CVEN 5534

Assignment 2

Due: Thursday, Feb. 3.

On the next page is a schematic of a biological wastewater treatment process (called

activated sludge) to carry out carbon (COD), nitrogen, phosphorus, and sulfur cycling by

microorganisms for removal of COD, nitrogen, and phosphorus from wastewater (sulfur

transformation also will occur).

Revisit your biogeochemical element cycle (assignment 1).

1. Define the microbial, physical, or chemical processes that would dominate in each tank

(fermentation, anoxic, aeration, digester).

2. Predict the soluble, particulate and gas-phase forms of the element you studied in

assignment 1 that would dominate in teach tank and in the liquid effluent and the

dewatered biosolids.

3. Define the microorganism populations involved in the transformations. You do not

need to give species – just the types of microorganisms (e.g., aerobic heterotrophic

bacteria, sulfate-reducing bacteria, nitrifying bacteria, phosphorus-accumulating bacteria,

etc.)

Stream

Waste Biomass

and Sludge

Anoxic

Tank

Aeration Tank

SETTLER Fermentation

Tank

Treated

Effluent

Influent:

Soluble

COD

TKN

SO4

PO4

Particulate:

COD

Organic N

Organic P

Anaerobic Sludge Digester

Recycled Biomass

Dewatered

Biosolids Disposal