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  • Nutrition in Plants | Study

    Nutrition in Plants | Study

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    Nutrition: It is the mode of taking food by an organism and its utilization by the body.

    Nutrients: The components of food that provide nourishment to the body.

    All organisms take food and utilise it to get energy for the growth and maintenance of their bodies. (Scroll down to continue …)

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    Autotrophs: Autotrophs are the green plants which synthesise their food themselves by the process of photosynthesis.

    Photosynthesis: the process of preparation of own food by the Green plants with the help of chlorophyll (found in green plants), carbon dioxide and water taken from the environment in presence of sunlight is known as photosynthesis.

    Plants use simple chemical substances like carbon dioxide, water and minerals for the synthesis of food.

    Chlorophyll and sunlight are the essential requirements for photosynthesis.

    Complex chemical substances such as carbohydrates are the products of photosynthesis.

    Solar energy is stored in the form of food in the leaves with the help of chlorophyll.

    Oxygen is produced during photosynthesis.

    Oxygen released in photosynthesis is utilised by living organisms for their survival.

    Fungi derive nutrition from dead, decaying matter.

    They are saprotrophs.

    Plants like Cuscuta are parasites.

    They take food from the host plant.

    A few plants and all animals are dependent on others for their nutrition and are called heterotrophs.

    Parasitic: Organisms that live on the body of other organisms. All parasitic plants feed on other plants as either:

    Partial Parasites: Obtain some of their nutrition from the host,

    Example: Painted cup

    Total Parasites: Dependent completely on the host for nutrition.

    Example: Mistletoe.

    Nutrition in plants

    Saprophytic: Organisms that obtain nutrition from dead and decaying plant and animal matter.

    Mushrooms, moulds and certain types of fungi and bacteria.

    Insectivorous Plants: Green plants which obtain their nourishment partly from soil and atmosphere and partly from small insects.

    Example: pitcher plant, bladderwort, and venus fly trap.

    Symbiosis: Mode of nutrition in which two different individuals associate with each other to fulfil their requirement of food.

    Lichens found on tree trunks is the association between algae and fungus.

    Algae obtains water from fungus and it in turn obtains food from algae.

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  • Nutrition in Animals | Study

    Nutrition in Animals | Study

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    Nutrition in Animals | Speed Notes

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    Classification based on Eating Habits:

    Herbivorous: Animals that eat plants or plant products.

    Example: Cow, sheep, goat, deer, elephant, kangaroo, giraffe, etc.

    Carnivorous: Animals that eat only flesh of other animals. They never eat plants.

    Examples: Tiger, lizard, lion, etc.

    Omnivorous: Animals consume plants as well as other animals as their food.

    Examples: Bear, dog, human being, etc.

    Parasites: Organisms that obtain their food from other animals either by living inside (endoparasites) or outside (ectoparasites) their body.

    Examples: Tapeworm and roundworm (inside body), tick and lice (outside body).

    Scavengers: Animals which feed on the remains of dead animals preyed by predators. Example: vulture, crows, jackal, etc. (Scroll down to continue …)

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    The main digestive glands which secrete digestive juices are:

    1. the salivary glands,
    2. the liver and

    (iii) the pancreas.

    The human digestive system consists of the alimentary canal and secretory glands.

    It consists of:

    1. buccal cavity,
    2. oesophagus,
    3. stomach,
    4. small intestine,
    5. large intestine ending in rectum
    6. anus.

    Animal nutrition includes nutrient requirement, mode of intake of food and its utilisation in the body.

    The stomach wall and the wall of the small intestine also secrete digestive juices.

    The modes of feeding vary in different organisms.

    Nutrition is a complex process involving:

    1. ingestion,
    2. digestion,
    3. absorption,
    1. assimilation and
    2. egestion.

    Digestion of carbohydrates, like starch, begins in the buccal cavity.

    The digestion of protein starts in the stomach.

    Bile secreted from the liver, the pancreatic juice from the pancreas and the digestive juice from the intestinal wall complete the digestion of all components of food in the small intestine.

    The digested food is absorbed in the blood vessels from the small intestine.

    The absorbed substances are transported to different parts of the body.

    Water and some salts are absorbed from the undigested food in the large intestine.

    The undigested and unabsorbed residues are expelled out of the body as faeces through the anus.

    The grazing animals like cows, buffaloes and deer are known as ruminants.

