On-site Wastewater Treatment Research Articles

Assessing relationships between onsite wastewater treatment system maintenance patterns and system-level variables

Globally, millions of households rely on onsite wastewater treatment systems (OWTSs), such as septic systems, to safely treat and dispose of wastewater. Conventional subsurface OWTSs are a common and affordable option for many landowners, and effectively remove pathogenic and nutrient pollution from wastewater when properly sited and maintained. However, OWTSs can also be a source of nonpoint pollution in watersheds when they are not functioning properly. To better understand the drivers of OWTS maintenance and failure, we explored relationships between OWTS age, environmental characteristics (edaphic conditions, topographic wetness index, and distance to stream), and repair and pumping records for OWTSs in Athens-Clarke County, Georgia, USA. Repair records indicated that 7.8 % of the 8826 OWTSs in the study were repaired over a 78-year period and that the median age of a repaired OWTSs was 65 years old. Pumping records showed that 12.2 % of the OWTSs were pumped in a 38-month period (an annualized rate of 5.7 %). The suite of widely available environmental variables we used as predictors were likely not granular enough to detect patterns of individual system maintenance at this scale. However, we found that the oldest OWTSs (>50 years) had the highest probabilities of being repaired and exhibiting signs of hydraulic failure. Notably, new OWTSs (2–10 years) were nearly as likely as the oldest systems to exhibit signs of hydraulic failure. These findings suggest that repair and replacement efforts should target older systems that are at or near the end of their serviceable life, and, in addition to continually monitoring older systems, all OWTSs should be inspected one year after installation. By leveraging data that may already exist, practitioners in other localities can use this reproducible approach to estimate the performance of OWTSs. Our data and methods will support efforts to prioritize wastewater infrastructure investments and policies.

Use of Shredded Recycled Plastic as Filter Bed Packing in a Vertical Flow Filter for Onsite Wastewater Treatment Plants: Preliminary Findings

Household wastewater is a problem, especially in areas with a dispersed settlement where there is no wastewater collection system or wastewater treatment plant. In this case, it is necessary to build a local or onsite wastewater treatment plant. This paper is an attempt to analyse the possibility of using recycled shredded ABS plastic (acrylonitrile butadiene styrene) as packing media in an experimental vertical flow filter for use in on-site wastewater treatment plants. Studies have shown that shredded recycled ABS is a promising filtration material that has several features important in the treatment process, like a large surface area, high mechanical strength and chemical inertness. The system was operated with a hydraulic load of 50 dm3/m2 (3 months). BOD5 (biochemical oxygen demand), COD (chemical oxygen demand), and total suspended solids (TSS) reduction efficiency in the primary effluent was high; 94.4%, 77.8%, and 92.8%, respectively.

Comparative Analysis of Metagenomic (Amplicon and Shotgun) DNA Sequencing to Characterize Microbial Communities in Household On-Site Wastewater Treatment Systems

The performance of on-site wastewater treatment systems (OWTSs) can be improved by altering digester design and by manipulating environmental variables that affect microbial community composition. Community composition can potentially be assessed using high-throughput DNA sequencing, but the two most common methods of community DNA sequencing (16S and shotgun sequencing) generally yield different taxonomic identification profiles and can perform differently according to the sampled environment. To evaluate the use of these two approaches in monitoring OWTS operation, we conducted a comparative parallel analysis using both 16S rDNA and shotgun sequencing in a controlled field study. Results indicate that when examining microorganisms above 0.1% relative abundance, 16S and shotgun sequencing produced similar results in terms of individual sample species richness and between-sample community similarity. However, shotgun sequencing provided comparatively higher taxonomic richness for the bacterial communities with lower abundance in the OWTSs. In addition, 16S sequencing resolved only 48 out of 188 bacterial communities identified by shotgun sequencing (using a 0.1% abundance cutoff). Three key bacterial genera (Desulfomicrobium, Simplicispira, and Phenylobacterium) in anaerobic digestion processes were differentially abundant for both sequencing methods. These data indicate that both sequencing methods provide similar overall profiles for bacterial communities in anaerobic digestor systems. However, shotgun sequencing provides significantly (p-value < 0.01) higher taxonomic richness overall. Thus, shotgun sequencing provides a more robust taxonomic and functional profile that can be used for the optimization of anaerobic digestor systems.

Several Small or Single Large? Quantifying the Catchment-Wide Performance of On-Site Wastewater Treatment Plants with Inaccurate Sensors.

