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by Clarence Valley Council Joined 01-01-0001 12:00 AM Posts 7

We are looking at aeration options for a 100ML reservoir that is used to store raw drinking water prior to treatment. The reservoir is not covered, is concrete lined and is filled from a variety of raw water sources through a bottom fed inlet. It is about 10 metres deep. We are trying to prevent future algal issues in the reservoir and wondering if there are any recommendations for good aeration systems or has successfully controlled algal blooms using aeration in a reservoir? We would also be interested if you have had success controlling algae using any other methods? We have been advised that chlorine may not always work and with some species of algae could potentially release toxins.

by brett.corven@esc.nsw.gov.au Joined 13-11-2015 09:54 AM Posts 24

100ML at 10m deep gives a minimum surface area of 1Ha. I'm sure you'll get sufficient oxygen transfer naturally and just need to mix to control stratification. Algae blooms are a function of nutrient availability and temperature. If the raw water is poor, mixing might help with blue-green algae but maybe not others.

by roland.heatley@mpsc.nsw.gov.au Joined 06-08-2020 01:48 PM Posts 1

Depending on shape of the storage I've used a float mounted aerator angled slightly down with a prop that drew air into the stream developed by the prop. Worked very well and had a zone of influence over 40m and reached more than 5m deep. If I remember right about 5kws Italian Reo brand over 25 years ago. If you are after deeper influence you might want to drop a pipe with holes only need 1mm or so holes every 1.5m in 50mm HDPE connected to a compressor and run that occasionally with the surface aerator running most of the time. Depends if stratafication is your problem or nurient loading with warm conditions. The Reo solved our problem at Harden NSW in a lagoon about 60m long 30m wide and 5m deep, used one unit. Didn't run in winter only needed in summer. The pipes with holes worked in 30m deep reservoir at Halls Gap in Victoria.