    They quickly ingest, swallow their leafy food and store it in the rumen.

    Later, the food returns to the mouth and the animal chews it peacefully.

    Amoeba ingests its food with the help of its false feet or pseudopodia.

    The food is digested in the food vacuole.

    It pushes out finger-like pseudopodia which engulf the prey.

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  • Heat | Study

    Heat | Study

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    Heat: It is a form of energy, which makes any object hot or cold.

    The materials which allow heat to pass through them easily are conductors of heat.

    The materials which do not allow heat to pass through them easily are called insulators.

    Temperature: The degree of hotness of an object is called temperature.

    Heat is the cause of temperature.

    Our sense of touch is not reliable to measure the temperature. (Scroll down to continue …)

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    Heat:

    It is a form of energy, which makes any object hot or cold.

    Temperature: The degree of hotness of an object is called temperature. Our sense of touch is not reliable to measure the temperature.

    Thermometer is a device used for measuring temperatures.

    Heat is the cause of temperature.

    Clinical thermometer is used to measure our body temperature.

    Transfer of Heat: Heat flows from a hotter object to a colder object until both objects reach the same temperature.

    The heat flows from a body at a higher temperature to a body at a lower temperature.

    There are three ways in which heat can flow from one object to another.

    These are conduction, convection and radiation.

    Conduction: It is the process by which heat is transferred from the hotter end to the colder and end of an object.

    Convection: It is the flow of heat through a fluid from places of higher temperature to places of lower temperature by movement of the fluid itself.

    Radiation: It is the mode of transfer of heat in which energy is directly transferred from one place to another.

    It does not need any material medium.

    Dark-coloured objects absorb radiation better than the light-coloured objects.

    That is the reason we feel more comfortable in light-coloured clothes in the summer.

    Woollen clothes keep us warm during winter.

    It is so because wool is a poor conductor of heat and it has air trapped in between the fibres.

    Thermometer:

    Thermometer is a device used for measuring temperatures.

    Clinical thermometer:

    Clinical thermometer is used to measure our body temperature.

    A thermometer used to measure the temperature of our body is called a clinical thermometer.

    For other purposes, we use the laboratory thermometers.

    The range of these thermometers is usually from –10°C to 110°C.

    The normal temperature of the human body is 37°C.

    It consists of a long, narrow, uniform glass tube with a bulb containing mercury at one end.

    There is a kink near the bulb.

    The range of clinical thermometer is from 35°C to 42°C. (Or from 94°F to 108°F).

    Laboratory Thermometer:

    Laboratory Thermometer: It is a thermometer used to measure the temperature of objects other than our body.

    It consists of a column of mercury enclosed in a glass casing.

    The column is continuous without any kink.

    It measures a range of temperature from -10˚C to 110˚C.

    Sea Breeze:

    Sea Breeze: Durign the day, the land heats up faster than the sea.

    Warm air above the land rises and cold air from sea takes its place.

    Warm air from the land moves towards the sea to compele the cycle.

    This produces a sea breeze from the sea to the land.

    Land Breeze:

    Land Breeze: At night the land cools faster than sea.

    The warm air above the sea rises.

    This warm air is replaced by colder air from the land producing a land breeze.

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  • Acids, Bases and Salts | Study

    Acids, Bases and Salts | Study

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    There are three types of Substances: Acids, Bases and Salts

    Acids: Acids are sour in taste. They are corrosive in nature.

    A concentrated acid cuts through clothes and eats away the wool.

    If it falls on the skin, it can cause burns.

    They are good conductors of electricity, as they allow the passage of electric current through them. (Scroll down to continue …)

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    Types of Acids:

    (i) Mineral Acids: These are acids prepared from minerals present in the earth’s crust.

    (ii) Organic Acids: These are acids produced by plants and animals (except hydrochloric acid).

    1. Weak Acids: These do not dissociate completely in solution.
    2. Examples: tartaric acid, lactic acid.
    3. Strong Acids: These dissociate completely in solution. Example: nitric acid, sulphuric acid.

    Neutralization: It is the reaction between an acid and a base which results in formation of salt and water.

    Acid + Base ———-> Salt + Water

    Example: HCl + NaOH ———-> NaCl + H2O

    Neutralisation in Everyday Life:

    Indigestion: Too much acid in stomach causes indigestion. It is neutralized by taking an antacid like milk of magnesia.

