Soil Aquifer Treatment Research Articles

Removal of Endocrine Disrupting Compounds in Water Reclamation Processes

With increasing water demands, the impetus to use treated wastewater to augment nonpotable and potable water supplies is growing. There is also increasing concern that recycled wastewater might contain contaminants harmful to human health or the aquatic environment. Contaminants of concern include endocrine disrupting compounds (EDCs), compounds that can interfere with the proper functioning of hormone systems. The goal of this research was to develop approaches combining bioassays with chemical analysis to study removal of EDCs by different reclamation treatment process. Hydraulic corresponding composite samples were collected for individual unit operation and analyzed using HPLC-ELIAS, GC-NCI-MS, and bioassays. Whereas estrogenic activity was accounted for by chemical components of primary effluents, more androgenic activity was found than could be explained by testosterone concentrations. Generally. secondary treatment removed EDCs very efficiently. For effluents in which estrogenic activity remained, it was mainly comprised of 17-estradiol and estrone whereas androgen activity was caused by remaining testosterone. Secondary treatment employing nitrification/denitrification more efficiently removed EDCs than facilities employing no nitrification. Powered activated carbon, soil-aquifer treatment and integrated membrane systems (microfiltration/reverse osmosis) efficiently removed endocrine disrupting activity This title belongs to WERF Research Report Series ISBN: 9781843397588 (Print) ISBN: 9781780403939 (eBook)

Recent Progress in Slow Sand and Alternative Biofiltration Processes

Slow sand filtration is typically cited as being the first “engineered” process in drinking-water treatment. Proven modifications to the conventional slow sand filtration process, the awareness of induced biological activity in riverbank filtration systems, and the growth of oxidant-induced biological removals in more rapid-rate filters (e.g. biological activated carbon) demonstrate the renaissance of biofiltration as a treatment process that remains viable for both small, rural communities and major cities. Biofiltration is expected to become even more common in the future as efforts intensify to decrease the presence of disease-causing microorganisms and disinfection by-products in drinking water, to minimize microbial regrowth potential in distribution systems, and where operator skill levels are emphasized.Recent Progress in Slow Sand and Alternative Biofiltration Processes provides a state-of-the-art assessment on a variety of biofiltration systems from studies conducted around the world. The authors collectively represent a perspective from 23 countries and include academics, biofiltration system users, designers, and manufacturers.It provides an up-to-date perspective on the physical, chemical, biological, and operational factors affecting the performance of slow sand filtration (SSF), riverbank filtration (RBF), soil-aquifer treatment (SAT), and biological activated carbon (BAC) processes. The main themes are: comparable overviews of biofiltration systems; slow sand filtration process behavior, treatment performance and process developments; and alternative biofiltration process behaviors, treatment performances, and process developments.This title belongs to Water Research Foundation Report SeriesISBN: 9781843391203 (Print)ISBN: 9781780402451 (eBook)

Evaluation of wastewater post-treatment options for reuse purposes in the agricultural sector under rural development conditions

Reuse of wastewater is a sustainable and renewable source of water, mainly used in the agricultural sector and can contribute to rural development. Agriculture is the second highest sector for water consumption in the Gaza Strip, using more than 50% of water abstractions from the stressed polluted Gaza's coastal aquifer. This paper aims to present and evaluate two available wastewater post-treatment options which could be employed to reuse wastewater for agriculture in Gaza: sand filtration using a textured geo-membrane sand filter and the Soil Aquifer Treatment (SAT) system. This evaluation is based on applying hierarchy grey relational analysis and the comparison matrix through an environmental assessment for each option using a semi-empirical methodology that combines results from field tests and computer hydrological simulations. In addition, it is based on a social and economic and the operational aspects for the Gaza City Wastewater Treatment Plant (WWTP) and its infiltration basin. The evaluation factors for the two options are juxtaposed in a Comparison Matrix with associated weighted scores and pre-defined scales to quantify the evaluation process before using the hierarchy grey relational analysis. The results show that the operational costs and the environmental aspects are the main factors that affect the evaluation process for wastewater post-treatment options. The sand filtration (with textured geo-membrane) option is ranked higher than the SAT system for this particular case study with an overall integrated grey relational grade equal to 0.3276, compared to 0.2596 for the SAT system.

