Certain cyanobacteria produce cyanotoxins including anatoxin-a, anatoxin-as, aplysiatoxin, cylindrospermopsin, domoic acid, microcystin LR, nodularin R (from Nodularia), or saxitoxin. Sometimes a mass-reproduction of cyanobacteria results in algal blooms.  These toxins can be neurotoxins, hepatotoxins, cytotoxins, and endotoxins, and can be dangerous to animals and humans. Several cases of human poisoning have been documented but a lack of knowledge prevents an accurate assessment of the risks
(Source: http://en.wikipedia.org/wiki/Cyanobacteria)

Pictures from Lake  Fanning (Debbie Hall)   2008  |  2009 |  (Opens in new window)

2/ European Environment and Health Committee re Denmark http://www.euro.who.int/eehc/implementation/20061008_14

"...About 70.000 families depend on small private water supplies. The majority of these water supplies face problems with either nitrate pollution due to extensive agriculture production and/or pollution with pesticides or bacterial contamination. But all water supplies, including small private supplies, are now under regular control by the local authorities and action is taken if the water quality is poor..."

3/ Odense River Basin case study August 2009 (Denmark)http://www.aquamoney.ecologic-events.de/sites/download/Odense_River_Basin_Fact_Sheet.pdf

"...In the Odense river basin, eutrophication is the main environmental problem. Agriculture is the main contributor to pollution of both the river and the river basin..."

4/ Denmark - Water related agencies http://www.water-technology.net/industry/denmark.html

4/ OECD - Denmark environment http://www.oecd.org/dataoecd/12/31/39577343.pdf
"...Denmark still has water quality problems, particularly in lakes and coastal areas (fjords), but also in rivers and groundwater. The new Action Plan for the Aquatic Environment 2005-15 (VMP III) aims to further reduce nitrogen leaching by 13% and to address phosphorus pollution (through a tax on phosphorus added to animal feed). Reduction targets have been set countrywide, but without looking at cost-effectiveness in meeting site-specific water quality objectives; indeed the whole of Denmark’s land area is classified as vulnerable under the EU Nitrates Directive, and all Danish waters are sensitive under the EU Urban Waste Water Treatment Directive. There is a need for a holistic (river-basin) approach when addressing water quality and quantity issues, and efforts are needed to compare the costeffectiveness of measures among households, industry and agriculture sectors. This is the source of major inefficiency in addressing nitrogen pollution..."
 

5/ Denmark - energy from bio waste http://www.um.dk/publikationer/Eksportraadgivning/FocusDenmark/0304/html/chapter15.htm
"...ENERGY/ENVIRONMENT: The environmental requirements for Danish livestock farmers are tightening up. Slurry and smell problems have to be resolved. By building a new biogas plant directly connected to an existing power and heating station, the two plants will create a mutual synergy to the benefit of both energy and environment

220 Danish farmers, chiefly pig producers and mink breeders, have plans to build the world’s largest biogas plant in Holstebro in Jutland. The plant will be placed directly alongside the town’s large power and heating station and will exploit the station’s surplus heat for production of nutrients from the farmers’ slurry.

Danish pig farmers and mink producers are facing a number of tightened environmental controls which force them either to cut back production or find new ways to dispose of animal waste. By building the biogas plant and exploiting the synergy with the power and heating station, the farmers believe they have found the ideal solution.

“By treating slurry for a good deal of the undesirable substances such as phosphorus, farmers can maintain their current production even with the stricter requirements on animal units per hectare,” says Alan Lunde, agricultural consultant in Holstebro and technological enthusiast for the biogas plant.

Phosphorus is a very soluble substance, but while it previously was needed for arable production, it has now become a ticking environmental bomb. Especially in the area around Holstebro where water is discharged directly into a number of large wetlands which the EU has designated habitat areas. The treated phosphorus can now be profitably sold to others instead, who have a shortage of phosphorus.

“Our main concern is to treat the slurry,” says Lunde. “By directly connecting the plant to a large power and heating station, the project is made financially viable and the power and heating station can exploit each others’ advantages. It’s an unexpectedly simple solution.”

Holstebro’s power and heating station produces district heating and electricity out of household garbage, straw and chip. The station’s turbines are run on natural gas. But for eight months of the year the station produces surplus heat which goes straight out into the air. The biogas plant can use this surplus heat for degrading the solid bio-waste from the farmers. The gas production that occurs can be exploited and partly replace the expensive natural gas in the power and heating station. Alternatively the biogas plant itself can produce electricity for the grid.

The area’s livestock farmers represent a combined total of 27,000 animal units, corresponding to 800,000 hogs – a figure supplemented by mink, poultry and pig carcasses. There are also a number of major food companies in the area and their waste will form an important part of the biomass supply. Taken together, it is heading to become the world’s largest biogas plant.

The size and the interested parties’ close geographical connection to the area have encouraged the initiators to thinking along unconventional lines. Especially concerning logistics which constitute heavy financial costs for other biogas plants in the world.

“Why does slurry have to be transported in tankers?” asks Alan Lunde. ”When we collect and transport slurry in tankers, the price is around EUR 4.50 per ton. But if a pipe system was established with central collection points which could also return treated slurry directly to the farmers’ fields, we calculate that the price per ton can be reduced to EUR 2.50. With figures like that the idea starts making good financial sense.”

The project has attracted attention not only among farming circles in Denmark but also in political circles. The obvious environmental advantages of the project and its synergy with the power and heating station, supplementing the district heating supply in the cold months, have created considerable interest in Amsterdam where district heating for a large new suburban area is being planned. For in Holland, pig producers have even bigger environmental problems than in Denmark.

“Collaboration partners in the EU are now ready,” says Lunde. ”The European angle suddenly makes it possible to maximise exploitation regarding technology, politics and economics. The plant in Holstebro could be the real breakthrough for biogas plants in the future. Not just as an energy supply, but as a plant which solves a lot of the agricultural industry’s growing environmental problems.”...."

6/  EU project treats agro waste for bio gas (2009) http://ec.europa.eu/research/headlines/news/article_09_06_04_en.html
http://www.kooperation-international.de/en/daenemark/themes/info/detail/data/41818/?PHPSESSID=c332 

"...the Danish Government last April launched the 'Green Growth' action plan, which targets the agricultural sector. 'Biogas is one of the focus areas in this action plan and Denmark set a goal that by the year 2020, 40% of the manure from animal production shall be used for the production of renewable energy,' Mr Frandsen highlighted. 'Biogas is the key instrument to achieve this goal.'..."
 

Here are just a few websites regarding this issue: 

I noticed this article in Cottage Life magazine, Winter 2009 edition (just came out) and thought it might be of interest.Talks about a community group that fought against a proposed landfill site - appears had help via a senior advisor (Maude Barlow) on water issues for the UN (she's also a national chairperson Council of Canadians), David Suzuki and others. 
1.Council for Canadians (founded by Maude Barlow, Farley Mowatt, Margaret Atwood et al): http://www.canadians.org/water/
2. UN web site re their 'Water for Life' program 2005-2015: http://www.un.org/waterforlifedecade/
 /Debbie Hall