ICT develops new technology for decentralised sewage and organic solid waste bio-methanisation
07 September 2021
Indian Institute of Chemical Technology (IICT), a constituent unit of the Council of Scientific and Industrial Research (CSIR) has developed a new high rate biomethanation technology for the integrated treatment of sewage and organic solid waste and concomitant generation of biogas and bio manure.
The new technology can be used to treat groundwater as well as wastewater and convert it to potable water. It can be used for sewage and organic solid waste treatment with decentralised applications in various parts of India.
Solid and liquid wastes are major challenges faced by big cities as also by the rapidly urbanising areas, and sustainable technologies are needed for tackling them. An integrated treatment of sewage along with organic solid waste in India could help evolve a sustainable technology to overcome the solid and liquid waste disposal issues.
Jointly developed by A Gangagni Rao, Chief Scientist and S Sridhar, Senior Principal Scientist, CSIR- Indian Institute of Chemical Technology (IICT), the high rate biomethanation based on Anaerobic Gas lift Reactor (AGR) technology can be used for the treatment of organic solid waste and concomitant generation of biogas and bio manure along with Nanofiltration (NF) setup
The technologies supported by the ‘Waste Management Technology’ programme of the Department of Science & Technology (DST), Govt. of India have received national patents individually.
These AGR and NF membrane technologies at the Technology Readiness Level of 9 have been tested in the field. According to Rao and Sridhar, urban and local bodies and gated communities comprising around 50,000 to 1,00,000 population could benefit from this technology. Instead of sending the organic solid waste and liquid waste to the common bigger facilities in the city, the same waste could be treated at source only in decentralised manner.
An integrated model plant comprising AGR and NF technologies has been established at CSIR-IICT, Hyderabad, for the simultaneous treatment of sewage (100 liters/day) and organic solid waste (250 kg/day) for the generation of value-added products such as biogas, bio manure, and reusable water. The integrated technology has been field-tested and has been working continuously for the past two years.
This integrated approach of sewage and organic solid waste treatment could be exploited anywhere in India, where municipalities comprising around 50,000 to 1,00,000 population generate approximately 2 to 4 million litres per day of sewage and 5 to 10 metric tonnes per day of organic solid waste.
Highlights of the new process:
- Best features of high rate anaerobic digester;
- Novel pre- and post-processing mechanisms;
- Advanced digester design’
- Smaller digester volume;
- Easier to scale-up and multiplication;
- Semi-automatic plant operation;
- Higher biogas yield;
- Generation of organic fertilizer;
- Locally available enriched microbial consortia;
- Remunerative for decentralised application;
- Distributive biogas plants at waste generation source;
- Allows use of by-products that makes the plant sustainable; and
- Requires small footprints and less operating and maintenance costs.
The new process ensures efficient production of good quality water free of contaminants such as heavy metal ions, hardness, dissolved solids, turbidity, and bacteria, etc without loss of minerals.
The membrane in the system is indigenously synthesized and made of hydrophilised polyamide NF membrane
The vertical placement of spiral wound membrane modules in the system allows stable plant operation for longer time periods without the use of chemical cleaning agents.