Oxidizer Demand in the Unsaturated Zone of a Surface‐Spreading Soil Aquifer Treatment System

Core Ideas We investigated the Shafdan SAT system, known for its good performance. We showed that oxidation of organic and nitrogen compounds occurs in the vadose zone. We calculated the oxidizer balance over the vadose zone and the overall system. The balance reveals 42.5 ± 12. mg/L of oxygen consumption in the vadose zone. Soil aquifer treatment (SAT) is increasingly considered to be a favorable polishing method before the use of secondary or tertiary wastewater effluents for unrestricted irrigation or disposal to the sea. Most of the oxidation processes of organic compounds as well as of nitrogen compounds take place in the unsaturated zone of the SAT. A material balance over the unsaturated zone of a high‐frequency SAT system reveals that 90% of the removal of organic matter and complete ammonium oxidative removal already occur within the unsaturated zone. This is observed, despite the short (less than 3 wk) water retention time in this zone, compared with the subsequent 6‐ to 36‐mo retention time within the aquifer. An oxidizer balance over the unsaturated zone reveals that 42.5 ± 12 mg/L of oxygen is consumed in the unsaturated zone. This consumption level is five times higher than the oxygen saturation level under the conditions prevailing in the effluent. The implications of this excessively high oxygen demand in the vadose zone on manganese mobilization in the aquifer are addressed.

Water Quality Improvements in Soil Aquifer Treatment (SAT) Simulated Soil Columns

Artificial recharge of Aquifers with treated wastewater is one of the most promising techniques for its reuse. Usually laboratory and pilot scale field studies are conducted for investigating the feasibility of wastewater recharge for any aquifer. The addition of sand to the local soil can improve the performance of the Soil Aquifer Treatment (SAT) process. Thus, a laboratory study was conducted to investigate the effect of sand amendment with local Sandy Clay Loam (SCL) texture soil collected from Anna University Sewage Treatment Plant (STP), Chennai, India. Four 35 cm long PVC soil columns were fabricated and were filled with 5 % (R5), 10 % (R10), 15 % (R15) and 20 % (R20) sand amended soil. The experiments were run simultaneously for a period of ten cycles with 3 days wet/4 days dry cycles. Water samples were collected at the outlet of the columns and analysed for TDS, ammonia, nitrite and nitrates. The removal of ammonia was through nitrification process which was found to be a dominant removal mechanism of nitrogen. When reduction performance achieved with different sand amendment columns were compared, it could be seen that R10 column yielded with least nitrate value of 0.69 and 1.57 mg/l after 1st and 3rd wetting day.

A study of columns to reduce mineral and biological pollutants during recharge operation by treated municipal wastewater

One of the most important methods for reusing treated wastewater is soil aquifer treatment (SAT). For simulation of SAT pounds, three columns of 30 cm in diameter and 250 cm in height were filled with sandy loam soil and used to assess the removal of chemical and biochemical oxygen demands (COD and BOD), nitrogen, phosphate, total dissolved solid, total coliform, and fecal coliform from treated wastewater. The soil surfaces of columns were covered by different materials; one by geotextile, another by coarse structural debris, and the third one remained bare. These columns were saturated by treated wastewater from Mahdasht–Karaj treatment plant. All of the experiments were conducted under permanent saturated soil condition. The removal percentages of geotextile soil column were 84.7, 77, 67.7, 99.5, 99.7, and 79.9 for BOD, COD, TSS, coliform, fecal coliform, and phosphate, respectively, and low efficiency for nitrate removal in all columns. Also it was observed that more waterlogging time leads to a decrease in pollutant removal. Using geotextile and structural debris as soil surface covers will lead to a reduction in pollutants transfer and help in stabilizing the soil system as a filter.

