and Its Process Dr. Sai Bhavani Sevella¹, Saileja Sevella² 1Assistant Professor, Department of Environmental science, Nizam College, Osmania University, Hyderabad, Telangana, India. 2Assistant Professor, Department of Business Management, University College for women, Koti, Hyderabad, Telangana, India.

Abstract: Waste water is the used water, wastewater treatment as water use because it is so interconnected with the other uses of water. Much of the water used by homes, industries, and businesses must be treated before it is released back to the Environment. Nature has an amazing ability to cope with small amounts of water wastes and pollution, but it would be overwhelmed if we didn't treat the billions of gallons of wastewater and produced every day before releasing it back to the environment. Water treatment plants reduce pollutants in wastewater to a level nature can handle. In this paper, the focus is on wastewater treatment and process of treating sewage water. Keywords: Environment, Pollutants, Treatment plants, Wastewater. 1 Introduction

Wastewater (or waste water) is any water that has been contaminated by human use. Wastewater is "used water from any combination of domestic, industrial, commercial or agricultural activities, or storm water, and any sewer inflow or sewer infiltration". Therefore, wastewater is a by product of domestic, industrial, commercial or agricultural activities. The characteristics of wastewater vary depending on the source. Types of wastewater include: domestic wastewater from households, municipal wastewater from communities (also called sewage) and industrial wastewater. Wastewater can contain physical, chemical and biological pollutants.

Households may produce wastewater from flush , sinks, dishwashers, washing machines, bath tubs, and showers. Households that use dry toilets produce less wastewater than those that use flush toilets.

Wastewater may be conveyed in a that conveys only sewage. Alternatively, wastewater can be transported in a that conveys both storm water runoff and sewage, and possibly also industrial wastewater. After treatment at a wastewater treatment plant, treated wastewater (also called effluent) is discharged to a receiving water body. The terms "wastewater

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reuse" and "water reclamation" apply if the treated waste is used for another purpose. Wastewater that is discharged to the environment without suitable treatment can cause water pollution.

In developing countries and in rural areas with low population densities, wastewater is often treated by various on-site sanitation systems and not conveyed in sewers. These systems include septic tanks connected to drain fields, on-site sewage systems (OSS), systems and many more. Wastewater treatment is a process used to remove contaminants from wastewater or sewage and convert it into an effluent than can be returned to the water cycle with minimum impact on the environment, or directly reused. The latter is called water reclamation because treated wastewater can be used for other purposes. The treatment process takes place in a wastewater treatment plant (WWTP), often referred to as a Water Resource Recovery Facility (WRRF) or a Plant (STP). Pollutants in municipal wastewater (households and small industries) are removed or broken down. The treatment of wastewater is part of the overarching field of sanitation. Sanitation also includes the management of and solid waste as well as storm water (drainage) management. By-products from wastewater treatment plants, such as screenings, grit and sewage may also be treated in a wastewater treatment plant. Objectives of the study  To study about wastewater treatment and the process of wastewater treatment.  To know about the type of wastewater to be treated and to know about the sources of wastewater Why Treat Wastewater? It's a matter of caring for our environment and for our own health. There are a lot of good reasons why keeping our water clean is an important priority: FISHERIES: Clean water is critical to plants and animals that live in water. This is important to the fishing industry, sport fishing enthusiasts, and future generations. WILDLIFE HABITATS: Our rivers and ocean waters teem with life that depends on shoreline, beaches and marshes. They are critical habitats for hundreds of species of fish and other aquatic life. Migratory water birds use the areas for resting and feeding. RECREATION AND QUALITY OF LIFE: Water is a great playground for us all. The scenic and recreational values of our waters are reasons many people choose to live where they do. Visitors are drawn to water activities such as swimming, fishing, boating and picnicking. HEALTH CONCERNS: If it is not properly cleaned, water can carry disease. Since we live, work and play so close to water, harmful bacteria have to be removed to make water safe.

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2 Review of Literature a) Wastewater is usually a combination of one or more of the following which makes it polluted water:  Domestic effluent consisting of black water (excreta, urine and faecal sludge, i.e. wastewater) and grey-water (kitchen and bathing wastewater).  Water from commercial establishments and institutions, including hospitals.  Industrial effluent where present.  Storm-water and other urban run-off. b) Wastewater is the water which has already been used and carries organic pollutants. 1 Effects of wastewater pollutants , Sources and process of wastewater Effects of wastewater pollutants

If wastewater is not properly treated, then the environment and human health can be negatively impacted. These impacts can include harm to fish and wildlife populations, oxygen depletion, beach closures and other restrictions on recreational water use, restrictions on fish and shellfish harvesting and contamination of drinking water. Environment Canada provides some examples of pollutants that can be found in wastewater and the potentially harmful effects these substances can have on ecosystems and human health:

 Decaying organic matter and debris can use up the dissolved oxygen in a lake so fish and other aquatic biota cannot survive;  Excessive nutrients, such as phosphorus and nitrogen (including ammonia), can cause eutrophication, or over-fertilization of receiving waters, which can be toxic to aquatic

