Role of saturated and unsaturated zone in soil disposal of septic tank effluent

1988 ◽  
Vol 15 (4) ◽  
pp. 709-716 ◽  
Author(s):  
K. R. Johnson ◽  
J. W. Atwater
Keyword(s):  
Oxygen Demand ◽  
Ground Surface ◽  
Pilot Scale ◽  
Scientific Basis ◽  
Separation Distance ◽  
Saturated Soil ◽  
Fecal Coliforms ◽  
Septic Tank ◽  
Absorption System ◽  
Septic Tank Effluent

The guidelines for the use of the septic tank – soil absorption system (ST–SAS) in the Province of British Columbia are very specific in regard to the separation distance between the ground surface and the groundwater table (minimum 1.2 m), and between the tile field and perimeter drains or ditches (minimum 3.0 m). A pilot-scale experiment employing waterproof channels filled with a saturated soil was used to evaluate the scientific basis for these guidelines. Septic tank effluent was applied to unsaturated columns and the inlet end of the channels and samples were taken at different points in the channels. Measurements were made of total and fecal coliforms, chemical oxygen demand, ammonia, nitrate, and orthophosphate. Coliform reductions within the channels were at least 30 000-fold with total coliform numbers generally lying below 200 coliforms/100 mL and fecal coliforms generally less than 50 coliforms/100 mL. Varying degrees of nitrification occurred in the unsaturated columns, resulting in relatively high concentrations of nitrate in some of the channel sections (1–7 mg/L in channels filled with sand and 0.1–1.0 mg/L in channels filled with loamy sand). The removal of orthophosphate was greater than 90% in all of the channel sections, independent of the saturated or unsaturated zones. Reductions in measured influent parameters were substantial in all of the channels. This suggests that the guidelines may be conservative with respect to these particular soils. Of concern are the high nitrate values observed in some of the channels, therefore consideration of nitrification potential should be made in conjunction with the potential for reduction of other contaminants. Key words: septic tank, soil absorption system, saturated soil, unsaturated soil, coliforms, nutrients.

scholarly journals Treatment of Septic Tank Effluent by Membrane Bioreactor: A Laboratory–scale Feasibility Study

2017 ◽  
Vol 8 (1) ◽  
Author(s):  
C–Y. Chang ◽  
Roger Ben Aim ◽  
S. Vigneswaran ◽  
J–S. Chang ◽  
S–L. Chen
Keyword(s):  
Membrane Fouling ◽  
Membrane Bioreactor ◽  
Extracellular Polymeric Substances ◽  
Oxygen Demand ◽  
Cod Removal ◽  
Laboratory Scale ◽  
Septic Tank ◽  
Term Operation ◽  
Water Cleaning ◽  
Septic Tank Effluent

A laboratory scale membrane bioreactor (MBR) fed on real septic tank effluent was studied at different levels of alkalinity (0, 250 and 500 mg NaHCO3/L addition) and sludge retention time (SRT, complete sludge retention, 10 and 20 days). A long–term operation of 267 days was divided into 5 stages to examine the SRT and alkalinity influences on parameters related to nitrification, chemical oxygen demand (COD) removal, extracellular polymeric substances (EPS) production and membrane cleaning. The results of the study showed that the removals of TCOD, SCOD and NH4+–N varied between 86–94%, 71–86%, and 70–94%, respectively. Appropriate alkalinity supplement and SRT control can enhance the COD removal and nitrification. Irreversible membrane fouling occurred fast and water cleaning for the improvement of filtration capacity was ineffective. The results also revealed that the rejection of EPS played a major role both in the enhancement of removal efficiency as well as the increase of filtration resistance during the operation.