A hybrid process of biofiltration of secondary effluent followed by ozonation and short soil aquifer treatment for water reuse

The Shafdan reclamation project facility (Tel Aviv, Israel) practices soil aquifer treatment (SAT) of secondary effluent with hydraulic retention times (HRTs) of a few months to a year for unrestricted agricultural irrigation. During the SAT, the high oxygen demand (>40 mg L−1) of the infiltrated effluent causes anoxic conditions and mobilization of dissolved manganese from the soil. An additional emerging problem is the occurrence of persistent trace organic compounds (TrOCs) in reclaimed water that should be removed prior to reuse. An innovative hybrid process based on biofiltration, ozonation and short SAT with ∼22 d HRT is proposed for treatment of the Shafdan secondary effluent to overcome limitations of the existing system and to reduce the SAT's physical footprint. Besides efficient removal of particulate matter to minimize clogging, coagulation/flocculation and filtration (5–6 m h−1) operated with the addition of hydrogen peroxide as an oxygen source efficiently removed dissolved organic carbon (DOC, to 17–22%), ammonium and nitrite. This resulted in reduced effluent oxygen demand during infiltration and oxidant (ozone) demand during ozonation by 23 mg L−1 and 1.5 mg L−1, respectively. Ozonation (1.0–1.2 mg O3 mg DOC−1) efficiently reduced concentrations of persistent TrOCs and supplied sufficient dissolved oxygen (>30 mg L−1) for fully oxic operation of the short SAT with negligible Mn2+ mobilization (<50 μg L−1). Overall, the examined hybrid process provided DOC reduction of 88% to a value of 1.2 mg L−1, similar to conventional SAT, while improving the removal of TrOCs and efficiently preventing manganese dissolution.

Soil Aquifer Treatment as Disinfection Unit

AbstractThe Shafdan wastewater treatment system treats the municipal wastewater of the Tel-Aviv metropolitan area, which contains 22 cities with a population of about two million. The conventional mechanical–biological treatment is followed by managed groundwater recharge. The effluent undergoes soil aquifer treatment (SAT) by controlled passage through the unsaturated zone and an average retention time of 960 days in the aquifer. The SAT provides effluent polishing treatment as well as seasonal and multiannual storage, which are much needed in the semiarid Mediterranean climate. The Shafdan SAT operates without disinfection prior to the land spreading of the secondary effluents or after the water is reclaimed from the aquifer. Despite that, since 1995 there has not been even a single positive test of fecal coliforms (FC) in any of the reclamation wells, and since 2001, all of the enterovirus tests in an observation well located midway between the infiltration basins and the reclamation wells were negativ...

Ammonia Behaviour in Wastewater Reclamation by Soil Aquifer Treatment

Groundwater use is increasing all over India and Chennai is not an exception. A good possibility exists to recharge artificially the excess treated wastewater through Soil Aquifer Treatment (SAT) and use the recharged water for purposes other than drinking. Soil column experiments were performed, in order to study the ammonia, nitrite and nitrate reduction from Real Secondary Treated Wastewater (RWW). SAT was simulated in four 15 cm long soil columns packed with soils of Sandy Clay Loam (SCL) texture collected from Anna University Sewage Treatment Plant (STP), Chennai, India. Soil Columns were ponded with wastewater to a depth of 2.5 cm above the soil surface and operated for a period of Ten cycles under 4 different alternating wet and dry cycles, 0.25 day wet/1.75 days dry (R1), 0.25 day wet/2.75 days dry (R2), 0.25 day wet/3.75 days dry (R3) and 0.25 day wet/7.75 days dry (R4). The effect of wetting and drying periods on SAT ammonia removal performance was assessed comparing ammonia, nitrite, nitrate nitrogen and TDS rates. The removal of ammonia was through nitrification process which is found to be a dominant removal mechanism of nitrogen. Nitrification differed according to the different drying cycle’s time with fixed flooding period. When the reduction performance achieved with different drying cycles were compared, it could be seen that longer drying periods with R3 column yielded with the least nitrate value of 0.58 mg/l. From this study, it was found that with the fixed wetting period, maximum drying period is required for nitrate reduction and minimum drying period is required for TDS reduction.

