2000 Doctorate in Civil Engineering, Civil Engineering Department, University of Patras, Patras, Greece.
1990 Diploma, Civil Engineering Department, University of Patras, Patras, Greece.
RESEARCH, TEACHING, or OTHER INTERESTS
Environmental Engineering, Water Science and Technology, Pollution, General Materials Science
87
Scopus Publications
3201
Scholar Citations
30
Scholar h-index
59
Scholar i10-index
Scopus Publications
High-rate algal ponds in wastewater treatment: a critical look at recent developments Styliani E. Biliani, Ioannis D. Manariotis Environmental Science Water Research and Technology, 2026 This review critically examines recent advances in high-rate algal ponds for wastewater treatment, highlighting performance improvements, operational challenges, and opportunities for scale-up and resource recovery.
Formation of a High-Density Algal-Bacterial Flocculent Biomass in a Pilot-Scale Raceway Pond Treating Municipal Wastewater Styliani E. Biliani, Dimitrios Kakavas, Ioannis D. Manariotis Applied Sciences Switzerland, 2026 This study provides novel insights into the gradual development of an algal-bacterial self-flocculent biomass in a 400 L pilot-scale raceway pond for wastewater treatment to enhance sustainability and minimize environmental footprint. The synergetic interaction of algal-bacteria consortia improves nutrient removal while enabling biomass concentration increase. Initially, the microalgae-bacteria biomass was gradually developed by increasing the operating volume from 60 to 400 L. After 80 days, the biomass reached a plateau at a concentration of about 4 g L−1, and exhibited excellent settling characteristics. The initial settling velocity was 14.8 cm min−1 and a settling time of 3 min was required to achieve efficient separation. The reactor achieved high treatment efficiency of about 95% for all nutrients (organic matter, nitrogen and phosphorous) after the 80th day. The kinetic analysis showed that nutrient removal followed first-order kinetics, with soluble chemical oxygen demand and ammonia removal reaching 0.017 and 0.020 h−1, respectively. The results demonstrate high pollutant removal efficiencies and design guidelines for the use of increased concentrations of microalgae–bacteria consortia in urban wastewater treatment practice, an alternative green way for solving present-day wastewater treatment problems.
Physicochemical Characterization of Biochar Sorbents Produced at Different Temperatures from Malt Spent Rootlets Andreas Tzachristas, Panagiota D. Natsi, Panagiota E. Politi, Nikolaos Mourgkogiannis, Ioannis D. Manariotis, Hrissi K. Karapanagioti Processes, 2026 Biochars are currently proposed as soil amendments or sorbent materials. There is an extensive scientific literature that deals with biochars originating from different raw materials. However, a holistic physicochemical characterization with simple analytical techniques is needed to provide insights on the characteristics of the biochars produced from malt spent rootlets (MSRs) and how they vary using different pyrolysis temperatures. This way, their properties can be fully understood, and they can be used for commercial purposes more effectively. Initially, the texture of the biochars were visualized by SEM and was quantified by the adsorption/desorption of nitrogen and the Brunauer, Emmett, and Teller (BET) equation. Additionally, the moisture content, the ash content and the pH of each sample were measured. Furthermore, the electrical conductivity of each sample was measured. Different techniques were used to determine the properties of carbon and of the surface functional groups (Total Carbon, XRD, ATR-FTIR) and leachable organic matter. Also, sorption of the methylene blue dye solution has been studied, which is an indication of mesopores for each biochar. Molasses number was also determined, as this is an indicator of macropores. Finally, the chlorine removal rate was determined for each type of biochar. The experiments marked that the change in mass of biochars has stopped after three hours at 50 °C in the drying oven. The measured moisture content ranged from 6 to 11%. The specific surface area of our materials, calculated through the BET equation, for low temperature biochars (e.g., 28 m2/g, at 350 °C), is much lower than that of high temperature pyrolyzed biochar (e.g., 286 m2/g, at 850 °C). The pH value ranged from 7 to 10. The electrical conductivity values of samples ranged from 800 μS/cm to 2.55 mS/cm, and these decreased during the measurement after the second wash with deionized water. Crystallinity increased with increasing pyrolysis temperature whereas the number of functional groups decreased. MSR biochars produced at temperatures equal or higher than 750 °C demonstrate different characteristics to the ones produced at lower temperatures.
