We have developed and tested a method that allows to get raw materials with further manufacturing of fuel briquettes or organic fertilizers, as well as significantly reduce the cost of sewage treatment, reduce production area, dramatically reduce environmentally hazardous emissions.
Today, the sediment after mechanical processing goes to the treatment of activated sludge (by a consortium of bacteria), and then discharged as gel on aeration fields. Organic residue (carbon) oxidize by air oxygen to carbon dioxide and water. Water goes to the filtration, and carbon dioxide goes to the atmosphere. Carbon dioxide is a "greenhouse" gas and thus the fields of aeration is a powerful source of greenhouse effect.
The process of decomposition of the active sludge gel takes up to 3-4 years. All this time, huge areas of treatment facilities - concrete aeration fields - flooded with thousands of tons of recyclable substances. This requires large expenditures on maintenance, dredging, clearing of basins and so on.
The proposed method allows to reduce the utilization time of sewage sludge (activated sludge) from 3 years to 3 weeks. We have developed special flocculant to speed up the process of gel decomposition. As a result, gel breaks into water and solid precipitate. Water flows to the filtration. The sediment contains from 70% to 85% of carbon in the form of organic compounds and from 15% to 30% as inorganic. It will create a peat-like mass. After a simple further processing we can use it as raw material for production of fuel briquettes or production of organic fertilizer. It becomes available due to the fact, that organic compounds in the gel have no time to react with the oxygen of the air and are stored in the sediment, thus being carbon-reach raw material.
The proposed method allows to reduce the utilization time of sewage sludge from 3 years to 3 weeks.
Our technology does not assume in any way to disrupt existing technology and does not require special equipment. Recycling of raw material occurs on commercially available standard equipment. This technology is suitable for disposal of livestock of pig farms that is a very big problem today all over the world.
What is Cationic Polymer Flocculant?
Cationic Polymer Flocculant is the initiator of the physicochemical process of adhesion of small particles of dispersed systems to larger ones under the influence of adhesion forces with the formation of coagulation structures and the formation of an enlarged sediment. Coagulation leads to the precipitation of suspended fine particles of biological sludge from the colloidal sludge solution, which are present in the wastewater and cannot be removed by the filtration system due to its small size and weight.
Ingredient of the Cationic Polymer Flocculant
Data Sheet msds.pdf | 146 KB
Some of Our Documented Experiments
At the sewage treatment facilities of the city of Chernihiv, we conducted four industrial tests for intensive dewatering of an aqueous suspension of sludge. During pumping of an aqueous suspension of sludge, a coagulation accelerator specially developed by us was applied to it. As a result, within 14 days, 12842 cubic meters of an aqueous suspension was separated for 7432 cubic meters of water and 5410 cubic meters of residue.
Since dehydration is very fast, the sludge in the aqueous suspension does not have time to ferment, and carbon in the form of carbon dioxide does not have time to evaporate. As a result, we get a dry residue very similar to peat or lignite, but the calorific value of this new fuel significantly higher.
Other fuel pellets:
|Wood pellets||Peat pellets||Lignite|
|Calorific value Kcal/kg|
|Calorific value Kcal/kg||4100||4200||3100|
The dry residue described above was used to make test lots of fuel pellets with the addition of organic raw materials (wood chips, coal dust). The results of the fuel’s analysis are below:
X-ray fluorescence analysis of inorganic components, %
|Pellets||Add wood chips||Add coal powder|
The results of the analysis of pellets from the siege of the Chernihiv (Ukraine) Sewage Treatment Plant
|Pellets||Add wood chips||Add coal powder|
|Calorific value 1, MJ/kg|
|Calorific value 1, MJ/kg||16,76||18,39||19,20|
|Calorific value 2, Kcal/kg|
|Calorific value 2, Kcal/kg||4004||4396||4589|
|Dry residue, %|
|Dry residue, %||92,03||92,93||92,63|
|Organic components, %|
|Organic components, %||70,75||76,86||66,62|
|Inorganic (Ash), %|
|Inorganic (Ash), %||29,25||23,14||33,38|
Sewage to Energy
Wastewater to power technology
The average wastewater flow per person per day is about 60 gallons or 227 liters. The Atakam’s technology can recover at least 4% of dry fuel from the wastewater (after active sludge treatment) with average condition (average recover is 5%). In this way we can produce 2.4 gallons or 9.8 liters (approximately 5 kg) of dry pellets per day per person. This technology allows to use an existing equipment and does not require any modernizations of activated sludge stage and dramatically reduce the size of drying fields (if any). In this way we can produce 2.4 gallons or 9.8 liters (approximately 5 kg) of dry pellets per day per person. The calorific value of the fuel ranges from 3500 to 4300 kilocalories per kilogram.
