Septic tank discharges as multi-pollutant hotspots in catchments

Richards, Samia; Paterson, Eric; Withers, P. J. A.; Stutter, Marc

doi:10.1016/j.scitotenv.2015.10.160

Cited by 79 publications

(49 citation statements)

References 20 publications

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“…-N values were between 16 and 565 and 2 and 144 mg/L, respectively. The results in Richards et al (2016) also confirmed that the STE was rich in nutrients, metals, and microbial populations; these high concentrations were not treated and thus posed a great risk to stream waters. NH 4 ?…”

Section: Resultsmentioning

confidence: 59%

“…In their first-of-its-kind research, Richards et al (2016) analysed effluents from 32 septic tanks in different communities in northern Scotland. Their findings indicate that the ranges for COD and TSS were orders of magnitude higher than those indicated by the upper limits shown in Fig.…”

Section: Resultsmentioning

confidence: 99%

“…It is reported that around 25, 15, and 4 % of the US, Australian, and UK population, respectively, use septic tanks as their primary wastewater treatment option (Richards et al 2016;Sabry 2010;Zamalloa et al 2013), showing that STS use is not limited to underdeveloped countries.…”

Section: Introductionmentioning

confidence: 99%

“…Consequently, the quality of the septic tank effluent (STE) leaving the system is affected by these factors, potentially rendering the effluent a risk for humans and ecosystems if this small point discharge reaches surface or ground water. Richards et al (2016) carried out a comprehensive study involving the full characterization of effluents from 32 residential household septic tanks of varying designs, ages, operational conditions, and maintenance levels. The authors concluded that STE may pose a great pollution risk for NH 4 ?…”

Section: Introductionmentioning

confidence: 99%

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Treatment of septic tank effluent using moving-bed biological reactor: kinetic and biofilm morphology

Almomani

Khraisheh

2016

Int. J. Environ. Sci. Technol.

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Septic tanks are very commonly used wastewater collection systems throughout the world, and especially in rural areas. In this study, the use of moving-bed biological reactors (MBBR) for the treatment of septic tank effluent (STE) was examined. The study was conducted in two phases. In Phase I, the performance of septic tanks from four projects working under different operational conditions and with different service lives was followed to determine the parameters that required further treatment. In Phase II, four specially designed continuous flow pilotplant MBBRs and one laboratory-scale batch reactor were tested for their efficiency in treating STE. Experiments were carried out at various temperatures (8-25°C) and with different hydraulic retention times (HRTs). MBBR effectively reduced STE's nutrients and chemical oxygen demand by 90 and 85 %, respectively, over 180 days of operation. The average ammonia removal rate at 25°C increased from 0.279 to 0.540 kg N/m 3 when the reactor HRT changed from 5.7 to 13.3 h. Under these conditions, the ammonia removal kinetics were successfully correlated with a theta model with an average h value of 1.054. The biofilm morphology showed a stable and global biomass coverage ([70 %) and a high percentage of live cells. A thinner biofilm was observed when the MBBR operated at high temperatures. The results of this study showed that MBBR is a promising technology for post-treatment of septic tank effluent.

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Section: Resultsmentioning

confidence: 59%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Treatment of septic tank effluent using moving-bed biological reactor: kinetic and biofilm morphology

Almomani

Khraisheh

2016

Int. J. Environ. Sci. Technol.

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“…Septic tank effluent (STE) poses a potential danger to human health and aquatic ecosystems if it reaches the surface or ground water without proper purification [6,7], but the basic functions of ST are retention of solids storage of sludge and scum and then breakdown of these substances in an anaerobic digestion process, and finally discharge of the partially treated effluent to soakaway soil [7] or biological installation for further treatment. In many publications it is suggested that soil clogging is usually accelerated under increasing hydraulic loading rates of STE or under increasing concentrations of organic matter and suspended solids at a given hydraulic loading rate [8][9][10].…”

Section: Introductionmentioning

confidence: 99%

Septic Tank Effluent Pretreatment Using Different Filter Materials as a Prevention from Clogging

Nieć

Spychała

Mazurkiewicz

2016

Eng. Prot. Environ.

