Wastewater Treatment and Its Process Dr
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Wastewater Treatment 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 sewage 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, surface runoff 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 toilets, 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 sanitary sewer that conveys only sewage. Alternatively, wastewater can be transported in a combined sewer 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 126 | P a g e 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), vermifilter 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 Sewage Treatment 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 human waste and solid waste as well as storm water (drainage) management. By-products from wastewater treatment plants, such as screenings, grit and sewage sludge 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. 127 | P a g e 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. toilet 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 128 | P a g e 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 grey water 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. 129 | P a g e Solids and emulsions from paper mills, factories producing lubricants or hydraulic oils, foodstuffs, etc. Water used in hydraulic fracturing Produced water from oil & natural gas production. Other related activities or events: Urban runoff 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, activated sludge 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