The California Energy Commission (CEC) will give $3 million in funding to Southern California Gas Co. (SoCalGas) to improve its hydrothermal processing (HTP) technology to generate twice as much energy from the digestion of organic material when treating wastewater sludge thereby improving current wastewater treatment technology.
Hydrothermal Processing (HTP) is a thermo-chemical method to convert wet biosolids into crude biofuel products. The procedure requires moderate temperatures and pressures (Temperatures from 300 to 370 ºC, Pressures from 120 to 190 atmospheres) and residence times of 5 to 20 minutes. The byproduct of the process are crude biofuel that can be converted into biodiesel, gases such as C02 and CO, water, biochar and ash. The energy recovered is contingent on the certain conditions such as residence times, characteristics of the sludge and catalytic factors. HTP is a uncomplicated technology and is literally a hot, pressurized tube.
There has been exciting technological advancements in the space over the past seven years and scientists and engineers have successfully accelerated hydrothermal conversion technology into a scalable process which lets sewage sludge undergo treatment without necessarily undergoing drying. The thermal efficiency of the HTP system is high (70 to 90%) and necessitates only 14% of that energy to process it. HTP has less one third less greenhouse gas emissions compared to the usual anaerobic digestion processes and cuts operations costs by half.
Because the biofuel produced is not miscible with water, it can be separated into light and heavy crude by extraction. The light crude can be converted into diesel alternative while the heavy crude can be co-fired with solid fuels (e.g. for power generation).
Another added advantage over anaerobic digestion is that it thoroughly removes leftover biosolids eliminating the need to transport unusable biosolid to landfills. This further reduces operations costs for wastewater treatment plants.
The team is excited to apply the improved technology beyond the lab and test it in an actual wastewater treatment plant. The improvement to the existing technology will allow SoCalGas to achieve its vision of being the cleanest natural gas utility in North America. They are looking to use the technology to process not only wastewater but also other leftover materials such as landfill waste and food waste into carbon-neutral renewable energy that eliminates the need for fossil fuels to help mitigate climate change. SoCalGas has committed to substitute 20 percent of its traditional natural gas sources with renewable natural gas by 2030.
In a paper it published recently entitled California’s Clean Energy Future: Imagine the Possibilities, SoCalGas committed to an inclusive and integrated plan to reach California’s ambitious environmental goals. The plan is an all-encompassing approach to mitigate climate change. It also emphasizes energy affordability and calls for the development of long-term renewable energy storage utilizing current infrastructure.
Researchers at the University of California, Davis has assessed that using renewable energy from organic waters can power of 2.3 million homes translating to significant cost reductions and less greenhouse gas production.
A pilot project is to be located at the Central Contra Costa Sanitary District (Central San) Wastewater Treatment Plant in Martinez, California. It is funded in part by the California Energy Commission, SoCalGas and other private participants.
If you are a municipality in Ontario and in need of a biosolids management solution, please feel free to contact us on 1 (877) 479-1388.
Sources:
http://biomassmagazine.com/
http://www.genifuel.com