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Lagunage consiste a la realisation des grand bassin
Using the biological treatment (wheter aerobic or anaerobic microorganism). Depend on the organic concentration of the wastewater and tye space available with the help of first treament that usually use chemical to pericitipate solids that available in the wastewater.
sewage treatment with naturel lagooning for small agglomerations or filter planted with reeds (vertical or horizental flow) , very simple , economic and ecological
Lagooning is a natural water purification technique based on deseutrophication. The principle is to recreate "buffer" media or basins in which waste or polluted water will transit before being released into the natural environment
Mechanical treatment may be necessary based on the type of wastewater and the level of purity required. If mechanical treatment is not necessary then water can be treated using chemicals in processes such as chlorination, fluorination, or softening. Other methods include physical removal of waste such as filtration using screening or through sand filtration which will depend on gravity and the size of waste particles. Also, we may clean wastewater using biological methods and aeration tanks.
Treating wastewater has the aim to produce an effluent that will do as little harm as possible when discharged to the surrounding environment, thereby preventing pollution compared to releasing untreated wastewater into the environment. [5]
Sewage treatment generally involves three stages, called primary, secondary and tertiary treatment.
Primary treatment consists of temporarily holding the sewage in a quiescent basin where heavy solids can settle to the bottom while oil, grease and lighter solids float to the surface. The settled and floating materials are removed and the remaining liquid may be discharged or subjected to secondary treatment. Some sewage treatment plants that are connected to a combined sewer system have a bypass arrangement after the primary treatment unit. This means that during very heavy rainfall events, the secondary and tertiary treatment systems can be bypassed to protect them from hydraulic overloading, and the mixture of sewage and stormwater only receives primary treatment.
Secondary treatment removes dissolved and suspended biological matter. Secondary treatment is typically performed by indigenous, water-borne micro-organisms in a managed habitat. Secondary treatment may require a separation process to remove the micro-organisms from the treated water prior to discharge or tertiary treatment.
Tertiary treatment is sometimes defined as anything more than primary and secondary treatment in order to allow rejection into a highly sensitive or fragile ecosystem (estuaries, low-flow rivers, coral reefs, ...). Treated water is sometimes disinfected chemically or physically (for example, by lagoons and microfiltration) prior to discharge into a stream, river, bay, lagoon or wetland, or it can be used for the irrigation of a golf course, green way or park. If it is sufficiently clean, it can also be used for groundwater recharge or agricultural purposes.
The best way of treating wastewater without mechanical treatment is through phtyoremidiation process. This way of treatment requires sufficient land and different plants like Typha, Duckweed, penywort, etc. These plants grow on wastewater leaving behind the treated water. COD removal of upto 90% can be achieved from this method
Secondary (biological) treatment removes the dissolved organic matter that escapes primary treatment. This is achieved by microbes consuming the organic matter as food, and converting it to carbon dioxide, water, and energy for their own growth and reproduction. The biological process is then followed by additional settling tanks (“secondary sedimentation", see photo) to remove more of the suspended solids. About 85% of the suspended solids and BOD can be removed by a well running plant with secondary treatment. Secondary treatment technologies include the basic activated sludge process, the variants of pond and constructed wetland systems, trickling filters and other forms of treatment which use biological activity to break down organic matter.
In case of no power for wastewater treatment we can use wetland or natural ponds (anaerobic, facultative and maturation ponds) and i prefer wetland systems