Groundwater Eco-Distribution System for the Combination of SAT and Therapy-Electrolysis Methods

Abstract. Groundwater quality is generally affected by the soil type and being polluted naturally due to the soil properties itself. This paper aims to examine the effectiveness of reducing the contamination of groundwater by a simple treatment using duo soil aquifer treatment (SAT) and therapy-electrolysis processes. The SAT was applied using physical recharge well system (REWES) in deep clay medium. The filtration in the well was also properly designed to purify the abstraction and treat discharges. Other contaminations such as fluoride, nitrate, chloride and turbidity in the groundwater were treated by therapy-electrolysis techniques. This treatment method reduces more than 64% of contaminations contain without affecting its mineralogy. Therefore, these duo treatments have the best combination of methods to reduce the unneeded contaminations without affecting the groundwater purity. A groundwater eco-distribution system is useful to be implemented in terms of economic process and is ecological friendly for water distribution facilities.

Soil Aquifer Treatment for Additional Upgrading Wastewater Effluent

Soil Aquifer Treatment for Additional Upgrading Wastewater Effluent

Assessing the Suitability of sites for Reclaimed Water Recharge using Hydrogeophysical and Hydrochemical Analysis

&lt;div&gt; &lt;p&gt;An electrical resistivity survey was carried out in the premises of Chennai Metrowater Sewage treatment plants and Anna University to assess the suitability of underlying aquifer for reclaimed water recharge and also to understand groundwater conditions. The geo-electrical methods used in the survey are Vertical Electrical Sounding (VES) using the Schlumberger Configuration. The instrument used is ABEM Terrameter SAS 1000. The VES data from 5 locations were interpreted using IX1Dv2 software. The resistivity varies from 3.96 Ωm to 2796 Ωm while the thickness varies from 0.58 m to 43.05 m. The EC value for VES 1 and VES 3 are 26400 &amp;micro;S/cm and 1551 &amp;micro;S/cm, the TDS value for VES 1 and VES 3 are 16,896 mg/L and 993 mg/L respectively. From this investigation, the thickness of the first layer obtained by VES method along with clay and sand ratio is the deciding factor to assess the suitability of reclaimed water recharge. The study reveals that the Clay and Sand % should be between 30 - 40 and 60 - 70 respectively for reclaimed water recharge. Koyambedu and Anna University STP and surrounding area are found suitable for reclaimed water recharge using Soil Aquifer Treatment. &amp;nbsp;&lt;/p&gt; &lt;/div&gt; &lt;p&gt;&amp;nbsp;&lt;/p&gt;

Dissolved organic matter removal during coal slag additive soil aquifer treatment for secondary effluent recharging: Contribution of aerobic biodegradation

Recycling wastewater treatment plant (WWTP) effluent at low cost via the soil aquifer treatment (SAT), which has been considered as a renewable approach in regenerating potable and non-potable water, is welcome in arid and semi-arid regions throughout the world. In this study, the effect of a coal slag additive on the bulk removal of the dissolved organic matter (DOM) in WWTP effluent during SAT operation was explored via the matrix configurations of both coal slag layer and natural soil layer. Azide inhibition and XAD-resins fractionation experiments indicated that the appropriate configuration designing of an upper soil layer (25 cm) and a mixture of soil/coal slag underneath would enhance the removal efficiency of adsorption and anaerobic biodegradation to the same level as that of aerobic biodegradation (31.7% vs 32.2%), while it was only 29.4% compared with the aerobic biodegradation during traditional 50 cm soil column operation. The added coal slag would preferentially adsorb the hydrophobic DOM, and those adsorbed organics could be partially biodegraded by the biomass within the SAT systems. Compared with the relatively lower dissolved organic carbon (DOC), ultraviolet light adsorption at 254 nm (UV-254) and trihalomethane formation potential (THMFP) removal rate of the original soil column (42.0%, 32.9%, and 28.0%, respectively), SSL2 and SSL4 columns would enhance the bulk removal efficiency to more than 60%. Moreover, a coal slag additive in the SAT columns could decline the aromatic components (fulvic-like organics and tryptophan-like proteins) significantly.

