from raw sewage

Here’s something rather important that you might not know: there may be a worldwide phosphorus shortage within the next few decades. The majority of the world’s phosphorus is currently mined from non-renewable phosphate rock deposits, and widely used in crop fertilizers. Scientists have begun to question just how much more phosphorus is left, and what the agriculture industry will do once it runs out. The answer – or some of it, at least – could be bobbing in a pool of raw sewage. Ostara, a Canadian nutrient recovery company, has developed a method for harvesting phosphorus from municipal wastewater and converting it to fertilizer.

The Process

Ostara’s PEARL Nutrient Recycling Process, developed at Vancouver’s University of British Columbia, utilizes something called a proprietary fluidized bed reactor. The cone-shaped device is installed in a wastewater treatment plant, where it removes ammonia and most of the phosphorus from untreated sewage. Magnesium is added within the reactor, creating a concrete-like substance known as struvite. This struvite, in turn, is processed into a nitrogen/phosphorus/magnesium slow-release fertilizer sold as Crystal Green. Ostara claims that numerous trials have proven the fertilizer to be safe, and because of its slow-release properties, it stays in the soil instead of running off into waterways.

Cleaner water

The removal of so much phosphorus, needless to say, makes the wastewater that much cleaner when it finally returns to the natural environment. Hopefully, Ostara’s system should decrease the occurrence of toxic blue-green algae blooms, which can occur when wastewater containing too many nutrients enters a body of water such as a river. While wastewater treatment plants already remove much of the phosphorus and other nutrients, the installation of a reactor would greatly reduce the bioload on the plant, allowing it to save a poopload (sorry) of power and operating costs.

Less blockages

While struvite is produced on purpose inside reactors, it also occurs naturally when phosphorus and nitrogen combine with magnesium in a wastewater treatment plant’s sludge stream. This unasked-for struvite clogs lines and valves, reduces flow rates, and has to be removed either mechanically, or by running acid through the lines. By harvesting most of the phosphorus, a reactor is said to virtually eliminate struvite build-up, further lowering the plant’s operating costs, and increasing its capacity.

The system in use

With the combination of reduced operating costs, extra processing capacity, and revenue generated by fertilizer production, Ostara claims that a wastewater treatment plant utilizing a PEARL reactor could exceed $1 million in net savings per year. And it isn’t all just theoretical, either – Edmonton, Alberta’s Gold Bar wastewater treatment plant has been using a reactor since 2007, and has seen good results. Every day, the reactor extracts over 80% of the phosphorus and 15% of the ammonia from 500,000 liters of sludge (20% of the plant’s total sludge stream), and converts it to 500 kg (1,102 lbs) of ready-to-use Crystal Green. Pilot plants have also proven successful in British Columbia, Virginia and Oregon.

Sourced & published by Henry Sapiecha

One estimates that half of the energy consumed by data centres goes toward cooling computer processors, with most of the removed hot air simply being blown into the atmosphere. Instead, IBM sees that heat being captured & used to warm the air in other areas of the building, to heat water, or to be converted into usable electricity. The company has already developed an on-chip water-cooling system for computer clusters, which is being demonstrated on the Swiss Aquasar supercomputer. It utilizes a network of microfluidic capillaries inside a standard heat sink, attached to the surface of each chip. Water flows within a few microns of the semiconductor material, picking up heat from it, then piping the warm water to a heat exchanger – from there, the cooled water returning to the computers, using a closed loop system.

As with last year’s list, given that all of these technologies are already in experimental use, it’s a very good bet that they will indeed one day find their way into our lives. Whether that day is within the next five years, however, is another thing-time will tell

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Biodiesel Co-Products

Science (Oct. 9, 2007) — Biofuel research isn’t just a matter of finding the right type of biomass—corn grain, soybean oil, animal fat, wood or other material—and converting it into fuel. Scientists must also find environmentally and economically sound uses for the by-products of biofuel production. Agricultural Research Service (ARS) scientists Brian Kerr and William Dozier have done just that.

Current biodiesel supplies are often made from the triglycerides, or fat, found in soybean oil. But processing biodiesel from soybean oil also yields crude glycerin, also known as glycerol, which has a purity level of about 85 percent. It also contains small amounts of salt, methanol and free fatty acids. If glycerol is refined to 99 percent purity, it can be used in many products, including pharmaceuticals, foods, drinks, cosmetics and toiletries.