On-site wastewater treatment plants (OSTs) often lack monitoring, resulting in unreliable treatment performance. They thus appear to be a stopgap solution despite their potential contribution to circular water management. Low-maintenance but inaccurate soft sensors are emerging that address this concern. However, how their inaccuracy impacts the catchment-wide treatment performance of a system of many OSTs has not been quantified. We develop a stochastic model to estimate catchment-wide OST performances with a Monte Carlo simulation. In our study, soft sensors with a 70% accuracy improved the treatment performance from 66% of the time functional to 98%. Soft sensors optimized for specificity, indicating the true negative rate, improve the system performance, while sensors optimized for sensitivity, indicating the true positive rate, quantify the treatment performance more accurately. This new insight leads us to suggest programming two soft sensors in practical settings with the same hardware sensor data as input: one soft sensor geared to high specificity for maintenance scheduling and one geared to high sensitivity for performance quantification. Our findings suggest that a maintenance strategy combining inaccurate sensors with appropriate alarm management can vastly improve the mean catchment-wide treatment performance of a system of OSTs.

Performance Evaluation of Commercial Package Systems Used in Kuwait for on-Site Treatment and Reuse of Domestic Wastewater

Kuwait’s wastewater management scheme consists of a huge centralized sewerage system that transports all wastewater generated for treatment at central municipal plants for wastewater treatment. However, there are a few remote sites that are still not connected to the public sewerage system. In such sites, on-site systems such as conventional septic tank or package systems are commonly used. This study assessed the performance of two package systems used in Kuwait for on-site wastewater treatment and reuse. Wastewater samples were collected weekly for five months from influent and effluent streams of two package systems located at Ahmedi and Kadhmah areas of Kuwait. Comparison of the means of the laboratory results to the guidelines of Kuwait Public Authority for Environment (KEPA) indicated that the effluents of the two systems are suitable to be reused as irrigation water. However, results obtained also showed that performances of both units were highly fluctuating.

Organics removal from office wastewater in attached growth biological process of a packaged onsite wastewater treatment system

Organics removal from office wastewater in attached growth biological process of a packaged onsite wastewater treatment system

The sustainability of wastewater treatment efficiency and its estimated impact for onsite wastewater treatment plant systems in semi-urban areas: a Khan Yunis case study

The sustainability of wastewater treatment efficiency and its estimated impact for onsite wastewater treatment plant systems in semi-urban areas: a Khan Yunis case study

Nitrification potential of daily-watered biofiltration designs for high ammonium wastewater treatment

The vegetated biofiltration systems (VBS), also known as bioretentions or rain gardens, are well-established technology for treatment of urban stormwater and recently greywater, offering multiple benefits to urban environments. However, the impact of high ammonium strength wastewater (60 mg/L) on the nitrification process in these systems is not well understood. Hence, a laboratory-based column study was conducted to uncover dominant nitrification mechanisms, based on the learnings from similar onsite wastewater treatment systems. The experimental columns tested the effect of contact time (filter media depth, 150 mm, 300 mm and 700 mm), media oxygenation (active and passive) and alkalinity/pH (marble chips 5 % weight), as well as optimal operational conditions (inflow loading, concentrations, and dissolved oxygen (DO)). All nitrogen species (NH4+, NO3−, NO2−), chemical oxygen demand (COD) and physical parameters (DO, pH, electrical conductivity) were monitored across seven events over thirteen weeks. The results show that dosing with 30 and 60 mg/L of NH4+ resulted in 700 mm sand column depth to perform almost complete nitrification of NH4+ to NO3− (< 90 %), while 300 mm designs achieved partial nitrification of NH4+ to NO2−, likely due to limited contact time and inefficient nitrite oxidizing bacteria activity. Nitrification potential of all designs further supported that appropriate aerobic contact time is necessary for effective nitrification. Inflow concentration of NH4+ and DO did not significantly impact nitrification performance, while reducing daily volume loading reduced NO3− and NO2− leaching. Active and passive aeration and alkalinity buffering did not positively affect ammonium removal. While there is a potential to apply both nitrification-denitrification and anammox processes to future VBS design, further understanding of aeration and alkalinity on microbially driven nitrification processes is needed.