Pilot study of SBR biological treatment and microfiltration for reclamation and reuse of municipal wastewater

2000 ◽  
Vol 42 (1-2) ◽  
pp. 263-268 ◽  
Author(s):  
R. Messalem ◽  
A. Brenner ◽  
S. Shandalov ◽  
Y. Leroux ◽  
P. Uzlaner ◽  
...  
Keyword(s):  
Water Reuse ◽  
Municipal Wastewater ◽  
Batch Reactor ◽  
Groundwater Resources ◽  
Oxygen Demand ◽  
Pilot Scale ◽  
Fecal Coliforms ◽  
Wastewater Reclamation ◽  
Two Stage ◽  
Stage Scheme

In Israel the shortage of water and concern for the quality of groundwater resources have led to an awareness that a national wastewater reclamation program must be developed. Such a program could cover a major part of the agricultural water demand and could facilitate disposal of effluents without health hazards or environmental problems. A two-stage pilot-scale system comprising secondary sequencing batch reactor (SBR) treatment and tertiary microfiltration was operated for the treatment of Beer-Sheva municipal wastewater. The self-cleaning, continuous microfiltration system comprised a filter module made up of hollow fiber microporous membranes, with a pore size distribution of less than 0.1 μm, encapsulated into a bundle. The unit, which has a nominal filtration area of 4 m2, can treat 4–5 m3 of sewage per day, at a nominal rate of about 500 L/h. SBR treatment of the raw sewage produced an effluent with a biochemical oxygen demand (BOD) of <20 mg/L and total suspended solids (TSS) of <20 mg/L. Further treatment by microfiltration resulted in a BOD <5 mg/L, TSS <1 mg/L and turbidity <0.2 nephelometric turbidity units (NTU). Bacterial counts showed 6-log removal of coliforms and fecal coliforms. These results indicate that the two-stage scheme is capable of producing an effluent that meets or even surpasses the requirements for unrestricted water reuse for agriculture.

Reactor performance and pathogen removal during wastewater treatment by vermifiltration

2016 ◽  
Vol 6 (1) ◽  
pp. 65-73 ◽  
Author(s):  
Sudipti Arora ◽  
A. A. Kazmi
Keyword(s):  
Pathogenic Bacteria ◽  
Oxygen Demand ◽  
Pilot Scale ◽  
Inhibitory Effect ◽  
Fecal Coliforms ◽  
Soluble Form ◽  
Reactor Performance ◽  
Pathogen Removal ◽  
Antimicrobial Substances

The application of vermifiltration could reduce the load of chemical and biological pollutants present in wastewater, reducing the pressure over water requirements and allowing the reclamation of the treated water. In the present study, vermifiltration has shown a great potential for chemical pollutants and pathogen removal in wastewater through the synergistic interactions of earthworms and microorganisms. The results of a pilot-scale study showed a higher percentage removal of biochemical oxygen demand (88%), chemical oxygen demand (78%), total suspended solids (83%) and log removal of fecal coliforms (2.61), fecal streptococci (2.50), Salmonella (2.20) and Escherichia coli (2.48) to the levels considered acceptable for reuse in irrigation purposes. Specifically, earthworms in the vermifilter were able to transform insoluble organic material to soluble form followed by selective digestion of the material to finer size, and further degradation by the microorganisms in the reactor. In vitro antimicrobial assay tests also showed that the present microflora had strong inhibitory efficiency against Staphylococcus aureus, E. coli, Pseudomonas aeruginosa and Klebsiella aerogenes. The observed inhibitory effect was found to be responsible for the phenomenon mentioned above, with release of antimicrobial substances by earthworms and associated microflora that showed antimicrobial potency against pathogenic bacteria. The kinetics evaluation showed the predominance of a first order removal model during vermifiltration.

