The UASB reactor as an alternative for the septic tank for on-site sewage treatment

2004 ◽  
Vol 48 (11-12) ◽  
pp. 221-226 ◽  
Author(s):  
A.L.S.S. Coelho ◽  
M.B.H. do Nascimento ◽  
P.F.F. Cavalcanti ◽  
A.C. van Haandel
Keyword(s):  
Suspended Solids ◽  
Sewage Treatment ◽  
Uasb Reactor ◽  
Septic Tank ◽  
Operational Cost ◽  
Large Area ◽  
Construction Costs ◽  
Effluent Quality ◽  
In Series ◽  
Proper Performance

Although septic tanks are amply used for on site sewage treatment, these units have serious drawbacks: the removal efficiency of organic material and suspended solids is low, the units are costly and occupy a large area and operational cost is high due to the need for periodic desludging. In this paper an innovative variant of the UASB reactor is proposed as an alternative for the septic tank. This alternative has several important advantages in comparison with the conventional septic tank: (1) Although the volume of the UASB reactor was about 4 times smaller than the septic tank, its effluent quality was superior, even though small sludge particles were present, (2) desludging of the UASB reactor is unnecessary and even counterproductive, as the sludge mass guarantees proper performance, (3) the UASB reactor is easily transportable (compact and light) and therefore can be produced in series, strongly reducing construction costs and (4) since the concentration of colloids in the UASB effluent is much smaller than in the ST effluent, it is expected that the infiltration of the effluent will be much less problematic.

Operational performance of an RBC unit in conjunction with a septic tank

1981 ◽  
Vol 8 (4) ◽  
pp. 477-483 ◽  
Author(s):  
J. W. Atwater ◽  
G. Bradshaw
Keyword(s):  
Suspended Solids ◽  
Monitoring Program ◽  
Primary Treatment ◽  
Operational Performance ◽  
Septic Tank ◽  
Rotating Biological Contactor ◽  
Effluent Quality ◽  
In Series ◽  
Solids Removal ◽  
Federal Guidelines

A rotating biological contactor (RBC) unit in series with a septic tank for primary solids removal and sludge storage was monitored for 21 months. The results of that monitoring are summarized in this paper. The treatment configuration produced an effluent that met federal guidelines of 20 mg/L for BOD5, and 25 mg/L for suspended solids. When solids were allowed to accumulate in the septic tank beyond 12 months, there was a marked increase in loading of the RBC with a resultant decrease in effluent quality. A linear relationship could be shown between clarified effluent BOD5 and applied BOD5. The data from this monitoring program suggest that surface area requirements of RBC units utilizing septic tanks for primary solids removal are three times those utilizing conventional primary treatment. When high levels of nitrate were in the unit, feed denitrification occurred concurrently with carbonaceous oxidation.

Alternative Approaches for Upgrading Effluent Quality for Lagoon Based Systems

1993 ◽  
Vol 28 (10) ◽  
pp. 201-205
Author(s):  
Brian Evans ◽  
Stephen Nutt ◽  
Tony Ho ◽  
Henryk Melcer
Keyword(s):  
Suspended Solids ◽  
Total Population ◽  
Sewage Treatment ◽  
Effluent Quality ◽  
Waste Sludge ◽  
Clean Environment ◽  
Alternative Approaches ◽  
The Cost ◽  
Phosphorus Levels ◽  
Lagoon Systems

The province of Ontario is Canada's most populous province with over 8 million residents out of a total population of 27 million. The province has 512 sewage treatment plants of which 137 or 27% are lagoons. Improved environmental effluent quality standards since the introduction of the lagoons has resulted in many of these being unable to achieve proper effluent quality. Typical effluent quality requirements across the province require a minimum of secondary treatment, that is 15 mg/l of BOD and suspended solids and 1 mg/l of total phosphorus. The movement towards a clean environment has resulted in phosphorus levels as low as 0.3 mg/l TP and in an increasing number of cases, full nitrification year round. Because many of these lagoons serve small populations in the 100 - 3 000 population equivalents category, the cost of upgrading such lagoons to tertiary quality effluent is significant. Two approaches for upgrading conventional lagoon systems were evaluated. They are called the Sutton and New Hamburg processes after the towns in Ontario where they were first installed. The Sutton process consists of extended aeration plant, followed by polishing lagoons with waste sludge sent directly to the lagoons, while the New Hamburg process consists of conventional lagoons followed by intermittent sand filtration.

