Dear sir,

The desciption show my final objective from the study that i need to produce more biogas to use them in the prodcution of electricity and heat to ensure that WWTP is self-sufficient .

To produce more gaz i need to optimize the anaerobic digestion of sludge in Wwtp .

I know that the main factors are Température, PH, and mixing and  many others.

SO i think to integrate Solar energy to heat the Digestor and maintain constant temperature inside the digester  but till now i don't know what is the reserach state in this field and where is the Gap to fulfill during my phd work .

Hello,

there are several technologies to improve the biogas yield in anaerobic digestion of sewage sludge. You may want to have a look at the following:

http://www.cambi.no/wip4/detail.epl?cat=10636

The sludge is heated and pressurized followed by rapid expansion prior to the digester. This improves among others the biogas yield and the sludge dewatering properties.

The suggestion of biogas optimization is based on parameters  optimization during the process such as temperature,pH, mixing, and so on. The nature of substrate, type of anaerobic digester can affect the biogas production, the sludge retention time and anaerobic tank selection are very important.

Dear Chanel

This is very vast subject, but assuming that your digester design is correct and the SRT given sufficient the limit will normally be given the hydrolysis of your incoming substrate.

Here Thermal Hydrolysis as suggested by Roman (For this you can also look at the company Sustec)  is one, possibility, but also chemical hydrolysis i.e. with O3 or Mechanical lysis like application of Ultrasound, Cavitation, or even ball mills has been studied. Common demand for all this possibilities is that if shall be interesting the energy consumption must be lower than the additional energy applied - which is not always given. 

More interesting I would believe would be the utilisation of  enzymes if these can be applied for a reasonable prise. I imagine that this can be done either in a biological pretreatment or by addition direct to the digester. An interesting partner could her be Novozymes.

You can try using algal biomass as co feedstock it  improves biogas production. Pretreatment is also necessary.

Dear jimoh, what you propose is to introduce algae to sludge ?? So the feeding material will have more potential to produce biogaz ??

Exactly.

You should analyze the energy input and sludge production of the wastewater treatment plant first. Then you should investigate the BMP of the sludge. Based on the enery input and biogas potential of the sludge, you will affirm whether the energy autonomy could be realized. Usually, 1 m3 of biogas (contains 60% of CH4) could be converted to 2 kwh of electricity. 

Pretreatment is necessary to improve the biogas yield of sludge, and many papers could be found.

Thank you Cheng Ming Zhang for your response .