Effect of soil fortified by polyurethane foam on septic tank effluent treatment

2011 ◽  
Vol 63 (6) ◽  
pp. 1230-1235 ◽  
Author(s):  
J. Y. Nie ◽  
N. W. Zhu ◽  
K. M. Lin ◽  
F. Y. Song
Keyword(s):  
Hydraulic Conductivity ◽  
Sewage Treatment ◽  
Oxygen Demand ◽  
Column Experiment ◽  
Effective Porosity ◽  
Effluent Treatment ◽  
Septic Tank ◽  
Natural Soil ◽  
Nitrogen And Phosphorus ◽  
Septic Tank Effluent

Fortified soil was made up of a mixture at a mass ratio 4/1000–6/1000 of sponge and natural soil according to the results of column experiment. The fortified soil had bigger porosity and higher hydraulic conductivity than the natural soil. The columns packed with 900 mm of the fortified soil endured a flow rate equivalent to 100 L/m2/d of septic tank effluent and the average chemical oxygen demand, nitrogen, and phosphorus removal rates were around 92%, 75% and 96%, respectively. After 100 weeks of operation, the saturated hydraulic conductivity of the fortified soil kept higher than 0.2 m/d. The bigger porosity of sponge improved the effective porosity, and the bigger specific surface area of sponge acted as an ideal support for biomat growth and ensured the sewage treatment performance of the fortified soil. The comparable performance was due to a similar and sufficient degree of soil clogging genesis coupled with bioprocesses that effectively purified the septic tank effluent given the adequate retention times.

scholarly journals Nexus between sanitation and groundwater quality: case study from a hard rock region in India

2019 ◽  
Vol 9 (4) ◽  
pp. 703-713 ◽  
Author(s):  
S. Murty Bhallamudi ◽  
R. Kaviyarasan ◽  
A. Abilarasu ◽  
Ligy Philip
Keyword(s):  
Groundwater Quality ◽  
Hard Rock ◽  
Oxygen Demand ◽  
Shallow Groundwater ◽  
Fecal Coliforms ◽  
Septic Tank ◽  
Effluent Quality ◽  
Deep Aquifers ◽  
Top Soil ◽  
Shallow Groundwater Table

Abstract Groundwater quality in the towns of Namakkal and Erumaipatti in India was studied to understand the nexus between surface sanitation and groundwater quality in hard rock regions. In total, 32 wells, both shallow open and deep bore wells, were monitored over a two-year period. The presence of fecal coliforms (FCs) up to 600 CFU/100 mL in wells as deep as 100 m showed that bacteriological contamination had reached deep aquifers through fractures and fissures. Statistical analyses showed that bore wells located in Namakkal were bacteriologically more contaminated than those in Erumaipatti (p = 0.017 for FC) because of urbanization, the type of top soil and the shallow groundwater table. Wells in densely toileted areas of Namakkal were more contaminated than those located in open defecation areas. After replacing a soak pit with a septic tank, concentrations of FC and chemical oxygen demand (COD) in the leachate at a depth of 2.1 m reduced from 2,500 to 1,000 CFU/100 mL and from 200 to 50 mg/L, respectively, after 150 days of the construction of septic tanks. To improve the hygiene and sanitation, the provision of toilets along with on-site waste management systems, capable of achieving required effluent quality, are essential.

scholarly journals Organic Matter, Solid and Pathogen Removals from Black Water in A Pilot-Scale Solar Septic Tank

2020 ◽  
pp. 74-83
Author(s):  
Tatchai Pussayanavina ◽  
Thammarat Koottatep ◽  
Le My Dinh ◽  
Sopida Khamyai ◽  
Wattanapong Sangchun ◽  
...  
Keyword(s):  
Nutrient Loading ◽  
Oxygen Demand ◽  
Total Solid ◽  
Pilot Scale ◽  
Septic Tank ◽  
Operational Conditions ◽  
E Coli ◽  
Log Reduction ◽  
Black Water ◽  
Solar Powered