A Comprehensive Review on Sewage Sludge Biochar: Characterization Methods and Practical Applications Erofili-Vagia Gkogkou, Alkistis Kanteraki, Ekavi Aikaterini Isari, Eleni Grilla, Ioannis D. Manariotis, Ioannis Kalavrouziotis, Petros Kokkinos Environments Mdpi, 2026 Sewage sludge (SS) management and wastewater (WW) treatment remain among the most critical environmental challenges. The pyrolysis of sewage sludge to produce biochar (BC) represents a sustainable and circular strategy for waste valorization and pollution mitigation. This scoping review provides a comprehensive overview of BC derived from SS (BCxSS), with particular emphasis on how pyrolysis conditions affect key physicochemical characteristics such as yield, ash content, pH, surface area, and functional groups. Although substantial research has focused on the removal of heavy metals and organic pollutants using BCxSS, far less attention has been directed toward its potential for pathogen adsorption and inactivation, revealing a notable research gap. Recent studies highlight BCxSS as a versatile material with considerable promise in adsorption and catalysis. However, its application in pathogen removal remains insufficiently investigated, underscoring the need for further investigation into sorption mechanisms and biochar–microbe interactions.
Nutrient Removal Mechanisms of Algal-Bacteria Consortia in Secondarily Treated Wastewater Styliani E. Biliani, Ioannis D. Manariotis Environmental Processes, 2025 This study aimed to evaluate how the different environmental conditions affect the nutrient removal mechanism of algal-bacteria consortia. For the first time, the dark cycle nutrient removal mechanism was investigated offering an essential reference for enhancing wastewater treatment systems. Algal-bacteria consortia behavior was studied under different air supply (0 to 12 and 0 to 24 h) and illumination (24 h light and 12:12 h light: dark) periods. The highest nitrate and phosphorus removal was obtained with continuous light irradiation and air supply. The results demonstrated that illumination duration was a more important factor than air supply. So, when the light and air ceased on the 12-hour, the removal rate zero-order constants during darkness decreased by 36 and 55% for nitrates and phosphorus, respectively, compared to the 24-hour illumination and aeration culture. Nitrates appeared to be eliminated quite faster than phosphorus in the light, and slightly faster in the dark period. Refeeding of the culture during the dark period, without additional air, did not prevent nutrient removal, which was lower by about 58 and 45% for nitrates and phosphorus, respectively, compared to the removal in the light period. Algal-bacteria cultures can effectively remove nitrates and phosphorus from wastewater even during the dark period, providing valuable data for designing algal-based outdoor wastewater treatment systems.
Biochar made from Luffa cylindrica and applied as a bifunctional electrocatalyst in Zn-air batteries Natalia Tsoukala, Antonios-Alkinoos Papadopoulos, Vasiliki Premeti, Alexandros K. Bikogiannakis, Eftychia Martino, Angelos Amoiridis, Eleana Kordouli, Katerina Govatsi, Ioannis D. Manariotis, Georgios Kyriakou, Anastasios Keramidas, Dionissios Mantzavinos, Panagiotis Lianos Rsc Advances, 2024 Biochar has been prepared by pyrolysis of Luffa cylindrica (the vegetable sponge produced by Luffa aegiptiaca) and activated by mixing the pyrolyzed powder with KOH and pyrolyzed again.
Biochar from residues of anaerobic digestion and its application as electrocatalyst in Zn–air batteries Konstantinos Pergamalis, Charalampos Chaliotis, Antonios–Alkinoos Papadopoulos, Natalia Tsoukala, Angelos Amoiridis, John Vakros, Lamprini Sygellou, Eleana Kordouli, Katerina Govatsi, Michael Kornaros, Ioannis D. Manariotis, Anastasios Keramidas, Dionissios Mantzavinos, Panagiotis Lianos Journal of the Taiwan Institute of Chemical Engineers, 2024
A decision support system for highway pavement management in Greece Dimitrios D. Theodorakopoulos, Athanasios P. Chassiakos, Ioannis D. Manariotis, Panagiotis Patarias Proceedings of the International Conference on Applications of Advanced Technologies in Transportation Engineering, 2002
Information management in a decision support system for pavement management Proceedings of the Eight International Conference on Civil and Structural Engineering Computing, 2001
