Soil Aquifer Treatment System Research Articles

Estimating bacterial breakthrough behaviors based on bacterial retention profiles in porous media

AbstractTraditional methods for assessing bacterial transport in soil or permeable sand aquifers, such as flow‐through experiments, breakthrough curve (BTC), and retention profile (RP) analysis, face challenges due to their complexity and the labor‐intensive nature of in situ implementations. This study seeks to address the question: How can the transport behavior of bacteria in soil be predicted in a simpler and more cost‐effective manner using RPs? We introduce an RP method designed to overcome these challenges by utilizing soil sampling at various depths to model bacterial breakthrough behaviors with greater efficiency. By employing the one‐site attachment/detachment model within the Hydrus 1D framework, our research compares the RP method (three RPs) against the conventional approach (BTC + RP), showcasing its efficacy through column experiments with bioluminescent Escherichia coli in humic acid‐coated sand. The results indicate that the accuracy of RP method aligns closely with traditional methods in predicting bacterial transport. This technique allows for the use of solid samples collected from a limited number of depths to predict breakthrough behaviors accurately, making it suitable for evaluating bacterial transport in settings such as farmlands, contaminated lands, riverbanks, and soil aquifer treatment systems. Our findings underscore the RP method's role in streamlining experimental procedures and its potential application in environmental science and agronomy.

Impact of sand media continuous drying and rewetting cyclic on nutrients transformation performance from reclaimed wastewater effluent at soil aquifer treatment

Reusing reclaimed wastewater became a practical resource for water utilization in groundwater recharge and irrigation activities. However, the quality of reclaimed wastewater needs improvement to meet the environmental regulations and reduce contamination risks. A laboratory-scale study simulated a soil aquifer treatment (SAT) system, exploring the synergistic effects of wet and dry cycles alongside key physicochemical parameters on pollutant removal efficiency using a glass column filled with quartz sand as the filtration medium. The investigation focused on the cyclic wetting and drying phases to unravel their impact on removing NH4+, NO3−, and PO43−. The synthetic wastewater introduced into the system exhibited varying pollutant concentrations during wet and dry periods, influenced by dynamic soil water content (WC%), pH, dissolved oxygen (DO), and oxidation–reduction potential (ORP). The high removal rates of 93% for PO43− and 43% for Total N2 demonstrate the system’s capability to reduce concentrations significantly under dynamic alternating between wet and dry conditions. Results unveiled that the wet period consistently yielded higher removal rates for N2 species. Interestingly, for PO43−, the dry periods demonstrated a higher removal efficiency. Moreover, the study identified an average NO3− production during the experimental phases as a byproduct of nitrification. The average NO3− production in wet periods was 2.5 mg/L, whereas it slightly decreased to 2.2 mg/L in dry periods. These findings underscore the nuanced influence of wet and dry conditions on specific pollutants within SAT systems. Applying the logistic regression model and principal component analysis demonstrated the statistical significance of WC, pH, DO, and ORP in predicting wet/dry conditions, providing quantitative insights into their influential roles on the nutrient dynamic concentrations. This study contributes valuable data to our understanding of SAT systems, offering practical implications for designing and implementing sustainable wastewater treatment practices and pollution management across diverse environmental contexts.

Assessing the Fate of Benzophenone-Type UV Filters and Transformation Products during Soil Aquifer Treatment: The Biofilm Compartment as Bioaccumulator and Biodegrader in Porous Media.

The fate of selected UV filters (UVFs) was investigated in two soil aquifer treatment (SAT) systems, one supplemented with a reactive barrier containing clay and vegetable compost and the other as a traditional SAT reference system. We monitored benzophenone-3 (BP-3) and its transformation products (TPs), including benzophenone-1 (BP-1), 4,4'-dihydroxybenzophenone (4DHB), 4-hydroxybenzophenone (4HB), and 2,2'-dihydroxy-4-methoxybenzophenone (DHMB), along with benzophenone-4 (BP-4) and avobenzone (AVO) in all involved compartments (water, aquifer sediments, and biofilm). The reactive barrier, which enhances biochemical activity and biofilm development, improved the removal of all detected UVFs in water samples. Among monitored UVFs, only 4HB, BP-4, and AVO were detected in sediment and biofilm samples. But the overall retained amounts were several orders of magnitude larger than those dissolved. These amounts were quantitatively reproduced with a specifically developed simple analytical model that consists of a mobile compartment and an immobile compartment. Retention and degradation are restricted to the immobile water compartment, where biofilm absorption was simulated with well-known compound-specific Kow values. The fact that the model reproduced observations, including metabolites detected in the biofilm but not in the (mobile) water samples, supports its validity. The results imply that accumulation ensures significant biodegradation even if the degradation rates are very low and suggest that our experimental findings for UVFs and TPs can be extended to other hydrophobic compounds. Biofilms act as accumulators and biodegraders of hydrophobic compounds.