Kerr, Dozier and Iowa State University colleague Kristjan Bregendahl studied whether crude glycerin could be used to supplement the feed of laying hens, broilers and swine. They found that crude glycerin provided a supply of caloric energy that equaled or exceeded the caloric energy available in corn grain. Feeds containing up to 10 percent glycerin had little to no adverse effect on laying hen egg production or broiler body weight gain. Pig body weight gain, carcass composition and meat quality also showed little to no adverse change after equivalent levels of crude glycerin were added to their feed.

Safe levels for salt, methanol and free fatty acids in crude glycerin consumed by nonruminant livestock still need to be determined. But as corn grain ethanol production and conversion soar, corn grain supplies for livestock feed are decreasing. Using crude glycerin to supplement feed supplies could provide livestock producers with a readily available, inexpensive and energy- packed alternative to corn grain.

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On Crude ‘Oil’ From Pig Manure

Science (June 17, 2008) — After a close examination of crude oil made from pig manure, chemists at the National Institute of Standards and Technology (NIST) are certain about a number of things. Most obviously, “This stuff smells worse than manure,” says NIST chemist Tom Bruno.

But a job’s a job, so the NIST team has developed the first detailed chemical analysis revealing what processing is needed to transform pig manure crude oil into fuel for vehicles or heating. Mass production of this type of biofuel could help consume a waste product overflowing at U.S. farms, and possibly enable cutbacks in the nation’s petroleum use and imports. But, according to a new NIST paper, pig manure crude will require a lot of refining.

The ersatz oil used in the NIST analyses was provided by engineer Yuanhui Zhang of the University of Illinois Urbana-Champaign. Zhang developed a system using heat and pressure to transform organic compounds such as manure into oil.

As described in the new paper, Bruno and colleagues determined that the pig manure crude contains at least 83 major compounds, including many components that would need to be removed, such as about 15 percent water by volume, sulfur that otherwise could end up as pollution in vehicle exhaust, and lots of char waste containing heavy metals, including iron, zinc, silver, cobalt, chromium, lanthanum, scandium, tungsten and minute amounts of gold and hafnium. Whatever the pigs eat, from dirt to nutritional supplements, ends up in the oil.

While the thick black liquid may look like its petroleum-based counterparts, the NIST study shows that looks can be deceiving. “The fact that pig manure crude oil contains a lot of water is unfavorable. They would need to get the water out,” Bruno says.

The measurements were made with a new NIST test method and apparatus, the advanced distillation curve, which provides highly detailed and accurate data on the makeup and performance of complex fluids. A distillation curve charts the percentage of the total mixture that evaporates as a sample is slowly heated. Because the different components of a complex mixture typically have different boiling points, a distillation curve gives a good measure of the relative amount of each component in the mixture. NIST chemists enhanced the traditional technique by improving precision and control of temperature measurements and adding the capability to analyze the chemical composition of each boiling fraction using a variety of advanced methods.

NIST researchers analyzed the graphite-like char remaining after the distillation by bombarding it with neutrons, a non-destructive way of identifying the types and amounts of elements present. Two complementary neutron methods detected the heavy metals listed above.

Bruno and colleagues currently spend much of their time analyzing military jet fuels and are not planning a major foray into pig manure. But Bruno concedes that the effort may have a payoff. “Who knows, it might help decrease the nuisance of manure piles.”

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Chicken manure to energy

Environmentally friendly, climate neutral and reliable: For the first time ever on display world wide at VIV Europe will be a gasification system which transforms biomass for example from poultry manure into energy. The clou of the Big Dutchman innovation is that, except for nitrogen, all the components which are important for fertilisation are preserved in the residual ash. Genuine dual use is thus achieved – quite independently of wind and sunshine.

The manure is dried, pressed into pellets and conveyed to a gasifier where it is converted into gas by means of thermochemical conversion. The only by-product which remains is ash – which is a very valuable fertiliser. Subsequently the energy produced in this way is processed in the combined heat and power plant (CHP) to generate electricity and heat. Furthermore, in addition to chicken manure, other by-products such as digestate from biogas plants or sugar cane can also be used for the same purpose.

