Tank Experiments Research Articles

Tolerance of fry of three tilapia varieties exposed to low temperatures

As tilapia aquaculture expands globally, cold sensitivity remains a critical issue, leading to significant losses due to poor growth, disease susceptibility, and high mortality. This study evaluated the cold tolerance in fry of three tilapia varieties, incorporating a comprehensive analysis of 3240 specimens. The fry, segregated by variety into different tanks, were observed during summer to assess their performance. The study focused on two commercially prominent varieties, known for their rapid weight gain, and a third variety developed by the Federal University of Lavras, specifically bred for resilience to local climatic conditions. Following a 15-day acclimation period in experimental tanks, the fry were monitored for feeding to apparent satiety. Daily assessments included counting mortalities and measuring water temperature and dissolved oxygen levels. Survival data were analyzed using multivariate Cox regression, with survival curves derived via the Kaplan-Meier method. Lifespan predictions from these curves were compared using the log-rank test. Results indicated that older fry were more resilient to cold stress. Notably, the MGTUP variety, bred for local environmental adaptability, demonstrated superior cold tolerance. This variety also exhibited the lowest mortality rates across all age groups. These findings suggest that utilizing locally adapted tilapia varieties can significantly mitigate losses in aquaculture, especially in cold-prone regions.

Ocean current turbine power take-off design using fluid dynamics and towing tank experiments

This study investigates the performance and power generation capabilities of a small-scale hydrokinetic turbine by comparing numerical simulations with experimental measurements. The key difference between the two models comes from the initial numerical analysis which focused only on the permanent magnet DC motor (PMDC) motor’s parameters and did not account for the gear-head reduction that leads to discrepancies in current and torque predictions, especially at lower input voltages. In practice, friction losses within the gear-head increased the required current and torque, highlighting inefficiencies in the motor gear-head system. A modified experimental setup incorporated a magnetic coupling to address leakage issues and enhance system reliability. While the magnetic coupling resulted in a slight reduction in speed, current, and torque, it improved the overall integrity of the system which is essential for marine applications. The comparison between experimental results and Blade Element Momentum (BEM) simulations showed good agreement at lower speeds, but the simulations under-predicted power at higher speeds, likely due to the model’s limitations in capturing complex hydrodynamic phenomena. This shows the need for comprehensive analysis, integrating both numerical and experimental approaches to optimize turbine performance. Future research will focus on refining experimental methodologies and further improving turbine design and efficiency for hydrokinetic energy systems.

A Novel Embedded Side Information Transmission Scheme Based on Polar Code for Peak-to-Average Power Ratio Reduction in Underwater Acoustic OFDM Communication System

In this paper, we proposed an embedded side information (SI) transmission scheme based on polar code construction for PAPR reduction using the PTS scheme in the underwater Acoustic (UWA) Orthogonal Frequency Division Multiplexing (OFDM) communication system. We use polar codes due to the ability of the arbitrarily designed code rate. Additionally, polar codes can be employed to establish a nested code structure consisting of multiple subsets. The SI bits can be embedded in a polar codeword by exploiting these features. Thus, the approach does not occupy existing data rates or cause additional loss in data transmission rates. At the same time, it embeds m-sequence into the polar code as an indicator vector for the blind SI detector, which makes the blind SI detector able to autonomously discriminate SI at the receiver. Simulation and tank experiment results indicate that the proposed embedded SI transmission scheme has the potential to significantly decrease the likelihood of whole-symbol error caused by SI errors. Meanwhile, the proposed PTS scheme eliminates the need to wait for the entire packet to be received before obtaining the SI, thereby preventing waste of data storage devices and ensuring real-time performance of the Underwater Acoustic Communication (UAC) OFDM system. This achieves symbol-level real-time calculation for the system.

High Vulnerability of Rhodolith Bed Frameworks and Underlying Sediment to Ongoing Ocean Climate Change