Efficient removal of toxicity associated to wastewater treatment plant effluents by enhanced Soil Aquifer Treatment

The regeneration of wastewater has been recognized as an effective strategy to counter water scarcity. Nonetheless, Wastewater Treatment Plant (WWTP) effluents still contain a wide range of contaminants of emerging concern (CECs) even after water depuration. Filtration through Soil Aquifer Treatment (SAT) systems has proven efficient for CECs removal although the attenuation of their associated biological effects still remains poorly understood. To evaluate this, three pilot SAT systems were monitored, two of them enhanced with different reactive barriers. SATs were fed with secondary effluents during two consecutive campaigns. Fifteen water samples were collected from the WWTP effluent, below the barriers and 15 m into the aquifer. The potential attenuation of effluent-associated biological effects by SATs was evaluated through toxicogenomic bioassays using zebrafish eleutheroembryos and human hepatic cells. Transcriptomic analyses revealed a wide range of toxic activities exerted by the WWTP effluents that were reduced by more than 70% by SAT. Similar results were observed when HepG2 hepatic cells were tested for cytotoxic and dioxin-like responses. Toxicity reduction appeared partially determined by the barrier composition and/or SAT managing and correlated with CECs removal. SAT appears as a promising approach to efficiently reduce effluent-associated toxicity contributing to environmental and human health preservation.

Optimizing phosphate removal by manipulating manganese and cobalt levels in soil aquifer treatment system

Manganese (Mn2+) and cobalt (Co2+) metals have been reported to exhibit complex interactions with phosphate (PO43-) ions, which can influence their mobility, reactivity, and removal behavior in soil aquifer treatment system (SAT). This study aimed to investigate the role of manganese (Mn2+) and cobalt (Co2+) in phosphate (PO43-) removal within a soil aquifer treatment system. A lab-scale column experiment was conducted using sand as the filtration media, and a synthetic wastewater containing 20 mg/L PO43-, 60 mg/L Mn2+, and 40 mg/L Co2+ was used. The breakthrough curves showed efficient removal of PO43- during the infiltration process, with concentrations reaching as low as 1 mg/L. The regression analysis revealed that Mn2+ had a strong negative correlation effect on PO43- concentration, indicating its stimulatory role in PO43- removal. Conversely, Co2+ showed a strong positive correlation effect, suggesting its promoting effect on PO43- concentration. Optimization analysis identified optimal concentrations of 57.4 mg/L for Mn2+ and 4.8 mg/L for Co2+ that interacted with lower PO43- concentrations, achieving the desired outcome of reducing PO43- levels. These findings highlight the importance of considering Mn2+ and Co2+ concentrations in soil aquifer treatment systems for effective phosphate removal.

Determination of degradation/reaction rate for surface water quality of recycled water using Lake2K model for large-scale water recycling.

The depletion of groundwater resources in the water-stressed regions has led to the overuse of surface water reservoirs. Recharging groundwater by rejuvenating dried surface reservoirs using recycled water is a new sustainable solution. To ensure the prevention of groundwater contamination and associated health risks (as recycled water is used), it is crucial to assess the surface reservoir water quality. The study for the first time suggests the Lake2K model, a one-dimensional mechanistic mass-balance model, to simulate the changes in water quality in a series of man-made surface water reservoirs where recycled water flows under an indirect groundwater recharge scheme (soil aquifer treatment system). The model was developed, calibrated, and validated using field observations to estimate degradation/reaction rate constants for various water quality parameters. The observed average degradation/reaction rate constants for parameters including ammonia-N, nitrate-N, total nitrogen, total organic carbon, and organic phosphorous were 0.043day-1, 0.04day-1, 0.043day-1, 0.055day-1, and 0.056day-1, respectively, which were found to be relatively high compared to existing literature, indicating a greater degradation of these parameters in warmer climates. The results showed that the water quality improved significantly as the water progressed through the reservoirs, aligning with field observations. Additionally, the simulated seasonal variations revealed that the maximum growth rate of phytoplankton occurred during July, August, and September for each reservoir, while the nutrient pool (nitrate-N and orthophosphates) experienced the greatest depletion during this growth period. These findings shed light on the dynamics of surface water quality in regions facing water scarcity and contribute to the development of sustainable groundwater management strategies.