Influence of a compost layer on the attenuation of 28 selected organic micropollutants under realistic soil aquifer treatment conditions: Insights from a large scale column experiment

Soil aquifer treatment is widely applied to improve the quality of treated wastewater in its reuse as alternative source of water. To gain a deeper understanding of the fate of thereby introduced organic micropollutants, the attenuation of 28 compounds was investigated in column experiments using two large scale column systems in duplicate. The influence of increasing proportions of solid organic matter (0.04% vs. 0.17%) and decreasing redox potentials (denitrification vs. iron reduction) was studied by introducing a layer of compost. Secondary effluent from a wastewater treatment plant was used as water matrix for simulating soil aquifer treatment. For neutral and anionic compounds, sorption generally increases with the compound hydrophobicity and the solid organic matter in the column system. Organic cations showed the highest attenuation. Among them, breakthroughs were only registered for the cationic beta-blockers atenolol and metoprolol. An enhanced degradation in the columns with organic infiltration layer was observed for the majority of the compounds, suggesting an improved degradation for higher levels of biodegradable dissolved organic carbon. Solely the degradation of sulfamethoxazole could clearly be attributed to redox effects (when reaching iron reducing conditions). The study provides valuable insights into the attenuation potential for a wide spectrum of organic micropollutants under realistic soil aquifer treatment conditions. Furthermore, the introduction of the compost layer generally showed positive effects on the removal of compounds preferentially degraded under reducing conditions and also increases the residence times in the soil aquifer treatment system via sorption.

Modeling the transport behavior of 16 emerging organic contaminants during soil aquifer treatment

In this study, four one-dimensional flow and transport models based on the data of a field scale experiment in Greece were constructed to investigate the transport behavior of sixteen organic trace pollutants during soil aquifer treatment. At the site, tap water and treated wastewater were intermittently infiltrated into a porous aquifer via a small pilot pond. Electrical conductivity data was used to calibrate the non-reactive transport models. Transport and attenuation of the organic trace pollutants were simulated assuming 1st order degradation and linear adsorption. Sorption was found to be largely insignificant at this site for the compounds under investigation. In contrast, flow path averaged first order degradation rate constants were mostly higher compared to the literature and lay between 0.036d−1 for clofibric acid and 0.9d−1 for ibuprofen, presumably owing to the high temperatures and a well adapted microbial community originating from the wastewater treatment process. The study highlights the necessity to obtain intrinsic attenuation parameters at each site, as findings cannot easily be transferred from one site to another.

Selection of organic process and source indicator substances for the anthropogenically influenced water cycle

An increasing number of organic micropollutants (OMP) is detected in anthropogenically influenced water cycles. Source control and effective natural and technical barriers are essential to maintain a high quality of drinking water resources under these circumstances. Based on the literature and our own research this study proposes a limited number of OMP that can serve as indicator substances for the major sources of OMP, such as wastewater treatment plants, agriculture and surface runoff. Furthermore functional indicators are proposed that allow assessment of the proper function of natural and technical barriers in the aquatic environment, namely conventional municipal wastewater treatment, advanced treatment (ozonation, activated carbon), bank filtration and soil aquifer treatment as well as self-purification in surface water. These indicator substances include the artificial sweetener acesulfame, the anti-inflammatory drug ibuprofen, the anticonvulsant carbamazepine, the corrosion inhibitor benzotriazole and the herbicide mecoprop among others. The chemical indicator substances are intended to support comparisons between watersheds and technical and natural processes independent of specific water cycles and to reduce efforts and costs of chemical analyses without losing essential information.

