Daniel Mamais

• Professor (Associate) at National Technical University of Athens

Vertical subsurface flow constructed wetlands (VSSF CWs) were employed to investigate the use of biochar that could be produced with local agricultural biomass through pyrolysis, recycled glass from local recycling companies and gel beads with decreased packing volume and shipping cost as substrate alternatives to sand. The materials were assessed...

This work investigated the long-term (>1000 days) performance of an integrated process consisting of an upflow anaerobic sludge blanket (UASB) coupled to a two-stage (saturated and unsaturated) vertical subsurface flow constructed wetland (VSSF-CW) for the treatment of up to 91.3 ± 10.3 m3/d domestic wastewater. The UASB reactor operated under ambi...

The combination of treatment wetlands (TWs) with microbial electrochemical technologies (MET) is often studied in the lab to improve the performance and decrease the footprint of TWs. In this article we evaluated the long-term performance of four pilot-scale vertical sub-surface flow TWs for major pollutants' and organic micropollutants' removal fr...

This work investigated the greenhouse gas (GHG) emissions from vertical sub-surface flow constructed wetlands (VSSF CWs) receiving the effluent from an upflow anaerobic sludge blanket (UASB) that is treating domestic wastewater. Specifically, methane (CH4) and nitrous oxide (N2O) were monitored along with carbon dioxide (CO2) emissions since they a...

Antimicrobial resistance (AMR) is a serious problem for modern society, not only associated with clinical environments, but also the natural environment. Conventional wastewater treatment plants (WWTPs) are important nodes for the dissemination of antibiotic resistance to the aquatic environment since they are reservoirs of antibiotic-resistant bac...

The performance of a laboratory-scale 40 L anaerobic membrane bioreactor (AnMBR) treating municipal wastewater with and without iron supplementation was evaluated at ambient temperatures at a hydraulic retention time (HRT) of 6 h and sludge retention time (SRT) of 50 days. The system exhibited satisfactory performance during the summer and winter p...

Non-steroidal anti-inflammatory drugs (NSAIDs) and endocrine disruptors (EDCs) are among the most important categories of contaminants of emerging concern (CECs), and many advanced technologies have been developed for their elimination from water and wastewater, including nano-zero valent iron (nZVI). This study investigates the performance of nZVI...

The application of the integrated UASB-CW system serves as an efficient technology for sanitation and water reclamation. The combination of this wastewater treatment scheme with an agroforestry system, which is irrigated by reclaimed water, aims to be an interesting demonstration of a circular approach to wastewater management. This work focuses on...

The challenge of water reclamation on decentralized water-scarce areas could be addressed with the application of low-cost nature-based solutions. This work investigated the performance of an integrated upflow anaerobic sludge blanket (UASB) reactor coupled with a two-stage vertical flow constructed wetlands system designed to treat the sewage of a...

This work evaluated four pilot-scale constructed wetlands (CWs), three of which were filled with electroconductive material to enhance the complex physical, chemical and biological reactions and one that was filled with gravel but aerated, for the treatment of domestic wastewater under different organic loading (OLR) values. The difference among th...

In this work, 38 different organic emerging contaminants (ECs), belonging to various chemical classes such as pharmaceuticals (PhCs), endocrine-disrupting chemicals (EDCs), benzotriazoles (BTRs), benzothiazoles (BTHs), and perfluorinated compounds (PFCs), were initially identified and quantified in the biologically treated wastewater collected from...

This work investigates the operation of a full-scale scheme for domestic wastewater treatment at ambient temperature consisting of two parallel upflow anaerobic sludge blanket (UASB) reactors coupled to a two-stage system of saturated and unsaturated vertical flow constructed wetlands (CWs) in series. The system is designed to treat up to 100 m 3 /...

Evaluation of the operation of an integrated UASB – Vertical sub-surface flow (VSSF) constructed wetland (CW) system for the treatment of domestic wastewater in a Greek village to produce reclaimed water that is suitable for agricultural irrigation.

The enhancement of constructed wetlands (CW) performance in terms of biological and physicochemical processes can be achieved with the use of alternative filling materials, that aid the metabolism of specific bacteria. Comparing to the conventional CW design guidelines (DWA, 2018) which is around 20 g COD m-2 d-1¸ electroconductive CWs are capable...

