels of inclusion in effluent system of treatment of the improvement of the cashew being highly good with reasonable levels of removal of CDO. However, the use combined with other techniques of daily pay-treatment for these effluent ones revealed to still be more efficient for the context of the treatment of effluent and discarding in receiving bodies in acceptable standards for resolution CONAMA 357/2005. While the significant generation of solid residues the process of adsorption with agroindustrial residues (in special the chitosan) is a technical viable alternative, however, when applied only for the treatment of the effluent ones for discarding in bodies of water, the economic viability is harmed and minimized ambient profits. Though, it was proven that if used for ends of I reuse, the viability is equalized and justifies the investments. There was a study of the photochemistry process which have are applicable to the treatment of the effluent ones, having resulted more satisfactory than those gotten for the UV-Peroxide techniques. There was different result on the one waited for the use of catalyses used in the process of Photo. The catalyses contained the mixing oxide base of Cerium and Manganese, incorporated of Potassium promoters this had presented the best results in the decomposition of the involved pollutants. Having itself an agreed form the gotten photochemistry daily paytreatment resulted, then after disinfection with chlorine the characteristics next the portability to the water were guarantee. The job of the humid oxidation presented significant results in the removal of pollutants; however, its high cost alone is made possible for job in projects of reuses, areas of low scarcity and of raised costs with the capitation/acquisition of the water, in special, for use for industrial and potable use. The route with better economic conditions and techniques for the job in the treatment of the effluent ones of the improvement of the cashew possesses the sequence to follow: conventional process of separation water-oil, photochemistry process and finally, the complementary biological treatment

Comparação entre planejamento estatístico experimental e análise dimensional em operações de mistura e separação para sistema óleo-água

This work aims to determine a better methodology to help predicting some operational parameters to a new design of mixer-settler on treating wastewater produced by petroleum industry, called MDIF (Misturador-Decantador à Inversão de Fases/ Mixer-Settler based on Phase Inversion MSPI). The data from this research were obtained from the wastewater treatment unit, called MSPI-TU, installed on a wastewater treatment plant (WTP) of PETROBRAS/UO-RNCE. The importance in determining the better methodology to predict the results of separation and extraction efficiency of the equipment, contributes significantly to determine the optimum operating variables for the control of the unit. The study was based on a comparison among the experimental efficiency (E) obtained by operating MSPI-TU, the efficiency obtained by experimental design equation (Eplan) from the software Statistica Experimental Design® (version 7.0), and the other obtained from a modeling equation based on a dimensional analysis (Ecalc). The results shows that the experimental design equation gives a good prediction of the unit efficiencies with better data reliability, regarding to the condition before a run operation. The average deviation between the proposed by statistic planning model equation and experimental data was 0.13%. On the other hand, the efficiency calculated by the equation which represents the dimensional analysis, may result on important relative deviations (up 70%). Thus, the experimental design is confirmed as a reliable tool, with regard the experimental data processing of the MSPI-TU

Desenvolvimento de um sistema foto-oxidativo visando aplicação no tratamento de águas produzidas em campos de petróleo

Increasing concern with the environment, in addition to strict laws, has induced the industries to find altenatives to the treatment of their wastes. Actually, the oil industry has sought solutions to overcome a big environmental problem, i.e., oil field produced water being discharged to the sea. These effluents have organic compounds dissolved, such as polycyclic aromatic hydrocarbons, phenols, benzene, toluene, ethylbenzene and xylenes (BTEX). These compounds are difficult to be removed and have high toxicity. The advanced oxidation processes - AOP are effective to degradation of these organic compounds, because they generate hydroxyl radicals with high potential of oxidation. This work includes the reactor photochemical development applied in the photodegradation treatment (by photo-Fenton process) of wastewaters containing organic compounds dissolved, aiming at treatment and recovery the oil field produced water. The studied reactor allowed the evaluation of two ultraviolet radiation sources that is the main factor to describe the feasibility of the photo¬Fenton treatment, i.e., sun and black light fluorescent lamps, and other relevant variables the process: concentration of reagents, irradiated area and also various reactor configurations to maximize the use of radiation. The organic matter degradation was verified with samples collected during the experimental and analyzed with a total organic carbon analyzer (TOC), which expressed the results in terms of mgC/L. The solar radiation was more effective than radiation from the lamps. it's an important factor for the operation costs cutting. Preliminary experiments applied to oil field produced water treatment have showed satisfactory results, reducing up to 76 % of organic matter