    Ant sting: When an ant bites, it injects formic acid into the skin. The effect is neutralized by rubbing moist baking soda (sodium hydrogen carbonate) or calamine (containing zinc carbonate).

    (iii) Soil treatment: When the soil is too acidic, it is neutralized by treating with

    quicklime (calcium oxide) or slaked lime (calcium hydroxide).

    Bases: Bases are bitter in taste and soapy to touch.

    Types of Bases:

    1. Weak Bases: These naturally produce less hydroxide ions in solution. Example: magnesium hydroxide, ammonium hydroxide.
    2. Strong Bases: These produce more number of hydroxide ions on dissolving in water. Example: Sodium hydroxide(NaOH), Potassium hydroxide (KOH)

    Substances which are neither acidic nor basic are called neutral.

    An acid and a base neutralise each other and form a salt. A salt may be acidic, basic or neutral in nature.

    Solutions of substances that show different colour in acidic, basic and neutral solutions are called indicators.

    Indicators: It is special chemical that changes its colour to indicate the presence of a chemical substance.

    It is used to confirm the presence of an acid, a base or a neutral solution.

    Classification of Indicators:

    Natural Indicators:

    1. Litmus: It is extracted from lichens. It is available in the form of strips of paper or in the form of a solution.· Acid turns blue litmus red. Bases turn red litmus blue.
    2. Turmeric: It remains yellow in neutral and acidic solutions but turns red in alkaline solutions.
    3. China rose: It turns acidic solutions to dark pink (magenta) and basic solution to green.
    4. Red cabbage: It turns acidic solutions to red and basic solutions to blue.

    Other Indicators:

    1. Methyl Orange: It gives pinkish red colour with acidic solutions and yellow colour with bases.
    2. Phenolphthalein: It is an acid-base indicator. It is colourless in acidic solutions but turns pink in alkali solutions.
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  • Physical and Chemical Changes | Study

    Physical and Chemical Changes | Study

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    Physical And Chemical Changes | Speed Notes

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    Changes can be of two types, physical and chemical.

    Physical changes are changes in the physical properties of substances.

    Due to physical chages new substances are not formed.

    Physical changes may be reversible.

    Examples: crushing a can, glowing of an electric bulb, tearing of paper, mixing of sand and water. (Scroll down to continue …)

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    Chemical Changes are changes in which the composition and chemical properties of the substance get changed.

    In chemical changes new substances are produced. The most of the chemical changes are irreversible and permanent.

    Note: Some chemical changes are reversible, known as reversible chemical changes.

    Example: burning of a candle, formation of curd from milk, ripening of fruits.

    Some Chemical Reactions in daily life:

    Rusting of Iron: Rusting is the process in which iron turns into iron oxide.

    It happens when iron comes into contact with water and oxygen. The process is a type of corrosion that occurs easily under natural conditions.

    Prevention of Rusting:

    1. By Painting
    2. By Oiling and greasing
    3. By Chromium plating
    4. By Galvanizing
    5. By Alloying

    Cooking of food: Cooking causes breakdown of complex molecules of carbohydrates, fats and proteins into smaller molecules.

    It is regarded as a decomposition reaction.

    Cooked food is easier to digest than uncooked food.

    3. Decay of Organic Substances: Microorganisms like fungi and bacteria produce enzymes which break down complex organic compounds into smaller substances.

    It is also regarded as a decomposition reaction.

    Some substances can be obtained in pure state from their solutions by crystallization.

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  • Respiration in Organisms | Study

    Respiration in Organisms | Study

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    Respiration is essential for survival of living organisms.

    It releases energy from the food.

    The oxygen we inhale is used to breakdown glucose into carbon dioxide and water.

    Energy is released in this process.

    The breakdown of glucose occurs in the cells of an organism (cellular respiration). (ScrollScroll down to continue…)

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    During heavy exercise when the supply of oxygen to our muscle cells is insufficient, food breakdown is by anaerobic respiration (without oxygen)

    Types of Respiration:

    External respiration also known as breathing refers to a process of inhaling oxygen from the air into the lungs and expelling carbon dioxide from the lungs to the air.

    Exchange of gases both in and out of the blood occurs simultaneously.

    Internal Respiration: Process in which food is broken down in body cells.

    Internal respiration is further classified into two types as aerobic respiration and anaerobic respiration

    (a) Aerobic Respiration: Aerobic respiration takes place in the presence of oxygen. Carbon dioxide and water are the end products of aerobic respiration. respiration happens in most of the organisms.