A Decade of Change at West-Southwest Sewage Treatment Works, Chicago, Illinois, U.S.A.

1984 ◽  
Vol 16 (12) ◽  
pp. 555-571
Author(s):  
Nicholas J Melas ◽  
Raymond R Rimkus
Keyword(s):  
Suspended Solids ◽  
Sewage Treatment ◽  
Oxygen Demand ◽  
Ammonia Nitrogen ◽  
The West ◽  
West Side ◽  
Effluent Quality ◽  
Effluent Standards ◽  
Solids Processing

The Metropolitan Sanitary District of Greater Chicago's West-Southwest Sewage Treatment Works consists of the West Side Treatment Works, an Imhoff facility placed in operation in 1930, and the Southwest Sewage Treatment Works, an activated sludge plant placed in operation in 1939. This paper focuses on the decade of “1970's” and examines changes in plant operating procedures along with plant additions and improvements that were implemented in order to meet stringent water quality and effluent standards. The effect of the energy crisis and the measures taken at the West-Southwest Sewage Treatment Works to lessen its impact are reported. Over the study period, very costly and energy intensive solids processing operations were either curtailed or eliminated. New and innovative processes of sludge handling were developed and implemented. The net effect of these changes in solids processing coupled with modifications in the secondary wastewater treatment operations have resulted in a significant improvement in the effluent quality of the plant. In the early seventies, the effluent concentration for suspended solids, biochemical oxygen demand, and ammonia-nitrogen were 30, 23, and 12 mg/l, respectively; the corresponding values for these parameters in 1981 averaged 6, 6, and 1.4 mg/l.

Combination of up-flow anaerobic sludge blanket reactor and a novel cascade sponge reactor for sewage treatment

2011 ◽  
Vol 63 (6) ◽  
pp. 1255-1264 ◽  
Author(s):  
K. Patel ◽  
A. K. Mungray
Keyword(s):  
Fecal Coliform ◽  
Sewage Treatment ◽  
Total Coliform ◽  
Uasb Reactor ◽  
Anaerobic Sludge ◽  
Combined Process ◽  
Effluent Quality ◽  
Anaerobic Sludge Blanket ◽  
The Cost

Performance of the combined process of up-flow anaerobic sludge blanket (UASB) reactor and cascade sponge reactor (CSR) for sewage treatment was studied. UASB-CSR system was operated at HRTs of 24 h, 16 h, and 8 h at an average wastewater temperature of 29°C. It comprises of the most efficient combined process not only for CODT (98.9%), BODT (98.5%), TSS (99.3%), total nitrogen (89.1%), total phosphorus (99.0%), total coliform (99.9%) and fecal coliform (99.9%) removal but also for reducing excess sludge production. Fecal coliform counts were found 23 MPN/100 ml only in final effluents. The effluent quality of the system sufficiently meets the discharged standards which regulate wastewater discharge into drains. The parameters of CSR are closely related to those of the potable water after certain advanced treatment which can be reused in many ways. Moreover, it does not require any external aeration and thus the cost associated with energy and devices required for aeration are cut to zero.

Evaluation of sludge properties in a pilot-scale UASB reactor for sewage treatment in a temperate region

2011 ◽  
Vol 64 (10) ◽  
pp. 1959-1966 ◽  
Author(s):  
K. Syutsubo ◽  
W. Yoochatchaval ◽  
I. Tsushima ◽  
N. Araki ◽  
K. Kubota ◽  
...  
Keyword(s):  
Suspended Solids ◽  
Sewage Treatment ◽  
Oxygen Demand ◽  
Pilot Scale ◽  
Upflow Anaerobic Sludge Blanket ◽  
Uasb Reactor ◽  
Anaerobic Sludge ◽  
Methanogenic Activity ◽  
Working Volume ◽  
Anaerobic Sludge Blanket