Desenvolvimento de um sistema foto-oxidativo visando aplicação no tratamento de águas produzidas em campos de petróleo

Increasing concern with the environment, in addition to strict laws, has induced the industries to find alternatives to the treatment of their wastes. Actually, the oil industry has sought solutions to overcome a big environmental problem, i.e., oil field produced water being discharged to the sea. These effluents have organic compounds dissolved, such as polycyclic aromatic hydrocarbons, phenols, benzene, toluene, ethylbenzene and xylenes (BTEX). These compounds are difficult to be removed and have high toxicity. The advanced oxidation processes - AOP are effective to degradation of these organic compounds, because they generate hydroxyl radicals with high potential of oxidation. This work includes the reactor photochemical development applied in the photodegradation treatment (by photo-Fenton process) of wastewaters containing organic compounds dissolved, aiming at treatment and recovery the oil field produced water. The studied reactor allowed the evaluation of two ultraviolet radiation sources that is the main factor to describe the feasibility of the photo- Fenton treatment, i.e., sun and black light fluorescent lamps, and other relevant variables the process: concentration of reagents, irradiated area and also various reactor configurations to maximize the use of radiation. The organic matter degradation was verified with samples collected during the experimental and analyzed with a total organic carbon analyzer (TOC), which expressed the results in terms of mgC/L. The solar radiation was more effective than radiation from the lamps. It's an important factor for the operation costs cutting. Preliminary experiments applied to oil field produced water treatment have showed satisfactory results, reducing up to 76 % of organic matter

Estudo da remoção de Ba2+, Ni2+, Cd2+, Cu3+, Cr3+, Sr2+, Zn2+ por eletrocoagulação em água associada à produção de petróleo

Among the waste generated in the petrochemical industry water associated with oil production is the most important. It is considered one of the great challenges due to the presence of considered toxic chemicals present in this composition. The presence of these substances difficult to reuse the water associated with the enhanced recovery processes, so that prior to their reuse or disposal, treatment is necessary. This paper aimed to study the removal efficiency of chemical species: Ba2+, Ni2+, Cd2+, Cu2+, Cr3+, Sr2+ and Zn2+, present in the composition of the water associated with oil production by electrocoagulation. The evaluation of removal of these chemical species was performed by laboratory tests using electrochemical batch reactors and continuous flow. Initial tests were performed with electrocoagulation of synthetic wastewater in batch reactor using iron electrode. Results of removal of Zn2+ and Ni2+ were 78 % and 59 % respectively. While the percentage of removed Ba2+ was 19 % by 30 minutes of treatment and by applying current of 1.10 A. The tests were performed on effluent batch reactor applying the electrochemical technique with stainless steel electrodes 304, the objective was to remove part of the dispersed oil and also of organic compounds in the effluent. Under the experimental conditions used, the maximum result was obtained TOG was 60 % and TOC was approximately 50 % compared to the initial concentration. In the experiments carried out in continuous reactor, with effluent semisynthetic, have been used electrodes of iron and aluminum and the results were 100 % removal of Cd2+, Cu2+, Cr3+ and Zn2+ and 77 % of Sr2+. These percentages were only attainable through the use of the iron electrode. However, when the electrode was replaced by aluminum, there was a reduction in the percentage of removal to 65 %, using the same flow rate and current. Therefore according to the results obtained using the iron electrode was more effective in removing these metals and the conditions of lower current and lower flow rate was satisfactory, as observed in the experimental design adopted