This work examined the short and long-term effects of different free ammonia (FA) and free nitrous acid (FNA) levels on (i) acclimatized biomass treating sludge reject water via nitrite in a sequencing batch reactor (SBR) and (ii) non-aclimatized biomass treating municipal wastewater via nitrate in the activated sludge process. In the acclimatized...

Increased groundwater and soil contamination by hexavalent chromium have led to the employment of a variety of detoxification methods. Biological remediation of Cr(VI) polluted aquifers is an eco-friendly method that can be performed in situ by stimulating the indigenous microbial population with organic and inorganic electron donors. In order to s...

The purpose of this study is to investigate the effect of free nitrous acid (FNA) and free ammonia (FA) on the anoxic phosphorus uptake rate (PUR) of polyphosphate-accumulating organisms (PAOs) via the utilization of nitrite. With this goal, upon developing a PAO-enriched culture in a sequential batch reactor, a series of batch experiments were con...

Wastewater treatment plants (WWTPs) exhibit significant energy consumption and produce large amounts of Greenhouse Gas emissions (GHG emissions). Energy efficiency and reduction in GHG emissions in WWTPs have become important issues, especially in view of the climate crisis. The core objective of this work is to assess the energy and carbon footpri...

Hexavalent chromium is a carcinogenic heavy metal that needs to be removed effectively from polluted aquifers in order to protect public health and the environment. This work aims to evaluate the reduction of Cr(VI) to Cr(III) in a contaminated aquifer through the stimulation of indigenous microbial communities with the addition of reductive agents...

Nano zerovalent iron (nZVI), produced from green tea extracts, was incorporated in a cation exchange resin (R-nFe) to investigate its performance regarding the removal of four non-steroidal anti-inflammatory drugs (NSAIDs): ibuprofen (IBU), naproxen (NPX), ketoprofen (KTP) and diclofenac (DCF). The effect of contact time, NaCl pretreatment, pH, R-n...

The purpose of this study is to investigate the effect of Free Nitrous Acid (FNA) and Free Ammonia (FA) on enhanced biological phosphorus removal (EBPR) and in particular on the aerobic phosphorus uptake rate (PUR). To this end, a PAO-enriched biomass was developed at a lab-scale reactor in order to fuel a series of ex-situ batch experiments to tes...

In the situation of water scarcity in which we currently find ourselves, safeguarding the water resources, by promoting wastewater reuse and recovery, is becoming increasingly important. Therefore, in the perspective of circular economy, the treatment with nature-based solutions (NBS) of wastewater in order to reuse it, while also recovering resour...

This work examined the start-up of a full-scale upflow anaerobic sludge blanket (UASB)-vertical flow constructed wetland (CW) for domestic wastewater treatment. The UASB reactors were inoculated with sludge originating from an industrial anaerobic reactor and the start-up period due to the slow growth rate of anaerobic sludge and the low temperatur...

The natural capacity of several microbes to reduce Cr(VI) to Cr(III) has been considered of much interest in order to remediate soil and groundwater polluted with Cr(VI). The objective of this work is to evaluate the enhancement of the activity of indigenous Cr(VI) reducing bacteria by the addition of carbon source and to investigate the synergisti...

The composition of mixed dechlorinating communities varies considerably in field and laboratory conditions. Dechlorinators thrive alongside with distinctive populations that help or hinder dechlorination. The variability of the composition of dechlorinating communities inevitably precludes a firm consensus regarding the optimal strategies for biost...

An innovative way to treat municipal wastewater and produce energy at the same time is anaerobic treatment. Anaerobic processes are traditionally used for high-strength wastewater or municipal sludge treatment and only recently have been applied for the treatment of low strength municipal wastewater To investigate the performance of anaerobic waste...

High-rate activated sludge (HRAS) systems are designed to shift the energy-intensive processes to energy-saving and sustainable technologies for wastewater treatment. The high food-to-microorganism (F/M) ratios and low solid retention times (SRTs) and hydraulic retention times (HRTs) applied in HRAS systems result in the maximization of organic mat...

The effect of sulfate presence on reductive dechlorination of chlorinated ethenes has been a matter of conflict among the limited reports found in literature. This paper aims to clarify the misconceptions regarding the performance of trichloroethene biotransformation under sulfate reducing conditions by evaluating the effect of different sulfate co...

