Projects / Programmes
Treatment of textile wastewater using a membrane bioreactor
| Code |
Science |
Field |
Subfield |
| 2.14.02 |
Engineering sciences and technologies |
Textile and leather |
Textile chemistry |
| Code |
Science |
Field |
| T350 |
Technological sciences |
Chemical technology and engineering |
textile wastewater, membrane bioreactor, membrane fouling, membrane filtrations, permeate evaluation.
Researchers (1)
| no. |
Code |
Name and surname |
Research area |
Role |
Period |
No. of publicationsNo. of publications |
| 1. |
24021 |
PhD Irena Petrinić |
Chemical engineering |
Head |
2007 - 2010 |
0 |
Organisations (1)
Abstract
The main environmental impact of the textile industry derives from the “wet processes”, mainly implemented by the textile finishing industry. The textile industry can be characterized as a high water consumer and the overall sector in Europe is suffering due to more stringent discharge limits, raising water costs and partly limited water resources. The sector is loosing competitiveness on international markets, which results in closure of companies and re-location to countries outside of Europe. Up to date few or no process water recycling technologies are in place. Across the textile sector batch processes and washes are applied and due to the inefficiency of the applied process, chemicals are added in excess and are only partly used in the process. The main objective of the project is, therefore, to develop environmental technologies in order to reduce the water consumption and to reduce environmental impacts by reducing the amounts of process chemicals discharged by using membrane based separation processes and membrane bioreactors (MBR). Membrane bioreactors (MBR) are an emerging technology of major potential in wastewater treatment. They provide a relatively compact alternative to conventional biological treatment options, producing a ‘guaranteed’ high quality effluent even at high and varying organic loading rates. The process relies on membrane filtration to effectively retain all the biomass in the bioreactor opposed to conventional treatment, where biomass is wasted. The MBR process is well suited for industrial effluents which generally require long retention times for the effective biological treatment of the less degradable organic pollutants present. Membrane bioreactors achieve an effluent quality, which is in many cases far better than the required discharge standard. However the permeate after MBR treatment still contains salts, which reduce the feasibility of water re-use. The goal is to obtain a reduction of water consumption, effluent generation and a reduction of environmental impacts by establishing implementation routes of recycling technologies for the textile industry sector. The aim of the project is, therefore, to develop of a wastewater recycling system, which can be adapted easily for the different types of textile industries to achieve a reduction of emissions (surplus and chemical substances in waste water, especially colours and dyes). Based on an intensive analysis of the manufacturing processes and the resulting wastewater, a concept for part stream related processes-integrated measures and recycling technologies using ultrafiltration and membrane bioreactor treatment followed by nanofiltration and/or reverse osmosis treatment will be developed.
Significance for science
The results of this project provide a major contribution to the understanding of membrane bioreactor system, in terms of the development of processes for wastewater treatment.
A membrane bioreactor (MBR) enables wastewater treatment with a combination of biological treatment and membrane filtration. Membrane (microfiltration (MF) / ultrafiltration (UF)) replaces the sedimentation tank and sand filter. MBR retains suspended solids, and the sludge settling-time is insignificant, which is a substantial difference in comparison to conventionally-activated sludge processes. The main advantage of MBR systems is the very low value of COD in the treated water and the high microbiological quality of the treated water, whilst it is practically free of microorganisms and viruses (including pathogens), as well as a modernization of the process by upgrading existing systems with low capital costs. Due to the longer retention time in the MBR, a biodegradation of some less soluble compounds is also very good.
The main contribution influencing scientific research is the analysis of the process parameters of flow and biomass concentration on the density probability for the distribution of retention time and the dynamics of membrane fouling. The research results provide for the determination of optimum conditions regarding process implementation in order to achieve a high removal-efficiency of the organic matter, and to provide guidance for the eventual elimination of deficiencies in the existing membrane bioreactor system, and thus designing new systems.
Unfortunately, the MBR has also some disadvantages. One of the most important is membrane fouling. The ventilation and continuous circulation of activated sludge is required for a proper functioning of the MBR which means high operating costs for the necessary electricity. In addition, an adequate flow through the membrane has to be ensured, which is only achieved when the membrane surface is of sufficient size, but unfortunately the membrane prices are very high. Therefore, the investment and operating costs are much higher than for conventional wastewater treatment. Due to the development of new hybrid systems, the operating and investment costs of MBR are reduced, so we believe that usage of the MBR will increase.
Significance for the country
The MBR system for wastewater treatment has been rapidly developing over recent years. This is because of the increasingly strict requirements for the quality of treated water, which is of great global importance, since it also increases the awareness of environmental preservation and the protection of natural resources. Choosing a system regarding wastewater treatment depends on the types and quantities of wastewater from the economic, urban, and environmental perspectives. When considering the significant production of sludge in conventional plants for wastewater treatment, sludge disposal is becoming an almost identical problem to the environmental burden of untreated wastewater, so it is very important to find new solutions for such wastewater treatment, which would thus reduce sludge production. Additional problems arise when monitoring and operating systems for wastewater treatment, such as the high sensitivity to periodic fluctuations in the flow of wastewater, the space capacities required for building the systems, and the several-months for establishing those stable microbial communities, which are necessary for the effective removal of organic compounds from wastewater. These constitute a sufficient reason for finding new wastewater treatment technologies, where membrane technology is certainly one.
Membrane technology and the development of reactor systems, which combine conventional technology with activated sludge and filtration processes, is developing very quickly. The number of installed systems in Europe is growing daily, where a better understanding of bioreactor system is provided by the results from several research projects, published in scientific literature.
This system, which integrates physical, chemical and biological processes, and includes three phases is extremely complicated to analyze and requires a multidisciplinary approach for describing. MBR systems are still being developed, in addition to the setting of frames that would enable comparable individual systems. The conditions of the process and the effectiveness of various MBR systems is determined for achieving this.
All the above-mentioned, has strengthened research towards the development of a membrane bioreactor, which is reflected in:
• defining the hydrodynamic characteristics of a membrane bioreactor for creating the foundation for processes on a larger scale,
• description of the kinetics of the wastewater degradation process within a membrane bioreactor, so that knowledge of the hydrodynamic characteristics may affect the effectiveness of the wastewater treatment process by developing a complete mathematical model of the process.
• searching for optimal conditions for a process implementation that would affect the reduction of investment and operational costs, as well as the efficiency improvement of the reactor system.
• defining a process for membrane fouling, which is the main disadvantage of this technology.
Most important scientific results
Final report,
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Most important socioeconomically and culturally relevant results
Final report,
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