Bioremediation
Class 12 · Biotechnology
4 ideas in Class 12 Biotechnology, explained in plain words, with games and quizzes to practise.
Sewage and BOD
Part of: Cleaning Water
Used water carries dissolved and floating organic and mineral loads plus gut and soil microbes. The oxygen-demand test tells how much oxygen microbes need to digest that load: higher readings mean dirtier water. With fresh water running short, measuring dirt decides treatment.
Why it matters. This one number routes whole cities' water plans. Knowing what sewage holds plus what the test means helps you read any water report correctly.
Key words
- sewage
- : Used water carrying dissolved and floating waste loads.
- BOD
- : Oxygen microbes need to digest water dirt.
- organic load
- : Carbon-rich waste that microbes can digest.
- microflora
- : The mixed tiny life living in a sample.
- effluent
- : Treated water flowing out of a plant.
Try it in two minutes
- List sewage parts: dissolved loads, floating loads, mixed microbes.
- Ask what the oxygen test counts: oxygen for digesting dirt.
- Ask why higher readings demand stronger treatment.
Try at home. Rank three home liquids by likely oxygen demand.
Treatment Stages
Part of: Cleaning Water
Treatment plants clean in three waves. First, screens and settling pull out floating and sinking solids. Next, hungry microbes digest dissolved organics on trickling stone beds or in bubbled sludge tanks. Last, advanced steps strip leftover nitrogen, phosphorus and fine bits before release.
Why it matters. Skipping waves overloads later ones and dirties rivers. Knowing each wave's catch helps you spot which stage failed from outflow readings.
Key words
- primary treatment
- : Physical pulling of floating and sinking solids.
- secondary treatment
- : Germ digestion of dissolved organic loads.
- trickling filter
- : A stone bed where germ films digest passing dirt.
- activated sludge
- : Bubbled germ masses digesting tank dirt.
- tertiary treatment
- : Advanced stripping of nutrients and fine bits.
Try it in two minutes
- Order the waves: pull solids, digest dissolved, strip leftovers.
- Ask which wave uses microbes and which uses screens.
- Ask what the last wave strips that germs leave behind.
Try at home. Order three cleaning waves for one dirty bucket.
Solid and Biomedical Waste
Part of: Solid Waste and Cleanup
Solid rubbish splits into rotting organics and long-lasting non-rotters. Organics can compost into soil food, while clinic waste needs strict colour bins: yellow for body and soiled matter, red for tainted plastics, white for sharps, blue for glass and metal bits. Sorting at the source keeps handlers safe.
Why it matters. Mixed rubbish spreads disease and blocks recycling. Knowing streams plus bin colours lets you sort any pile safely at its source.
Key words
- biodegradable
- : Waste that rots down through living action.
- composting
- : Controlled rotting of organics into soil food.
- segregation
- : Sorting waste at its source into right bins.
- sharps
- : Cutting or piercing clinic waste like needles.
- biohazard mark
- : The warning sign posted on risky waste.
Try it in two minutes
- Split rubbish into rotting versus long-lasting piles.
- Ask what composting gives back to soil.
- Match each clinic item to its colour bin.
Try at home. Sort five home items into rot, recycle or sharps bins.
Microbes That Clean Up
Part of: Solid Waste and Cleanup
Many germs eat what we cannot: farm sprays, oil smears and factory leftovers become their food. Cleanup crews either work germs where the filth lies or haul filth to germ beds, turning poisons into milder bits. Matching germ, food and conditions decides success.
Why it matters. Living cleanup can beat digging and burning on cost and care. Knowing how germs eat poisons helps you judge when biology fits the spill.
Key words
- bioremediation
- : Cleaning filth using living organisms.
- biodegradation
- : Breaking matter down through living action.
- in situ
- : Treated where the filth lies.
- ex situ
- : Hauled away for treatment elsewhere.
- xenobiotic
- : A human-made chemical new to nature.
Try it in two minutes
- Ask what germs eat that we cannot.
- Contrast treating on the spot versus hauling to beds.
- Ask what conditions hungry germs still need.
Try at home. Pick on-spot or haul-away cleanup for two spills.
What your child will practise
- Microbes That Clean Up: Desert Quick Fire (Quick Fire)
- Sewage and BOD: Space Puzzle (Clue Puzzle)
- Sewage and BOD: Space Quick Fire (Quick Fire)
- Solid and Biomedical Waste: Ocean Quick Fire (Quick Fire)
- Treatment Stages: Jungle Puzzle (Clue Puzzle)
- Quiz: Microbes That Clean Up (8 questions)
- Quiz: Sewage and BOD (8 questions)
- Quiz: Solid and Biomedical Waste (8 questions)
- Quiz: Treatment Stages (8 questions)