Feasibility Study of Wastewater Treatment by Soil Aquifer System

The treatment of wastewater is very important before disposal into various water bodies. But, the sustainability of the water treatment method is challenging for the environment. Soil Aquifer Treatment (SAT) is a controlled aquifer recharge system that further improves the quality of the feed water as it passes through the soil. This paper provides an overview of SAT systems for wastewater treatment and reuse. Wastewater samples are collected from the college canteen. Initially, canteen wastewater without pre-treatment was analyzed after that pre-treatment such as coagulation using neem leaves powder was carried out for canteen wastewater and then introduced into SAT system. The results concluded that sandy loam soil was better than clayed soil for magnesium and sodium removal through SAT and sandy soil was not recommended for Magnesium and Sodium removal. Sandy soil was better than clayed soil for zinc and Iron removal through SAT system and sandy loam soil was not recommended for zinc and iron removal.

Dissolved organic nitrogen removal and its mechanisms during simulated soil aquifer treatment

Soil aquifer treatment systems are known to further remove contaminants in wastewater effluent when applied through infiltration into the ground. Dissolved organic nitrogen (DON) in the effluent, a precursor for nitrogenous disinfection by-products (DBPs) such as N-nitrosodimethylamine (NDMA), is of great concern upon subsequent use of the groundwater infiltered into the aquifer. In this study, the vadose zone of the soil aquifer treatment system was simulated using 1 m laboratory soil columns under unsaturated conditions representing the vadose zone. The final effluent of a water reclamation facility (WRF) was applied to these columns to investigate the removal of N species with a focus on DON, as well as NDMA precursors. DON removal achieved was up to 99 % with an average of 68 % and was accompanied by a 52 % nitrate increase suggesting the occurrence of ammonification and nitrification through the soil columns. Around 62 % of total DON removal was seen at <10 cm travel distance, which was in accordance with higher adenosine triphosphate (ATP) concentrations at the top of the column due to more oxygen and organic matter availability. Total Dissolved N removal was drastically lowered to 4.5 % in the same column without microbial growth, which highlights the importance of biodegradation. The columns were capable of removing 56 % of the fluorescent dissolved organic matter (FDOM). Soil columns could remove NDMA precursors up to 92 % through the column with the initial concentration of 89.5 ng/L, possibly due to the removal of DON fractions. The results demonstrate the capability of the vadose zone in further treatment of DON and other organic matter before reaching the groundwater through infiltration or indirect discharge to surface water. Differences in applied water quality and the site-specific oxic conditions in SAT systems could lead to variable removal efficiencies.

Cover Image, Volume 22, Issue 2

Vadose Zone JournalVolume 22, Issue 2 COVER IMAGEFree Access Cover Image, Volume 22, Issue 2 First published: 17 March 2023 https://doi.org/10.1002/vzj2.20257AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Graphical Abstract On the cover: Design principles for the soil aquifer treatment (SAT) system. See Shi et al., “Design of a bioaugmented soil aquifer treatment for efficient removal of p-nitrophenol,” https://doi.org/10.1002/vzj2.20242. Volume22, Issue2March/April 2023 RelatedInformation

Elucidating the relationship between gaseous O2 and redox potential in a soil aquifer treatment system using data driven approaches and an oxygen diffusion model

Knowledge concerning the redox potential (Eh) conditions in the vadose zone of a soil aquifer treatment (SAT) system constitutes valuable information for assessing water quality and operational efficiency. The complex nature of Eh conditions in SAT limits the ability to predict and quantify them using detailed models. Alternatively, data-driven models can be used for predictions and relationship analysis. Hourly measurements of Eh, volumetric water content (θ), soil temperature (T), and gaseous oxygen (O2) were obtained at multiple depths of a SAT vadose zone. A correlation analysis showed that O2 correlated with Eh for most temporal components. Only the monthly component of T and the daily component of θ were correlated with Eh. A detailed multiple linear regression (MLR) analysis illustrated that the gaseous O2, at shallow depths, can explain the majority (above 80%) of the Eh variability. The MLR curve demonstrated breakpoints in the Eh response to O2 at shallow depths, which were identified using a piecewise regression. These breakpoints explain, in part, the different stages of microbial activity throughout the SAT wetting and drying cycles. Combining an oxygen transport analytical model with the piecewise regression enabled the Eh prediction through easy-to-acquire T and θ measurements. At deeper depths, the Eh–O2 relationship demonstrates a step-function characteristic, which indicates that the changes in Eh occur due to the arrival of a low-Eh solution. Thus, the Eh dynamic in the SAT vadose zone is mostly controlled by aerobic conditions.