Concepção e estudo de um biofiltro para tratamento de compostos orgânicos voláteis COVs

In the last decade, biological purification of gaseous waste has become an important alternative to many conventional methods of exhaust air treatment. More recently, biofiltration has proved to be an effective and inexpensive method for the treatment of air contaminated with volatile organic compounds (VOCs). A biofilter consists in a reactor packed with a porous solid bed material, where the microorganisms are fixed. During the biofiltration process, polluted air is transported through the biofilter medium where the contaminant is degraded. Within the biofilm, the pollutants in the waste gases are energy and carbon sources for microbial metabolism and are transformed into CO2, water and biomass. The bed material should be characterized by satisfactory mechanical and physical properties as structure, void fraction, specific area and flow resistance. The aim of this research was the biofilter construction and study of the biological degradation of ethanol and toluene, as well as the modeling of the process. Luffa cylindrica is a brazilian fiber that was used as the filtering material of the present work. The parameters and conditions studied were: composition of nutrients solution; effect of microflorae strains, namely Pseudomanas putida and Rhodococcus rhodochrous; waste gas composition; air flow rate; and inlet load of VOCs. The biofilter operated in diffusion regime and the best results for remotion capacity were obtained when a microorganisms consortion of Pseudomanas putida and Rhodococcus rhodochrous,were used, with a gas flow rate of 1 m3.h-1 and molar ratio nitrogene/phosphore N/P=2 in the nutrients solution. The maximum remotion capacity for ethanol was around 90 g.m-3.h-1 and 50 g.m-3.h-1 to toluene. It was proved that toluene has inhibitory effect on the ethanol remotion When the two VOCs were present in the same waste gas, there was a decrease of 40% in ethanol remotion capacity. Luffa cylindrica does not present considerable pressure drop. Ottengraf and van Lith models were used to represent the results obtained for ethanol and toluene, respectively. The application of the transient model indicated a satisfactory approximation between the experimental results obtained for ethanol and toluene vapors biofiltration and the ones predicted it

Análise da adição de resíduo oriundo do tratamento de esgotos em massa cerâmica utilizada para fabricação de telhas

Sludge of Wastewater Treatment Plants (WTPs) disposal is a problem for any municipality, for this reason the amount of sludge production is now a key issue in selecting treatment methods. It is necessary to investigate new applications for this waste type, due to the restrictions imposed by the environmental organs. The raw materials used in the Red Ceramic, are generally very heterogeneous, for this reason, such materials can tolerate the presence of different types of wastes. In Rio Grande do Norte, the roof tiles production corresponds to 60,61% from the total of ceramic units produced. Due to the importance of the ceramic industry of roof tiles for the state, allied to the environmental problem of the sludge disposal, this work had for objective to verify the possibility of the incorporation of sewage sludge in ceramic body used for production of roof tiles. In the research, sludge originating from drying beds of WTP of the Central Campus from UFRN and clays originating from a ceramic industry from Goianinha/RN were used. The raw materials were characterized by techniques of: analysis of particles distribution by diffraction to laser; real density; consistence limits; chemical analysis by X-ray fluorescence; mineralogical analysis by X-ray diffraction; organic matter; and solids content. Five batches of roof tiles were manufactured in the approximate dosages of 2%, 4%, 6%, 8% and 10%. To evaluate the properties of each final product, tests of water absorption, impermeability, bending strength, leachability and solubility were accomplished. The roof tiles manufactured with sludge presented characteristics similar to the roof tiles without sludge in relation to the environmental risk. The results showed that it is possible to use approximately up to 4% of sludge in ceramic bodies for production of roof tiles. However, it is observed that the high amount of organic matter (71%) present in the sludge is shown as factor that limits the sludge incorporation in ceramic bodies, worsening the quality of the roof tiles. It is necessary the use of mixtures of different raw materials under point of view of the granulometry and of the other chemical and mineralogical properties for the obtaining of a satisfactory mass to the production of ceramic roof tiles