The result is extremely impressive: The amount of energy produced in a 150 kW gasifier allows to supply thermal energy for 25 households for more than one year (maximum 10 kW heat output) and to provide 200 households one year long with electricity (at an annual average use of 0.75 kW per household).

Hall 12C.050

150 kW gasification system with conveyor belt, switching and control cabinet, gasifier, gas cooling and gas cleaning (from left to right)

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Waste into Valuable Fuel

Science (Feb. 4, 2008) — CSIRO and Monash University have developed a chemical process that turns green waste into a stable bio-crude oil. The bio-crude oil can be used to produce high value chemicals and biofuels, including both petrol and diesel replacement fuels.

“By making changes to the chemical process, we’ve been able to create a concentrated bio-crude which is much more stable than that achieved elsewhere in the world,” says Dr Steven Loffler of CSIRO Forest Biosciences.

“This makes it practical and economical to produce bio-crude in local areas for transport to a central refinery, overcoming the high costs and greenhouse gas emissions otherwise involved in transporting bulky green wastes over long distances.”

The process uses low value waste such as forest thinnings, crop residues, waste paper and garden waste, significant amounts of which are currently dumped in landfill or burned.

“By using waste, our Furafuel technology overcomes the food versus fuel debate which surrounds biofuels generated from grains, corn and sugar,” says Dr Loffler.

“The project forms part of CSIRO’s commitment to delivering cleaner energy and reducing greenhouse gas emissions by improving technologies for converting waste biomass to transport fuels.”

The plant wastes being targeted for conversion into biofuels contain chemicals known as lignocellulose, which is increasingly favoured around the world as a raw material for the next generation of bio-ethanol.

Lignocellulose is both renewable and potentially greenhouse gas neutral. It is predominantly found in trees and is made up of cellulose; lignin, a natural plastic; and hemicellulose.

CSIRO and Monash University will apply to patent the chemical processes underpinning the conversion of green wastes to bio-crude oil once final laboratory trials are completed.

The research to date is supported by funding from CSIRO’s Energy Transformed Flagship program, Monash University, Circa Group and Forest Wood Products Australia.

National Research Flagships CSIRO initiated the National Research Flagships to provide science-based solutions in response to Australia’s major research challenges and opportunities. The nine Flagships form multidisciplinary teams with industry and the research community to deliver impact and benefits for Australia.

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From Food Industry Waste

Science (Mar. 31, 2009) — The AZTI-Tecnalia technological centre, experts in food research, have put a biogas plant into operation in order to investigate novel systems of sustainable energy production based on the use of waste and sub-products from the food industry.

This new plant exploits the enormous potential of obtaining biogas from the organic matter contained in agricultural food waste, and will help the food industry to reduce the environmental impact caused by organic waste.

The plant, located at the AZTI-Tecnalia premises in Derio, aims to obtain biogas rich in methane by the process of anaerobic digestion* of the organic material contained in the sub-products from food, in order to transform it into electrical and heat energy. In the same way, for 2010, the technological centre foresees adapting the plant and making a commitment to that renewable source of energy which has seen the greatest surge in recent years: hydrogen. So, the aim is to be able to obtain hydrogen and methane from the same combined fermentation process.

AZTI-Tecnalia specialists are thus researching the viability of obtaining benefit from a number of agricultural food sub-products, alone or in combination (co-digestion) with other elements from various sources, such as sludge from purifying plants or food waste from mass consumption. Amongst others are mixtures from animal husbandry silage (purines), together with waste from agricultural food industries (leftovers from fruit and vegetable markets, milk whey, fish ends, aquaculture waste, etc.

With the biogas plant it is possible to reduce the environmental impact caused by organic waste. The emissions of greenhouse effect gases into the atmosphere are reduced, smells are considerably reduced and the final value of the waste is enhanced, As a consequence, the industry can adapt itself to environmental and social requisites, at the same time as its processes are more efficient through making better use of available resources.

The plant is available to government bodies and to food enterprises and environmental services who are interested in developing R+D projects applied to the energy valuation of food sub-products, with the aim of obtaining information for decision-making in the installation of this kind of plant at an industrial scale.