Design of a bioaugmented soil aquifer treatment for efficient removal of p‐nitrophenol

AbstractSecondary effluent reclamation and reuse is an effective solution to the water shortage problem, and the safety of reused water is a matter of increasing concern. p‐Nitrophenol (PNP), a common secondary effluent pollutant, can be efficiently removed using the eco‐friendly bioaugmented soil aquifer treatment (SAT) system at the laboratory scale. In this study, a sewage treatment plant in Changchun was selected as a case study to apply the bioaugmented SAT system for field scenarios efficiently. The bioaugmented SAT system was simulated using HYDRUS‐1D code. Biodegradation and adsorption coefficient were conducted from the batch experiment. Based on the degradation experiments, the concentration of bacteria injected into SAT system was designed to be 6 × 1018 colony‐forming units (CFU) m−3. To enhance the efficiency of the bioaugmented SAT system, the key parameters were optimized based on the sensitivity analysis and the response surface methodology, which showed that the optimal operating conditions were an initial concentration of 86.11 mg L−1, a medium of 4.27‐m thickness, and a wet/dry ratio of 0.28. Specifically, alternated wetting–drying conditions and increasing the medium thickness reduced PNP within a specific range. This work demonstrates the performance and applicability of the bioaugmented SAT system for removal PNP in secondary sewage effluent.

Effects of Operating and Media Conditions on the Change of Reclaimed Water Quality in Soil Aquifer Treatment (SAT) System: Experimental and Simulation Study

Effects of Operating and Media Conditions on the Change of Reclaimed Water Quality in Soil Aquifer Treatment (SAT) System: Experimental and Simulation Study

Using integrative samplers to estimate the removal of pharmaceuticals and personal care products in a WWTP and by soil aquifer treatment enhanced with a reactive barrier

The need and availability of freshwater is a major environmental issue, aggravated by climate change. It is necessary to find alternative sources of freshwater. Wastewater could represent a valid option but requires extensive treatment to remove wastewater-borne contaminants, such as contaminants of emerging concern (CECs). It is urgent to develop not only sustainable and effective wastewater treatment techniques, but also water quality assessment methods. In this study, we used polar organic chemical integrative samplers (POCIS) to investigate the presence and abatement of contaminants in an urban wastewater treatment plant (WWTP) and in soil aquifer treatment (SAT) systems (a conventional one and one enhanced with a reactive barrier). This approach allowed us to overcome inter-day and intraday variability of the wastewater composition. Passive sampler extracts were analyzed to investigate contamination from 56 pharmaceuticals and personal care products (PPCPs). Data from the POCIS were used to estimate PPCPs' removal efficiency along the WWTP and the SAT systems. A total of 31 compounds, out of the 56 investigated, were detected in the WWTP influent. Removal rates along WWTP were highly variable (16-100 %), with benzophenone-3, benzophenone-1, parabens, ciprofloxacin, ibuprofen, and acetaminophen as the most effectively removed chemicals. The two SAT systems yielded much higher elimination rates than those achieved through the primary and secondary treatments together. The SAT system that integrated a reactive barrier, based on sustainable materials to promote enhanced elimination of CECs, was significantly more efficient than the conventional one. The removal of the recalcitrant carbamazepine and its epoxy- metabolite was especially remarkable in this SAT, with removal rates between 69–81 % and 63–70 %, respectively.

Manganese and cobalt metals interrelations with ammonium performance in soil aquifer treatment

This study aimed to discover and explore the impacts and interactions of applying Mn2+ and Co2+ metals in NH4 removal performance under nitrification conditions through soil aquifer treatment. A laboratory scale column was used to simulate the soil aquifer treatment system using quartz sand as packed media to infiltrate the synthetic wastewater mixture from 35 mg/L of NH4, 60 mg/L Mn2+ and 40 mg/L of Co2+ concentrations. The experimental and linear regression model results demonstrate a significant relationship between NH3-N concentration with Mn2+ and Co2+ concentration with a p-value &lt; 0.05, indicating a substantial influence of Mn2+ and Co2+ presence on ammonium bioremediation. Co2+ has a negative correlation interaction with NH3-N, which means Co2+ has increased ammonium oxidation by stimulating the degradation bacteria and cell growth to supplement and improve the activity of ammonium degradation bacteria. However, applying a high concentration of Mn2+ works as an inhibitor for NH3-N bioremediation. Using a high concentration of Mn2+ negatively impacts bacteria, causing a toxic effect and decreasing the bacteria's degradability for ammonium.

