scholarly journals Potential Applications of Biogas Produced in Small-Scale UASB-Based Sewage Treatment Plants in Brazil

Energies ◽  
2020 ◽  
Vol 13 (13) ◽  
pp. 3356 ◽  
Author(s):  
Fabiana Passos ◽  
Thiago Bressani-Ribeiro ◽  
Sonaly Rezende ◽  
Carlos A. L. Chernicharo

Rural sanitation is still a challenge in developing countries, such as Brazil, where the majority population live with inadequate services, compromising public health and environmental safety. In this context, this study analyzed the demographic density of these rural agglomerations using secondary data from the Brazilian Institute of Geography and Statistics (IBGE). The goal was to identify the possibilities associated with using small-scale upflow anaerobic sludge blanket (UASB) reactors for sewage treatment, mainly focusing on biogas production and its conversion into energy for cooking, water heating and sludge sanitization. Results showed that most rural agglomerations lacking the appropriate sewage treatment were predominant from 500 to 1500 inhabitants in both northern and southern Brazilian regions. The thermal energy available in the biogas would be enough to sanitize the whole amount of sludge produced in the sewage treatment plants (STPs), producing biosolids for agricultural purposes. Furthermore, the surplus of thermal energy (after sludge sanitization) could be routed for cooking (replacing LPG) and for water heating (replacing electricity) in the northern and southern regions, respectively. This would benefit more than 200,000 families throughout rural areas of the country. Besides the direct social gains derived from the practice of supplying biogas for domestic uses in the vicinity of the STPs, there would be tremendous indirect gains related to the avoidance of greenhouse gas (GHG) emissions. Therefore, an anaerobic-based sewage treatment may improve public health conditions, life quality and generate added value products in Brazilian rural areas.

2011 ◽  
Vol 63 (1) ◽  
pp. 100-107 ◽  
Author(s):  
B. Heffernan ◽  
J. B. van Lier ◽  
J. van der Lubbe

This article evaluates the performance of 10 large scale upflow anaerobic sludge blanket (UASB) sewage treatment plants (STP) located in semi-tropical areas, 7 plants were located in Brazil, 2 in India and 1 in the Middle East. In addition to the UASB, essential functional units of the STP which potentially impact on the UASB are also evaluated. Most grit removal systems were performing adequately, however in one plant very little grit was being removed. This could have serious implications for the performance of the plant as in a relatively short period of time the reactors could become full of grit. The performance results obtained in this study (COD, BOD and TSS removal efficiencies) are compared to the results of recent literature publications and also to the results of some early pilot and full scale studies. The results found here are broadly similar to those result reported in the recent literature but show a lower performance in comparison with the early pilot scale plants. Factors such as improper design, poor operating procedures, insufficient maintenance and the presence of high sulphate concentrations have been identified as the main reasons for the lower performance.


1999 ◽  
Vol 40 (8) ◽  
pp. 107-113 ◽  
Author(s):  
Carlos Augusto L. Chernicharo ◽  
Marcílio dos Reis Cardoso

This paper presents the development and field evaluation of a partitioned UASB reactor, conceived for the treatment of domestic sewage from small villages and areas with large variation of the daily flowrate. In such situations, conventional single compartment UASB reactors are submitted to very extreme hydraulic conditions, that can disturb the behaviour of the treatment system. In the partitioned reactor, which is constituted of three digestion compartments, three gas separation devices and a single settler compartment, an adequate distribution of the variable incoming wastewater into one, two or three digestion chambers, allows the establishment of more stable up flow velocities and less occurrence of dead zones. As a result, a better contact between substrate and biomass can be achieved and an improved performance of the system can be expected. The partitioned UASB reactor was evaluated during a period of 16 months of continuous operation. The system presented a vary good performance during most of the operational period, showing very high efficiencies when the reactor was operated at a HRT of 7.5 hours. In this phase, the unit presented COD removal efficiencies around 80% and an average SS concentration in the final effluent of 32 mgSS/L. The research is still going on, focussing on the evaluation of the system under higher hydraulic loads and on the assessment of sludge activity and dehydration potential. Due to the operational simplicity and low cost of the system, it is believed that this type of reactor can become a very attractive alternative for domestic sewage treatment in small villages, particularly in Brazil where the number of rural areas with wastewater treatment is negligible.


