Water and Wastewater Processes

Water lies at the core of the human activity. As such, it receives the highest attention in the Division of Environmental, Water and Agricultural Engineering. Key activities are related to understanding and developing processes for treating drinking or irrigation waters from various natural and artificial sources, as well as treating domestic and industrial effluents. This primarily includes chemical and biological processes related to water and wastewater treatment.

Environmental Microbiology

The field of environmental microbiology deals with different pathogenic microorganisms (viruses, bacteria, parasitic protozoan and helminthes) involved in different environments. Basically, the area concentrates in water milieu, but soil and air are also included. The spread, survival, growth and interaction with different environmental parameters of these pathogens are the main focus of research. In addition, environmental microbiology looks upon the methodology of isolation and identification of these pathogens from water, soil and air, using classical and new molecular biology methods. Indicators of these pathogens are also investigated in depth to simplify environmental monitoring. Among the environmental systems related to environmental microbiology are biofilms, wastewater and water treatment, sludge and compost manipulation, food microbiology, agriculture and water reuse. In the 1970’s IWA established a group of international experts, which is well established today. Called: “Health-Related Water Microbiology” (HRWM), the group holds bi-annual meetings globally.


Environmental Biotechnology

Environmental biotechnology is a broad and expanding field of modern environmental research, aimed at studying the development, use and regulation of biological systems for remediation of contaminated environments (land, air, water and sediments), for environment-friendly processes and prevention of pollution (green manufacturing technologies and sustainable development) and for sensing and monitoring of pollution. The primary role of environmental biotechnology is to develop efficient approaches for sustainable development and for understanding processes in the natural environment. Environmental biotechnology processes work according to known biological principles, however, due to the complexity of biological processes, implementation of these principles requires a great number of empirical solutions. Teaching and research that provide knowledge of the primary biotechnological processes and their increased efficiency in combination with advanced separation processes, are essential for scientists and engineers. Research at the environmental biotechnology laboratory focuses on (i) biodetoxification of toxic aromatic compounds through the use of microbial and/or enzymatic processes, with special emphasis to fungal biotechnology; (ii) pressure driven membrane separation processes applied for upgrading treated wastewater effluents for unrestricted reuse; and development of tools for predicting and evaluating biofilm formation, biofouling control, removal of micropollutants. The major disciplines involved are: biochemical engineering, environmental microbiology, enzymology, microscopy and analytical chemistry.


Aquatic Chemistry

Research activity in the field of applied aquatic chemistry focuses, on one hand, on development of physico/chemical and biochemical processes for the treatment of (1) drinking water and (2) municipal, agricultural and industrial wastewaters. On the other hand, efforts are devoted to studying reactions in the aqueous phase, which have an important role in environmental processes, whether natural or engineered. Examples of such studies include research on the kinetics of the oxidation of H2S(aq) at low pH by a variety of Fe(III) complexes; a study the mechanism and kinetics of the precipitation of important solids in water and wastewater processes (e.g. struvite precipitation in anaerobic digesters); exploration of the kinetics of dissolution of solids relevant to water treatment processes (e.g. dolomite dissolution kinetics); development of titration-based analytical tools to aid process control (e.g. analysis of Volatile Fatty Acids formation in anaerobic reactors); and the effect of oxidation via advanced oxidation tools (e.g. plasma reactor).on organic and inorganic species.


Industrial Wastewater Treatment

Studies on physical mechanisms related to biological treatment of industrial wastewater including bioflocculation and bio-sorption; research and development for the integration of physical, chemical and biological processes for treatment and reuse of industrial wastewater; studies on the outcome of pollutants of industrial origin during treatment processes; the effect of soil site remediation processes on pollutants; ; sludge and biosolids characterization, and development of treatment strategies; and studies on energy balances in wastewater treatment plants for reducing energy requirements and improving energy production from biogas.


Water and Wastewater Engineering

Water and wastewater engineering attempts to solve problems regarding water and wastewater quality and quantity. To this end, alternative water sources were developed such as on-site grey water and reuse, and on-site rainwater harvesting. These efforts work to enhance more sustainable urban water usage and management. Processes occurring in sewer systems are also investigated, such as factors affecting the volatilization of hydrogen-sulphide and methods to eliminate hydrogen-sulphide. Additional activities include quantifying leakage from gravity sewers, as a first step towards mitigation of this problematic phenomenon. Researchers study and develop extensive wastewater treatment systems that combine both engineering and advanced microbiological methods. A recent effort involves processes affecting water quality in catchment basins. In this project, researchers develop models, both mechanical and datadriven, to describe these processes. They also try to quantify multi-phase transport and outcome of selected pollutants.


Biological Processes for Water and Wastewater Treatment

Biological wastewater treatment is used for treating domestic wastewater as well as industrial and agricultural wastewater. The aim of biological treatment is the removal of contaminants (organics, nutrients, or/and specific contaminants) from the polluted water to produce effluents suitable for safe reuse or discharge into the environment. Biological treatment technologies use microorganisms to degrade the contaminants. Biological wastewater treatment technologies can be classified in a number of ways: according to the method in which bacteria are retained in the reactor (attached growth, suspended growth), reactor operating conditions (aerobic, anoxic, anaerobic), or energy usage, i.e. intensive energy systems versus energy extensive systems. An integrated approach is used in all research studies at the Laboratory of Environmental Systems, including biological reactor design and operation, microbiological studies, chemical analysis and advanced analytical techniques. Teaching and research at the laboratory provide firsthand knowledge of the major processes and mechanisms involved in biological wastewater treatment that is essential for scientists and engineers dealing with environmental issues.