An independent article from WaterWorld (April 2003).
A) For Cogeneration – They will spend 245,000 $ to save 30,000 $ per year.
Compared to DDI “Cube” or “ Square” Heat Exchanger that will cost (for example) 97,900$ (with installation) and will save about 366,000 $ PER YEAR as Sludge to Sludge Heat Recovery system.
B) DDI Heat Exchanger will probably have less maintenance cost then the Micro-Turbines in the Cogeneration solution.
C) Market has over 3,300 Anaerobic Digestion Waste Water Treatment Facilities, (Maybe x 3 Heat Exchangers). So many, many WWTF can use Heat Recovery.
D) DDI estimated cost per 1 million BTUH at Minimum 7 $ only. (Now it is much higher). See “Energy Saved by using Heat-Recovery” program on the web
This study claims cost at 24.3 $ per 1 million BTUH
(1 KWH = 3415 BTUH
292.8 KWH = 1 million BTUH
Cost per KWH 2.46 +6.37 = 8.83 cents
292.8 x 0.083 $ / KWH = cost per 1 million BTUH = 24.3 $ = cost for 1,000,000 BTUH
E) Cogeneration will generate ONLY 41 % of Annual Energy demand in the plant.
But with DDI Heat Recovery System installed they can achieve much more.