The fate of several emerging pollutants in a Greek river system was assessed through analytical measurements and mathematical modelling. Target compounds selected in this study consist of five endocrine disrupting chemicals and four non-steroidal anti-inflammatory drugs. Two sampling campaigns were implemented to assess target compounds concentrati...

A small footprint wastewater treatment plant that consists of a membrane bioreactor coupled with a reverse osmosis unit (MBR-RO) has been placed and set in operation for 24 months in the R&D department of the Athens Water Supply and Sewage Company (EYDAP) in order to evaluate the quality of the treated effluent and to explore the feasibility of reu...

BACKGROUNG The objectives of this study were to provide a detailed qualitative and quantitative characterization of different reject water types and to evaluate the effect of temperature and type of external organic carbon source on short‐cut nitrification/denitrification process performance for the treatment of reject water with a high ammonia con...

The objective of this work is to evaluate biological groundwater treatment systems that will achieve hexavalent chromium removal from groundwater at hexavalent chromium (Cr(VI)) groundwater concentrations in the 0 – 200 μg/L range under anoxic conditions. The effect of type of organic substrate added as feed to the groundwater treatment system (mil...

A compact membrane bioreactor and reverse osmosis (MBR–RO) system was installed and set in operation in KEREFYT, EYDAP, in order to assess the potential reuse applications of the reclaimed water. Practicing the sewer mining (SM) approach, the feed of the unit was directly drained from the sewage network. Monitoring of system’s performance was perfo...

This work aims at developing a new software tool for the monitoring, control and mitigation of the carbon footprint of WWTPs, called C-FOOT-CTRL. GHG emissions are emitted from various stages of treatment in a WWTP. Currently, in developed countries the energy required for wastewater treatment accounts for approximately 3% of the total electricity...

Water scarcity, either due to increased urbanisation or climatic variability, has motivated societies to reduce pressure on water resources mainly by reducing water demand. However, this practice alone is not sufficient to guarantee the quality of life that high quality water services underpin, especially within a context of increased urbanisation....

The project C-FOOT-CTRL develops a standalone software tool composed by different modules. An on-line data module is in charge of communicating to different on-line data providers and sending these data to the Database module. Model predictions based on on-line input data and mechanistic models including N2O emission calculation will provide on-lin...

The fate of four benzotriazoles [1-H-benzotriazole (1-H-BTRi), tolyltriazole (TTRi), xylyltriazole (XTRi) and 1-hydroxy-benzotriazole (1-OH-BTRi)] and three benzothiazoles [benzothiazole (BTH), 2-hydroxy-benzothiazole (2-OH-BTH) and 2-amino-benzothiazole (2-amino-BTH)], during chlorination batch experiments was investigated. In the first step, thei...

Microbial reductive dechlorination is part of a complex dynamic system, which, apart from dehalorespiration, comprises (a) production of hydrogen from the fermentation of organic substrates, and (b) competition for hydrogen or short-chain fatty acids (e.g. butyrate or acetate) from competing terminal electron-accepting processes, such as sulfate re...

The objective of this work is to develop and evaluate biological groundwater treatment systems that will achieve hexavalent chromium reduction and total chromium removal from groundwater at hexavalent chromium (Cr(VI)) groundwater concentrations in the 0–200 μg/L range. Three lab-scale units operated, as sequencing batch reactors (SBR) under aerobi...

BACKGROUND Microbial reduction of Cr( VI ) to the much less toxic Cr( III ), although practiced for the treatment of liquid wastes has not been implemented for the treatment of groundwater due to the absence of electron donors (organic substrates) and the lack of data on inhibition of biological Cr( VI ) removal. The objective of this work is to ev...

Laboratory tests were conducted with four non-steroidal anti-inflammatory drugs (naproxen, ibuprofen, diclofenac and ketoprofen) under different redox conditions (aerobic, anoxic, anaerobic and sulfate-reducing conditions) in order to assess abiotic and biotic degradation in a river water/sediment system. The river water was sampled from Sperchios...

Both photodegradation and hydrolysis of non-steroidal anti-inflammatory drugs (NSAIDs) and endocrine disrupting chemicals (EDCs) were investigated in order to evaluate their photochemical fate in aquatic environment and to assess the effect of season and specific characteristics of water (pH, humic acids and nitrate concentration) on the removal of...

