The process of wastewater treatment and removal of emerging pollutants (1)-converted

1. The process of wastewater treatmentand removal of emergingpollutants 1.introduction A wastewater treatment plant is a water treatment plant for the purification of wastewater, whose main objective is to collect the water of a population or industrial sector and remove the pollutants from it in order to return it later to the water cycle, either by discharge to the sea or by direct reuse. The various substances to be removed include residues, oils, sands and various settleable solids, compounds with nitrates, ammonia and phosphates. The problem is that conventional wastewater treatment plants are not designed to remove pollutants of an emergent nature, as will be discussedbelow.

2. types oftreatment • Physicaltreatments • These are processes that involve physical separation, generally of solids. These processes often depend on the physical properties of the contaminants, such as viscosity, particle size, buoyancy, etc. They include screening, precipitation, separation and filtering of solids. • Chemicaltreatments • These are processes that depend on the chemical properties of the impurities or reagents introduced into the water. The iron and oxygen elimination, the phosphate and nitrate elimination, the coagulation, the electrochemical processes, the oxidation, the ion exchange, etc. should behighlighted. • Biological treatments DISPLAY • These processes use biological processes that attempt to eliminate colloidal impurities. They are microorganisms that act on suspended solids and convert them into sedimentable solids. They may be aerobic or anaerobic processes, such as active sludge, trickling filters, anaerobic co-digestion, or aeratedlagoons. • stages oftreatment • Pretreatment • This is the preliminary stage of treatment of the wastewater treatment plant. In this process, the wastewater flow entering the station is regulated and measured. In thisstage,

3. the larger solids, sand and grease contained in the black water are removed.These • compounds are removed byfiltration. • Pre-aeration is also usually performed to reduce the volatile organic compounds dissolved in the water, which give off a bad odor and increase the COD value of the water. Devices used include the coarse shaft, coarse roughing, fine roughing, anddegreasing/degreasing. • The initialtreatment • This first stage has the task of removing suspended solids, which is done by a gravity sedimentation process or by precipitation, either assisted or by the addition of chemical substances. Solids are removed by screening based on particlesize. • Compounds such as aluminum, flocculating polyelectrolytes, and iron salts are then added, and phosphorus dissolved in small colloids or in a very fine suspension is precipitated using hydraulicmachinery. • The main methods include the primary decanter (gravity sedimentation), the levitation method (separation of suspended solids by bubbling), and chemical treatment with the addition of reagents to increase the sedimentation of dissolvedsolids. • Secondarytreatment • The objective of this second stage is to eliminate the dissolved organic matter in colloidal state by biochemical oxidation processes. In addition, biological substances caused by human waste are degraded. In these treatments there are aerobic and anaerobic processes. Aerobic processes are carried out in the presence of oxygen supplied by injection into storagetanks.

4. Anaerobic processes are carried out in the absence of oxygen. Inthese processes, fermentation reactions of organic matter take place and are converted into released energy, CO2, CH4, and C. Some of the most commonly used anaerobic and anaerobic processes are active sludge, green filters, aerated lagoons, bacterial beds, and anaerobic digestion. There are also physicochemical processes such as particulate beds. These processes reduce much of the BOD and eliminate the remainder of the settleable solids. Generally, there are combinations between these different processes, resulting in biological processes with two or morestages. Biological reactors such as moving bed or membrane reactors can also be used, but their construction and operating costs are usually higher than those of a conventional filter treatmentplant. This stage also includes secondary sedimentation, where the treated water and the sludge produced in the biological process areseparated. We also Provide waste water treatment in Pakistanmachinery .you can check italso. 3.4 Tertiarytreatment In this final treatment stage, processes are carried out to eliminate pathogens, such as fecal bacteria, in order to raise the quality standards required for return to the water cycle through discharge to the sea, rivers, lakes, aquifers, reservoirs, and other water systems. This type of treatment is carried out only in wastewater treatment plants that discharge into a protectedarea.

5. The processes carried out include, first of all, filtration in sand filters,where a large part of the substances is kept in suspension. The remaining activated carbon retains the rest of thetoxins. Lagoon treatment provides the necessary sedimentation and an additional biological benefit. It basically mimics the natural self-purification processes of a river or lake. Not only are lagoons extremely aerobic, resulting in habitual stream growth, but filtering invertebrates aid in the process of removing solids. On the other hand, artificial wetlands consist of a series of reed belts or similar, which cause a process of phytoremediation (decontamination ofsoils). During this phase, nutrient decomposition also takes place. Nitrogen is removed by biological oxidation by bacteria such as Nitrobacter or Nitrosomonas, which convert NH 3 to nitrates and then to N 2 . In this denitrification process, nitrates and nitrites are utilized by these bacteria under anaerobic conditions, producing nitrogen gas and CO 2 and water as endproducts. Phosphorus is removed through the process of enhanced biological phosphorus removal, in which polyphosphate-forming bacteria take up phosphorus from the water. The resulting sludge is complicated to handle, but this is a minor drawback compared to the increased efficiency of the phosphorus removalprocess. Finally, the wastewater is disinfected to reduce the number of organisms formed in the intermediate stages. The most common methods are ozonation, UV light treatment or chlorine treatment.Chlorine disinfection is still the most common form of disinfection, especially in Pakistan, whileUV

6. disinfection is becoming increasingly important in Pakistan. We alsoprovide mechanicalwastewater treatment in Pakistan, so you can check here for waterdisinfected 4. removal of emergingpollutants Water is a natural resource, scarce and essential for human life, which also enables environmental sustainability. It is both in qualitative and quantitative terms.