ABSTRACTRhodoliths are non‐geniculate, free‐living coralline red algae that can accumulate on the seafloor and form structurally complex habitats supporting highly biodiverse communities termed rhodolith beds. Limited understanding of key rhodolith kinetical attributes and how they scale with environmental variability limits ability to predict changes in rhodolith bed distribution and abundance in a globally changing ocean climate. We carried out two experiments in an oscillatory wave tank to test the effects of (1) rhodolith (Boreolithothamnion glaciale) density and wave velocity on rhodolith displacement and abrasion over a hard substratum and (2) rhodolith density on rhodolith displacement and the stability of underlying sediment. We established that on a hard substratum, (1) a threshold wave velocity of ~0.3 m s−1 is required to induce noticeable displacement in average‐sized rhodoliths and (2) rhodolith abrasion increases (quasi‐linearly) with wave velocity up to this threshold. We also showed that (3) for a same rhodolith density, rhodolith displacement is at least two times smaller on a sedimentary than hard substratum and (4) the loss of sediment underneath rhodoliths decreases (quasi‐linearly) with an increase in rhodolith density. Rates documented and strong scaling with changes in water motion and rhodolith density indicate that relatively small changes in the density of rhodoliths or hydrodynamic forces can quickly destabilize rhodolith bed frameworks and underlying sediment. These rates can be used to develop predictive models of change in rhodolith bed distribution and abundance that can in turn inform development of more accurate, science‐based rhodolith bed conservation strategies.

Advances in giant clam (Tridacnidae spp.) sclerochronology and sclerochemistry

Understanding past environmental change through high-resolution palaeoenvironmental proxy reconstructions provides crucial baselines for understanding global environmental changes, particularly during the Quaternary Period. Such data are crucial for testing and refining climate models to enable better adaptations to current and future climate changes. Giant clams (Tridacnidae spp.), the largest bivalve mollusc in the Indo-Pacific region, possess distinctive features such as long lifespan, rapid growth, high-resolution growth patterns, wide distribution habitat, and stable shell geochemical composition. These attributes make giant clams a promising and dependable novel palaeoenvironmental archive, offering numerous available geochemical proxies. In this review, we examined preview studies on giant clams conducted for sclerochronology research, spanning publications from 1986 to 2023. The previous studies have proven that isotopic and trace elements proxies of the giant clam, including δ18O, δ13C, Sr/Ca, Mg/Ca, Ba/Ca, and Fe/Ca, can faithfully reconstruct palaeoclimate records including sea surface temperature, dissolved inorganic carbon, insolation, extreme weather events and primary productivity at ultra-high resolution. These proxies have been successfully employed for palaeoclimatic and palaeoenvironmental reconstructions from the Miocene to the present across a range of locations from South Japan to Northern Australia to the Red Sea. These studies have illuminated changes in interannual climate cycles, climate variation, and human migrations over thousands to millions of years. They have generated quantitative records that are valuable for testing and refining numerical climate models, understanding the relationship between past climate cycles and future climate variability, and providing insights into human-environment interactions over time. In the end, the review also addresses the challenges and provided recommendations for future research, highlighting persisting gaps in understanding the influence of microstructure on the shell, age dating of fossil samples, uncertainty in proxies, the need for tank experiments, and access to ultra-high resolution palaeoenvironmental records.

Contrast of hydraulic conductivity induces transport of combined pollutants in high- and low-permeability systems

The transport process of pollutants in the environment can be influenced by heterogeneous geologic architecture and pollutant interactions. However, there has been a lack of research on co-transport behaviors of combined pollutants in heterogeneous aquifers. In this study, a series of two-dimensional tank experiments were carried out to study the transport behavior of toluene and naphthalene in both homogeneous and heterogeneous aquifers. The results revealed that the coexisting solutes facilitated the transport of toluene and naphthalene in the homogeneous aquifers, potentially due to competitive adsorption between these compounds. In the high- and low-permeability systems, the transport rates for both toluene and naphthalene decreased while exhibiting characteristics such as early arrival, long tails, and multiple peaks. The spatial analysis of pollutant distribution indicated that hydraulic conductivity contrast played a critical role in inducing back diffusion phenomenon. Furthermore, toluene exhibited more pronounced matrix diffusion compared to naphthalene in heterogeneous aquifers, characterized by higher concentrations, wider diffusion range in low-permeability zones. And the β value for toluene is smaller than naphthalene in CTRW model, indicating that the former is more sensitive to the hydraulic conductivity contrast. This study provides novel insights into understanding the co-transport behavior of combined pollutants in heterogenous aquifers.