The collective literature suggests that cheese whey powder is a low cost material and an efficient substrate to support microbial inorganic or organic pollutants removal. This study investigates the effectiveness of liquid cheese whey as an electron donor on reductive dechlorination of TCE for the replacement of butyrate, an industrial-grade chemic...

Within this study, different configurations for wastewater treatment were evaluated in terms of energy requirements and greenhouse gases emissions. The results showed a higher carbon footprint of the extended aeration system compared to the conventional activated sludge process. Energy recovery from biogas burning was an important factor for the fi...

This study investigates how the feeding pattern of e(-) donors might affect the efficiency of enhanced in situ bioremediation in TCE-contaminated aquifers. A series of lab-scale batch experiments were conducted using butyrate or hydrogen gas (H2) as e(-) donor and a TCE-dechlorinating microbial consortium dominated by Dehalococcoides spp. The resul...

Polycyclic aromatic hydrocarbons (PAHs) are aromatic hydrocarbons with two or more fused benzene rings originating from natural and anthropogenic sources. PAHs are widespread environmental contaminants in aquatic environments and mainly originate from fossil fuel combustion and from the release of petroleum and petroleum products (Tian et al. 2009,...

This work puts forth a heuristic approach for investigating compromises between quality of fit and parameter reliability for the Monod-type kinetics employed to model microbial reductive dechlorination of trichloroethene. The methodology is demonstrated with three models of increasing fidelity and complexity. Model parameters were estimated with a...

The collective literature on dechlorination performance in the presence of sulfate can be interpreted to suggest that dechlorination at sites with elevated sulfate concentrations may be incomplete. Previous work comparing laboratory and field data concluded that the presence of sulfate in sites contaminated with trichloroethylene (TCE) might delay...

Endocrine disrupting chemicals and non-steroidal anti-inflammatory drugs are two important groups of emerging pollutants due to their toxicological and chemical characteristics and their persistent detection in the aquatic environment. Wastewater treatment plants are a significant pathway for their transfer to the water courses. It is well evidence...

Membrane bioreactors (MBRs) are currently considered a mature technology for municipal wastewater treatment with many full scale applications worldwide. The drive for the wider implementation of MBR technology can be the increasingly stringent legislation concerning the reuse or discharge of the treated effluent. In this work it is shown that the s...

This is the first study that investigates in detail the effect of different sulfate concentrations on trichloroethene-dechlorinating microbial communities, both in terms of dechlorinating performance and microbial composition. The study used a series of Dehalococcoides-containing trichloroethene-dechlorinating microbial communities, which operated...

Trichloroethylene (TCE), a compound classified as carcinogenic substance, is widely used in industrial and commercial sectors. Its improper storage and/or neglectful disposal have resulted in groundwater contamination in industrialized sites all over the world. Microbial anaerobic reductive dechlorination is an important mechanism of in situ remedi...

This work examined the impact of three natural minerals (zeolite, bentonite and perlite), three coagulants [ferric chloride, alum and polymeric aluminium chloride (PACl)] and a cationic polymer (MPE50) on the reduction in membrane fouling in membrane bioreactors (MBRs). The experiments were conducted using an ultrafiltration (UF) membrane module th...

Endocrine disrupting chemicals (EDCs) are compounds of mainly anthropogenic origin that interfere with the endocrine system of animals and humans thus causing a series of disorders. Wastewater treatment plants are one of the major routes for transporting such chemicals to the water courses. In the context of this study, several chlorination batch t...

The concentrations of nine emerging contaminants, including pharmaceutically active compounds (PhACs) (ibuprofen, IBF; naproxen, NPX; diclofenac, DCF; ketoprofen, KFN) and endocrine disrupting chemicals (triclosan, TCS; bisphenol, BPA; nonylphenol, NP; nonylphenol monoethoxylate, NP1EO; nonylphenol diethoxylate, NP2EO), were determined in wastewate...

Three large Wastewater Treatment Plants (WWTP) in Greece with occasional severe foaming were selected in order to evaluate the influence of the recycle of foaming filamentous bacteria from the solids handling processes to their foaming problems. According to the results, a range of 3–39% of the total quantity of viable foaming filamentous bacteria...