In this study, continuous operation of a pilot-scale upflow anaerobic sludge blanket (UASB) reactor for sewage treatment was conducted for 630 days to investigate the physical and microbial characteristics of the retained sludge. The UASB reactor with a working volume of 20.2 m3 was operated at ambient temperature (16–29 °C) and seeded with digested sludge. After 180 days of operation, when the sewage temperature had dropped to 20 °C or lower, the removal efficiency of both total suspended solids (TSS) and total biochemical oxygen demand (BOD) deteriorated due to washout of retained sludge. At low temperature, the cellulose concentration of the UASB sludge increased owing to the rate limitation of the hydrolytic reaction of suspended solids in the sewage. However, after an improvement in sludge retention (settleability and concentration) in the UASB reactor, the process performance stabilized and gave sufficient results (68% of TSS removal, 75% of total BOD removal) at an hydraulic retention time (HRT) of 9.7 h. The methanogenic activity of the retained sludge significantly increased after day 246 due to the accumulation of Methanosaeta and Methanobacterium following the improvement in sludge retention in the UASB reactor. Acid-forming bacteria from phylum Bacteroidetes were detected at high frequency; thus, these bacteria may have an important role in suspended solids degradation.

scholarly journals Influence of Pre-Hydrolysis on Sewage Treatment in an Up-Flow Anaerobic Sludge BLANKET (UASB) Reactor: A Review

Water ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 372 ◽  
Author(s):  
Rajinikanth Rajagopal ◽  
Mahbuboor Choudhury ◽  
Nawrin Anwar ◽  
Bernard Goyette ◽  
Md. Rahaman
Keyword(s):  
Suspended Solids ◽  
Biogas Production ◽  
Sewage Treatment ◽  
Oxygen Demand ◽  
High Rate ◽  
Uasb Reactor ◽  
Organic Loading Rate ◽  
Anaerobic Sludge ◽  
Two Phase ◽  
Anaerobic Sludge Blanket

The up-flow anaerobic sludge blanket (UASB) process has emerged as a promising high-rate anaerobic digestion technology for the treatment of low- to high-strength soluble and complex wastewaters. Sewage, a complex wastewater, contains 30–70% particulate chemical oxygen demand (CODP). These particulate organics degrade at a slower rate than the soluble organics found in sewage. Accumulation of non-degraded suspended solids can lead to a reduction of active biomass in the reactor and hence a deterioration in its performance in terms of acid accumulation and poor biogas production. Hydrolysis of the CODP in sewage prior to UASB reactor will ensure an increased organic loading rate and better UASB performance. While single-stage UASB reactors have been studied extensively, the two-phase full-scale treatment approach (i.e., a hydrolysis unit followed by an UASB reactor) has still not yet been commercialized worldwide. The concept of treating sewage containing particulate organics via a two-phase approach involves first hydrolyzing and acidifying the volatile suspended solids without losing carbon (as methane) in the first reactor and then treating the soluble sewage in the UASB reactor. This work reviews the available literature to outline critical findings related to the treatment of sewage with and without hydrolysis before the UASB reactor.

Reduced Hydraulic Detention Time for Complete Nutrient Removal with Innovative Biological Reactors

1991 ◽  
Vol 24 (10) ◽  
pp. 217-229 ◽  
Author(s):  
F. Rogalla ◽  
M. Payraudeau ◽  
P. Sauvegrain ◽  
J. Sibony
Keyword(s):  
Nutrient Removal ◽  
Western Europe ◽  
Suspended Solids ◽  
Wastewater Treatment Plants ◽  
Sewage Treatment ◽  
Nitrogen And Phosphorus ◽  
Solids Retention ◽  
In Series ◽  
Reduced Space ◽  
Limiting Parameters

To limit pollution discharges through wastewater into surface waters, increasingly stringent effluent standards particularly for nutrient removal require extensive upgrading of conventional wastewater treatment plants. Large sewage treatment plants in Western Europe are often located in densely urbanised areas where land is unavailable. To avoid additional unit processes for nitrogen and phosphorus removal, innovative solutions are demonstrated. A compact reactor is presented that achieves low pollutant residuals (carbonaceous matter, suspended solids, nitrogen and phosphorus) in reduced space and a few examples of full scale applications are given. Through extensive pilots tests, the limiting parameters for nutrient removal are established on sewage after pretreatment and lamella settling. The biological treatment by two granular filters in series combines biodegradation and suspended solids retention without further particle separation. The anoxic reactor removal rates varied between 0.3 and 1.5 kg N-NO3/m3 d, depending on temperature and available carbon. Nitrification on the aerobic filter increases from 0.3 kg to 1 kg N-NH4/m3 d with temperature in a range between 5 to 20 °C. Total nitrogen residuals below 10 mg/l and effluent phosphorus below 1 mg/l can be achieved with hydraulic retention times of around 3 hours.

