The document discusses secondary water treatment technologies. Secondary treatment removes biodegradable organic matter from wastewater. Common secondary treatment methods include activated sludge, filtration, and oxidation ponds. Activated sludge involves aerating sewage through air or mechanical means for 1-20 hours to support microbial activity. Filtration can occur mechanically by filtering suspended particles or biologically in trickling filters using a fixed media bed. Oxidation ponds contain algal and bacterial cultures that oxidize organic matter into nutrients.

1. WATER POLLUTION:
SECONDARY TREATMENT
TECHNOLOGIES
PRESENTED BY
JENIN R (2021005036)

2. SECONDARY WATER TREATMENT
•SECONDARY TREATMENT (MOSTLY BIOLOGICAL WASTEWATER TREATMENT) ISTHE
REMOVAL OF BIODEGRADABLE ORGANIC MATTER (IN SOLUTION OR SUSPENSION) FROM
SEWAGE OR SIMILAR KINDS OF WASTEWATER

3. METHODS OF SECONDARY TREATMENT
•ACTIVATED SLUDGE
•FILTRATION
•OXIDATION POND

4. ACTIVATED SLUDGE

5. AERATED SLUDGE
•SEWAGE IS AERATED BY AIR OR BY MECHANICAL MEANS
•THE RESIDENCE TIME OF WATER IN THIS SYSTEM IS 1 - 20 HRS
•VIGOROUS AERATION IS NEEDED TO PREVENT WATER FROM DROPPING DOWN TO 2-3
MG/LIT THAT SLOWS DOWN THE RESPIRATORY ACTIVITY OF ORGANISMS IN WATER

6. FILTRATION
• MECHANICAL FILTRATION– UNTREATED WATER PASSES THROUGH A MESH FILTER THAT TRAPS
SUSPENDED PARTICLES ON THE SURFACE OR WITHIN THE FILTER
• BIOLOGICAL FILTRATION(TRICKLING FILTER)- IT CONSISTS OF A FIXED BED OF ROCKS, COKE, GRAVEL,
POLYURETHANE FOAM, SPHAGNUM PEAT MOSS, CERAMIC, OR PLASTIC MEDIAOVER WHICH SEWAGE OR
OTHER WASTEWATER FLOWS DOWNWARD AND CAUSES A LAYER OF MICROBIALSLIME (BIOFILM) TO
GROW, COVERING THE BED OF MEDIA.

8. OXIDATION POND
• CONVENTIONAL OXIDATION POND CONTAINS THE ALGAL BACTERIAL CULTURE, WHICH OXIDIZES A
ORGANIC MATTER INTO CO2, H2O, H2S,NH3 AND OTHER DECOMPOSITION PRODUCTS THAT ARE USED AS
NUTRIENTS LIKE NITRATE, PHOSPHATE, SULPHATE.

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