Wastewater is water that’s has been used as for washing, flushing or in any manufacturing process and so contain waste products e.g. sewage.
Municipal wastewater is domestic wastewater mixed with effluents from commercial and industrial works e.g. sewage and food waste.
Wastewater treatment is defined as “the process of removing contaminants from wastewater, both runoff (effluents) and domestic and includes physical, chemical and biological processes to remove physical, chemical and biological contaminants” (Oilgae 2014). Its objective is to produce a waste stream (or treated effluent) and a solid waste or sludge suitable for discharge or reuse back into the environment. It is designed either to use the natural purification processes of streams
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The importance of biological treatment at the secondary stage is:
Using the schematic diagram on page 8, the major physical components involved in the secondary treatment stage consists of:
1) Bioreactor: Designed to provide the required detention time and to ensure that the activated sludge and the influent wastewater are mixed thoroughly. The screened de-gritted wastewater flows out of each grit chamber from the preliminary stage and into the bioreactors which contains a mixture of screened de-gritted wastewater and return activated sludge. The combined flow is aerated to enable the biomass to breakdown soluble and some insoluble pollutants. At this stage biological treatment is facilitated. There are 2 bioreactors, each with an anoxic zone (void of all forms of oxygen) containing 4 mixers each located midway down the depth of the tank, used to gently turn the wastewater and to not add oxygen to the
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Ozone is the product of oxygen molecules which are separated by an energy source into oxygen atoms that collide with an oxygen molecule to form an unstable gas. In most wastewater treatment plants, the generation of ozone is done on site because of its instability also its fast rate of decomposition to elemental oxygen after generation. By, the use of high voltage alternating current approximately (6–20 kilovolts) across a dielectric discharge gap containing oxygen-bearing gas. Wastewater color removal demands an ozone quantity which in most cases fluctuates between 50 to 100 mg/l, for color decrease of 85-92%. This dosage flourishes simultaneously a COD reduction about 40%, while BOD a small increase in the area of approximately 3-7% has been
Entire towns and rural households that lack wastewater treatment systems discharge raw wastewater directly into rivers and streams through open lines known as “straight pipes.” (O’Dell, 2005). The lack of proper wastewater disposal promotes environmental degradation and creates potential health hazards, including contamination of drinking water sources.
But one can’t look at “water” in a monolithic sense, because not all water is usable for drinking or irrigation. Usable water can be defined, in this instance, as a source that is reliable, consistent, and clean enough to drink or use for irrigation. This includes rivers, lakes, wells, but it does not include oceans or contaminated water. In some circumstances, the water that is at first promising can then become contaminated; water standing in irrigation ditches can become a fertile breeding ground for mosquitoes and other carriers of disease. In addition, the over-use or diversion of water can impact its quality, creating water heavy ...
Disinfection is applied in water as well as wastewater treatment as a finishing step so as to destroy pathogens but the cause of concern regarding the disinfection process is the formation of disinfection byproducts (DBPs). Natural organic matter (NOM) in water has been considered as the predominant DBP precursors. Disinfectants are powerful oxidants that oxidize the organic matter present in water forming DBPs. Chlorine, ozone, chlorine dioxide, and chloramines are the most common disinfectants used nowadays and each produces its own suite of chemical DBPs in finished drinking water (Richardson, 2003). DBPs so formed pose a threat to human health because of their potential to cause cancer and reproductive/developmental effects. Most developed nations have regulated concentration of DBPs so as to minimize exposure to potentially harmful DBPs while maintaining adequate disinfection and control of targeted
Stephenson, R., & Blackburn, J. J. (1998). The Industrial Wastewater Systems Handbook. New York: Lewis Publishers.
The Kwinana Desalination Plant, located south of Perth, Western Australia, turns seawater from Cockburn Sound into nearly 140megalitres of drinking water per day, supplying the Perth metropolitan area.