Atakam’s proprietary formulated cationic polymer flocculant in combination with a technology of converting residue to the carbon-reach substance allow to produce ready-to-use fuel (pellets) for power plant
The following calculation based on the most conservative numbers:
4000 kcal/kg is equal 4.7 kWh of thermal energy.
The average efficiency of electric power plant is 35%.
Therefore, 4.7 kWh x 0.35 = 1.6kWh of electricity. (1kg -> 1.6kWh) or: to produce 1 kWh of electricity we need (1/1.6) 0.625kg of the fuel.
For 1 Megawatt/hour accordingly we need 625kg of fuel.
For 100 MW/h we need 62500 kg or 62.5 tons of fuel per hour.
For a 100MW power plant we need 62.5 tons burned each hour or 1500 tons per day.
A town with 100,000 residents can generate up to (5kg x 100,000) 500,000 kg or 500 tons of fuel pellets per day and feeds the electric power station of over 30 MW which produces (30MW x 24h) 720 MWh per day.
The average household electric consumption in the US is 876 kWh per month or (876 / 30) 29 kWh per day. It means the plant of 30MW can serve around 24,000 homes.
A 1 million city can generate over 300 MW of electricity only from wastewater generated carbon fuel.
Of course, in real world those numbers will be different. There are a lot of ways where wastewater goes off the sewage system. There is a big difference in consumption in different regions. But even if we will get a half of those potential power, we can cover a big sector of electric power needs.
For countries that are highly industrialized and have high energy consumption (Nordic countries, USA, Australia, etc.), the amount of energy needed for a city of 1 million is about 1500 MW. To give an order of magnitude, that's a typical amount of power generated by a large nuclear power plant or hydroelectric dam (even bigger ones go up to 3000 and more).
For some slightly less power-hungry countries (most European countries, also china and south Africa), the number is closer to 500 MW (which is about as much as a mid-sized coal or natural gas fired plant makes in the US).
For most Asian, south-American, and north African countries, the number is closer to 100-150 MW for a city of 1M.
For most sub-Saharan African countries (excluding south Africa), the number is typically less than 50 MW.
According to US Energy Information Administration the new development still uses combustion steam turbine generator as the most effective and reliable. The combustion steam turbines still the most often used solution on all new constructions.
Form EIA-860, 2017 Annual Electric Generator Report
The average construction cost of the plant based on dry carbon pellets is a little bit more than the plant working on natural gas. We are expecting $1000 - $2000 per kilowatt depends on local conditions. The exact capacity-weighted cost of the construction should be determined on site.
EIA’s long-term projections show that most of the electricity generating capacity additions installed in the United States through 2050 will be natural gas combined-cycle and solar photovoltaic (PV). Onshore wind looks to be competitive in only a few regions before the legislated phase-out of the production tax credit (PTC), but it becomes competitive later in the projection period as demand increases and the cost for installing wind turbines continues to decline.
The significantly lower price of sewer-derived fuel makes it very competitive. This allows to build power plants with a significantly lower cost than other energy generators based on renewable sources. The technology of the manufacturing and using of combined steam generators is very reliable and well tested. Today, this remains the main way of converting thermal energy into electrical energy. To the next step along this path may be to use the Stirling engine. Atakam company is already developing a design of a source of electricity and heat for a single-family household, which is based on the Stirling engine technology. On a large application, using combined steam turbine technology to turn heat into electricity remains the most used and the most profitable.
Form EIA-860, 2017 Annual Electric Generator Report
Along with electricity generation plant the dry carbon fuel line should be installed on the local sewage treatment plant. The average cost of construction is 15%-20% of the cost of power generator. This cost will be reimbursed fast because of very low cost of the fuel.
The cost of common coal for 100 MW plant is a $60 per ton of coal multiplied by 60 tons per hour consumed by the plant. It is $3600 per hour or $2,600,000 per month. The cost of the fuel produced from municipal sewage is 4-8 (or even more) times lower.
Frequently Asked Questions
During the experiment, 100 kg of flocculant spent on processing of 15,000 tons of sludge. Thus, only 0.0067 kg or 6.7 g of the flocculant was spent on processing of one ton of sludge.
For the implementation of our technology, it is not necessary to change the existing technology in any way; special equipment is not required. Processing of the obtained raw materials can be done on the standard equipment.