Removal of indigenous coliphages and fecal coliforms by a novel sewage treatment system consisting of UASB and DHS units

2002 ◽  
Vol 46 (11-12) ◽  
pp. 303-309 ◽  
Author(s):  
S. Uemura ◽  
K. Takahashi ◽  
A. Takaishi ◽  
I. Machdar ◽  
A. Ohashi ◽  
...  
Keyword(s):  
Removal Efficiency ◽  
Sewage Treatment ◽  
Treatment System ◽  
Fecal Coliforms ◽  
Upflow Anaerobic Sludge Blanket ◽  
Anaerobic Sludge ◽  
Combined System ◽  
Treatment Unit ◽  
Indicator Microorganisms ◽  
Sewage Treatment System

A novel sewage treatment system, which consists of an upflow anaerobic sludge blanket (UASB) pre-treatment unit and the following downflow hanging sponge (DHS) unit for polishing up the UASB effluent, was developed as a cost-effective and easy-maintenance sewage treatment system for developing countries. A long-term experiment with actual sewage was conducted in order to evaluate its treatment efficiency of organic substances, nutrients, and pathogen indicator microorganisms such as total coliphages, F+-specific RNA coliphages (RNA coliphages), and fecal coliforms. The main objective of this paper is to investigate the removal efficiency of those indicator microorganisms by the UASB-DHS combined system. The results obtained from the continuous flow experiment indicated a fairly promising removal of the indicator microorganisms, i.e., the log10 reductions of total coliphages, RNA coliphages, and fecal coliforms (based on sewage and DHS effluent) achieved were 2.01 log, 2.02 log, and 2.57 log, respectively. The UASB-DHS combined system was superior to the conventional activated sludge process in the reduction of fecal coliforms, but in the reductions of total and RNA coliphages, the system showed somewhat less removal efficiency. The vertical reducing patterns of the indicator microorganisms along the DHS reactor were also discussed.

Combination of a UASB reactor and a curtain type DHS (downflow hanging sponge) reactor as a cost-effective sewage treatment system for developing countries

2000 ◽  
Vol 42 (3-4) ◽  
pp. 83-88 ◽  
Author(s):  
I. Machdar ◽  
Y. Sekiguchi ◽  
H. Sumino ◽  
A. Ohashi ◽  
H. Harada
Keyword(s):  
Sewage Treatment ◽  
Cost Effective ◽  
Ammonia Nitrogen ◽  
Treatment System ◽  
Uasb Reactor ◽  
Municipal Sewage ◽  
Combined System ◽  
Treatment Unit ◽  
Pre Treatment ◽  
Sewage Treatment System

The second generation of our originally proposed sewage treatment system, which consists of a UASB reactor as an anaerobic pre-treatment unit and curtain-type DHS (downflow hanging sponge) reactor as an aerobic post-treatment unit, was installed at a municipal sewage treatment site. A 550-day continuous experiment demonstrated that the whole combined system successfully achieved 94–97% of unfiltered-BOD removal, 81–84% of unfiltered-COD removal, and 63–79% of SS removal, at an overall HRT of 8 h (6 h for UASB and 2 h for DHS units). The combined system performed an excellent organic removal as well as a fairly efficient nitrification, i.e. 52–61% of ammonia-nitrogen removal. Our proposed combined system possesses prominent advantages: requiring neither external aeration input nor excess sludge withdrawal.

scholarly journals Removal and Survival of Fecal Indicators in a Constructed Wetland after UASB Pre-Treatment

2021 ◽  
Vol 13 (16) ◽  
pp. 9302
Author(s):  
Fabio Conti ◽  
Elena Cristina Rada ◽  
Paolo Viotti ◽  
Massimo Raboni
Keyword(s):  
Removal Efficiency ◽  
Fecal Coliforms ◽  
Upflow Anaerobic Sludge Blanket ◽  
Uasb Reactor ◽  
Anaerobic Sludge ◽  
Experimental Plant ◽  
Fecal Indicators ◽  
Increased Risk ◽  
North Brazil ◽  
Pre Treatment