Ozone (O3) is generated on-site at water treatment facilities by passing dry oxygen or air through a system of high-voltage electrodes. Ozone is one of the strongest oxidants and disinfectants available. Its high reactivity and low solubility, however, make it difficult to
Ozonation is very useful in pulp wastewater treatment. This process can convert COD to BOD. Many chemical compounds are sensitive to ozonation process. So this process can have a large impact in decrease the concentration of AOX in pulp wastewater and other colored/colorless chemical compounds.
The formation of the biofilm depends on factors like the type of surface used, presence of polymeric molecules on the surface and cell-cell interactions. Wastewater is passed through the surfaces on which the biofilms are attached. The microorganisms in the biofilm utilize the organic matter present in the wastewater and subsequently, the biofilms grow. There are four predominant reactor types that utilize this technology. Trickling Filters (TFs), Rotating Biological Contactor (RBC) Systems, Constructed Wetlands and Membrane Bioreactors (MBRs) (Sehar & Naz, 2016).
Mixed with activated sludge where tha waste water contain source of food to the microbes in the activated sludge.
Wastewater is any water that has been adversely affected in quality by anthropogenic influence. It comprises of liquid waste discharged by domestic residences, commercial properties, industry, and/or agriculture and can encompass a wide range of potential contaminants and concentrations. Any type of wastewater that passes through a sewer can be referred to as sewage. Wastewater can be categorized by different groups. These groups are domestic, municipal, commercial and industrial wastewater and non-point sources. There are two major types of wastewater treatments which are biological and physical/chemical treatment.
Waste water treatment plants are essential to communities of all sizes and must work efficiently. Waste water treatment plant primary priority and responsibility is the treatment of incoming sewage water by the removal of biological and chemical wastes so it can be treated and recycled for future use. There are many government agencies and standards set forth to govern and observe the successful treatment of sewage such as: the Department of Environmental Quality, the National Pollutant Discharge Elimination System and the Clean Water Act of 1972. Compliance and constant monitoring of the treatment plant’s operations are important; as they protect the surrounding community. A spill or backflow of sewage due to a complete system malfunction could potentially be detrimental to the environment and local community. A precise system, of which must be compliant according to government standards, is critical to maintain low levels of wastes that are returned to neighboring water systems after treatment.
The basic set of reactions that involve this process are: Cl + O3 -->ClO + O2 and ClO + O -->Cl + O2 The net result: O3 + O -->2O2 Chlorine is initially removed in the first equation by the reaction with ozone to form chlorine monoxide. Then it is regenerated through the reaction with monatomic oxygen in the second equation. The net result of the two reactions is the depletion of ozone and atomic oxygen.6 Chlorofluorocarbons (CFCs), halons, and methyl bromide are a few of the ozone depletion substances (ODS) that break down ozone under intense ultraviolet light.
Safe water and sanitation as a basic human right, household water treatment, rainwater harvesting ... and reports from Kyoto, Madagascar, Uzbekistan, Guinea and other countries around the world.
Domestic households and industrial and agricultural practices often produce wastewater that can cause rivers and lakes to become polluted. This is typically called sewage and wastewater pollution. Sewage is a term for wastewater that usually contains feces, urine, and laundry waste. With there being billions of people on earth, treating sewage is a big priority. Untreated sewage can contam...
Water plays such an important role in our daily lives. 70% of our body is composed of water. 70% of the earth surface is also made up of water, but out of the 70%, only 1/3 of water is consumable. In fact, this amount has been continuously to decrease as more and more industries began to pollute and damage the water. For example, many toxic chemicals may be released into the water thus making the water impure. Such pollutions and damages lead the water to be contaminated and inconsumable as it may cause severe diseases. Water purification can remove all the unnecessary bacteria and viruses from the water that is hazardous for our health. Water purification may also improve the flavor and appearance of water. It removes the unpleasant odor. Therefore, water purification became one of the most useful and popular process used by people all over the world today. It is by far the most recommended and safest water treatment that is commonly used to purify damaged water into consumable water. Water purification provides us with safe, pure and clean water to consume and use.