Integrating Pyrolysis or Combustion with Scrubbing to Maximize the Nutrient and Energy Recovery from Municipal Sewage Sludge
Based on mass and energy balance calculations, this work investigates the possibility of recovering heat and nutrients (nitrogen and phosphorus) from municipal sewage sludge using pyrolysis or combustion in combination with a gas scrubbing technology. Considering a wastewater treatment plant (WWTP)...
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| Format: | Article |
| Language: | English |
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MDPI AG
2021-08-01
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| Series: | Recycling |
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| Online Access: | https://www.mdpi.com/2313-4321/6/3/52 |
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| author | Ali Saud Jouni Havukainen Petteri Peltola Mika Horttanainen |
| author_facet | Ali Saud Jouni Havukainen Petteri Peltola Mika Horttanainen |
| author_sort | Ali Saud |
| collection | DOAJ |
| description | Based on mass and energy balance calculations, this work investigates the possibility of recovering heat and nutrients (nitrogen and phosphorus) from municipal sewage sludge using pyrolysis or combustion in combination with a gas scrubbing technology. Considering a wastewater treatment plant (WWTP) with 65,000 t/a of mechanically dewatered digestate (29% total solids), 550 t/a nitrogen and 500 t/a phosphorus were recovered from the 4900 t/a total nitrogen and 600 t/a total phosphorus that entered the WWTP. Overall, 3600 t/a (73%) of total nitrogen was lost to the air (as N<sub>2</sub>) and clean water, while 90 t/a (15%) of total phosphorus was lost to clean water released by the WWTP. Both in combustion and in pyrolysis, the nitrogen (3%) released within thermal drying fumes was recovered through condensate stripping and subsequent gas scrubbing, and together with the recovery of nitrogen from WWTP reject water, a total of 3500 t/a of ammonium sulfate fertilizer can be produced. Furthermore, 120 GWh/a of district heat and 9700 t/a of ash with 500 t/a phosphorus were obtained in the combustion scenario and 12,000 t/a of biochar with 500 t/a phosphorus was obtained in the pyrolysis scenario. The addition of a stripper and a scrubber for nitrogen recovery increases the total electricity consumption in both scenarios. According to an approximate cost estimation, combustion and pyrolysis require annual investment costs of 2–4 M EUR/a and 2–3 M EUR/a, respectively, while 3–5 M EUR/a and 3–3.5 M EUR/a will be generated as revenues from the products. |
| first_indexed | 2024-03-10T07:16:42Z |
| format | Article |
| id | doaj.art-aef8fec91b9a4d8db75b34b568bbb89c |
| institution | Directory Open Access Journal |
| issn | 2313-4321 |
| language | English |
| last_indexed | 2024-03-10T07:16:42Z |
| publishDate | 2021-08-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Recycling |
| spelling | doaj.art-aef8fec91b9a4d8db75b34b568bbb89c2023-11-22T15:02:44ZengMDPI AGRecycling2313-43212021-08-01635210.3390/recycling6030052Integrating Pyrolysis or Combustion with Scrubbing to Maximize the Nutrient and Energy Recovery from Municipal Sewage SludgeAli Saud0Jouni Havukainen1Petteri Peltola2Mika Horttanainen3Department of Sustainability Science, Lappeenranta-Lahti University of Technology LUT, 53850 Lappeenranta, FinlandDepartment of Sustainability Science, Lappeenranta-Lahti University of Technology LUT, 53850 Lappeenranta, FinlandEndev Ltd., Mannerheimintie 20 B, 00100 Helsinki, FinlandDepartment of Sustainability Science, Lappeenranta-Lahti University of Technology LUT, 53850 Lappeenranta, FinlandBased on mass and energy balance calculations, this work investigates the possibility of recovering heat and nutrients (nitrogen and phosphorus) from municipal sewage sludge using pyrolysis or combustion in combination with a gas scrubbing technology. Considering a wastewater treatment plant (WWTP) with 65,000 t/a of mechanically dewatered digestate (29% total solids), 550 t/a nitrogen and 500 t/a phosphorus were recovered from the 4900 t/a total nitrogen and 600 t/a total phosphorus that entered the WWTP. Overall, 3600 t/a (73%) of total nitrogen was lost to the air (as N<sub>2</sub>) and clean water, while 90 t/a (15%) of total phosphorus was lost to clean water released by the WWTP. Both in combustion and in pyrolysis, the nitrogen (3%) released within thermal drying fumes was recovered through condensate stripping and subsequent gas scrubbing, and together with the recovery of nitrogen from WWTP reject water, a total of 3500 t/a of ammonium sulfate fertilizer can be produced. Furthermore, 120 GWh/a of district heat and 9700 t/a of ash with 500 t/a phosphorus were obtained in the combustion scenario and 12,000 t/a of biochar with 500 t/a phosphorus was obtained in the pyrolysis scenario. The addition of a stripper and a scrubber for nitrogen recovery increases the total electricity consumption in both scenarios. According to an approximate cost estimation, combustion and pyrolysis require annual investment costs of 2–4 M EUR/a and 2–3 M EUR/a, respectively, while 3–5 M EUR/a and 3–3.5 M EUR/a will be generated as revenues from the products.https://www.mdpi.com/2313-4321/6/3/52combustionenergy recoverynutrient recoverypyrolysissewage sludgethermal treatment |
| spellingShingle | Ali Saud Jouni Havukainen Petteri Peltola Mika Horttanainen Integrating Pyrolysis or Combustion with Scrubbing to Maximize the Nutrient and Energy Recovery from Municipal Sewage Sludge Recycling combustion energy recovery nutrient recovery pyrolysis sewage sludge thermal treatment |
| title | Integrating Pyrolysis or Combustion with Scrubbing to Maximize the Nutrient and Energy Recovery from Municipal Sewage Sludge |
| title_full | Integrating Pyrolysis or Combustion with Scrubbing to Maximize the Nutrient and Energy Recovery from Municipal Sewage Sludge |
| title_fullStr | Integrating Pyrolysis or Combustion with Scrubbing to Maximize the Nutrient and Energy Recovery from Municipal Sewage Sludge |
| title_full_unstemmed | Integrating Pyrolysis or Combustion with Scrubbing to Maximize the Nutrient and Energy Recovery from Municipal Sewage Sludge |
| title_short | Integrating Pyrolysis or Combustion with Scrubbing to Maximize the Nutrient and Energy Recovery from Municipal Sewage Sludge |
| title_sort | integrating pyrolysis or combustion with scrubbing to maximize the nutrient and energy recovery from municipal sewage sludge |
| topic | combustion energy recovery nutrient recovery pyrolysis sewage sludge thermal treatment |
| url | https://www.mdpi.com/2313-4321/6/3/52 |
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