There is another option. There is a sludge consuming bacteria made by a company called BactaPur that will guarantee 1" of sludge removal per week (with adequate oxygen levels). This bacteria is completely benign to humans, fish, and pretty much everything else except for organic sludge. However, it ONLY works on organic sludge, so it's important to figure out what percentage of your sludge layer is organic v.s. inorganic to see if it will truly be effective for your application. Our sister company Air Diffusion Systems (can I say that?)has applied this technology on several occasions in waste water lagoons with great success. It can get kind of pricey and a little labor intensive depending on the size of your pond and how much sludge you want removed. Take a look at the video below for an example of the application.

http://www.youtube.com/watch?v=TQsvITpXav0


Richard Dennis
EP Aeration
rich@epaeration.com
www.epaeration.com
(800) 556-9251