An aerobic treatment system or ATS , often called (wrong) aerobic septic system, is a small-scale sewage treatment system similar to a system septic tank, but who use aerobic processes for digestion rather than just anaerobic processes used in septic systems. This system is usually found in rural areas where public sewage is unavailable, and can be used for single residences or for a small group of homes.
Unlike traditional septic systems, aerobic treatment systems produce high quality secondary waste, which can be sterilized and used for surface irrigation. This allows much greater flexibility in the placement of the recharge area, as well as cutting the required size of the recharge area by half.
Video Aerobic treatment system
Process
The ATS process generally consists of the following phases:
- Pre-treatment stage to remove large solids and other unwanted substances.
- Aeration stage, in which aerobic bacteria digest biological waste.
- Settling stage allows an undigested solid to settle. This forms a sludge that should be periodically removed from the system.
- The disinfectant stage, in which chlorine or such disinfectant is mixed with water, to produce an antiseptic output. Another option is UV disinfection, where water is exposed to UV light inside the UV disinfection unit.
The disinfectant stage is optional, and is used where sterile effluents are needed, as is the case where waste is distributed above the ground. The most commonly used disinfectant is the calcium hypochlorite tablet, specially made for waste treatment systems. The tablet is meant to break down quickly in the sun. The stable form of chlorine survives after the wastes are dispersed, and can kill plants in the infiltration field.
Because ATS contains a living microbial ecosystem to digest waste products in the water, excessive amounts of items such as bleach or antibiotics can damage the ATS environment and reduce the effectiveness of the treatment. Non-digestible items should also be avoided, as they will accumulate in the system and require more mud drainage.
Maps Aerobic treatment system
Type of aerobic care system
Small-scale aerobic systems generally use one of two designs, a fixed film system, or a continuous flow, a suspended growth aerobic system (CFSGAS). Pre-treatment and effluent handling are similar for both types of systems, and the difference lies in the aeration stage.
Movie system fixed
The film system still uses porous media that provides beds to support biomass films that digest waste materials in wastewater. The design for the fixed film system varies greatly, but falls into two basic categories (although some systems may combine both methods). The first is a system in which the media is moved relative to the wastewater, alternately immerse the film and expose it to the air, while the second uses stationary media, and varies the flow of waste water so that the film alternately is immersed and exposed to air. In both cases, biomass must be exposed to wastewater and air for aerobic digestion to occur. The film itself can be made of suitable porous materials, such as plastics or peat moss. The simple system uses stationary media, and relies on intermittent and gravitational-driven wastewater streams to provide periodic exposure to air and waste water. The general mobile media system is a rotating biological contactor (RBC), which uses a slowly rotating disk on the horizontal axis. Approximately 40 percent of the disk is submerged at a certain time, and the shaft rotates at a rate of one or two revolutions per minute.
Continuous flow, deferred growth aerobics system
The CFSGAS system, as the name implies, is designed to handle continuous flow, and does not provide beds for bacterial films, relying more on bacteria suspended in wastewater. Suspension and aeration are usually provided by air pumps, which pump air through the aeration chamber, providing constant stirring of waste water in addition to oxygenation. Media to promote the growth of fixed film bacteria can be added to several systems designed to handle higher levels of biomass than usual in wastewater.
Retrofit or portable aerobic system
Another increasingly common use of aerobic treatment is for the remediation of anaerobic septic systems failing or failing, by retrofitting existing systems with aerobic features. This class of products, known as aerobic remediation, is designed to remediate biological failure and anaerobic distribution system failure by significantly reducing biochemical oxygen demand (BOD5) and total suspended solids (TSS) of effluents. The reduction of BOD5 and TSS reverses the developed bio. Furthermore, waste with high dissolved oxygen and aerobic bacteria flows into the distribution component and digests the bio-mat. Thus in a single tank system where solids have no place to settle, or no clarifying area can damage the land. the line as a solid is stirred in the tank.
Composting toilets
Compostable toilets are designed to handle only toilet waste, rather than public housing wastewater, and are usually used with water-free toilets rather than flush toilets associated with the above aerobic treatment system type. This system treats waste as a moist solid, rather than in a liquid suspension, and thus separates the urine from the stool during treatment to maintain the correct water content in the system. An example of composting toilets is the multrum clivus (Latin for 'sloping space'), which consists of a sloping space separating urine and dirt and a fan to provide positive ventilation and prevent the smell from exiting the toilet. In the room, urine and faeces are independently broken down not only by aerobic bacteria, but also by fungi, arthropods, and earthworms. Treatment time is very long, with minimum time between solid waste disposal a year; during maintenance the volume of solid waste decreased by up to 90 percent, with most being converted to water vapor and carbon dioxide. Pathogens are eliminated from long-term waste in unfriendly conditions in the treatment room.
Comparison with traditional septic system
The aeration stage and the disinfectant stage are the main differences from traditional septic systems; in fact, an aerobic treatment system can be used as a secondary treatment for effluent septic tanks. These stages increase the initial cost of the aerobic system, as well as the maintenance needs of the passive septic system. Unlike many other biofilters, aerobic treatment systems require constant supply of electricity to drive the air pump increasing the overall system cost. Disinfectant tablets should be replaced periodically, as well as electrical components (air compressors) and mechanical components (air diffusers). On the positive side, aerobic systems produce higher quality effluents than septic tanks, and thus the absorption field can be smaller than conventional septic systems, and output can be disposed in areas that are too sensitive to the environment for septic system output. Some aerobic systems recycle waste through sprinkler systems, using them to water the grass where regulations are approved.
Quality of effluent
Since the effluent from ATS is often discharged to the surface of the recharge area, its quality is very important. Typical ATS will, when properly operated, produce effluents with less than 30 mg/liter of BOD5, 25 mg/L TSS, and 10,000 cfu/mL of coliform fecal bacteria. It's clean enough that it can not support a biomass or "slime" layer like a septic tank.
ATS waste is relatively odorless; the right operating system will produce waste that smells musty, but not like waste. Aerobic treatment is very effective for reducing odors, that it is the preferred method to reduce the odor from manure produced by farms.
See also
- List of wastewater treatment technologies
References
External links
- Aerobic Maintenance Unit at Northern Arizona University
Source of the article : Wikipedia
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