This paper aims to reconcile discrepancies among reports of dechlorination performance in the presence of sulfate, by analyzing data from the literature, presenting results from laboratory experiments performed with mixed anaerobic microbial cultures, and synthesizing respective findings. A complete set of metrics for dechlorination progress was de...

The aim of this study was to assess the feasibility of co-digesting lipids originated from domestic wastewater along with sewage sludge. Three lab-scale single stage mesophilic anaerobic digesters were operated under a constant hydraulic retention time (15 days). One system (C) was fed on a daily basis with sewage sludge and served as the control s...

The objective of this study was to evaluate the ability of Microthrix parvicella for long-chain fatty acids uptake under anaerobic, anoxic, and aerobic conditions as well as its ability to utilize volatile fatty acids and long-chain fatty acids under anoxic and aerobic conditions. According to the results, a hypothesis on the competition between fl...

The objective of this study was to evaluate the ability of Microthrix parvicella for long‐chain fatty acids uptake under anaerobic, anoxic, and aerobic conditions as well as its ability to utilize volatile fatty acids and long‐chain fatty acids under anoxic and aerobic conditions. According to the results, a hypothesis on the competition between fl...

This paper presents the results of an investigation that aimed to evaluate the efficiency of various inorganic coagulants and organic polymers to combat filamentous foaming and bulking problems, caused by the proliferation of M. parvicella and/or Gordona amarae. The duration of the investigation covered 14 months. During this period foam samples we...

The aim of this work was to evaluate the long-term performance of a Membrane Bioreactor (MBR) that operated continuously for 2.5 years and to assess membrane fouling and biomass activity under various operating conditions. Furthermore, a method for the characterisation of influent wastewater was developed based on its separation into various fracti...

The paper presents experimental evidence that selection and addition of an appropriate type of Powdered Activated Carbon (PAC) and alternatively or in combination ozonation of the water can be very effective in removal of both geosmin and 2-MIB from surface waters intended for supplying potable water. According to the experimental results, it was s...

Microthrix parvicella is the dominant filamentous microorganism prevailed in biological nutrient removal (BNR) activated sludge systems experiencing temporarily or even permanently filamentous bulking and foaming problems. Reports regarding the ability of M. parvicella to uptake and utilize long chain fatty acids (LCFA) are rather controversial. In...

The scope of the study presented in this paper is to determine the fate of the filamentous bacteria Gordona amarae and Microthrix parvicella in anaerobic digestion operating under mesophilic and thermophilic conditions. In order to detect and quantify foaming bacteria in the anaerobic digesters, a fluorescent in situ hybridization (FISH) method was...

Diuron biodegradation was studied in activated sludge reactors and the impacts of aerobic and anoxic conditions, presence of supplemental substrate and biomass acclimatization on its removal were investigated. Diuron and three known metabolites, namely DCPMU (1-(3,4-dichlorophenyl)-3-methylurea), DCPU (1-3,4-dichlorophenylurea) and DCA (3,4-dichlor...

The two most dominant technologies in sludge dewatering are belt filter presses and centrifuges. The objective of this work is to evaluate the two technologies in parallel operation, using full scale data from two wastewater treatment plants of different size. According to the data obtained, centrifuges produced a drier cake and exhibited slightly...

The aim of this study was to compare two alternative toxicity assessment methods to determine wastewater toxicity and predict treatment plant process upsets. The toxicity of two synthetic organic compounds (triclosan and 4-n-nonylphenol), which are commonly detected in municipal wastewater, and municipal and industrial wastewaters with different he...

The toxic effects of triclosan (TCS) and nonylphenol (4-n-NP) on activated sludge heterotrophic and autotrophic microorganisms were evaluated. Toxicity experiments with specific oxygen uptake rate (SOUR) and ammonia uptake rate (AUR) revealed that TCS was much more toxic to heterotrophic and autotrophic microorganisms than 4-n-NP. In experiments wi...

The biodegradability of several potential endocrine disrupting compounds, namely 4-n-nonylphenol (4-n-NP), nonylphenol monoethoxylate (NP1EO), nonylphenol diethoxylate (NP2EO), bisphenol A (BPA), triclosan (TCS), di-(2-ethylhexyl)-phthalate (DEHP), perfluorooctanoate (PFOA) and perfluorononanoate (PFNA) was evaluated in this study, using OECD metho...