Perspective on the electrochemical recovery of phosphate from wastewater streams

AbstractThe presently increasing global population demands increased food production. Consequently, phosphate – an indispensable fertilizer component – will be needed in ever greater amounts. Current levels of mining of phosphate's most important constituent element, phosphorus (P), are unsustainable, and P rock is predicted to soon be completely depleted. Because P is a non‐renewable resource, techniques to recover and reuse waste phosphate are necessary. Large amounts of unused phosphate exist in both municipal and agricultural wastewater streams, as well as in sewage sludge. Approaches to recovering phosphate from these sources fall into three main categories: biological, chemical, and electrochemical. Biological phosphate recovery has seen some plant‐scale use, but significant drawbacks including the complication of operation have prevented it from becoming widespread. The most common method of phosphate recovery, chemical phosphate recovery, has been applied at scale with success due to the stability and reliability of the process. However, disadvantages such as the exorbitant amounts of alkali dosing required to maintain the high pH necessary for phosphate precipitation leave room for improvement. In recent years, electrochemical phosphate recovery has gained traction because of its potential to overcome the weaknesses of traditional chemical approaches by utilizing water electrolysis to induce a high pH without the need for an added base. But before plant‐scale electrochemical methods can be considered economically viable, the steep energy requirements of water electrolysis must be mitigated through the development of improved electrocatalysts or circumvented through the discovery and application of new electrochemical processes to generate hydroxyl ions needed to induce a high pH. In this review, the three broad categories of phosphate recovery techniques are discussed and an outlook on the future of electrocatalysis for phosphate recovery is presented. Particularly, the requirements for improved and Earth‐abundant electrocatalysts are considered alongside a critical discussion of the possibility of a decentralized network of onsite wastewater treatment facilities powered by renewable electricity.

Performance of the anaerobic baffled reactor for primary treatment of rural domestic wastewater in Iraq

Abstract The purpose of this work is to evaluate the performance of the anaerobic baffled reactor (ABR) for on-site primary treatment of domestic wastewater in rural areas of Iraq. The performance of the three-chamber ABR has been investigated at four different hydraulic retention times (HRTs) ranging from 6 to 36 h. The results showed that the chemical oxygen demand (COD) removal efficiency is enhanced with increasing HRT, where it was recorded at 75, 71, 63, and 56% removals rate of COD at HRTs of 36, 24, 12, and 6 h, respectively. The mean steady-state removals of total suspended solids are 91, 78, 72, and 67% at HRTs of 36, 24, 12, and 6 h, respectively. Also, it was shown that there was low-nutrients removal within the ABR. Consequently, the effluent ABR wastewater needs to be post-treated before being discharged to the receiving water bodies. In general, it is concluded that the ABR could introduce a solution for on-site primary treatment of domestic wastewater in rural communities in Iraq.

Evaluation of Effectiveness of On-site Wastewater Treatment Systems Located at Roadside Rest Areas: Recognition and Diagnosis of Existing Problems in the Operation of Selected Facilities

Abstract The effects of a dynamic increase in the total length of expressways in Poland include the issue of wastewater generation and disposal at roadside rest areas, which has been gaining importance, especially regarding the safety of local water ecosystems. Currently, the total number of roadside rest areas in Poland is nearly 400, yet in the future it could double, because of road infrastructure expansion and the need to improve road travel comfort. The most common approaches to wastewater disposal are septic tanks or wastewater treatment plants. In view of Poland’s environmental goals, only the second solution can be regarded as a form of final wastewater disposal. The aim of this study was to analyse available solutions for wastewater treatment at roadside rest areas, analysis of the effectiveness of their performance and identification, and diagnosis of existing problems. The tested facilities contained solutions based on biological wastewater treatment, preceded by a mechanical stage with the use of a two-chamber primary settling tank. Two solutions involved a sequencing batch reactor, and the remaining ones used submerged fixed-bed bioreactors. Finally, the obtained results showed unsatisfactory wastewater treatment effectiveness. Parameters such as chemical oxygen demand (COD) were exceeded at five of the six study sites, biochemical oxygen demand (BOD5) was exceeded at three sites, and total suspended solids was exceeded at two sites, which indicates a disturbance in the operation of the treatment plant. The reason for the poor effluent was primarily inadequate technological supervision of the operation of these facilities.

Matrix-associated microbial communities in a nitrogen-removing on-site wastewater treatment system are largely structured by niche processes.

