Blue green algae in treated wastewater and lakes (city of Bengaluru, India)


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  • seshadri
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Re: Blue green algae in treated wastewater

Yes Water hyacinth grows profusely in the organic / chemical rich waters and they become a menace too. They putrefy waters and make them works for further use too. Though, they add good organic residue to the system. Collection and use of water hyacinth is another laborious one. Good to avoid them. There are kith and kin of this is tropics viz. Pistia, Hydrilla, Lemna, Salvinia and the major plans viz. Lilly, lotus are contribute to the chemical / organic rich waters. We need to create a constructed wetland to introduce them and remediate the waters. Reeds are the other ones that are studied widely for such purposes. Recent studies (20 years) show the use of Vettiver (Chrosopogon zizanoids) in remediating waste waters.
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  • Heiner
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  • I am a retired organic farmer and interested in nutrient cycles. As an volunteer I now travel mainly to poor countries and together with locals I would like to find new ways of sustainable agriculture. This is beyond the regulations of IFOAM.
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Re: Blue green algae in treated wastewater

Dear all,

see attached a picture of a green fishpond in Zimbabwe. I was told there are hundreds of fish in this pond. Since there was no pump or any other equipment to add oxygen, I think it was a well balanced fishpond. No fish was at the surface, snaping for air.
The ec value was 450 micro-siemens (one crucial point?) and as far as I know, no human wastewater was poured in.
But I know from sweden the combination of fish production and wastewater treatment is possible in in well balanced system. It needs harvesting from time to time....

writes the farmer ;-)

Heiner, the old farmer.....
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  • AquaVerde
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Re: Blue green algae in treated wastewater

Dear All,

Maybe my inputs provide some help to your endeavours.

Maybe see 19 min video presentation 2016 by Dr Ian Dodkins of Swansea University, UK about subject matters most:
Dr Ian Dodkins talks about the function and design of "Floating Treatment Wetlands". Looking at floating islands around the world Ian shows us how floating islands have been used to treat polluted water, protect coastal areas from erosion and used as a place to live.

Summary: clear statements regarding N&P !!! ~ 7% & ~ 6% "uptakes" (uptake by plants) compared to the ~ 62% N & ~ 75% P reduction effects by biofilm including sedimentation and periodic desludging of the sediments after a maximum of ~8 years.

Furthermore see PDF about Dr Ian Dodkins 2014 work:
Kindly see page 33 for the picture of his theoretical model!

additional PDF by Headley & Prof. Tanner, NZ 2006:
picture source Headley & Tanner:

We use under our climatic conditions additional floating OLOIDs (see ) in pond-wwtp's and lakes to gently equalize water body and add O2. We call it an Open Source "Mangrove"-wwtp.

See picture of ~500 p.e. wwtp:

Best Regards,

"simple" Sanitation-Solutions by gravity
Low-Tech Solutions with High-Tech Effects
"Inspired by Circular Economy and Cooperation"
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