A Tank Experiment of the Autonomous Detection of Seabed-Contacting Segments for Submarine Pipelaying Operations

A Tank Experiment of the Autonomous Detection of Seabed-Contacting Segments for Submarine Pipelaying Operations

Evaluation of the applicability of beach erosion and accretion index in Qiongzhou Strait of China

In coastal erosion studies, the erosion and accretion index is a vital research tool for analyzing types of erosion and accretion. This index is primarily empirical or semi-empirical and is usually validated through tank experiments or open beach datasets, resulting in significant variation across different beach environments. In this study, 11 beach profiles of eight beaches measured along the Qiongzhou Strait in China, measured from 2018 to 2021, were analyzed to quantitatively determine coastal erosion or accretion by calculating each profile’s volume change per unit width. Additionally, sediment and wave data were used to calculate five erosion and accretion indices monthly to determine erosion and accretion conditions. These conditions were then compared with actual beach erosion and accretion data to evaluate the applicability of various discriminant indices. Furthermore, optimizing the threshold values of discriminant indices. The results show that: (1) Overall annual erosion and accretion are minimal, but seasonal variation is significant for beaches on both sides of the Qiongzhou Strait; (2) The five discriminant indices have some limitations in this study area, necessitating careful consideration when applying them to headland bay arc-shaped beaches with fetch-limited environments like the Qiongzhou Strait; (3) The selection of discriminant index parameters and their respective contribution degree of each parameter affects the formula’s applicability, with two-parameter formulas proving superior to the three-parameter formula in the study area; (4) Beach environmental factors, particularly those influenced by headlands and fetch-limited environments, impact the indices’ applicability; (5) Increasing the threshold value to a certain extent can improve the formula’s applicability.

Submerged and completely open solid–liquid triboelectric nanogenerator for water wave energy harvesting

AbstractTriboelectric nanogenerator (TENG) is an emerging wave energy harvesting technology with excellent potential. However, due to issues with sealing, anchoring, and difficult deployment over large areas, TENG still cannot achieve large‐scale wave energy capture. Here, a submerged and completely open solid–liquid TENG (SOSL‐TENG) is developed for ocean wave energy harvesting. The SOSL‐TENG is adapted to various water environments. Due to its simple structure, it is easy to deploy into various marine engineering facilities in service. Importantly, this not only solves the problem of difficult construction of TENG networks at present, but also effectively utilizes high‐quality wave energy resources. The working mechanism and output performance of the SOSL‐TENG are systematically investigated. With optimal triggering conditions, the transferred charge (Qtr) and short‐circuit current (Isc) of SOSL‐TENG are 2.58 μC and 85.9 μA, respectively. The wave tank experiment is taken for fully demonstrating the superiority of the SOSL‐TENG network in large‐scale collection and conversion of wave energy. Due to the excellent output performance, TENG can harvest wave energy to provide power for various commercial electronic devices such as LED beads, hygrothermograph, and warning lights. Importantly, the SOSL‐TENG networks realizes self‐powered for electrochemical systems, which provides a direction for energy cleanliness in industrial systems. This work provides a prospective strategy for large‐scale deployment of TENG applications, especially for harvesting wave energy in spray splash zones or at the surface of the water.image

Analysis and control of hydrofoil vortex-induced vibration

This paper primarily investigates the relationship between the wake vortices and vortex-induced vibrations in hydrofoil structures, as well as explores effective methods to suppress structural vibrations in hydrofoils using a piezoelectric control system. By combining CFD simulations with PIV experiments, the study compared the vortex characteristics at the trailing edge of hydrofoils with different geometries. Furthermore, by integrating the results from the water tank experiments, the research revealed the sensitivity of vortex-induced resonance to the regularity and periodicity of the von Kármán vortex street. Subsequently, the FxLMS algorithm was fine-tuned based on a phenomenological model of vortex-induced resonance. Active control experiments on vortex-induced vibrations of the hydrofoil were conducted using a piezoelectric control system built on this algorithm, achieving a maximum vibration reduction rate of 56%. Finally, the instability and limitations of the control effectiveness were analyzed, and future research directions were proposed to improve control strategies and the system's temporal responsiveness.

Continuous and funnel-gate configurations of a permeable reactive barrier for reclamation of groundwater laden with tetracycline: experimental and simulation approaches

