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.

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.

A low-cost municipal sewage treatment system witha combination of UASB and the “fourth-generation”downflow hanging sponge reactors

2005 ◽  
Vol 52 (1-2) ◽  
pp. 323-329 ◽  
Author(s):  
M. Tandukar ◽  
S. Uemura ◽  
I. Machdar ◽  
A. Ohashi ◽  
H. Harada
Keyword(s):  
Municipal Wastewater ◽  
Low Cost ◽  
Sewage Treatment ◽  
Pilot Scale ◽  
Treatment System ◽  
Uasb Reactor ◽  
Fourth Generation ◽  
Municipal Sewage ◽  
Combined System ◽  
Successful Operation

This paper presents an evaluation of the process performance of a pilot-scale “fourth generation” downflow hanging sponge (DHS) post-treatment system combined with a UASB pretreatment unit treating municipal wastewater. After the successful operation of the second- and third-generation DHS reactors, the fourth-generation DHS reactor was developed to overcome a few shortcomings of its predecessors. This reactor was designed to further enhance the treatment efficiency and simplify the construction process in real scale, especially for the application in developing countries. Configuration of the reactor was modified to enhance the dissolution of air into the wastewater and to avert the possible clogging of the reactor especially during sudden washout from the UASB reactor. The whole system was operated at a total hydraulic retention time (HRT) of 8 h (UASB: 6 h and DHS: 2 h) for a period of over 600 days.The combined system was able to remove 96% of unfiltered BOD with only 9 mg/L remaining in the final effluent. Likewise, F. coli were removed by 3.45 log with the final count of 103 to 104 MPN/100 ml. Nutrient removal by the system was also satisfactory.

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.

scholarly journals Behavior of the Medically Used Radionuclides in a Municipal Sewage Treatment System.

RADIOISOTOPES ◽  
2001 ◽  
Vol 50 (8) ◽  
pp. 343-352 ◽  
Author(s):  
Ayako NAKAMURA ◽  
Susumu OSAKI ◽  
Naofumi HAYABUCHI
Keyword(s):  
Sewage Treatment ◽  
Treatment System ◽  
Municipal Sewage ◽  
Sewage Treatment System

Post-treatment of anaerobic effluents in constructed wetland systems

2001 ◽  
Vol 44 (4) ◽  
pp. 213-219 ◽  
Author(s):  
J. T. de Sousa ◽  
A. C. van Haandel ◽  
A. A.V. Guimarães
Keyword(s):  
Suspended Solids ◽  
Control Unit ◽  
Coarse Sand ◽  
Post Treatment ◽  
Uasb Reactor ◽  
Municipal Sewage ◽  
Nitrogen And Phosphorus ◽  
Treatment Unit ◽  
Hydraulic Load ◽  
Pre Treatment

This papers describes the behaviour of wetlands as a post-treatment unit for anaerobically treated sewage for the removal of organic matter, suspended solids, nutrients (nitrogen and phosphorus) and faecal coliforms. Raw sewage was treated in a UASB reactor with a retention time of 5 h and the effluent was used in four units of wetlands with coarse sand as the medium and operated with different hydraulic loads. Three of the units had emerging macrophytes (Juncus sp), whereas the fourth one was operated as a control unit without plants. During the 12 months of operation, the organic material removal efficiency (measured as COD) was in the range of 79 to 85%, whereas suspended solids removal varied from 48 to 71%. Faecal coliform removal was very high (99,99%); phosphorus was also efficiently removed (average efficiency of 90% for the lowest hydraulic load), but nitrogen removal was only partial (45 to 70% for ammonia and 47 to 70% for TKN). The experimental results clearly show the technical feasibility of using wetlands for treatment of municipal sewage after a pre-treatment in the UASB reactor.

OUTPUT OF RADIOPHARMACEUTICAL NUCLIDES OF KNOWN INJECTED DOSES FROM A MUNICIPAL SEWAGE TREATMENT SYSTEM

2005 ◽  
Vol 88 (2) ◽  
pp. 163-168 ◽  
Author(s):  
Ayako Nakamura ◽  
Naofumi Hayabuchi ◽  
Tomoe Osaki ◽  
Susumu Osaki
Keyword(s):  
Sewage Treatment ◽  
Treatment System ◽  
Municipal Sewage ◽  
Sewage Treatment System

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.

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