Removal of Dissolved Organic Matter and Disinfection By-products Formation Potential in the Upper Layer during Soil Aquifer Treatment

Removal of Dissolved Organic Matter and Disinfection By-products Formation Potential in the Upper Layer during Soil Aquifer Treatment

Oxygen profiling of the unsaturated zone using direct push drilling.

A methodology for oxygen profile measurements in the unsaturated zone is developed based on direct push drilling using sampling liners equipped with homemade silicone septa. The oxygen measurement is carried out by puncturing the septum with a commercial retractable optode needle fitted with a fluorescent tip. Metrological characteristics and method validation were carried out under laboratory conditions using different levels of oxygen and various water contents. The relative standard deviations under dry and water saturated soil conditions were less than 0.3% and 5% for 0.5 mg L(-1) of oxygen and less than 2% and 3% for 9 mg L(-1). Field demonstrations in a calcareous-sandstone soil aquifer treatment system with a layered clayey, marl and sandstone lithology of widely different water contents provided down to 30 m deep profiles of the dissolved oxygen level with less than 1.5 m spatial resolution. A single sensor was used for over 50 field measurements, though recalibration was required after approximately 30 measurements due to the deterioration of the fluorescent tip.

Experimental Study on Nitrogen Removal of Domestic Sewage Using Two-Stages Soil Aquifer Treatment System with Pre-Denitrification Process

For unstable high water ammonia shortcomings of soil infiltration system for rural sewage, one kind of new soil infiltration systems-two-stages soil aquifer treatment (SAT) system with pre-denitrification process was designed. The results show that when the hydraulic loading is within 0.06-0.08 m3/(m2·d), the effluent CODCr and NH4+-N concentration reach GB18918-2002 level A standard, the removal rate is 91%-94% for CODCr and 95%-98% for NH4+-N. The TN concentration is below 20 mg/L, meeting GB18918-2002 level B standard, and the removal rate is 71%-75%. The TN removal is dramatically affected by reflux ratio.

Ammonia-oxidizing archaea versus bacteria in two soil aquifer treatment systems.

So far, the contribution of ammonia-oxidizing archaea (AOA) to ammonia oxidation in wastewater treatment processes has not been well understood. In this study, two soil aquifer treatment (SATs) systems were built up to treat synthetic domestic wastewater (column 1) and secondary effluent (column 4), accomplishing an average of 95% ammonia removal during over 550 days of operation. Except at day 322, archaeal amoA genes always outnumbered bacterial amoA genes in both SATs as determined by using quantitative polymerase chain reaction (q-PCR). The ratios of archaeal amoA to 16S rRNA gene averaged at 0.70 ± 0.56 and 0.82 ± 0.62 in column 1 and column 4, respectively, indicating that all the archaea could be AOA carrying amoA gene in the SATs. The results of MiSeq-pyrosequencing targeting on archaeal and bacterial 16S rRNA genes with the primer pair of modified 515R/806R indicated that Nitrososphaera cluster affiliated with thaumarchaeal group I.1b was the dominant AOA species, while Nitrosospira cluster was the dominant ammonia-oxidizing bacteria (AOB). The statistical analysis showed significant relationship between AOA abundance (compared to AOB abundance) and inorganic and total nitrogen concentrations. Based on the mathematical model calculation for microbial growth, AOA had much greater capacity of ammonia oxidation as compared to the specific influent ammonia loading for AOA in the SATs, implying that a small fraction of the total AOA would actively work to oxidize ammonia chemoautotrophically whereas most of AOA would exhibit some level of functional redundancy. These results all pointed that AOA involved in microbial ammonia oxidation in the SATs.