Mechanism of downward migration of quinolone antibiotics in antibiotics polluted natural soil replenishment water and its effect on soil microorganisms

Reclaimed water is widely concerned as an effective recharge of groundwater and surface water, but trace organic pollutants produced by traditional wastewater treatment plants (WWTPs) would cause environmental pollution (water and soil) during infiltration. Therefore, the effects of reclaimed water containing ofloxacin (OFL) and ciprofloxacin (CIP) in antibiotics polluted natural soil (APNS) were investigated by simulating soil aquifer treatment systems (SATs). The experiment results showed that OFL and CIP in water were adsorbed and microbially degraded mainly at 30 cm, and the concentration of OFL and CIP in soil increased with depth, which were mainly due to the desorption from APNS. Concurrently, the change in replenishment water concentration also significantly affected OFL and CIP in pore water and soil. Although OFL and CIP inhibited the diversity of soil microbial community, they also promoted the growth of some microorganisms. As the dominant bacteria, Proteobacteria and Acidobacteriota can effectively participate in the degradation of OFL and CIP. The degradation effects of soil microorganisms on OFL and CIP were 45.48% and 42.39%, respectively, indicating that soil microorganisms selectively degraded pollutants. This experiment was carried out on APNS, which provided a reference for future studies on the migration of trace organic pollutants under natural conditions.

Transfer of trace organic compounds in an operational soil-aquifer treatment system assessed through an intrinsic tracer test and transport modelling.

Soil Aquifer Treatment (SAT) can provide supplementary treatment of trace organic compounds (TrOCs) such as pharmaceutical and industrial compounds present in Secondary Treated Wastewater (STWW). Concern on presence of unregulated TrOCs in natural systems has raised recently as well as the interest in SAT systems for remediation. The present study quantifies, at the field scale over35 m of lateral groundwater flow, the effectiveness of the Agon-Coutainville SAT system (Manche, Normandy, France) for TrOCs removal by sorption and biodegradation through monitoring of seven TrOCs (oxazepam, carbamazepine, benzotriazole, tolyltriazole, caffein, paracetamol, ibuprofen) and major inorganic compounds as intrinsic tracers in STWW and groundwater during a 34-day STWW infiltration experiment during operational use of the SAT. Cationic exchanges and mixing between groundwater and STWW during the experiment were highlighted by major ions and geochemical simulations. Due to the low thickness of the unsaturated zone, a 1D analytical solution of the advection-dispersion equation (ADE) was applied on chloride data. Chloride was used as conservative intrinsic tracer to calibrate the horizontal flow and transport parameters such as the aquifer dispersion coefficient (D) and the average pore water velocity (ν) allowing estimation of the groundwater residence time. Transport and attenuation of the TrOCs were simulated assuming first-order degradation constant (μ) and linear retardation coefficient (R), calibrated to simulate the observed temporal changes in the breakthrough of TrOCs. Sorption was found to play a role in the transport of TrOCs, notably for oxazepam with a higher linear retardation coefficient value of 2.2, whereas no significant differences of retardation were observed for carbamazepine, tolyltriazole, benzotriazole (1.37, 1.35, 1.36 respectively). Estimated first order degradation rate constants, between 0.03d-1 for carbamazepine and 0.09d-1 for tolyltriazole, were generally high compared to the literature, possibly due to favourable redox conditions and important microbial activities within the system. This study provides evidence of the efficiency of the Agon-Coutainville SAT system for the removal of TrOCs.