    (b) Anaerobic Respiration: Anaerobic respiration takes place in the absence of oxygen.

    Anaerobic respiration usually happens in most of the microbes.

    Alcohol and carbon dioxide are formed at the end of anaerobic respiration.

    In some cases, lactic acid is formed at the end of anaerobic respiration.

    Respiration in Plants: Leaves have pores called stomata for gaseous exchange by diffusion.

    Stems have openings called lenticels for gaseous exchange by diffusion.

    Roots have stomatal pores for gaseous exchange of oxygen dissolved in soil water.

    Respiration in Animals: Respiration in animals vary according to their character like:

    Earthworm: Earthworms respire through their skin.

    Insect: Insects respire through entire body surface.

    Fish: Fishes respire through their gills.

    Frogs: Frogs respire through their thin, moist and smooth skin when in water and by lungs when on the land.

    Respiration in Humans: Inhaled air passes through nostrils into nasal cavity and then into lungs through windpipe.

    Breathing is a part of the process of respiration during which an organism takes in the oxygen-rich air and gives out air rich in carbon dioxide.

    The respiratory organs for the exchange of gases vary in different organisms.

    During inhalation, our lungs expand and then come back to the original state as the air moves out during exhalation.

    Increased physical activity enhances the rate of breathing.

    In animals like cow, buffalo, dog and cat the respiratory organs and the process of breathing are similar to those in humans.

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  • Transportation in Animals and Plants | Study

    Transportation in Animals and Plants | Study

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    Transportation in animals:

    In most of the animals the blood that circulates in the body distributes food and oxygen to different cells of the body.

    It also carries waste products from different parts of the body for excretion.

    Circulatory system consists of the heart and blood vessels.

    In humans, blood flows through arteries and veins and the heart acts as a pumping organ. (Scroll down to continue …)

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    Blood is the fluid which flows in blood vessels.

    It transport substance like digested food from the small intestine to the other parts of the body.

    Blood consists of plasma, RBC, WBC and platelets.

    Blood is red due to the presence of a red pigment, haemoglobin which binds with oxygen and transport oxygen to various parts.

    Heart rate:The human heart beats about 70 to 80 times per minute in an adult person. This is called heart rate.

    Arteries carry blood from the heart to all parts of the body.

    Veins carry blood from all parts of the body back to the heart.

    excretion: Removal of waste products from the body is called excretion.

    Excretory system of humans consists of two kidneys, two ureters, a urinary bladder, and urethra.

    Salts and urea are removed along with water as sweat.

    Fish excrete waste substances such as ammonia which directly dissolve in water.

    Birds, insects and lizard excrete uric acid in semi-solid form.

    Transportation in plants :

    Water and mineral nutrients are absorbed by roots from the soil.

    xylem: Nutrients are transported along with water to the entire plant via the vascular tissue called xylem.

    phloem: The vascular tissue for the transport of food to the various parts of the plant is phloem.

    A lot of water is lost by plants in the form of vapour through stomata during transpiration.

    Transpiration generates a force which pulls up water absorbed by the roots from the soil, to reach the stem and leaves.

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  • Reproduction in Plants | Study

    Reproduction in Plants | Study

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    All organisms multiply or reproduce offspring of their own kind.

    In plants there are two modes of reproduction, namely (a) Asexual reproduction and (b) Sexual reproduction.

    There are several methods of asexual reproduction such as fragmentation, budding, spore formation and vegetative propagation.

    Sexual reproduction involves the fusion of male and female gametes. (Scroll down to continue …)

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    In vegetative propagation new plants are produced from different vegetative parts such as leaves, stems and roots.

    Flower is the reproductive part of a plant.

    A flower may be unisexual with either the male or the female reproductive parts.

    A bisexual flower has both the male and the female reproductive parts.

    The male gametes are found inside the pollen grains and female gametes are found in the ovule.

    Pollination is the process of transfer of pollen grains from the anther of one flower to the stigma of the same or another flower.

    Pollination is of two types, self-pollination and cross-pollination.

    In self-pollination, pollen grains are transferred from the anther to the stigma of the same flower.

    In cross-pollination, pollen grains are transferred from the anther of one flower to the stigma of another flower of the same kind.

    Pollination takes place in plants with the help of wind, water and insects.

    The fusion of male and female gametes is called fertilization.

    Fertilized egg is called zygote.