Low Cost Packaged Sewage Treatment Plant for Production of High Quality Effluent at Small Works

1993 ◽  
Vol 27 (5-6) ◽  
pp. 405-412 ◽  
Author(s):  
B. Chambers ◽  
J. Whitaker ◽  
A. F. Elvidge
Keyword(s):  
Suspended Solids ◽  
Low Cost ◽  
Sewage Treatment ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Ammonia Nitrogen ◽  
Aeration Tank ◽  
Effluent Quality ◽  
Demonstration Plant ◽  
The Uk

In the UK there are over 7000 small works which treat the sewage from populations of less than 10,000. Many of these works are at risk of non-compliance with effluent quality consents and options for improving the standard of treatment are being pursued by many utilities. WRc and Anglian Water Services have developed designs for packaged sewage treatment plants to serve populations in the range of 1000-10,000. A demonstration plant has been constructed at the Waterbeach STW of Anglian Water to serve a population of about 6,500. Target effluent quality is 15:20:5mg/l of BOD, SS and ammonia nitrogen respectively on a 95 percentile basis. Following plant commissioning a process performance evaluation programme was commenced in February 1991. Nitrification was established after about 6 weeks of operation but suspended solids values have been affected by the presence of a stable foam on the surface of the aeration tank. Process modifications have reduced the effect of this phenomenon substantially and effluent quality has improved.

Effluent quality from 200 on-site sewage systems: design values for guidelines

2005 ◽  
Vol 51 (10) ◽  
pp. 163-169 ◽  
Author(s):  
K.J. Charles ◽  
N.J. Ashbolt ◽  
D.J. Roser ◽  
R. McGuinness ◽  
D.A. Deere
Keyword(s):  
Sewage Treatment ◽  
Systems Design ◽  
Critical Factor ◽  
Poor Performance ◽  
Septic Tank ◽  
Nutrient Loads ◽  
Effluent Quality ◽  
Septic Tanks ◽  
Guideline Values ◽  
Design Values

The quality of effluent from an on-site sewage treatment system is a critical factor in designing the disposal area and, hence, ensuring the sustained performance of the system. Contaminant concentrations in effluent are typically specified in regulatory guidelines or standards; however, the accuracy of these guideline values are brought into question due to the poor performance of septic tanks and the high failure rates of disposal systems reported here and elsewhere. Results from studies of septic tank effluent quality indicated that the effluent is of poorer quality than currently suggested by guidelines. Aerated wastewater treatment systems were found to perform to accreditation guidelines; however, insufficient nutrient data is presently available to assess nutrient loads. It is proposed that the 80th percentile of system performance be adopted as the design value for sizing effluent disposal areas to minimise failure associated with overloading. For septic tanks this equates to 660 mg L−1 SS, 330 mg L−1 BOD, 250 mg L−1 TN and 36 mg L−1 TP.

Mineralisation and pathogen removal in gravel bed hydroponic constructed wetlands for wastewater treatment

1995 ◽  
Vol 32 (3) ◽  
pp. 49-58 ◽  
Author(s):  
J. Williams ◽  
M. Bahgat ◽  
E. May ◽  
M. Ford ◽  
J. Butler
Keyword(s):  
Constructed Wetlands ◽  
Suspended Solids ◽  
Significant Contribution ◽  
Sewage Treatment ◽  
Secondary Treatment ◽  
Strongly Correlated ◽  
Pathogen Removal ◽  
Effluent Quality ◽  
Gravel Bed ◽  
The Uk

Gravel Bed Hydroponics (GBH) is a constructed wetland system for sewage treatment which has proved effective for tertiary treatment in the UK and secondary treatment in Egypt. Significant improvements in effluent quality have been observed in 100 m long field scale beds planted with Phragmites australis, resulting in large reductions in BOD, suspended solids and ammoniacal N. For such GBH beds, operating optimally with a residence time of about 6 hours, 2 to 3 log cycle reductions in the counts of indicator bacteria, certain bacterial pathogens and viruses are typically obtained. However, the efficiency of mineralisation was strongly influenced by flow-rate and the prevailing temperature. In addition, in the UK, overloading of the treatment system reduced the efficiency of removal of faecal coliforms, probably due to decreased adsorption to biofilms. Faecal coliform counts were also more strongly correlated to BOD than suspended solids. As a secondary treatment process, pathogen removal was consistently better in Egypt than the UK. Although GBH constructed wetlands do not fully satisfy the WHO guidelines for unrestricted irrigation, they can make a significant contribution to the control of pathogens in developing countries.

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