The experimentation plant, based on a sub-surface horizontal flow phytodepuration (SSHFP) unit with a pre-treatment by an upflow anaerobic sludge blanket (UASB) reactor, proved valuable in treating the sewage of a small rural community located in north Brazil. During a six-month trial, the plant achieved an average removal efficiency of 98.2% (1.74 log removal) for fecal coliforms (FC) and 96.0% (1.40 log removal) for Enterococci (EN), as well as 95.6% for BOD5, 91.0% for COD,00 and 95.4% for suspended solids (SS). The contribution of the UASB reactor to this overall performance was very significant as, alone, it achieved a yield of 62.7% for FC and 60% for EN, in addition to 65.2% for BOD5 and 65.0% for SS. EN was chosen, in addition to FC, because of its higher specificity and strong environmental persistence, leading to an increased risk to human health. In fact, the experimental results confirmed its lower removal efficiency compared to FC. The mechanical and biological mechanisms that led to such a removal efficiency of the two fecal indicators (FIs) are outlined in the article. The same mechanisms led to a good level of equivalence between the removal efficiency of the two FIs with the removal efficiency of SS and BOD5, for both the whole plant and the UASB reactor alone. The research demonstrated the close correlation between the concentrations of EN and FC for the plant effluent. This correlation can be explained by the following mathematical expression of the regression line Log EN = 0.2571 Log FC + 3.5301, with a coefficient of determination R2 = 0.912. This implies that the concentration of the more specific indicator EN could be calculated, with acceptable approximation, from the simple analysis of FC and vice versa. The experimental plant brought important health benefits to the local population. In particular, there were no significant odor emissions; moreover, the risk of fecal pathogenic diseases was drastically reduced; finally, there was no proliferation of insects and other disease vectors, due to the absence of stagnant or semi-stagnant water exposed to the atmosphere.

Buoyant Filter Bio-Reactor (BFBR)–a novel anaerobic wastewater treatment unit

2008 ◽  
Vol 58 (2) ◽  
pp. 373-377
Author(s):  
Soosan J. Panicker ◽  
M. C. Philipose ◽  
Ajit Haridas
Keyword(s):  
Removal Efficiency ◽  
Treatment Plant ◽  
Cod Removal ◽  
Upflow Anaerobic Sludge Blanket ◽  
Organic Loading Rate ◽  
Anaerobic Sludge ◽  
Treatment Unit ◽  
Biogas Yield ◽  
Cod Removal Efficiency ◽  
Anaerobic Sludge Blanket

The Buoyant Filter Bio-Reactor (BFBR) is a novel and very efficient method for the treatment of complex wastewater. Sewage is a complex wastewater containing insoluble COD contributed by fat and proteins. The fat and proteins present in the domestic sewage cause operational problems and underperformance in the Upflow Anaerobic Sludge Blanket Reactor, used now for treating sewage anaerobically. The biogas yield from the BFBR is 0.36 m3/kg COD reduced and the methane content was about 70–80%. Production of methane by anaerobic digestion of organic waste had the benefit of lower energy costs for treatment and is thus environmentally beneficial to the society by providing a clean fuel from renewable feed stocks. The BFBR achieved a COD removal efficiency of 80–90% for an organic loading rate of 4.5 kg/m3/d at a hydraulic retention time of 3.25 hours. The effluent COD was less than 100 mg/l, thus saving on secondary treatment cost. No pretreatment like sedimentation was required for the influent to the BFBR. The BFBR can produce low turbidity effluent as in the activated sludge process (ASP). The land area required for the BFBR treatment plant is less when compared to ASP plant. Hence the problem of scarcity of land for the treatment plant is reduced. The total expenditure for erecting the unit was less than 50% as that of conventional ASP for the same COD removal efficiency including land cost.

A novel and cost-effective sewage treatment system consisting of UASB pre-treatment and aerobic post-treatment units for developing countries

1997 ◽  
Vol 36 (12) ◽  
pp. 189-197 ◽  
Author(s):  
Izarul Machdar ◽  
Hideki Harada ◽  
Akiyoshi Ohashi ◽  
Yuji Sekiguchi ◽  
Hiroyuki Okui ◽  
...  
Keyword(s):  
Developing Countries ◽  
Low Cost ◽  
Sewage Treatment ◽  
Cost Effective ◽  
Post Treatment ◽  
Cod Removal ◽  
Treatment System ◽  
Treatment Unit ◽  
Pre Treatment ◽  
Sewage Treatment System

A novel sewage treatment system was proposed, which consists of a UASB anaerobic pre-treatment unit and the following DHS (downflow hanging sponge-cubes) aerobic post-treatment unit, as a low-cost and easy-maintenance process for developing countries. Over six months experiment by feeding sewage our proposed system achieved 94% of total-COD removal, 81% of soluble-COD removal, and nearly perfect SS removal and total-BOD removal at the overall HRT of 8.3 hr (7 hr in UASB and 1.3 hr in DHS unit). Moreover, the DHS reactor was capable of performing high (73–78%) nitrification. Our whole system requires neither external aeration input nor withdrawal of excess sludge.