    Zygote develops into an embryo.

    Fruit is the mature ovary whereas ovule develops into a seed, which contains the developing embryo.

    Seed dispersal is aided by wind, water and animals.

    Seed dispersal helps the plants to:

    1. prevent overcrowding,
    2. avoid competition for sunlight, water and minerals
    3. invade new habitats.
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  • Motion and Time | Study

    Motion and Time | Study

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    Motion: The action or process of moving or being moved.

    The distance moved by an object in a unit time is called its speed.

    Speed of objects help us to decide which one is moving faster than the other.

    The speed of an object is the distance travelled divided by the time taken to cover that distance.

    Its basic unit is mere per second (m/s). (Scroll down to continue …).

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    Periodic events are used for the measurement of time.

    Periodic motion of a pendulum has been used to make clocks and watches.

    Motion of objects can be presented in pictorial form by their distance-time graphs.

    The distance-time graph for the motion of an object moving with a constant speed is a straight line.

    Uniform Motion ANd Non – Uniform Motion:

    1. Uniform motion: An object moving with a constant speed is said to be in uniform motion. The average speed is the same as the actual speed.
    2. Non-Uniform motion: If the speed of a moving object keeps changing, the object is said to be in non-uniform motion.

    Speed: It is the distance covered by an object in a unit time.

    Speed = Total distance/ Total Time

    Basic unit of speed is m/s.

    Distance-Time Graph: Motion of objects can be presented in pictorial form by their distance-time graphs.

    The distance-time graph for the motion of an object moving with a constant speed is a straight line.

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  • Electric Current and its Effects | Study

    Electric Current and its Effects | Study

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    Flow of electrons through a conductor.

    It is convenient to represent electric components by symbols.

    Using these, an electric circuit can be represented by a circuit diagram.

    When an electric current flows through a wire, the wire gets heated.

    It is the heating effect of current. This effect has many applications. (Scroll down to continue …)

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    Wires made from some special materials melt quickly and break when large electric currents are passed through them.

    These materials are used for making electric fuses which prevent fires and damage to electric appliances.

    When an electric current flows through a wire, it behaves like a magnet.

    Electric Circuit: A complete pathway of the flow of electric current.

    Component of Electric Circuit: Component of electric circuit are following :

    Cell: Provides energy for the current to flow.

    Bulb: Lights ups when an electric current flows through it.

    Switch: Keeps the circuit off or on.

    Connecting wires: Help to conduct the electric current and complete the circuit.

    1.Heating Effect: The wire gets hot when an electric current passes through it.

    This is the heating effect of the electric current.

    Electric heater contains a coil of wire called element which becomes red hot when current passes through it.

    The amount of heat produced in a wire depends on its material, length and thickness.

    Fuse: It is a safety device which prevents damage to electric circuit.

    It is made by inserting a short wire into porcelain or insulating material.

    MCB: Stands for Miniature Circuit Breakers. These are switches which automatically turn off when current in a circuit exceeds the safe limit.

    Effects of Electric Current:

    Electric Current and its Effects

    2. Magnetic Effect: When electric current passes through a wire, it behaves like a magnet. This is the magnetic effect of the electric current. This was first observed by Hans Christian Oersted.

    A current carrying coil of an insulated wire wrapped around a piece of iron is called an electromagnet.

    Electromagnet: An electromagnet is a coil of wire wound on a soft iron core, used to separate magnetic material from the junk. Doctors use tiny electromagnets to take out small pieces of magnetic material that have accidentally fallen in the eye.

    Many toys also have electromagnets inside them.

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  • Light | Study

    Light | Study

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    Light: It is the natural agent that stimulates sight and makes things visible.

    Light travels along straight line.

    Any polished or a shining surface acts as a mirror.

    An image which can be obtained on a screen is called a real image. (Scroll down to continue …).

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    It is formed by light rays that actually pass through the screen.

    An image which cannot be obtained on a screen is called a virtual image.

    It is formed by light rays that seem to pass through the screen.

    The image formed by a plane mirror is erect.

    It is virtual and is of the same size as the object.

    The image is at the same distance behind the mirror as the object is in front of it.

    In an image formed by a mirror, the left side of the object is seen on the right side in the image, and right side of the object appears to be on the left side in the image.

    A concave mirror can form a real and inverted image.

    When the object is placed very close to the mirror, the image formed is virtual, erect and magnified.

