low frequency PM

I have an energy harvester that generates impulses at frequency as low as 25Hz.  Each impulse has a positive and negative parts.  The width of each impulse is ~8ms (positive+negative).  The PTP amplitude is ~5V.  I can use a bridge rectifier but in order to fully rectify the signal I'll need a very large capacitor, something I would like to avoid because of size and weight. 

Is there a suitable PM that can handle such an input? 

Thank you!