1993 ◽  
Vol 27 (9) ◽  
pp. 159-171 ◽  
Author(s):  
Eberhard Steinle

First an overview of the systems currently in use and being discussed for sludge treatment is presented will) particular emphasis on distinguishing between the object of the system (conditioning objective of the various phases in the system) and a system concept (concept of various phases of the system in sequence to attain the disposal objective). More detailed information is given as to the salient systems as used with smaller sewage treatment plants in rural areas, such as digestion, dewatering, hygienization, composting and thermal drying. A further item of discussion is how sludge treatment influences the sewage treatment process. For the critical emissions (nitrogen, phosphorus) demanded in Germany, and thus for the degree of sewage treatment required, the load of the sewage treatment system resulting from sludge treatment needs to be taken into account. Accordingly, operation of sludge treatment and sewage purification must always be harmonized. The extent of these return loads also limits the spatial centralization of the system phases; this applies in particular to smaller sewage treatment plants in rural areas. In conclusion, an attempt is made to present a perspective for the agricultural utilization of such sludge in Germany. Since the critical values for emissions have been further tightened by new regulations, thus considerably elevating the associated sophistication of monitoring techniques, it is to be expected that the use of sewage sludge in agriculture will also be further reduced in rural areas, especially since public awareness of emission control has considerably reduced the acceptance of sewage sludge as fertilizer.


2020 ◽  
Vol 81 (9) ◽  
pp. 1951-1960 ◽  
Author(s):  
C. S. Cabral ◽  
A. L. Sanson ◽  
R. J. C. F. Afonso ◽  
C. A. L. Chernicharo ◽  
J. C. Araújo

Abstract Two bioreactors were investigated as an alternative for the post-treatment of effluent from an upflow anaerobic sludge blanket (UASB) reactor treating domestic sewage, aiming at dissolved sulfide and methane removal. The bioreactors (R-control and R-air) were operated at different hydraulic retention times (HRT; 6 and 3 h) with or without aeration. Large sulfide and methane removal efficiencies were achieved by the microaerated reactor at HRT of 6 h. At this HRT, sulfide removal efficiencies were equal to 61% and 79%, and methane removal efficiencies were 31% and 55% for R-control and R-air, respectively. At an HRT of 3 h, sulfide removal efficiencies were 22% (R-control) and 33% (R-air) and methane removal did not occur. The complete oxidation of sulfide, with sulfate formation, prevailed in both phases and bioreactors. However, elemental sulfur formation was more predominant at an HRT of 6 h than at an HRT of 3 h. Taken together, the results show that post-treatment improved the anaerobic effluent quality in terms of chemical oxygen demand and solids removal. However, ammoniacal nitrogen was not removed due to either the low concentration of air provided or the absence of microorganisms involved in the nitrogen cycle.


2018 ◽  
Vol 77 (9) ◽  
pp. 2292-2300 ◽  
Author(s):  
Karina Cubas do Amaral ◽  
Miguel Mansur Aisse ◽  
Gustavo Rafael Collere Possetti ◽  
Marcelo Real Prado

Abstract Upflow anaerobic sludge blanket (UASB) reactors used in sewage treatment generate two by-products that can be reused: sludge and biogas. At the present time in Brazil, most of this resulting sludge is disposed of in sanitary landfills, while biogas is commonly burned off in low-efficiency flares. The aim of the present study was to use life cycle assessment to evaluate the environmental impacts from four different treatment and final destination scenarios for the main by-products of wastewater treatment plants. The baseline scenario, in which the sludge was sanitized using prolonged alkaline stabilization and, subsequently, directed toward agricultural applications and the biogas destroyed in open burners, had the most impact in the categories of global warming, terrestrial ecotoxicity, and human non-carcinogenic toxicity. The scenario in which heat resulting from biogas combustion is used to dry the sludge showed significant improvements over the baseline scenario in all the evaluated impact categories. The recovery of heat from biogas combustion decreased significantly the environmental impact associated with global warming. The combustion of dried sludge is another alternative to improve the sludge management. Despite the reduction of sludge volume to ash, there are environmental impacts inherent to ozone formation and terrestrial acidification.


