First it depends on the kind of the aging of the lake.

If an over fertilization of the lake appears a treatment with Bentophos may be effective. Thereby phosphates can be fixed.

About two years ago I was attending a conference where a scientist from Holland was describing remediation efforts in Dutch lakes. Since I was not working with freshwater systems, I did not pay attention to where the information was published.

I did a quick Google Scholar search using the key words I remembered from the talk and here are the results:

Lakes in the Netherlands, their origin, eutrophication and restoration: state-of-the-art

Ramesh D Gulati, Ellen van Donk

Publication date: 2002/1/1

Ecological Restoration of Aquatic and Semi-Aquatic Ecosystems in the Netherlands (NW Europe)

Pages; 73-106

You might also try this dissertation published at the University of Utrecht:

Restoration potential of benthic foraminiferal communities in hypoxic areas of Lake Grevelingen

authors Onselen, V.M. van

source Faculty of Geosciences Theses (2013)

A full-text version is not available on line but perhaps the faculty at Utrecht can provide you a copy.

And lastly:

Van Oosterhout, Frank, and Miquel Lürling. "Effects of the novel ‘Flock & Lock’lake restoration technique on Daphnia in Lake Rauwbraken (The Netherlands)." Journal of plankton research 33.2 (2011): 255-263.

As the Dutch would say:

goed geluk!

Kevin Olsen

Montclair State University