AZTI-Tecnalia is supporting the food industry in sustainable development, implementing measures to enhance its environmental performance. The biogas plant complements the activities undertaken by the centre at its food processing pilot plant, in which valuation trials of sub-products as new sources of raw materials for transformed foodstuffs are also carried out. Likewise, more profitable and innovative options are being sought in order to manage subproducts and waste generated by the food industry and studies of the Life Cycle Analysis (LCA) of the products are undertaken, analysing where the main costs and environmental impacts lie, and proposing, in consequence, situations for the enhancement and optimisation of the process.

* Anaerobic digestion is a biological process which transforms organic material into biogas and into a digested sludge, which can be used as organic enhancement in agricultural applications. Biogas mainly consists of carbon dioxide and methane, the latter with a high calorific value and which, thereby, can be used as a renewable source of electrical and/or thermal energy, or as a fuel for vehicles.

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Science (Aug. 22, 2009) — High-rate digestion with microfiltration is state-of-the-art in large sewage plants. It effectively removes accumulated sludge and produces biogas to generate energy. A study now reveals that even small plants can benefit from this process.

Sewage plants remove organic matter from wastewater. If the accumulating sludge decays, biogas is generated as a by-product. However, only 1156 of the 10,200 sewage plants in Germany have a digestion tank. Smaller operations, especially, baulk at the costs of a new digestion tank. Instead, they enrich the sludge with oxygen in the existing activation basin, and stabilize it.

“Activation basins require a lot of electricity. At the same time, enormous energy potential is lost, since no biogas is produced,” says Dr. Brigitte Kempter-Regel of the Fraunhofer Institute for Interfacial Engineering and Biotechnology IGB in Stuttgart. “A sewage plant eats up more electricity in the municipalities than their hospitals do.”

In a cost-benefit-study Dr. Kempter-Regel has shown that it also pays small sewage plants to transfer to more energy-efficient processes – even if they have to invest in a sludge digestion unit. “Based on a sewage plant for 28,000 inhabitants, we calculate that the plant can reduce its annual waste management costs from 225,000 euros by as much as 170,000 euros if sludge is decayed in a high-rate digestion unit with microfiltration, as opposed to treating it aerobically,” she says.

This process was developed at IGB and is much more effective than conventional digestion. Instead of the usual 30 to 50 days, sludge only remains in the tower for five to seven days. Around 60 percent of the organic matter is converted into biogas – the spoil is approximately a third more than in the traditional digestion process. The biogas obtained can be used to operate the plant, which, in the case study, would cut energy costs by at least 70,000 euros each year. High-rate digestion has the added advantage of producing less residual sludge needing disposal.

“This saves the operator another 100,000 euros,” says Kempter-Regel. In addition to high energy prices, budgets are also being hit hard by increasing waste management costs. The use of residual sludge in agriculture is controversial, and slurry can no longer be disposed of on landfills; burning the sludge is a very expensive alternative. So an effective reduction of sludge through digestion pays off. Even small sewage plants have already followed the recommendation of the Stuttgart Institute and converted to the high-rate digestion process.

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Within Pennies a Gallon

of Being Competitive

Science (May 20, 2010) — Existing technology can produce biodiesel fuel from municipal sewage sludge that is within a few cents a gallon of being competitive with conventional diesel refined from petroleum, according to an article in ACS’ Energy & Fuels. Sludge is the solid material left behind from the treatment of sewage at wastewater treatment plants.

David M. Kargbo points out in the article that demand for biodiesel has led to the search for cost-effective biodiesel feedstocks, or raw materials. Soybeans, sunflower seeds and other food crops have been used as raw materials but are expensive. Sewage sludge is an attractive alternative feedstock — the United States alone produces about seven million tons of it each year. Sludge is a good source of raw materials for biodiesel. To boost biodiesel production, sewage treatment plants could use microorganisms that produce higher amounts of oil, Kargbo says. That step alone could increase biodiesel production to the 10 billion gallon mark, which is more than triple the nation’s current biodiesel production capacity, the report indicates.

The report, however, cautions that to realize these commercial opportunities, huge challenges still exist, including challenges from collecting the sludge, separation of the biodiesel from other materials, maintaining biodiesel quality, soap formation during production, and regulatory concerns.

With the challenges addressed, “Biodiesel production from sludge could be very profitable in the long run,” the report states. “Currently the estimated cost of production is $3.11 per gallon of biodiesel. To be competitive, this cost should be reduced to levels that are at or below [recent] petro diesel

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