One of the sludge listserves recently sent around a link to a powerpoint presentation on a San Francisco “Bay Area Bisolids to Energy Partnership.” The talk was presented at an EPA Region 9 confab called “2009 Pacific Organic Residuals Symposium” (detailed here by EPA).  (Biosolids is sludge, by another name.)

This presentation, taken on it own, does not say much about the technologies under consideration, but we are told on one slide that it is “not incineration.”  With all the information on the slides about the energy value of biosolids, I suspect that they are in fact considering some form of incineration, and may be attempting to avoid calling it that.

My understanding is that sludge incineration has come a long way, and, if the feed is sufficiently dry, the process requires no fuel, and can in fact have a net fuel benefit/energy output, reducing inputs of traditional fuels.  So, this is likely where their thinking is heading.

Given the restrictions on land application in California that have arisen, it may be prudent to start looking at such B2E alternatives, which may be expensive, but can avoid problems with public concerns and  criticism of land application of sludge.  Such approaches do have appeal because they get rid of all the sludge, albeit converting it to gases and ash, which must be managed.

However, incineration (or B2E involving combustion) can be a difficult sell, also.  Emphasizing energy benefits has promise, as does  showing very specific details about how incinerators (or B2E faclities) are designed and managed, and by whom.

One thought:  Incinerators (or B2E facilities) require a certain level of engineering expertise, and hence may be more closely watched over, with a resulting potential greater level of public confidence, than land application out in the fields.