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organisms, promote excessive plant growth, reduce available oxygen, harm spawning grounds, alter habitat and lead to a decline in certain species;  Chlorine compounds and inorganic chloramines can be toxic to aquatic invertebrates, algae and fish;  Bacteria, viruses and disease-causing pathogens can pollute beaches and contaminate shellfish populations, leading to restrictions on human recreation, drinking water consumption and shellfish consumption;  Metals, such as mercury, lead, cadmium, chromium and arsenic can have acute and chronic toxic effects on species.  Other substances such as some pharmaceutical and personal care products, primarily entering the environment in wastewater effluents, may also pose threats to human health, aquatic life and wildlife.  Sources

Sources of wastewater include the following domestic or household activities:

 Human excreta (feces, urine, blood and other bodily fluids) often mixed with used toilet paper or wet wipes; this is known as black water if it is collected from flush toilets  Washing water (personal hygiene, clothes, floors, dishes, cars, etc.), also known as or sullage  Surplus manufactured liquids from domestic sources (drinks, cooking oil, pesticides, lubricating oil, paint, cleaning detergents, etc.)

Activities producing industrial wastewater include:

 Industrial site drainage (silt, sand, alkali, oil, chemical residues);  Industrial cooling waters (biocides, heat, slimes, silt)  Industrial processing waters  Organic or biodegradable waste including waste from hospitals, abattoirs, creameries, and food factories.  Organic or non-bio-degradable waste that is difficult-to-treat from pharmaceutical or pesticide manufacturing  Extreme pH waste from acid and alkali manufacturing  Toxic waste from metal plating, cyanide production, pesticide manufacturing, etc.

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 Solids and emulsions from paper mills, factories producing lubricants or hydraulic oils, foodstuffs, etc.  Water used in hydraulic fracturing  from oil & natural gas production.

Other related activities or events:

from highways, roads, railway tracks, car parks, roofs, pavements (contains oils, animal feces/manure, food waste, litter, petrol, diesel or rubber residues from tyres, soapscum, metals from vehicle exhausts, de-icing agents, herbicides and pesticides from gardens, etc.)  Agricultural pollution, direct and diffuse

Wastewater can be diluted or mixed with other types of water through the following mechanisms:

 Seawater ingress (high volumes of salt and microbes)  Direct ingress of river water  Rainfall collected on roofs, yards, hard-standings, etc. (generally clean with traces of oils and fuel)  Groundwater infiltrated into sewage  Mixing with other types of wastewater or fecalsludge

Process of wastewater

Biological processes can be employed in the treatment of wastewater and these processes may include, for example, aerated lagoons, or slow sand filters. To be effective, sewage must be conveyed to a treatment plant by appropriate pipes and infrastructure and the process itself must be subject to regulation and controls. Some wastewaters require different and sometimes specialized treatment methods. At the simplest level, treatment of sewage and most wastewaters is carried out through separation of solids from liquids, usually by sedimentation. By progressively converting dissolved material into solids, usually a biological floc, which is then settled out, an effluent stream of increasing purity, is produced.

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1. Phase separation

Clarifiers are widely used for wastewater treatment.

Phase separation transfers impurities into a non-aqueous phase. Phase separation may occur at intermediate points in a treatment sequence to remove solids generated during oxidation or polishing. Grease and oil may be recovered for fuel or saponification. Solids often require dewatering of sludge in a wastewater treatment plant. Disposal options for dried solids vary with the type and concentration of impurities removed from water.

Production of waste , however, may discourage wastewater treatment removing dissolved inorganic solids from water by methods like , , and distillation.

Primary settling tank of wastewater treatment plant in Dresden-Kaditz, Germany Sedimentation

Solids like stones, grit and sand may be removed from wastewater by gravity when density differences are sufficient to overcome dispersion by turbulence. Gravity separation of solids is the primary treatment of sewage, where the unit process is called "primary settling tanks" or "primary sedimentation tanks". It is also widely used for the treatment of other wastewaters. Solids that are heavier than water will accumulate at the bottom of quiescent settling 131 | P a g e

basins. More complex also have skimmers to simultaneously remove floating grease like soap scum and solids like feathers or wood chips. Containers like the API oil-water separator are specifically designed to separate non-polar liquids.

Filtration

Suspended solids and colloidal suspensions of fine solids may, generally following some form of coagulation, be removed by through fine physical barriers distinguished from coarser screens or sieves by the ability to remove particles smaller than the openings through which the water passes. Other types of water filters remove impurities by chemical or biological processes described below.

2.Oxidation

Oxidation reduces the biochemical oxygen demand of wastewater, and may reduce the toxicity of some impurities. converts organic compounds into carbon dioxide, water, and . Chemical oxidation is widely used for disinfection.

