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Biodegradable material is capable of decomposing without an oxygen source (anaerobically) into carbon dioxide, water, and biomass, but the timeline is not very specifically defined. Similarly, compostable material breaks down into carbon dioxide, water, and biomass; however, compostable material also breaks down into inorganic compounds.
Biodegradable additives can convert the plastic degradation process to one of biodegradation. Instead of being degraded simply by environmental factors, such as sunlight (photo-oxidation) or heat (thermal degradation), biodegradable additives allow polymers to be degraded by microorganisms and bacteria through direct or indirect attack.
In typical parlance, the word biodegradable is distinct in meaning from compostable.While biodegradable simply means an object is capable of being decomposed by bacteria or other living organisms, "compostable" in the plastic industry is defined as able to decompose in aerobic environments that are maintained under specific controlled temperature and humidity conditions.
Biodegradable polymers have a long history, and since many are natural products, the precise timeline of their discovery and use cannot be accurately traced. One of the first medicinal uses of a biodegradable polymer was the catgut suture , which dates back to at least 100 AD. [ 4 ]
There is also much debate about the total carbon, fossil fuel and water usage in manufacturing biodegradable bioplastics from natural materials and whether they are a negative impact to human food supply. To make 1 kg (2.2 lb) of polylactic acid, the most common commercially available compostable plastic, 2.65 kg (5.8 lb) of corn is required. [57]
By definition, biodegradable materials are formed or organic compounds which can thus be broken down by living organisms, such as bacteria, fungi, or water molds, and reabsorbed by the natural environment. [13] Whether a material is biodegradable is determined by its chemical structure, not the origin of the material from which it is made. [14]
Activated sludge tank at Beckton sewage treatment plant, UK.The white bubbles are due to the diffused air aeration system. The activated sludge process is a type of biological wastewater treatment process for treating sewage or industrial wastewaters using aeration and a biological floc composed of bacteria and protozoa.
Sedimentation (water treatment) Septic tank; Septic tank conversion [2] Sequencing batch reactor; Sewage treatment; Skimmer (machine) Slow sand filter; Stabilization pond; Supercritical water oxidation (SCWO) Thermal hydrolysis; Treatment pond; Trickle-bed reactor; Trickling filter; Ultrafiltration; Ultraviolet disinfection; Upflow anaerobic ...