On-site wastewater treatment systems (OWTSs) can be designed to promote microbial communities with naturally occurring metabolic functions desirable to wastewater treatment. Among such OWTSs are nitrogen-removing biofilters (NRBs), comprising a sand layer overlying a sand-lignocellulose (sand-lc) layer and intended to promote sequential nitrification and denitrification. The design of NRBs is based on the hypothesis that niche processes like environmental selection strongly structure the microbial communities, which predicts that immigrating wastewater communities and matrix-associated communities will be distinct and that the matrix communities in the two layers will be distinct. We characterized NRB microbial communities by 16S ribosomal RNA amplicon sequencing. Selection of the matrix-associated communities was indicated by clear differences from the immigrating community. For matrix-associated communities, alpha and beta diversity differed between the matrix layers, as did the relative abundances of many functional groups and genera. Functional groups with strict metabolisms were nearly exclusively detected in either the sand (ammonia and nitrite oxidizers) or sand-lc layer (methanogens), consistent with the niche hypothesis. Contrary to expectations, denitrifiers as a functional group were not present at greater relative abundance in the sand-lc than sand matrix because of a portfolio effect: some denitrifying genera were more abundant in the sand layer, whereas others were more abundant in the sand-lc layer. This study reveals niche processes acting at different levels of community organization for different biogeochemical functions, a crucial consideration in designing effective and reliable OWTSs to mitigate nitrogen pollution.

Future inundation of coastal on-site wastewater treatment systems in a region with pronounced sea-level rise

An often-overlooked impact of rising sea levels is the concurrent rise in coastal groundwater tables, which can result in subsurface inundation of below-ground infrastructure. This is an important consideration for rural coastal communities, many of which rely on on-site wastewater treatment systems (OWTS). Subsurface inundation and flooding of OWTS leads to treatment performance issues, potentially resulting in enhanced contaminant transport to coastal groundwater resources and the ocean via submarine groundwater discharge. We use SEAWAT to develop a variable-density groundwater flow model for the groundwater system underlying a densely populated rural community on the north shore of Nova Scotia, Canada. We then impose various climate change scenarios (sea-level rise, changes in recharge) to evaluate the risk of OWTS inundation from rising groundwater. We find that under current conditions as many as 9 % of OWTS in this small but densely populated watershed are either inundated or completely flooded. This number that could grow to 27 % of OWTS for the climate change scenario with the highest recharge and sea-level rise. As a secondary objective, we track the location of the modeled saltwater-freshwater interface, and investigate the potential salinization of groundwater resources used for drinking water supply. The modeled interface moved landward by ≤ 20 m and proved to be less of a concern than OWTS inundation, except for shoreline dwellings. We also use the modelling results to develop adaptation recommendations for OWTS installation regulations. This research contributes to an increasing number of groundwater modelling studies focusing on the impacts of sea-level rise on coastal subsurface infrastructure and provides important insight for rural coastal communities.

Comparison of O3, UV/O3, and UV/O3/PS processes for marine oily wastewater treatment: Degradation performance, toxicity evaluation, and flocs analysis

Efficient on-site treatment technology is crucial for mitigating marine oily wastewater pollution. This work investigates the ozone (O3), ultraviolet (UV)/O3, UV/O3/persulfate (PS) processes for the treatment of marine oily wastewater, including degradation performance, acute toxicity evaluation, and oil flocs analysis in a benchtop circulating flow photoozonation reactor. Degradation performances have been studied by measuring the degradation rate of total oil concentrations, specific oil components (n-alkanes and polycyclic aromatic hydrocarbons (PAHs)), and total organic carbon (TOC). The results show that UV/O3/PS could significantly enhance the removal efficiency than the other two processes, with above 90% of removal efficiency in 30 min. Acute toxicity analysis further shows that the wastewater quality is significantly improved by four-fold of the EC50 of Vibrio fischeri, and the mortality of Artemia franciscana decreases from 100% to 0% after 48 h exposure. Further, the morphology and functional groups of flocs have been further characterized, showing that the floating flocs could be further degraded especially in UV/O3/PS process. Our study further raised discussions regarding the future on-site application of O3-based systems, based on the results generated from the treatment efficiency, toxicity, and flocs characterization. The regulation of the oxidation strength and optimization of the reaction systems could be a practical strategy for on-site marine oily wastewater treatment.