The current study investigates removing tetracycline from water using batch, column, and tank experiments with statistical modelling using ANN for continuous tests. An artificial neural network (ANN) using the Levenberg-Marquardt back-propagation (LMA) training algorithm is constructed to compare the effectiveness of Tetracycline removal from aqueous solution using the sorption technique with prepared adsorbent. Several characterization analyses XRD, FT-IR, and SEM are employed for prepared Brownmillerite (Ca2Fe2O5)–Na alginate beads. The operating conditions of batch tests involved, contact time (0.1–3 h), initial of tetracycline (Co) of (100–250 mg/L), pH (3–12), agitation speed (50–250) rpm and dosage of adsorbent (0.2–1.2 g/50 mL). The outcomes of experiments have demonstrated that the optimum conditions for the batch test to achieve the maximum adsorbent capacity (qmax =7.845 mg/g) are achieved at pH 7, contact time 1.5 h, adsorbent dose 1.2 g/50 mL, agitation speed of 200 rpm, and initial concentration of TC 100 mg/L. Minimum mean square error (MSE) values of 7.09E-04 for 30 hidden neurons and 0.0029 for 59 hidden neurons in the 1D and 2D systems are accomplished, respectively. The artificial neural network model has exhibited excellent performance with correlation coefficients exceeding 0.980 for the operating variables, demonstrating its accuracy and effectiveness in predicting the experimental outcomes. According to sensitivity analysis, the influential parameter in the column test (1D) is the flow rate (mL/min), with a relative importance of 32.769%. However, in the tank test (2D), time (day) is signified as an influential parameter with a relative importance of 31.207%.

A novel superposition coding scheme based on polar code for multi‐user detection in underwater acoustic OFDM communication system

SummarySuperposition coding (SC) is a non‐orthogonal multiple access (NOMA) scheme for the downlink communication system, which allows signals of different users to be stacked and forwarded simultaneously in the same frequency band. The codeword for each user is assigned a different weight at the transmitter to avoid signal conflicts and interference after stacking, and successive interference cancellation (SIC) is adopted to decode. A novel SC scheme based on polar code, suitable for the downlink multi‐user underwater acoustic (UWA) communication system using orthogonal frequency division multiplexing (OFDM), is proposed in this paper. Polar code is utilized to create a nested code structure that is divided into several subsets. We exploit this feature of the polar codes and assign each subset to the corresponding user in the channel coding process. The information bits are placed on the independent subset for each user, and the random bits are placed on the subset of other users while all the users share the same set of frozen bits. Then, the codewords are stacked with different weights. The selection range of power factors can be expanded through the double superposition of the coding and the power domains, and higher system throughput and fairness can be achieved. The simulation and tank experiment results significantly verify the effectiveness of the proposed scheme, making it most suitable for the downlink UWA multi‐user communication systems.

Feeding Behavior and Bait Selection Characteristics for the Portunidae Crabs Portunus sanguinolentus and Charybdis natator

Understanding the feeding behavior of Portunidae crabs with different baits can improve bait selection and is crucial for improving the effectiveness of crab fishing gear. This study, conducted in indoor experimental tanks, used trajectory tracking software and two types of natural baits (mackerel (Scomber australasicus) and squid (Uroteuthis chinensis)) to understand the behavior of Portunus sanguinolentus and Charybdis natator. Spatial distribution results showed that P. sanguinolentus was frequently present in the starting area (S1) and bait area (S3) in the control and treatment groups. However, C. natator was frequently present and concentrated in the S1 area compared to the middle areas S2 and S3, and only in the mackerel treatments were they observed to move to the S3 areas. The spatial distribution results indicate that P. sanguinolentus shows a stronger willingness to explore its surroundings, while C. natator is generally in a stationary, wait-and-see state. The swimming speeds of P. sanguinolentus and C. natator showed different trends. P. sanguinolentus showed continuous movement with no fixed speed when no bait was present in the control groups. However, when treated with mackerel and squid, the average swimming speed of P. sanguinolentus was faster (>5 cm/s) in the first 10 min and showed a more stable movement speed when searching for the baits. C. natator showed a stationary or low movement speed when no bait was present in the control groups. However, when C. natator perceived the presence of the baits in the treatment groups, their movement speed increased in the first 10 min. In addition, there was no significant difference between male and female crabs of P. sanguinolentus and C. natator in movement speed in the control and treatment groups. Compared to C. natator, P. sanguinolentus might be more sensitive to natural baits, as shown by its movement from S1 to S3. The results indicate that the species of Portunidae crabs show different bait selections. Natural baits (mackerel and squid) are recommended for catching P. sanguinolentus in crab fisheries.

Experimental study on hydrodynamic performance of the semi-submersible vessel-shaped fish cage

Deep-sea net cages play a vital role in expanding offshore farming in modern marine fisheries. In this paper, a model-scale 1:40 tank experiment was conducted for a vessel-shaped truss-structured single-point mooring deep-sea aquaculture net cage. The study focused on the hydrodynamic characteristics, including the effect of current, wave, and net on the mooring force, heave, and pitch motion behaviors. Experimental results indicate that the mooring force increases with the current velocity, draught of the cage, and wave height, but decreases with the wave period increase. Both heave and pitch movements amplitudes increase with wave height. While heave motion amplitude initially declines and then ascends with wave periods, pitch motion shows the opposite pattern. Besides the net has an obvious damping effect on the pitch motion. These results can provide data support for the design and offshore installation of vessel-shaped truss-structured net cages in the future.

