Biological Trickle Filter for Waste Water Treatment of Biomass Gasification Power Plants - Bangalore, India

1. Background
Biomass gasification is an efficient technology producing heat and electricity out of dry biomass. Today, this technology is often used in rural areas in developing countries, where electricity is scarce and biomass production is high.

The biomass gasification technology, however, is not completely matured, yet. One of the problems, which have to be solved, is the treatment of syntheses gas after the gasification process. In order to remove tar and other impurities from the gas before feeding it into the combustion engine the gas is treated in gas washing columns. During this washing process waste water is produced, which has to be treated properly. So far mechanical/ chemical treatment systems have been used for waste water treatment in gasification power plants. However, from an economic and environmental point of view there is a great potential for improvements using biological treatment processes. Further, biological treatment systems can be combined in a synergetic way with the cultivation of agricultural crops and ornamental plants increasing the overall utility of gasification power plants. Thus the overall objective of this study is the development of an efficient and competitive biological treatment system for handling the waste water of a biomass gasification plant.

2. Proposed Study
Tests on waste water of a prototype biomass gasification reactor conducted by the University of Wädenswil showed in principle that planted trickle filter are able to treat waste water containing phenol, ammonium, nitrate and other hazardous contaminants, such as aromatic compounds, on a short-term basis. According to degradation rates of phenol and ammonium planted trickle filters seem to be efficient and competitive treatment systems. Based on these test results a planted trickle filter system shall be developed. In order to verify the filter’s capability a long-term study on a planted trickle filter treating waste water of a large-scale biomass gasification plant is required.
Due to lack of a large-scale gasification plants and representative waste water in Switzerland tests are proposed to be conducted at the RV College of Engineering (R.V.C.E.) in Bangalore, India. In cooperation with the Indian manufacturer of the power plants, Netpro Renewable Energy, and the R.V.C.E a biological trickle filter system shall be applied to an operating biomass gasification plant on the college’s compound in order to get a long-term monitoring about the degradation processes in the proposed system.

3. Study Objectives
The overall objectives is to conduct an long duration detail test on a biological trickle filter treating waste water of a biomass gasification plant observing its performance and evaluating its applicability to commercial application.

If the proposed system proves to be applicable to commercial application the treatment system shall be implemented in existing power plants in India as well as in power plants to be constructed In Switzerland and Germany.

4. Contact Details

Daniel Todt
d.todt@hsw.ch
Fachstelle für Ökotechnologien
Abteilung Umwelt und natürliche Ressourcen
Hochschule Wädenswil
http://hsw.ch

Prof. T. N. Ramamurthy
hetp@sify.com
Principal Coordinator RV-TIFAC-HETP
RV College of Engineering, Bangalore
http://rvce.ac.in