Phosphorus Recycling

In the 20th century the three nutrients nitrogen, phosphorus and potassium have enabled agriculture to increase its productivity. This is usually represented by three numbers (for example, 19-12-5). We obtain nitrogen from the air, but we must mine phosphorus and potassium. The world has enough potassium to last several centuries. But phosphorus supplies may start running out in the near future.

The reserves of phosphorus aren't very evenly distributed. The U.S. is the world’s second-largest producer of phosphorus (after China), at 19 percent of the total, but 65 percent of that amount comes from a single source: pit mines near Tampa, which may not last more than a few decades. Meanwhile nearly 40 percent of global reserves are controlled by a single country, Morocco, sometimes referred to as the “Saudi Arabia of phosphorus.” Although Morocco is a stable, friendly nation, the imbalance makes phosphorus a geostrategic ticking time bomb.

The conventional phosphorus fertilizer production cycle is an energy-intensive process that releases greenhouse gases into the environment at every stage:

• mining of phosphorus ore, 
• concentration into phosphate rock, 
• transportation from mine sites around the world, 
• centralized manufacture into fertilizer, and 
• transportation to customers.

Each year more than 100 million tons of phosphate rock are mined and processed into fertilizer. Over time this fertilizer enters the ecosystem as waste and agricultural runoff, leading to excessive nutrient levels, or a condition known as eutrophication. Eutrophication causes excessive algae growth in lakes, streams and oceans which depletes the oxygen supply in the water that is necessary to support aquatic life.

A Solution

Our food contains the nutrients taken up by plants which we expel back in to the environment by our digestive systems and toilets. Whilst traditional sources from rocks are being depleted there is quite a lot of it in sewage treatment plants. Thames Water has installed new technology from Ostara in its Slough plant. It strips phosphorous from sewage water producing around 120 tonnes of fertiliser each year. The end result is a produce called Crystal Green.    

1. Waste water streams from municipal and industrial treatment facilities, rich in phosphorus and nitrogen, provide essential nutrient streams for the recovery technology.
2. Fertilizer Production: Rather than view sewage as waste, the solution transforms waste water streams into a renewable resource, creating a planet-friendly fertilizer and saving millions in plant maintenance costs.
3. Agriculture: Crystal Green is the world's first fertilizer made from a local, renewable resource. Suitable in horticultural, turf and agriculture, its slow-release formulation results in considerably less nutrient leaching and runoff.
4. Food Consumption: The recovery technology is the ideal solution for growing urban areas where nutrient discharge limits become a challenge to meet in the face of rising volumes of waste water and associated costs.
5. Environmental Impact: By reclaiming the nutrients in their municipal, industrial and livestock waste waters, most countries could actually become phosphorus-independent – and help protect water resources from these otherwise polluting nutrients.

Useful links for more information:

• http://www.scientificamerican.com/article.cfm?id=phosphorus-a-looming-crisis
• http://www.crystalgreen.com/content/sustainability
• http://www.ostara.com/sustainability
• http://www.ostara.com/technology

Off shore wind turbines help to produce more fish

European fish stocks are under increasing pressure. The European Commission accepts that all important fish stocks in European waters can be described as overfished and a World Bank report claims that the worldwide cost of overfishing alone is a huge $50 Billion. The Common Fisheries Policy is our way of controlling overfishing by setting quotas for the amount fisherman are allowed to catch. Even with these quotas fish stocks are struggling to recover to sustainable levels and are being increasingly hampered by the effects of pollution and recently changing sea temperatures due to climate change.

Ironically the threat of climate change may bring about a positive change for fisheries in Europe. Offshore wind farms are looking more and more attractive as European states look to reduce their carbon emissions. It is predicted that 40GW of offshore wind capacity will be installed by 2020. This would roughly equate to 200km2 or 77 square miles covered by wind farms. This large portion of sea designated for electricity generation might be an unexpected boon to European fish populations.

Scientific studies of existing off shore wind farms are finding they can be a great benefit to the marine ecosystem they are placed in. One major benefit is that, due to safety concerns, no fishing can take place inside the wind farm. As some of these farms can be huge, the largest constructed is off the Kent coast and covers an area of 35km2, this effect can be significant. The wind farms effectively become Marine Conservation Zones (MCZs) where fishing is prohibited. This not only allows fish in the area to develop to full size but also stops the sea bed from being damaged from the scrapping of trawlers nets.

It is predicted that networks of offshore wind farms will greatly benefit fish populations by acting as MCZs. These zones may even help fisherman as fish and spawn will leave the protected areas and increase the population of nearby sea. It has been found that fisherman usually congregate near the edges of MCZs and experience much higher catches than in unprotected seas. More mature fish produce more spawn than younger fish so having an area of the sea where fish can grow to maturity can greatly help fish stocks and fisherman.

The foundations of the turbines themselves have also been show to have a positive effect. The steel ‘monopile’ the turbine is placed on has been shown to act as an artificial reef. This means smaller marine organisms grow on the hard structure, increasing the biodiversity of the area and producing a valuable food source for fish in the area.

Wind farms in the future could become teeming areas of bio-diversity and act as series of protected areas where fish can grow to maturity and reproduce in safety. The development of offshore wind farms will not only greatly reduce Europe’s carbon emissions and reliance on energy imports but may also let fish stocks recover so that they are once again being fished at a sustainable level.

These benefits pose the question of whether this should be done onshore as well. Most onshore wind farms are placed on fields grazed by sheep or cows. These grass fields are shown to be incredible un-diverse, biodiversity wise they are classed as deserts. The field itself however will financially support the farmer with only the turbines on it; maybe we should be looking to use these wind farms as nature reserves too?
This article was taken from Sheffield Renewables web site. Please check out their website.