RECENT SCHOLAR PUBLICATIONS
Formation of a High-Density Algal-Bacterial Flocculent Biomass in a Pilot-Scale Raceway Pond Treating Municipal Wastewater SE Biliani, D Kakavas, ID Manariotis Applied Sciences 16 (8), 3761 , 2026 2026
Physicochemical Characterization of Biochar Sorbents Produced at Different Temperatures from Malt Spent Rootlets A Tzachristas, PD Natsi, PE Politi, N Mourgkogiannis, ID Manariotis, ... Processes 14 (6), 1012 , 2026 2026
Impact of pyrolysis temperature and residence time on biochar reflectance: A case study of ground coffee biochar S Kalaitzidis, M Georgaki, M Wojtaszek-Kalaitzidi, J Vakros, I Manariotis EGU26 , 2026 2026
Performance of Azolla-Based Floating Wetland for Domestic Wastewater Remediation I Manariotis, SV Polyzou, S Biliani EGU26 , 2026 2026
Sewage sludge-derived biochar as a circular “waste-to-resource” strategy for wastewater treatment EV Gkogkou, EA Isari, E Grilla, ID Manariotis, IK Kalavrouziotis, ... EGU26 , 2026 2026
Decreasing Drinking Water Toxicity by Chlorine Removal Using Activated Carbons, Biomaterials and Biochars from Agro-industrial By-products A Tzachristas, ID Manariotis, S Dailianis, HK Karapanagioti Water, Air, & Soil Pollution 237 (6), 346 , 2026 2026 Citations: 1
Recent progress on carbonaceous materials and their composites as adsorbents for phenolic pollutants: A review MJ Ahmed, I Anastopoulos, F Marrakchi, ID Manariotis Journal of Analytical and Applied Pyrolysis, 107629 , 2026 2026 Citations: 1
High-rate algal ponds in wastewater treatment: a critical look at recent developments SE Biliani, ID Manariotis Environmental Science: Water Research & Technology 12 (5), 1359-1373 , 2026 2026
A Comprehensive Review on Sewage Sludge Biochar: Characterization Methods and Practical Applications G Erofili-Vagia, K Alkistis, IE Aikaterini, G Eleni, ID Manariotis, K Ioannis, ... Environments 13 (1), 45 , 2026 2026
Sequential flow inclined biofilm photobioreactor for wastewater treatment and microalgae biomass production VD Tsavatopoulou, AF Aravantinou, ID Manariotis Journal of Environmental Chemical Engineering, 120448 , 2025 2025 Citations: 1
An optimized Zn-air battery using a polymer-blend anion transfer membrane and a biochar electrocatalyst M Katsaiti, S Gjoshi, V Deimede, ID Manariotis, JK Kallitsis, ... Electrochimica Acta 532, 146510 , 2025 2025 Citations: 3
Nutrient removal mechanisms of algal-bacteria consortia in secondarily treated wastewater SE Biliani, ID Manariotis Environmental Processes 12 (2), 30 , 2025 2025 Citations: 6
Long-term behavior of syntrophic algal-bacterial biomass in a pilot-scale raceway pond treating domestic wastewater D Kakavas, S Biliani, I Manariotis EGU General Assembly Conference Abstracts, EGU25-6521 , 2025 2025
Pilot scale silage production from olive pomace S Biliani, J Vakros, N Athanassopoulos, I Manariotis EGU General Assembly Conference Abstracts, EGU25-5962 , 2025 2025
Effect of pyrolysis conditions on biochar characteristics and water evaporation MV Manarioti, P Pelekis, I Manariotis EGU General Assembly Conference Abstracts, EGU25-7955 , 2025 2025 Citations: 1
Biochar from residues of anaerobic digestion and its application as electrocatalyst in Zn–air batteries K Pergamalis, C Chaliotis, AA Papadopoulos, N Tsoukala, A Amoiridis, ... Journal of the Taiwan Institute of Chemical Engineers 165, 105826 , 2024 2024 Citations: 5
Performance Enhancement of Kality Wastewater Treatment Plant’s Up Flow Anaerobic Sludge Blanket Reactor Using Surface Response Methods J Girma, A Kemal, A Nigussie, D Mantzavinos, Z Frontistis, AA Ioannidi, ... Zede Journal 42 (1), 49-65 , 2024 2024
Biochar from olive tree twigs and spent malt rootlets as electrodes in Zn-air batteries T Kottis, N Soursos, K Govatsi, L Sygellou, J Vakros, ID Manariotis, ... Journal of Colloid and Interface Science 665, 10-18 , 2024 2024 Citations: 11
Study of the Suitability of Corncob Biochar as Electrocatalyst for Zn–Air Batteries N Soursos, T Kottis, V Premeti, J Zafeiropoulos, K Govatsi, L Sygellou, ... Batteries 10 (6), 209 , 2024 2024 Citations: 4
Silage production from olive mil wastes I Manariotis, S Biliani, M Varvara Manarioti, N Athanassolpoulos European Geosciences Union General Assembly 2024 (EGU24), 14721 , 2024 2024
MOST CITED SCHOLAR PUBLICATIONS