Demonstrating the operational feasibility of a solar-powered septic tank as an alternative and sustainable sanitation option for communities was presented in this study. The efficiency and technical feasibility of a solar septic tank (SST) were tested and evaluated in pilot scale for treatment of black water from communal toilets. The system consisted of a modified septic tank equipped with a disinfection chamber inside the tank. Solar radiation was collected as a heat source for heating and disinfection. The system could achieve high removal efficiencies of total chemical oxygen demand (TCOD), 5-day biological oxygen demand (BOD5), total solid (TS), and total volatile solid (TVS) of 97%, 94%, 91% and 96%, respectively. The inactivation efficiencies of E. coli and total coliforms in the SST were about 2.2 log reduction. The increased temperature inside the septic tank could help to inactivate pathogens and reduce the environmental issues related to conventional fecal sludge management. In turn, this improved the water quality of groundwater and surface water and minimize health risks. Influence of operational conditions including organic/nutrient loading rate and ratio between TCOD and TKN in the black water on the performance of the SST were discussed.

The movement of septic tank effluent through sandy soils near Perth. I. Movement of nitrogen

Soil Research ◽  
1984 ◽  
Vol 22 (3) ◽  
pp. 283 ◽  
Author(s):  
BR Whelan ◽  
NJ Barrow
Keyword(s):  
Organic Nitrogen ◽  
Exchange Capacity ◽  
High Rate ◽  
Septic Tank ◽  
Saturated Zone ◽  
Absorption System ◽  
Slime Layer ◽  
Septic Tank Effluent ◽  
Almost All ◽  
Aerobic Soil

The mocement and transformation of nitrogen under seven septic tank installations was studied. Samples of the effluent and of the soil solution beneath the discharge systems were taken and analysed for ammonium, nitrate and pH. Most of the nitrogen came from household toilets, and after passage through a septic tank, the nitrogen was mostly in the ammonium form. It remained in this form while it was in the ponded effluent above the slime layer in the absorption systems. Once it had passed through the slime layer into the unsaturated, aerobic soil below, it was usually oxidised to nitrate within 0.5 m. This was accompanied by a drop in pH of about two units. However, in one case in which the distance between the top of the slime layer and the water table was less than 0.8 m, ammonium was not oxidized to nitrate. This was taken to indicate that the saturated zone extending below the absorption system overlapped the capillary fringe and consequently the soil was anaerobic. Accumulation of organic nitrogen was restricted to the 0.5 m slime layer which accumulated on the sandy base of the soak wells and leach drains. The low cation exchange capacity of the soil and the high rate of conversion of ammonium in the effluent to nitrate in the unsaturated soil resulted in almost all of the nitrogen from the septic tanks entering the groundwater except that lost to plant uptake.

scholarly journals Performance evaluation of anoxic–oxic–anoxic processes in illuminated biofilm reactor (AOA-IBR) treating septic tank effluent

2020 ◽  
Vol 10 (4) ◽  
pp. 874-884
Author(s):  
Sittikorn Kamngam ◽  
Thammarat Koottatep ◽  
Nawatch Surinkul ◽  
Chawalit Chaiwong ◽  
Chongrak Polprasert
Keyword(s):  
Light Emitting Diode ◽  
Red Light ◽  
Oxygen Demand ◽  
Ammonia Nitrogen ◽  
Biofilm Reactor ◽  
Bacterial Biofilm ◽  
Septic Tank ◽  
Treatment Performance ◽  
N Removal ◽  
Septic Tank Effluent

Abstract This study was conducted to evaluate the treatment performance of the anoxic–oxic–anoxic processes in illuminated biofilm reactor (AOA-IBR) in removing organics and nitrogen contained in septic tank effluent. The 27 L of the AOA-IBR was illuminated with red light-emitting diode (LED) lamps (peak wavelength of 635 nm, intensity of 100 μmol/(m2s)). Three types of biofilm media, namely ball ring®, plastic sheets and zeolite beads, were placed in the anoxic, oxic and anoxic zones, respectively, of the reactor to support the growth of microalgal–bacterial biofilm. The AOA-IBR was continuously fed with septic tank effluent and operated at hydraulic retention times (HRTs) of 24, 48 and 72 h. The experimental results found the increases in chemical oxygen demand (COD), total nitrogen (TN) and ammonia nitrogen (NH4-N) removal efficiencies with increasing HRTs in which the HRT of 72 h resulted in 78.6, 72.8 and 90.6% removals of COD, TN and NH4-N, respectively. The effluent quality of the AOA-IBR could meet the ISO 30500 effluent standards for Non-Sewered Sanitation Systems. The predominant microalgal biofilm species was observed to be Oscillatoria sp., while Proteobacteria was the predominant bacterial phylum found in the biofilm growing in the reactor. The above results suggested the applicability of the AOA-IBR in improving septic tank treatment performance which should result in better water pollution control.

