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Thursday, May 26, 2011

Digestion tanks can produce biogas and save energy in sewage plants


A study from the Fraunhofer Institute in Germany has found that small sewage plants can also produce biogas to generate electricity.
Sewage plants remove organic matter from wastewater. The accumulating sludge then decays and biogas is generated as a by-product. However, according to the researchers, only 1,156 of the 10,200 sewage plants in Germany have a digestion tank.
While high-rate digestion with microfiltration to remove accumulated sludge and produce biogas is standard in state-of-the-art large sewage plants, it is not so common in small plants.
Smaller operations often feel that the cost of a new digestion tank is not worth it. Instead, they enrich the sludge with oxygen in the existing activation basin to stabilize it.
“Activation basins require a lot of electricity. At the same time, enormous energy potential is lost since no biogas is produced,” says Brigitte Kempter-Regel of the Fraunhofer Institute for Interfacial Engineering and Biotechnology IGB in Stuttgart. “A sewage plant eats up more electricity in the municipalities than their hospitals.”
“Based on a sewage plant for 28,000 inhabitants, we calculate that the plant can reduce its annual waste management costs from 225,000 euros [US $318,000] by as much as 170,000 euros if sludge is decayed in a high-rate digestion unit with microfiltration, as opposed to treating it aerobically,” Kempter-Regel added.
A process observing this was developed at IGB and it is said to be much more effective than conventional digestion. Instead of the usual 30 to 50 days, sludge only remains in the tower for five to seven days. Around 60% of the organic matter is converted into biogas.
The biogas can then be used to operate the plant which, according to the case study, would cut energy costs by at least 70,000 euros ($99,000) annually.
High-rate digestion also results in less residual sludge that needs disposal, which could save the operator another 100,000 euros.

3 comments:

Andreas said...

The Fraunhofer Institute - very sophisticated and very ingenious and very, very complicated. But basically totally right - there is a lot of energy in waste water sludge. There are cheaper solutions.
The demand for reliable, efficient and low-cost wastewater treatment systems is increasing worldwide especially in densely populated urban regions where adequate wastewater treatment systems do not exist and uncontrolled discharge of wastewater endangers environmental health and water resources.
Please see and read about this in: http://www.scribd.com/doc/17438999/WATER-WEB jump to side 23 DEWATS = Decentralized Wastewater Treatment System
And now for a combination we can offer a biogas system with an exellent production profile and now we can even offer a better fermenter technology based on an ingenious new development.
The Thermo-Gas-Lift System is a multi chamber proofing system wherein the gaseous overpressure takes over the mixing process. Instead of expensive and mechanical vulnarable mixing equipment we use the fermenter own gas production for mixing and heating of the fermenter fill. These fermenter are considerable cheeper in building and in operation. Make your waste problem to a rewardable business.
Andreas Abraham
algaenova @ email.de
SKYPE: nordictrader
http://de.linkedin.com/in/algaenova
http://www.circlelinkholdings.net/

Fields of action: organic waste to biogas - wind/solar energy to renewable,natural gas(methane), magnegas applications, diatom fertilizer against algae bloom ( --- for your interest :http://www.behance.net/gallery/DIATOM/632929 ) Placement programm: Funding of public listed companies (only!).

Biogas Plant in Bangalore said...

With the increasing human population the needs for the people also increases. Recycling waste not only save our natural resources but also help save energy.
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Biogas Plant in Bangalore said...

With the increasing human population the needs for the people also increases. Recycling waste not only save our natural resources but also help save energy.
Recycling of waste in Bangalore