Detection and Analysis of Microfibers and Microplastics in Wastewater from a Textile Company

Textile wastewater is polluted by inorganic/organic substances, polymers, dyes, and microfibers (MFs), which are microplastics (MPs) and natural fibers. This work is aimed at the preliminary investigation of MFs and MPs in textile industrial wastewater, and at evaluating the removal efficiency of an on-site wastewater treatment plant (WWTP). Ten samples of inflows and outflows of the WWTP of a textile company (applying a physic-chemical process) have been analyzed. Firstly, the samples underwent a pretreatment with 15% hydrogen peroxide at 25 °C for 5 days to remove organic compounds. Secondly, the MFs were recovered from the aqueous phase by pre-screening centrifugation, density separation, and filtration as alternative options. Filtration obtained the best performances, compared to the other recovery processes. Thirdly, the MFs were counted through optical microscopy and the MPs were identified through micro-FTIR. The MFs amount in the inflow samples was in the range of 893–4452 MFs/L. The outflow samples (310–2404 MFs/L) exhibited a 38–65% reduction compared to the inflows, demonstrating that up to 62% of residual MFs can enter the sewer network or the receiving water body. Cotton and wool, and numerous MPs (acrylic, polyester, polypropylene, polyamide, and viscose/rayon) were identified in the inflow and outflow samples (with the only exception of “dense” viscose (rayon), not detected in the outflows, and probably retained by the WWTP with the sludge). This study, even if just preliminary, offers interesting hints for future research on MFs/MPs detection in textile wastewater, and on the performance of a full-scale WWT process for their removal.

Soil water content and photosynthetically active radiation influences soil color assessment

Determining Munsell soil color in the field is subject to environmental conditions, including soil water content (SWC) and light intensity. New digital spectral technology designed for determining soil color may offer accurate assessments regardless of environmental conditions. This study was conducted to determine the impacts of SWC and light on visual observations and digital measurements of soil color value and chroma, the two color components most important for soil use interpretations for siting and designing onsite wastewater systems. Munsell color was measured using the XRite Capsure™ and visually using Munsell Color Books on 111 soil horizons from three South Carolina regions. While, in general, higher color values and lower chromas were determined from oven dried peds in comparison to field moist peds, the influence of SWC was region specific. Of most importance were higher color chromas documented from field moist peds compared to oven dried peds in the Coastal region. In this region, gley chromas were determined in unsaturated soils emphasizing the importance of carefully evaluating other landscape features when interpreting the soil for onsite wastewater treatment. While SWC affected the agreement between digital measurements and visual observations, in most regions the difference was less than one color chip and of no practical significance. Varying photosynthetically active radiation (PAR) did not affect digital measurements and had minimal influence on visual observations. Digital measurements of soil color value and chroma may offer validation of soil color under varying lighting conditions and could be a promising tool for training new soil evaluators in color assessment.

Climate Change and Onsite Wastewater Treatment Systems in the Coastal Carolinas: Perspectives from Wastewater Managers

Abstract Nearly one-half of the residents of North and South Carolina use decentralized or onsite wastewater treatment systems (OWTS). As the climate changes, coastal communities relying on OWTS are particularly vulnerable, as soil-based wastewater treatment may be reduced by water inundation from storm surge, sea level rise and associated groundwater rise, and heavy rainfall. Despite the vulnerabilities of OWTS to increased precipitation and sea level rise, there is little known about how onsite wastewater managers are responding to current and future climate risks. We conducted interviews with wastewater operators and installers and health regulators to understand the functioning, management, and regulation of OWTS in the current climate, challenges with rising sea levels and increases in extreme weather events, and what adaptation strategies could be implemented to mitigate negative impacts. Our results indicate that heavy precipitation and storm surges cause malfunctions for conventional septic systems where traditional site variables (e.g., soil type or groundwater level) are undesirable. Weather and climate are not required regulatory factors to consider in system selection and site approval, but many OWTS managers are aware of their impacts on the functioning of systems, and some are preemptively taking action to mitigate those impacts. Our findings suggest that filling gaps in the current communication structure between regulators and homeowners relying on OWTS is critical for coastal communities in the Carolinas to build climate resilience into decentralized wastewater infrastructure. Significance Statement This research aims to understand the functioning, management, and regulation of onsite wastewater treatment systems in the current climate, the challenges to these systems caused by rising sea levels and increases in extreme weather events, and the adaptation strategies that can be implemented to mitigate negative climate impacts. These results can be used by state government agencies, municipalities, and private sector wastewater managers to improve the resiliency of onsite wastewater treatment systems.