The effects of hydraulic and organic shock loads on the robustness of upflow anaerobic sludge blanket reactors treating sewage

2006 ◽  
Vol 54 (2) ◽  
pp. 49-55 ◽  
Author(s):  
R.C. Leitão ◽  
S.T. Santaellla ◽  
A.C. van Haandel ◽  
G. Zeeman ◽  
G. Lettinga
Keyword(s):  
Removal Efficiency ◽  
Cod Removal ◽  
Ph Stability ◽  
Upflow Anaerobic Sludge Blanket ◽  
Anaerobic Sludge ◽  
Hydraulic Shock ◽  
Treatment Unit ◽  
Shock Loads ◽  
Cod Removal Efficiency ◽  
Uasb Reactors

In this investigation, the robustness and stability of UASB reactors was evaluated on the basis of four indicators: (i) COD removal efficiency; (ii) effluent variability; (iii) pH stability; and (iv) recovery time. The experiments were carried out using six pilot-scale UASB reactors fed with domestic sewage and operated under different operational conditions. After establishment of a “steady-state”, organic and hydraulic shock loads (six times the loading rate during six hours) were imposed. The results show that the UASB reactors are robust systems with regards to COD removal efficiency and pH stability when exposed to shock loads. However, this reactor cannot attenuate the imposed fluctuation in the influent COD. A secondary treatment unit is needed to retain the expelled sludge occurring as a result of a hydraulic shock load, or prior to the shock, a sufficient amount of sludge needs to be discharged from the reactor.

Effects of hydraulic shock loads on small on-site sewage treatment unit

1997 ◽  
Vol 35 (8) ◽  
pp. 145-152 ◽  
Author(s):  
T. Panswad ◽  
L. Komolmethee
Keyword(s):  
Removal Efficiency ◽  
Sewage Treatment ◽  
Septic Tank ◽  
Hydraulic Shock ◽  
Treatment Unit ◽  
Shock Loads ◽  
Retention Period ◽  
Intermittent Feeding ◽  
Continuous Feed ◽  
Filter Unit

This research was to determine the effects of hydraulic shock loads by intermittent feeding on the removal efficiency of a small prefabricated real-sized septic tank/anaerobic filter unit. Besides the ‘control’ 24-hour continuous runs the other twice a day feeding periods covered 16, 12 and 8 hours per day, with the tank's retention time varying from 22.5 to 90 hours. It was demonstrated that the variation of the hydraulic feeding patterns ranging from 24-hour continuous feed to 8 h per day intermittent feed did not affect the performance of the system much. The percentage of BOD reduction was decreased from 85 to 82 and 81 percent for the feed times of 24, 16 and 8 hours per day, respectively. The tank capacity played a relatively major role in determining the removal efficiency of the process. The efficiency of BOD and SS reduction dwindled from 82.2 to 68.9 and 56.0% with the corresponding reduction in tank sizes from 90 to 45 and 22.5 hours retention, respectively. In any event, the unit could not satisfactorily remove nutrients. A retention period of not less than 48 hours is recommended if the Thai effluent standards are to be met. Equations for predicting the BOD removal capability were also developed.

A New Sewage Treatment System with Fluidized Pellet Bed Separator

1993 ◽  
Vol 27 (11) ◽  
pp. 185-192 ◽  
Author(s):  
Tatsuhiko Suzuki ◽  
Norihito Tambo ◽  
Genzo Ozawa
Keyword(s):  
Molecular Weight ◽  
Biological Treatment ◽  
Membrane Filter ◽  
Sewage Treatment ◽  
Treatment System ◽  
Organic Substances ◽  
Treatment Rate ◽  
Treated Water ◽  
Biological Filter ◽  
Sewage Treatment System

A new sewage treatment system which is composed of a fluidized pellet bed separator, aerobic biological filter and micro–membrane filter was studied. In the newly proposed system, at the first stage, higher molecular weight organic substances and suspended matter are removed by way of chemical coagulation and flocculation. For the operation, a new fluidized pellet bed separator with high separation rate of 200-300 m/day is introduced to improve the treatment rate. A large percentage of organ ic substances are removed by the new coagulation/flocculation process. Hence, the total BOD load to be applied to the following biological treatment becomes very low. In addition to this, the organic substances in the effluent from the fluidized pellet bed separator are on lylower molecular weight substances which are easily biologically decomposed. Therefore easily decomposing and lower concentration pollutants enable use of a simple biological treatment p rocess such as aerobic biological filter with as short a detention time as 1 hour. Finally, effluent from the biological filter is treated by a micro-membrane filter. By the membrane process, suspended matte rs in the biologically treated water can be removed completely. Phosphate concentration of the treated water is very low, which is caused by aluminum coagulation in the first step and biological intake of the nutrient in the second step followed by complete sol id liquid separation in the third step.

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
Keyword(s):  
Public Health ◽  
Thermal Energy ◽  
Rural Areas ◽  
Sewage Treatment ◽  
Upflow Anaerobic Sludge Blanket ◽  
Small Scale ◽  
Anaerobic Sludge ◽  
Water Heating ◽  
Sewage Treatment Plants ◽  
Majority Population

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.

Impact of microaeration bioreactor on dissolved sulfide and methane removal from real UASB effluent for sewage treatment

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
Keyword(s):  
Sewage Treatment ◽  
Oxygen Demand ◽  
Post Treatment ◽  
Upflow Anaerobic Sludge Blanket ◽  
Uasb Reactor ◽  
Anaerobic Sludge ◽  
Sulfide Removal ◽  
Dissolved Sulfide ◽  
Removal Efficiencies ◽  
Anaerobic Sludge Blanket

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.

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