Answer to Question #233538 in Chemical Engineering for pavani

Question

Explain about the primary treatment step in waste water treatment process?

Answer 1

Primary Treatment

The primary treatment process of the wastewater treatment procedure eliminates

materials that are going to settle or float; it comprises of several steps, which includes;

 screening (physical process)

 comminution.

 grit removal,

 sedimentation and

Screens are created out of narrow long metal bars, restricting bulky floating objects from

clogging up the pipes. On the other hand, comminatory is applied by grinding the debris that

hurls through the screens. Later sedimentation process (floating process) removes the ground

materials. Furthermore, grit chambers are made to hold certain solids (such as coffee grounds,

sand) from passing through and settling on the water, while grit results in excessive corrosion of

the pumps and pipes. Its disposal in cities combines with sewer systems to carry sand slit and

gravel that surface during the rain. Solids that are usually suspended pass through grit and screen

chambers are dispensed in sedimentation tanks from the sewage. Sedimentation tanks (primary

clarifiers) give two hours for gravity to settle, while the sewage flows through the objects slowly

sink to the ground. Then, the settled solids (sludge) are taken along by mechanical scrappers in

the tank bottom; sludge is then pumped out for disposal. At the same time, the mechanical

devices (surface-skimming) dispose of floating objects and grease.