In what sense. Are you talkong in terms of removing from the wild or a bloom scenario? Or are you talking about dewatering steps in an industrial/water treatment situation
well, in this case, the problem seems to be the source of nutrients for the algae...
In our town we have a similar case, and the only solution was not only to block the release of sewage into the lake, but to remove huge part of the sediments from the lake. After that there was carried out a short-term monitoring of the phytoplankton from that lake (some of the results are available in the following article: https://www.researchgate.net/publication/259762308_Hazard_risk_and_alert_level_in_assessment_of_a_rehabilitated_urban_lake )
P.S. Generally, if You will not solve the problem of the nutrient in-put (represented by the sewage waters), probably it will be very hard to have positive results in ”managing” the algae-populations.
Article Hazard risk and alert level in assessment of a rehabilitated...
You can do wild harvesting if needed. There was a method proposed by Grondahl 2009 on Ambio. I have also done a preliminary study on the practicality of the method. My work is an article in press but you can download it if you go to my profile. For Grondahl paper here is the link
http://www.ncbi.nlm.nih.gov/pubmed/19431936
Zsolt_Toeroek is right, trying to prevent is a good practice. But in our case even with many of the baltic and nordic states having stringent means of water quality control for many effluents, its still about 10 countries surrounding the Baltic. Here we are trying to turn the problem into an opportunity
We propose this as an addition of existing means of preventing eutrophication
Thank you to Zsolt_Toeroek for very good suggestion. In this particular lake the stoppage of sewage in next few months is seems to be impossible and also I feel even we stop the entry of sewage in to lake for atlest next two three years the problem of algal bloom will remain.