    A Convex mirror is the mirror that curves out; the reflecting surface is convex.

    Image formed is virtual, upright and diminished. Image formed by a convex mirror is erect, virtual and smaller in size than the object.

    A Concave lens is the lens that is thinner at the center than at the edges.

    It is a diverging lens.

    Image formed is virtual, erect and diminished.

    A convex lens can form real and inverted image.

    When the object is placed very close to the lens, the image formed is virtual, erect and magnified.

    When used to see objects magnified, the convex lens is called a magnifying glass.

    White light is composed of seven colors.

    Properties of Light:

    1. Rectilinear Propagation of Light: It is the property of light by which it travels in a straight line in any direction.

    The direction of path in which light make a ray.

    2. Reflection of Light: It is the bouncing back of light after striking the surface of an object.

    Shiny smooth surfaces reflect almost all the light.

    3. Dispersion: It is the phenomenon of splitting of white light into its seven colors. White

    light is mixture of: Violet, Indigo, Blue, Green, Yellow, Orange and Red (VIBGYOR) colors.

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  • Forests: Our Lifeline | Study

    Forests: Our Lifeline | Study

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    Forests: Our Lifeline | Speed Notes

    Notes For Quick Recap

    Forest: Large area of land thickly covered with trees, bushes, etc.

    We get various products from the forests around us.

    Forest is a system comprising various plants, animals and micro-organisms.

    In a forest, trees from the uppermost layer, followed by shrubs, the herbs to

    the lowest layer of vegetation. (Scroll down to continue …).

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    Different layers of vegetation provide food and shelter for animals, birds and insects.

    The various components of the forest are interdependent on one another.

    The forest keeps on growing and changing, and can regenerate.

    In the forest, there is interaction between soil, water, air and living organisms.

    Forests protect the soil from erosion.

    Soil helps forests to grow and regenerate.

    Deforestation: Cutting down of trees is known as deforestation.

    Importance of Forests:

    Forests:

    Provide timber,

    Purify air,

    Provide shelter,

    Prevent soil,

    Absorbs noise.
    Independence of Plants and Animals in Forest:
    Plants and animals depends on each other to remain alive.

    All organisms interact with each other and their physical environment to derive and survive.

    Effects of deforestation:
    Amount of carbon dioxide in air will increase, resulting in the increase of earth’s temperature. (Global Warming) Animals will not get food and shelter.

    Soil will not hold water, which will cause floods.

    Endanger lives and environment.
    Conservation of Forests:
    Do not allow overgrazing.

    Promote afforestation.

    Protect wildlife.

    Food Chain:

    Interdependence between producers and consumers studied in form of various linkage that appears as a chain or Interdependence of
    organisms which shows who eats whom.

    Food Web: A system of interdependent food chains used to represent various relationships in organisms.

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  • Wastewater Story | Study

    Wastewater Story | Study

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    Wastewater: Black-brown water which is rich in lather , mixed with oil that goes down the drains from skins, showers, toilets, laundries is called wastewater.

    sewage: Wastewater is generated in homes, industries, agricultural fields and in other human activities. This is called sewage. (Scroll down to continue …).

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    Sewage is a liquid waste which causes water and soil pollution.

    Wastewater is treated in a sewage treatment plant.

    Treatment plants reduce pollutants in wastewater to a level where nature can take care of it.

    Where underground sewerage systems and refuse disposal systems are not available, the low cost on-site sanitation system can be adopted.

    By-products of wastewater treatment are sludge and bio gas.

    Open drain system is a breeding place for flies, mosquitoes and organisms which cause diseases.

    We should not defecate in the open. It is possible to have safe disposal of excreta by low cost methods.

    Sewage Treatment:

    Aeration: Air is bubbled through the wastewater while it is continuously stirred.

    Filtration: Aerated water passes through a deep filter of layered sand, fine gravel and medium gravel.

    Chlorination: Chlorine is added and mixed to the filtered water until water is clear.

    Wastewater Treatment Plant (WWTP):

    Wastewater passes through screens to remove large objects.

    To go to a grit and sand removal tank at low speed.

    Water is allowed to settle in large tank.

    Floating solids are removed with skimmer.

    Settled solids (sludge) are removed  with scraper.

    Clear water is called clarified water.

    Water is then decomposed by anaerobic bacteria in a tank and air is passed.

    Microbes settled at bottom as activated sludge and water from top is removed.

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