Study on the influence of heave plate on energy capture performance of central pipe oscillating water column wave energy converter

This paper proposes a novel central pipe oscillating water column (OWC) wave energy converter (WEC) with a heave plate and investigates the influence of heave plate on energy capture performance of the OWC WEC through numerical methods. First, dynamic equations are established for floater and water column. Then, energy capture performance of the WEC is computed by solving relative motion equations using numerical methods. Wave tank experiments are conducted to validate the proposed numerical models. Finally, the influences of heave plate opening diameter and connecting column length on energy capture performance are investigated based on the proposed numerical models. The results indicate that increasing heave plate opening diameter decreases both the maximum capture width ratio (CWR) and response period. And increasing connecting column length widens the response bandwidth. When the heave plate opening diameter decreases from 350 mm to 0, the maximum CWR increases from 30.05% to 41.68% and the response period increases from 1.28 s to 1.72 s. When the connecting column length increases from 225 mm to 600 mm, the response band extends by 0.1 s. The proposed device and the obtained analysis results are of great significance for broadband and efficient wave energy generation.

Asymmetric competition for habitats between the temperate Japanese eel Anguilla japonica and the tropical Indo-Pacific eel A. marmorata

Habitat segregation is a common phenomenon among anguillids in rivers where multiple species coexist. However, despite the growing need to conserve their river habitats, the mechanisms underlying such segregation remain unknown. Here, we conducted tank experiments to investigate the competitive superiority for habitats between the temperate Japanese eel Anguilla japonica and the tropical Indo-Pacific eel Anguilla marmorata, which co-occur in East Asian subtropical rivers. Using eight interspecific pairs of these two species of comparable total length, we compared the use of a single pipe shelter, recorded over a 24-h experimental period, between solitary and paired conditions. The changes in shelter use patterns between conditions indicated that in the paired condition, the shelter was occupied by A. marmorata in five pairs (62.5%) by the end of the experiment while A. japonica appeared to occupy the shelter in only one pair (12.5%). Furthermore, agonistic behaviors, which occurred mainly at night, such as biting and head-butting, were observed much more frequently for A. marmorata toward A. japonica (mean ± standard deviation: 23.2 ± 36.6 times per individual) than for A. japonica toward A. marmorata (0.4 ± 0.5 times per individual), indicating an asymmetry in aggressiveness. These results suggest that A. marmorata can negatively affect the diurnal habitat use and nocturnal activities of sympatric A. japonica. These findings, combined with those from previous field studies, suggest that A. marmorata may competitively exclude A. japonica from stream habitats with large substrate sizes. This asymmetric competition can contribute to shaping their riverine distribution and composition within rivers where they co-occur.

Multiscale modeling of cavitation around high-speed object based on Euler-Lagrange model and overset mesh

Abstract Cavitation is a common phenomenon, which usually occurs inside the high-speed liquid or at the liquid-solid interface. The unsteady behaviors of cavitating flow, such as shedding and collapse, can cause intense pressure fluctuations and reduce the stability of devices such as under-water high-speed vehicles. In addition, cavitating flow changes the dynamic characteristics of the liquid and causes vibration of the structure as well, making it extremely difficult in achieving precise control. Using OpenFOAM, the present work employs the large eddy simulation (LES) approach to investigate the characteristics of the unsteady cavitating flow around a high-speed under-water object with using the overset mesh technology. The volume of fluid (VOF) approach jointed with the Lagrangian discreate bubble model (DBM) is used for capturing the multiscale cavitation features. The Schnerr & Sauer model is applied for the mass transfer between water and vapor in macroscale, while the Reynolds-Pel equation is incorporated for the growing and collapsing of microscale bubbles. Due to the difficulty in incorporating the multi-scale method into the problems with mesh motion, the present work employs the overset mesh method. Compared with the published small-scale water tank experiment, the LES simulation results fit well with the experimental phenomena, and the DBM can capture the small bubbles accurately. On the basis of model verification, the mechanisms of cavitation forming and collapsing is investigated and the effect of cavitation shedding on the motion of the object is also studied. Moreover, the nucleation, growth, collapse of bubbles, and the interaction between discrete bubbles and large cavities can be well revealed. Further, the multi-scale Euler-Lagrange model is also applied in the rotating propeller, the generation of tip vortex cavitation which is hard to be captured by traditional models is well presented.