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Septic tanks are common devices for primary wastewater treatment, however, they are prone to periodically raised effluent solids concentration, which can accelerate the clogging process in specific conditions. The aim of the study was to identify the impact of the secondary filter on the reduction of TS load and possibility to increase the operation time. The study was carried out in two series using six filters. In each series six filters (pipes with filtering material installed on the bottom) were used: three filters with filter mesh and the other three -with non-woven geo-textile. The filters were being filled with wastewater until clogging was achieved (wastewater table in pipes rising up to 50 cm). For the hydraulic conductivity estimation of falling water table tests were performed. Similar values of accumulated TS to dosed TS ratios were observed during the both series for the both filtering material types. The particle size distributions in the both filtering materials were similar. The fact of accumulation of particles of very small dimension (over 73% smaller than 5 µm), much smaller than the filtering material pores diameter might suggest that the process taking place was that of cake filtration. Despite the higher cumulated dry mass of filter cake and inside the filtering layer, the average hydraulic conductivity of non-woven geo-textile was higher than the average hydraulic conductivity of filter mesh. Probably thanks to the higher porosity of geo-textile higher amount of solids can be trapped inside the filtering material itself. The study showed the relatively low ratio of accumulated solids to supplied solids load; however, the accumulated mass seems to be significant for clogging prevention, especially in the case of several filtering layers usage. This way much more solids can be removed from the septic tank effluent (e.g., using four layers -about 10÷20%) and clogging process can be slowed down (two -three years longer operation time).

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Pharmaceutical Contaminants in Shallow Groundwater and Their Implication for Poor Sanitation Facilities in Low‐Income Countries

Quyen

Otaki

et al. 2021

Enviro Toxic and Chemistry

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Rudimentary on‐site sanitation systems (OSSs) are extensively used in low‐income countries despite the risk of groundwater contamination. The present study investigated the potential impact of community soak pits on sandy shallow aquifers in a rural area in Sri Lanka. Thirty‐two groundwater samples were collected and measured for the traditional indicators fecal bacteria Escherichia coli, total coliforms, nitrate, and chloride; 7 pharmaceuticals were added as wastewater indicators. Analysis showed that the local groundwater is infected by fecal bacteria, but it was unable to determine whether the source of fecal bacteria is the OSSs. Similarly, nitrate and chloride provided unclear evidence. Conversely, detection of 3 pharmaceuticals at trace levels in groundwater evidenced wastewater impact from OSSs. Caffeine was detected in 89% of the sample at a maximum concentration 7.9 ng/L, indicating fecal pollution. Carbamazepine was detected in 42% of the samples with a concentration of up to 6.9 ng/L, whereas sulfamethoxazole was detected in only 2 samples. The presence of carbamazepine and sulfamethoxazole was also consistent with recorded drug use of the residents. Escherichia coli showed a moderate positive correlation with caffeine concentration (Kendall's τ = 0.38, p = 0.017), indicating concurring short‐lifetime fecal bacteria and labile wastewater organic compounds. Nitrate showed a significant correlation with carbamazepine concentration (τ = 0.39, p = 0.016). Fecal bacteria and nitrate can be used in screening for micropollutants in domestic wells impacted by OSSs. The present case study emphasizes the potential impact of poor sanitation on groundwater resources and the necessity of sanitation improvement in achieving Sustainable Development Goals in developing countries. Environ Toxicol Chem 2022;41:266–274. © 2021 SETAC

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Septic tank discharges as multi-pollutant hotspots in catchments

Cited by 79 publications

References 20 publications

Treatment of septic tank effluent using moving-bed biological reactor: kinetic and biofilm morphology

Treatment of septic tank effluent using moving-bed biological reactor: kinetic and biofilm morphology

Septic Tank Effluent Pretreatment Using Different Filter Materials as a Prevention from Clogging

Pharmaceutical Contaminants in Shallow Groundwater and Their Implication for Poor Sanitation Facilities in Low‐Income Countries

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