Canada is known for its water with its abundance of rivers, lakes, and three oceans. It is also home to the largest fresh water lakes in the world. But when it comes to wastewater, most Canadians flush the toilet not thinking about where it all ends up. There are many innovative companies that are now looking closely at opportunities that can be tapped from the resources recovered in sewage sludge. They are optimistic about business prospects that will not only earn huge profits but also help clean the environment in the long term.
Source of Precious Metals
Precious metals such as gold could be present in sewer sludge through wastewater emitted by mining companies, jewelry makers, and industrial manufacturers. In a new study, scientists at the Arizona State University (ASU), Tempe, gathered sludge samples around the US and evaluated the metal content using a mass spectrometer that can identify different elements as they are ionized using a superhot plasma. The aim of the study was to measure the amount of metals that can be recovered. According to their findings, there is as much as $13 million worth of metals present in sludge every year in a city inhabited by at least a million people. This includes about $2.6 million in gold and silver.
Suwa City in Nagano Prefecture, Japan has attempted to extract gold from wastewater sludge. A treatment plant located near a number of precision equipment manufacturers was able to collect almost 2 kilograms of gold in every metric ton of ash residue from burning sludge. To put this in perspective, the amount recovered is higher than Japan’s Hishikari Mine, one of the world’s top gold mines, owned by Sumitomo Metal Mining Co Ltd, which contains 20-40 grams of the precious metal per ton of ore.
Utility as Fertilizers
Throughout much of civilization, manure has been used as fertilizer in agricultural farmlands for many centuries. Farmers use biosolids derived from sewage sludge to provide crops with required essential nutrients such as nitrogen and phosphorous. Organic matter found in biosolids enhances moisture retention, soil structure, permeability, reduces wind and water erosion, and enhances the uptake of plant nutrients. Modern techniques have improved the safety and quality of wastewater sewage, neutralizing pathogens and minimizing toxic natural and synthetic chemicals. Today, about 60% of the sewage sludge in the United States is already used in agriculture as fertilizer. Thus, sludge should not be dismissed as a liability but also a possible valuable resource.
Remondis, a global recycling company in Germany, has developed a wastewater treatment facility that can derive energy, clean water and valuable chemicals from sewage. This plant will begin with industrial-scale recovery of phosphorus — a vital raw material in crop production that may soon be in short supply. Their technique called TetraPhos allows phosphorus to be recovered from the ashes of incinerated sewage sludge in a very efficient manner. The ash is first dissolved into diluted phosphoric acid, then calcium, aluminum salts and iron are removed. The calcium can be recovered as gypsum and utilized in construction materials. The iron will be sold off and the aluminum used directly in the treatment facility as a precipitant in wastewater treatment.
Production of Renewable Energy
Industry experts estimate that if all biosolids in the United States were transformed into biomass energy, they would yield 7 million to 7.6 million megawatts of power. Compare this amount to the present installed capacity of wind power of only 43,000 megawatts.
Instead of throwing waste in a landfill, recycling biosolids into biodiesel fuel saves money and reduces greenhouse gas emissions. In fact, the global warming effect of methane gases from decaying landfill wastes is 20 times worse than carbon dioxide emissions.
Earth, Wind & Fire Technologies sees an opportunity to sell biodiesel or electricity that’s produced as a result of the wastewater treatment process. The company collects biosolids, microwaves them, produces pellets of dried human sludge and carbon-based landfill material and then runs an electrical current through it. The vapor created is captured and condensed into a No. 2 diesel fuel. The drop-in biodiesel burns cleaner than traditional diesel-biofuel mixtures and contains less particulates
Another technique involves sublimation, turning a substance from a solid form into gas without going through a liquid state. This produces methane gas that’s captured and burned to spin generators that feed electricity to the grid. It requires 30 tons of dry waste to yield enough methane to generate 1.2 megawatts of electricity. The company markets its diesel as “Microfuel Refinery” and could be the answer to the ineffective waste management and US dependence on foreign oil.
In Canada, the Bioenergy Systems for Viable Stationary Applications (BSVSA) program helps Canadian companies capitalize on the opportunity to invest in renewable energy by lowering the technical and cost barriers associated with the integration of locally-sourced biomass into stationary energy (heat and power) systems.
One of these renewable energy sources is biogas that can be used to generate power and electricity for Canadians. However, one major challenge is that biogas must first be cleaned of organic impurities and pollutants that could damage the specialized equipment used to capture and contain it. Quadrogen Power Systems in British Columbia is working on new technology to provide a solution. While older systems eliminate only a limited amount of the harmful impurities in biogas, their new technology removes virtually all of them, producing the cleanest biogas on the market. This ground-breaking cleanup system can also be utilized for both conventional power generation equipment and emerging technologies such as fuel cells.
If you are a municipality in Ontario and in need of a biosolids management solution, please feel free to contact us at 1 (877) 479-1388.
Sources:
http://www.sciencemag.org
https://www.scientificamerican.com