Removal of caffeine, nicotine and amoxicillin from (waste) waters by various adsorbents. A review I Anastopoulos, I Pashalidis, AG Orfanos, ID Manariotis, T Tatarchuk, ... Journal of Environmental Management 261, 110236 , 2020 2020 Citations: 329
Degradation of antibiotic sulfamethoxazole by biochar-activated persulfate: factors affecting the activation and degradation processes L Kemmou, Z Frontistis, J Vakros, ID Manariotis, D Mantzavinos Catalysis Today 313, 128-133 , 2018 2018 Citations: 200
Selection of microalgae for wastewater treatment and potential lipids production AF Aravantinou, MA Theodorakopoulos, ID Manariotis Bioresource technology 147, 130-134 , 2013 2013 Citations: 186
Degradation of PAHs by high frequency ultrasound ID Manariotis, HK Karapanagioti, CV Chrysikopoulos Water Research 45 (8), 2587-2594 , 2011 2011 Citations: 128
Low‐strength wastewater treatment using an anaerobic baffled reactor ID Manariotis, SG Grigoropoulos Water Environment Research 74 (2), 170-176 , 2002 2002 Citations: 123
Effect of cultivation media on the toxicity of ZnO nanoparticles to freshwater and marine microalgae AF Aravantinou, V Tsarpali, S Dailianis, ID Manariotis Ecotoxicology and environmental safety 114, 109-116 , 2015 2015 Citations: 114
Removal of mercury from aqueous solutions by malt spent rootlets VA Anagnostopoulos, ID Manariotis, HK Karapanagioti, ... Chemical engineering journal 213, 135-141 , 2012 2012 Citations: 106
Organic and nitrogen removal in a two-stage rotating biological contactor treating municipal wastewater DN Hiras, ID Manariotis, SG Grigoropoulos Bioresource technology 93 (1), 91-98 , 2004 2004 Citations: 95
Preparation and characterization of biochar sorbents produced from malt spent rootlets ID Manariotis, KN Fotopoulou, HK Karapanagioti Industrial & Engineering Chemistry Research 54 (39), 9577-9584 , 2015 2015 Citations: 90
Aqueous mercury sorption by biochar from malt spent rootlets LG Boutsika, HK Karapanagioti, ID Manariotis Water, Air, & Soil Pollution 225 (1), 1805 , 2014 2014 Citations: 89
Activation of persulfate by biochars from valorized olive stones for the degradation of sulfamethoxazole E Magioglou, Z Frontistis, J Vakros, ID Manariotis, D Mantzavinos Catalysts 9 (5), 419 , 2019 2019 Citations: 81
Degradation of sulfamethoxazole with persulfate using spent coffee grounds biochar as activator A Lykoudi, Z Frontistis, J Vakros, ID Manariotis, D Mantzavinos Journal of Environmental Management 271, 111022 , 2020 2020 Citations: 80
Bamboo-derived adsorbents for environmental remediation: A review of recent progress D Kalderis, A Seifi, TK Trang, T Tsubota, I Anastopoulos, I Manariotis, ... Environmental Research 224, 115533 , 2023 2023 Citations: 65
Oxidation of sulfamethoxazole by rice husk biochar-activated persulfate E Avramiotis, Z Frontistis, ID Manariotis, J Vakros, D Mantzavinos Catalysts 11 (7), 850 , 2021 2021 Citations: 64
Removal of biocolloids suspended in reclaimed wastewater by injection into a fractured aquifer model CV Chrysikopoulos, C Masciopinto, R La Mantia, ID Manariotis Environmental science & technology 44 (3), 971-977 , 2010 2010 Citations: 61
Activation of persulfate by biochar from spent malt rootlets for the degradation of trimethoprim in the presence of inorganic ions E Grilla, J Vakros, I Konstantinou, ID Manariotis, D Mantzavinos Journal of Chemical Technology & Biotechnology 95 (9), 2348-2358 , 2020 2020 Citations: 58
Phenanthrene removal from aqueous solutions using well-characterized, raw, chemically treated, and charred malt spent rootlets, a food industry by-product S Valili, G Siavalas, HK Karapanagioti, ID Manariotis, K Christanis Journal of environmental management 128, 252-258 , 2013 2013 Citations: 58
Effect of operating conditions on Chlorococcum sp. growth and lipid production AF Aravantinou, ID Manariotis Journal of environmental chemical engineering 4 (1), 1217-1223 , 2016 2016 Citations: 54
Design and analysis of a solar reactor for anaerobic wastewater treatment AC Yiannopoulos, ID Manariotis, CV Chrysikopoulos Bioresource technology 99 (16), 7742-7749 , 2008 2008 Citations: 54
Virus inactivation by high frequency ultrasound in combination with visible light CV Chrysikopoulos, ID Manariotis, VI Syngouna Colloids and Surfaces B: Biointerfaces 107, 174-179 , 2013 2013 Citations: 51