A fully adaptive time–frequency coupling model using self-attention mechanism based on deep operator network for very short-term forecasting of ship motion

Very short-term ship motion forecasting aims to predict future movements using historical ship motion data. While ship motion features both temporal and frequency characteristics, the latter is often neglected. This paper proposes a fully adaptive time–frequency coupling forecasting model using self-attention mechanism based on the Deep Operator Network (DeepONet), abbreviated as TFD. The multi-head attention layers enable the trunk net to adaptively learn the relationships between different frequencies in the frequency domain and assign varying weights accordingly. Thus, compared to the Fourier transform and multilayer perceptron-net enhance model based on DeepONet (FMD), which relies on manually specified filter frequencies, the TFD model is capable of fully learning the motion patterns in both the time and frequency domains, establishing nonlinear mapping relationships between them. It exhibits greater interpretability and generalization. The TFD model is tested for accuracy and generalization using ship motion data from the Iowa University experimental tank. The results indicate that, compared to the DeepONet and FMD, the TFD model reduces the mean square error (MSE) by up to 64.72% and 52.45%, with an average reduction of 55.57% and 42.47%. In terms of generalization, the forecasting MSE is reduced by up to 65.04% and 46.08%. Compared to the DeepONet and FMD, the proposed TFD model demonstrates significant improvements in forecasting horizon and generalization, providing a notable advantage in very short-term ship motion prediction applications.

Ameliorating effects of natural herbal supplements against water-borne induced toxicity of heavy metals on Nile tilapia, (Oreochromis niloticus)

The efficacy of herbal supplements in mitigating heavy metals (HMs) toxicity was investigated using a widely grown fish, the Nile tilapia (Oreochromis niloticus). The experiment was conducted over two phases: during the stress phase, the experimental fishes were exposed to sub-lethal concentrations of HMs, including lead, cadmium, zinc, and copper for 15 days; following which during the feeding phase, herbal supplements were given for 70 days to ameliorate their effects. Seven groups were established: the control negative group (CON−ve), control positive group (CON+ve, without any treatment), and five groups with supplementation of 1% turmeric (TUR), cinnamon (CIN), ginger (GIN), garlic (GAR), and their mixture (MIX), respectively. A total of 315 fishes were distributed evenly in experimental tanks (15 fishes per tank, in triplicates). The results revealed that exposure to HMs led to significant (p < 0.05) alterations in all the tested parameters, i.e., liver damage and growth reduction. The herbal supplements, especially the MIX groups, ameliorated the harmful effects of HMs and restored fish growth, digestibility, carcass composition, and liver health. In conclusion, the study demonstrated that the herbal supplements were effective in reducing the HMs-linked toxicity in Nile tilapia. Future studies pertaining to the mechanisms facilitated by the various herbal bioactive substances-linked tolerance to HMs in fishes are warranted.

Infiltration of secondary treated wastewater into an oxic aquifer: Hydrochemical insights from a large-scale sand tank experiment

To mitigate groundwater level decline, managed aquifer recharge (MAR) with secondary treated wastewater (STWW) is increasingly considered and implemented. However, the effectiveness and potential risks of such systems need evaluation prior to implementation. In this study, we present a large-scale sand tank experiment to analyse processes related to the infiltration of real STWW through the vadose zone and subsequent mixing with oxic native groundwater. The varying composition of STWW from 15 infiltration cycles over six months of operation and the retention times were the main drivers of the observed processes, which were characterized by a wide range of analytical techniques such as in situ high-resolution oxidation–reduction potential (ORP) measurements, closed mass balances of solutes, characterization of dissolved organic carbon (DOC), stable nitrate isotopes analysis, as well as numerical flow and transport modelling. Depending on the composition and infiltration rates of the STWW, both nitrification and denitrification could be observed, even simultaneously at different locations in the tank. Furthermore, due to the variability of the real STWW we observed enhanced arsenic mobilisation during times of elevated phosphate concentrations of the infiltrating STWW. Additionally, uranium was mobilised in our experimental system via carbonate mineral dissolution caused by the infiltrating STWW which was undersaturated of calcite for all infiltration cycles. Overall, our results showed the importance of conducting studies with waters of complex matrix, such as real STWW, and considering mixing with groundwater to assess the full range of possible processes encountered at MAR field sites.