scholarly journals Preliminary Study on Greywater Treatment Using Nonwoven Textile Filters

2019 ◽  
Vol 9 (15) ◽  
pp. 3205
Author(s):  
Marcin Spychała ◽  
Thanh Hung Nguyen
Keyword(s):  
Suspended Solids ◽  
High Efficiency ◽  
Effective Diffusion ◽  
Oxygen Demand ◽  
Biomass Concentration ◽  
Effluent Treatment ◽  
Septic Tank ◽  
Septic Tank Effluent ◽  
Pollutants Removal ◽  
Set Up

The objective of the study was to evaluate the usefulness of novel nonwoven textile filter technology for greywater treatment. This technology had already been used on a lab scale for septic tank effluent treatment; however, this study is the first time it has been used for greywater treatment. The set-up period with septic tank effluent (STE) feeding was significantly shorter than that of greywater feeding. The average capacities of both filter types were practically the same: 1.0–1.4 cm d−1. The relatively high efficiencies of chemical oxygen demand (CODCr) and biochemical oxygen demand (BOD5) removal (58.8–71.6% and 56.7–79.8%, respectively) were obtained thanks to the relatively low filtration velocity and effective diffusion of atmospheric air into the greywater. The relatively high efficiency of total suspended solids (TSS) removal (67.0–88.4%) was obtained by reducing the effective pore size of the filtration layer due to high biomass concentration and accumulation of suspended solids. Thanks to hydrostatic pressure, the filters can work practically with very low energy consumption. The pollutants removal efficiencies were satisfactory in respect to simple construction and maintenance, low investment and operational costs.

Performance of a system with full- and pilot-scale sludge drying reed bed units treating septic tank sludge in Brazil

2015 ◽  
Vol 71 (12) ◽  
pp. 1751-1759 ◽  
Author(s):  
Luisa Fernanda Calderón-Vallejo ◽  
Cynthia Franco Andrade ◽  
Elias Sete Manjate ◽  
Carlos Arturo Madera-Parra ◽  
Marcos von Sperling
Keyword(s):  
Oxygen Demand ◽  
Pilot Scale ◽  
Full Scale ◽  
Septic Tank ◽  
Feeding Strategies ◽  
Second Phase ◽  
Scale Unit ◽  
Belo Horizonte ◽  
Reed Bed ◽  
Sludge Drying

This study investigated the performance of sludge drying reed beds (SDRB) at full- and pilot-scale treating sludge from septic tanks in the city of Belo Horizonte, Brazil. The treatment units, planted with Cynodon spp., were based on an adaptation of the first-stage of the French vertical-flow constructed wetland, originally developed for treating sewage. Two different operational phases were investigated; in the first one, the full-scale unit was used together with six pilot-scale columns in order to test different feeding strategies. For the second phase, only the full-scale unit was used, including a recirculation of the filtered effluent (percolate) to one of the units of the French vertical wetland. Sludge application was done once a week emptying a full truck, during 25 weeks. The sludge was predominantly diluted, leading to low solids loading rates (median values of 18 kgTS m−2year−1). Chemical oxygen demand removal efficiency in the full-scale unit was reasonable (median of 71%), but the total solids removal was only moderate (median of 44%) in the full-scale unit without recirculation. Recirculation did not bring substantial improvements in the overall performance. The other loading conditions implemented in the pilot columns also did not show statistically different performances.

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