2017 ◽  
Author(s):  
Xili Duan ◽  
Isa R. Haque ◽  
Aloysius Ducey

This paper presents feasibility study and concept design of a thermal energy recovery system with an adsorption heat pump integrated with a small sewage treatment plant in northern Newfoundland communities. Treated fluids from the sewage treatment systems are quite warm even in winter. For example measured fluids temperature is averaged at 17 °C when air temperature is at −10 °C in the town of Whitbourne. This provides an attractive heat source particularly for winter seasons. Four heat pump concepts, i.e., vapour compression, absorption, adsorption and chemical heat pumps, were reviewed and compared. The results show that the adsorption system best fits the sewage treatment plants with minimum power requirements. Thermal fluidic parameters of the key components were designed with fluid flow and heat transfer analysis. A brief economic and environmental analysis showed that the integrated energy recovery unit would lead to a net reduction of CO2 emission and feasible payback time.


2019 ◽  
Vol 80 (3) ◽  
pp. 418-425 ◽  
Author(s):  
T. Bressani-Ribeiro ◽  
L. A. Chamhum-Silva ◽  
C. A. L. Chernicharo

Abstract There are hundreds of full-scale upflow anaerobic sludge blanket (UASB) reactors in operation in various parts of the tropical world, notably in India and Latin America, Brazil being the holder of the largest park of anaerobic reactors for sewage treatment in the world. Despite the recognized advantages of UASB reactors, there are problems that have prevented their maximum operational performance. Neglecting the existence and delaying the solution of these challenges can jeopardize the important advances made to date, impacting the future of anaerobic technology in Brazil and in other countries. This work aims to evaluate the operational performance of five full-scale UASB reactors in Brazil, taking into account a monitoring period ranging between two and six years. The main observed design, construction, and operational constraints are discussed. Some outlooks for important upcoming developments are also provided, considering that most of the observed drawbacks can be tackled without significant increases on reactor costs.


2021 ◽  
Vol 7 (1) ◽  
pp. 156-171
Author(s):  
Evangelos Petropoulos ◽  
Burhan Shamurad ◽  
Shamas Tabraiz ◽  
Yongjie Yu ◽  
Russell Davenport ◽  
...  

In this study, we investigated the feasibility of anaerobic sewage treatment at extremely low temperatures (4 °C) using two reactor setups: Upflow anaerobic sludge blanket reactors (UASB) without and with (AnMBRUASB(UF)) a membrane.


2014 ◽  
Vol 71 (3) ◽  
pp. 329-337 ◽  
Author(s):  
M. von Sperling

This paper presents a comparison between three simple sewage treatment lines involving natural processes: (a) upflow anaerobic sludge blanket (UASB) reactor–three maturation ponds in series–coarse rock filter; (b) UASB reactor–horizontal subsurface-flow constructed wetland; and (c) vertical-flow constructed wetlands treating raw sewage (first stage of the French system). The evaluation was based on several years of practical experience with three small full-scale plants receiving the same influent wastewater (population equivalents of 220, 60 and 100 inhabitants) in the city of Belo Horizonte, Brazil. The comparison included interpretation of concentrations and removal efficiencies based on monitoring data (organic matter, solids, nitrogen, phosphorus, coliforms and helminth eggs), together with an evaluation of practical aspects, such as land and volume requirements, sludge production and handling, plant management, clogging and others. Based on an integrated evaluation of all aspects involved, it is worth emphasizing that each system has its own specificities, and no generalization can be made on the best option. The overall conclusion is that the three lines are suitable for sewage treatment in small communities in warm-climate regions.


2011 ◽  
Vol 63 (4) ◽  
pp. 680-688 ◽  
Author(s):  
R. Walia ◽  
P. Kumar ◽  
I. Mehrotra

In India, recently, upflow anaerobic sludge blanket (UASB) based sewage treatment plants (STPs) have come up in a big way. Sequence adopted: screens- grit chambers- UASB reactors followed by one-day detention ponds (DP). Performance of DPs located at five STPs (27–70 ML/d) was evaluated over a period of one year from July 2004 to July 2005. The installation of these non-algal ponds reduced land requirement, but from treatment point of view it at best offered only removal of solids washed out of the UASB reactor. Total coliform count in the effluent from ponds ranging from 106 to 109 MPN/100 mL is more than the maximum permissible limit of 10,000 MPN/100 mL. A need has, therefore, been felt to evaluate the possibility of aerating the effluent from UASBR. During aeration, ORP and DO increase, whereas COD and BOD decrease. In a continuous aeration ~50% reduction in COD and nearly 50% increase in DO saturation (DO/DOs) can be achieved by increasing ORP from −100 to 122 mV. Regression equation established between ORP and COD/CODi & DO/DOs may find wide application.


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