Accelerating Microbial Activity of Soil Aquifer Treatment by Hydrogen Peroxide

Soil aquifer treatment (SAT), as a gravity-based wastewater reuse process, is limited by oxygen availability to the microbial community in the soil. Using oxygen from enzymatic degradation of H2O2 to generate hyper-oxygen conditions can exceed solubility limitations associated with aeration, but little is known about the effect of hyper-oxygen conditions on the microbial community and the dominant bio-reactions. This study examined the impact of H2O2 addition on the community structure and process performance, along with SAT depth. Overall, two soil columns were incrementally fed synthetic secondary effluents to simulate infiltration through SAT. The experimental column received 14 mg/L hydrogen peroxide to double the level of natural oxygen available. The microbial kinetics of nitrifiers and heterotrophs were evaluated. We found that all of the H2O2 was degraded within the top 10 cm of the column, accompanied by a higher removal of COD (23 ± 0.25%) and ammonia (31 ± 3%) in comparison to the reference column. Higher nitrogen removal (23 ± 0.04%) was obtained for the whole process using H2O2. Analysis of nitrifiers indicated that ammonia-oxidizing bacteria were most influenced, obtaining higher concentration and abundance when exposed to H2O2. DNA sequencing analysis of samples exposed to H2O2 revealed significant community structure and diversity differences among heterotrophs. This study shows that not only aerobic, but also anoxic, microbial activity and process performance in a SAT system could be accelerated in existing infrastructure with H2O2, which could significantly decrease the associated environmental footprint.

Continuous monitoring of a soil aquifer treatment system's physico-chemical conditions to optimize operational performance

Abstract. Soil aquifer treatment (SAT) is a tertiary process for wastewater treatment, where the wastewater infiltrates through a thick vadose zone for purification and storage in the underneath aquifer. SAT infiltration basins are typically flooded intermittently, while maintaining a fixed ratio between the wetting and the drying stages. However, infiltration basins exhibit different physical and chemical properties, limiting the generalization of SAT operation to attain optimal efficiency. Since frequent sampling of the soil pore water to verify the SAT's biodegradation efficiency can be arduous, continuous monitoring of the SAT vadose zone's physico-chemical conditions is required. In this study, redox potential (Eh) was continuously monitored, together with other variables, such as volumetric water content (θ), soil temperature, and gaseous oxygen (O2), at multiple depths of a SAT vadose zone throughout the year and while the system was constrained to different operational modes. Hydrological models were calibrated and validated to water content observations, and they illustrated the seasonal changes in water infiltration. Furthermore, it was shown that, under long wetting stages during winter, there was a reduction in the SAT's drainage capabilities. The Eh observations, under long wetting stages, demonstrated larger variability and very negative values as ambient temperature increased. Assembling the daily Eh observations illustrated that a wetting stage should cease after about 30 h, once suboxic conditions are established. A drying stage's optimal duration should be 36 h, according to the Eh and O2 observations during summer and winter. Ultimately, the study shows that the length of wetting and drying stages should be defined separately, rather than by adhering to the wetting / drying ratio.

Experimental study on soil aquifer treatment for water quality improvement

Laboratory fabricated soil column experiments were performed to differentiate among the mechanisms (i.e., adsorption, filtration, biodegradation) responsible for the changes in the water quality during Soil Aquifer Treatment (SAT). This study focuses on collecting and analyses the soil samples for its characterization. Similarly, treated wastewater was collected from sewage treatment plant, to characterize the quality before SAT. Then the study has been carried out with columns that are one meter in height and 6 cm diameter to understand the efficiency of the Soil Aquifer Treatment. Entire experiment has been carried out in the presence of sun light. Secondary treated wastewater has poured into soil column and collected at the outlet. Effluent from the column has been analyzed after SAT. After that the clogging layer specimens has taken from soil column and then the soil microbial concentration was estimated. The soil hydraulic conductivity was estimated, to characterize the mechanical and hydraulic behaviour of the clogging layer for before and after SAT. The relative significance of hydraulic loading in soil aquifer treatment system was analyzed and also the changes in the major soil components: Iron(Fe) and Manganese (Mn) oxides resulted from SAT application was measured. Maximum Chemical Oxygen Demand (COD) was reduced in 1.5 m unsaturated Vadoze depth Sandy Clay Loam (SCL) soil from 50.1 mg/l to 18.1 mg/l. During first wetting cycle of SAT, Dissolved Organic Carbon (DOC) was reduced from 12.5 mg/l to 6.5 mg/l. Nitrate(NO-3) and Nitrite(NO-2) was reduced 26 mg/l to 11.25 mg/l and 1.37 mg/l to 1 mg/l respectively. From adsorption studies, it was observed the clay soil has higher adsorption distribution coefficient. The relative hydraulic conductivity decline in SCL mixed clay soil was larger than SCL soil.

The effect of soil types on nitrogen and phosphorus removal from secondary treated municipal wastewater by using soil-aquifer treatment system

The effect of soil types on nitrogen and phosphorus removal from secondary treated municipal wastewater by using soil-aquifer treatment system