Aeration tank of an activated sludge process at the wastewater treatment plant in Dresden-Kaditz, Germany

Biochemical oxidation

Secondary treatment by biochemical oxidation of dissolved and colloidal organic compounds is widely used in sewage treatment and is applicable to some agricultural and industrial wastewaters. Biological oxidation will preferentially remove organic compounds useful as a food supply for the treatment ecosystem. Concentration of some less digestible compounds may be reduced by co- metabolism. Removal efficiency is limited by the minimum food concentration required to sustain the treatment ecosystem.

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Chemical oxidation

Chemical (including Electrochemical) oxidation is used to remove some persistent organic pollutants and concentrations remaining after biochemical oxidation. Disinfection by chemical oxidation kills bacteria and microbial pathogens by adding ozone, chlorine or hypochlorite to wastewater.

3. Polishing

Polishing refers to treatments made following the above methods. These treatments may also be used independently for some industrial wastewater. Chemical reduction or pH adjustment minimizes chemical reactivity of wastewater following chemical oxidation. Carbon filtering removes remaining contaminants and impurities by chemical absorption onto . Filtration through sand (calcium carbonate) or fabric filters is the most common method used in municipal wastewater treatment.

Reuse

Treated wastewater can be reused in industry (for example in cooling towers), in artificial recharge of aquifers, in agriculture and in the rehabilitation of natural ecosystems (for example in wetlands). In rarer cases it is also used to augment drinking water supplies. There are several technologies used to treat wastewater for reuse. A combination of these technologies can meet strict treatment standards and make sure that the processed water is hygienically safe, meaning free from bacteria and viruses. The following are some of the typical technologies: Ozonation, ultrafiltration, aerobic treatment (), forward osmosis, reverse osmosis, advanced oxidation.

Some water demanding activities do not require high grade water. In this case, wastewater can be reused with little or no treatment. One example of this scenario is in the domestic environment where toilets can be flushed using greywater from baths and showers with little or no treatment.

Irrigation with recycled wastewater can also serve to fertilize plants if it contains nutrients, such as nitrogen, phosphorus and potassium. In developing countries, agriculture is using untreated wastewater for - often in an unsafe manner. There can be significant health hazards related to using untreated wastewater in agriculture. The World Health Organization developed guidelines for safe use of wastewater in 2006.

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Suggestions to reduce the wastewater:  Reuse unwanted ice: Instead of dumping ice from overstayed ice trays from the freezers or ice coolers in the drain, spread it on the garden grass or around plants and let the ice melt into liquid.  Reuse unused drinking water: Drinking water stored for a long period has a stale taste, is murky, and also has a great probability of being contaminated by bacteria. Instead of disposing of it by pouring it out, you can use it for washing utensils and other household chores as it is not that dirty. Stale pet water can also be used on potted plants  Trap rainwater: Collecting rainwater is equally part of water reuse that many people do not recognize. The installation of gutters for diverting rainwater to where it can be stored does the work. After collection, the water can be used in the garden to water plants, for laundry, and many other purposes as rainwater are considerably clean and safe compared to other types of used water such as greywater.  Save pasta water: One of the most nutrient-rich kitchen water is used to boil vegetables and pasta. It can, therefore, serve a very good purpose in watering plants. Vegetable and pasta water can be collected in pots and after it has cooled down, it can be used to water the garden.  Employ the use of rain barrels: In most cases, rain from the roofs of our houses is just left to run off into the sewer systems. In a bid to save this water from going to waste, rain barrels can be used to collect the water by placing them under the gutter’s downspout. The water can then be used for various purposes such as laundry, watering plants, and general cleaning in the house.  Recycling dirty aquarium water: The water in the fish tanks must be routinely changed to get rid of excess toxic materials and waste dissolved in water that could harm the fish if left to accumulate. When refilling aquarium water, instead of disposing of the dirty water, one can use it for agricultural reuse like watering potted plants, vegetable nurseries, or lawn gardens. The water is very good for plants because it contains materials such as nitrogen, phosphorous, potassium, and ammonium and other microorganisms found in soil sediments, which can act as a natural fertilizer. In doing so, however, it is advisable not to water plants with used water from saltwater aquariums as it can harm the plants due to high salt content.

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 Turn off the tap while washing your face, brushing your teeth and shaving: Don’t think that keeping the tap on while doing these things takes up that much water? Plug the drain sometime and see just how much is collected in the sink. Multiply that over 365 days, likely a few times a day. That’s a lot of water.  Fix leaks: One drip per second equates to 19 litres of water per day. Check inside and outside your home to ensure no water is leaking.

Conclusion India generates a staggering 1.7 million tonnes of faecal waste a day. Official figures show that 78% of the sewage generated remains untreated and is disposed of in rivers, groundwater, or lakes. The major aim of wastewater treatment is to remove as much of the suspended solids as possible before the remaining water, called effluent, is discharged back to the environment. But, only one-third of India’s wastewater is currently treated, leading to the high burden of water-borne diseases. The government should pass strict rules for disposing of the wastewater. Those who don't follow the rules the government should take strict action against them.

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