Из Википедии, бесплатной энциклопедии
Перейти к навигации Перейти к поиску

Аэробное сбраживание - это процесс очистки сточных вод, предназначенный для уменьшения объема осадка сточных вод и обеспечения его пригодности [1] для последующего использования. [2] Совсем недавно была разработана технология, которая позволяет обрабатывать и сокращать другие [3] органические отходы, такие как пищевые, картонные и садовые отходы. Это бактериальный процесс, протекающий в присутствии кислорода. Бактерии быстро потребляют органическое вещество и превращают его в углекислый газ , воду и ряд органических соединений с более низким молекулярным весом. Поскольку нет новых поступлений органического материала из сточных вод, биота активного ила начинает умирать и используется в качестве пищи сапротрофами. bacteria. This stage of the process is known as endogenous respiration and it is process that reduces the solid concentration in the sludge.

Process[edit]

Aerobic digestion is typically used in an activated sludge treatment plant. Waste activated sludge and primary sludge are combined, where appropriate, and passed to a thickener where the solids content is increased. This substantially reduces the volume that is required to be treated in the digester. The process is usually run as a batch process with more than one digester tank in operation at any one time.[4]Air is pumped through the tank and the contents are stirred to keep the contents fully mixed. Carbon dioxide, waste air and small quantities of other gases including hydrogen sulfide are given off. These waste gases require treatment to reduce odours in works close to housing or capable of generating public nuisance.[4] The digestion is continued until the percentage of degradable solids is reduced to between 20% and 10% depending on local conditions[2] Where non-sewage waste is being processed, organic waste such as food, cardboard and horticultural waste can be significantly reduced in volume leaving an output that can be used as soil improver or biomass fuel.

Advantages[edit]

Because the aerobic digestion occurs much faster than anaerobic digestion, the capital costs of aerobic digestion are lower.

The process is usually run at ambient temperature and the process is much less complex than anaerobic digestion and is easier to manage.

Disadvantages[edit]

The operating costs are typically much greater for aerobic digestion than for anaerobic digestion because of energy used by the blowers, pumps and motors needed to add oxygen to the process. However, recent technological advances include non-electrically aerated filter systems that use natural air currents for the aeration instead of electrically operated machinery.

The digested sludge is relatively low in residual energy and although it can be dried and incinerated to produce heat, the energy yield is very much lower than that produced by anaerobic digestion.

Autothermal thermophilic aerobic digestion[edit]

Autothermal thermophilic aerobic digestion is a faecal sludge treatment design concept that uses the nutrients in the sludge and the metabolic heat of the bacteria to create high temperatures in the aerobic digester. This gradually shifts the microbial community towards thermophilic at temperatures typically at 55-degree Celsius or above.[5] While the higher aeration requirements of autothermal thermophilic aerobic digestion further increases energy use and potential smell nuisance, the increased temperature makes the resulting biosolids much safer for re-use.[6]

References[edit]

  1. ^ "Aerobic Diestion" (PDF). Water Environment Federation. Archived from the original (PDF) on 27 March 2016. Retrieved 19 March 2016.
  2. ^ a b "Handbook Biological Wastewater Treatment - Design of Activated Sludge Systems". Retrieved 19 March 2016.
  3. ^ "Aerobic Waste Digesters". Retrieved 17 March 2017.
  4. ^ a b "Aerobic digestion of sludge". Johns Creek Environmental Campus. Retrieved 19 March 2016.
  5. ^ Pembroke, J. Tony; Ryan, Michael P. (25 July 2019). "Autothermal Thermophilic Aerobic Digestion (ATAD) for Heat, Gas, and Production of a Class A Biosolids with Fertilizer Potential". Microorganisms. 7 (8): 215. doi:10.3390/microorganisms7080215. ISSN 2076-2607. PMC 6722850. PMID 31349557.
  6. ^ Layden, Noreen M. (November 2007). "Autothermal thermophilic aerobic digestion (ATAD) – Part I: Review of origins, design, and process operation". Journal of Environmental Engineering and Science. 6 (6): 665–678. doi:10.1139/S07-015.

WHY AEROBIC DIGESTION IS SET TO MODERNISE FOOD WASTE MANAGEMENT