Integration of silicate minerals for ammonium and phosphate removal with an on-site wastewater treatment prototype

Inadequately treated wastewater exiting from on-site water treatment systems (OWTS) contains high levels of ammonium and phosphate, which contribute to environmental nutrient pollution. Nutrient removal in small-scale OWTS can be challenging because the most effective known methods are designed for large-scale systems and rely on biological processes. This work focuses on the implementation of two natural silicate-based minerals, clinoptilolite and Polonite, as non-biological sorptive media for nutrient removal in an OWTS. Lab-scale batch sorption experiments showed that Polonite performance is maximized after suspended solids have been removed from blackwater via ultrafiltration. In contrast, clinoptilolite shows robust performance even with untreated blackwater. With both minerals installed in our full-scale OWTS prototype, nutrient removal performance increased from 47.5 ± 15.0% to 84.1 ± 6.3% removal for total N and from 32.3 ± 2.3% to 78.9 ± 5.9% removal for total P. Nevertheless, the target removal performance (&gt;80%) for total P was only achieved with high Polonite loading, which increased effluent pH outside the target range of 6 &lt; pH &lt; 9. Additionally, no loss in nutrient removal performance was observed when the OWTS was restarted after a 150-day idle period. To investigate the potential for media reuse and nutrient recovery, various media regeneration solutions were evaluated. For clinoptilolite, 1 M HCl, NaCl, and KCl all showed good regeneration ability at 2 h contact time, with KCl showing the highest (&gt;86%) ammonium recovery. For the first time, we demonstrated that a minor fraction (30–40%) of binding sites in Polonite can be regenerated using 1 M NaOH or KOH. We also found that the same 1 M HCl regeneration solution could be reused for four clinoptilolite regeneration cycles with no loss in performance. From these results, we discuss opportunities and limitations for implementing these materials in small-scale OWTS.

A Fixed-Film Bio-Media Process Used for Biological Nitrogen Removal from Sewage Treatment Plant

In this study, a lab-scale fixed-film bio-media process was developed and operated to evaluate nitrogen removal from domestic sewage treatment plants. For nitrogen removal, the fixed-film bio-media process was applied in series with anaerobic, anoxic, and aerobic units in three separate reactors that were operated continuously at the same loading rates and hydraulic retention time. A biofilm separation bioreactor was developed for on-site domestic wastewater treatment and the bioreactor employed synthetic fiber modules so that the biomass could be completely attached to the media. In this paper, the performance of the fixed-film bio-media process with an average flow rate was evaluated before and after stabilization of the treatment system for nitrogen removal. The results show that the fixed-film bio-media process was successful for improved nitrogen removal from secondary and tertiary treated wastewater, with a 77% decrease in the total nitrogen discharge. Rapid nitrification could be achieved, and denitrification was performed in the anoxic filter with external carbon supplements during tertiary treated sewage wastewater. However, aeration was supplied after the stabilization process to achieve the nitrification and denitrification reaction for nitrogen removal. However, stable aeration supply could enhance nitrification at moderate temperature with benefits from complete retention of nitrifying bacteria within the system due to bio-media separation.

Determination of cytotoxicity following oxidative treatment of pharmaceutical residues in wastewater

Pharmaceutical residues are released in the aquatic environment due to incomplete removal from wastewater. With the presence of multiple chemicals in sewage waters, contaminants may adversely affect the effectiveness of a wastewater treatment plant (WWTP). In certain cases, discharged metabolites are transformed back into their pristine structure and become bioactive again. Other compounds are persistent and can withstand conventional wastewater treatment. When WWTP effluents are released in surface waters, pristine and persistent chemicals can affect the aquatic environment. To complement WWTPs and circumvent incomplete removal of unwanted chemicals or pharmaceuticals, on-site wastewater treatment can contribute to their removal. Advanced oxidation processes (AOPs) are very powerful techniques for the abatement of pharmaceuticals, however, under certain circumstances reactive toxic by-products can be produced. We studied the application of on-site AOPs in a laboratory setting. It is expected that treatment at the contamination source can eliminate the worst polluters. Thermal plasma and UV/H2O2 oxidation were applied on simulation matrices, Milli-Q and synthetic sewage water spiked with 10 different pharmaceuticals in a range of 0.1 up to 2400μg/L. In addition, untreated end-of-pipe hospital effluent was also subjected to oxidative treatment. The matrices were activated for 180min and added to cultured HeLa cells. The cells were 24h and 48h exposed at 37°C and subsequently markers for oxidative stress and viability were measured. During the UV/H2O2 treatment periods no toxicity was observed. After thermal plasma activation of Milli-Q water (150 and 180min) toxicity was observed. Direct application of thermal plasma treatment in hospital sewage water caused elimination of toxic substances. The low cytotoxicity of treated pharmaceutical residues is likely to become negligible if plasma pre-treated on-site wastewater is further diluted with other sewage water streams, before reaching the WWTP. Our study suggests that AOPs may be promising technologies to remove a substantial portion of pharmaceutical components by degradation at the source. Further studies will have to be performed to verify the feasibility of upscaling this technology from the benchtop to practice.