Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
16 Cards in this Set
- Front
- Back
|
Relationship between TSS and SS |
All Settleable solids are suspended solids but not all TSS are settleable |
|
|
How much TSS is removed in Primary clarifiers? |
40-60% |
|
|
% Total solids typical of primary sludge |
3-6% |
|
|
% of solids in primary sludge solids that are volatile |
70-75% |
|
|
Key objectives of anaerobic digestion |
Stabilization of raw sludge solids, volatile solids/volume/pathogen reduction, gas production |
|
|
The name for the stable organic matter that is the product of anaerobic digestion |
Humus |
|
|
What is the driving force behind hydrolysis? |
Extracellular enzymes that are secreted by many bacteria. They break down the particulate organic matter into a soluble form that pass through a bacterial cell wall. |
|
|
What is the role of a buffer in anaerobic digestion? |
Maintains pH in the face of the production of many volatile acids |
|
|
What is the source of the alkalinity/buffer in a healthy anaerobic digester? Where does it come from? |
The bicarbonate ion (HCO3-). It's formed during the start-up of an anaerobic digester by the reaction between ammonia, carbon dioxide, and water. |
|
|
Below what pH does methane gas become prohibited? |
6.8 |
|
|
How does a digester become 'sour'? |
Without removal of the volatile organic acids by the methane formers, the acids will accumulate, further depressing the pH. |
|
|
NH3 + CO2 + H20 -> |
HCO3- + NH4+ |
|
|
What will a supernatant be high in? |
Ammonia |
|
|
Role of a secondary digester |
Allows liquids/solids separation and storage upstream of a dewatering facility. |
|
|
Volatile solids reduction is strongly influenced by what three things? |
The ratio of soluble-to-particulate organics, the fraction of unbiodegradable solids, and the removal efficiency in the primary clarifier. |
|
|
How is VSR influenced by the aeration basin? |
A lower MCRT results in more VS discharged to the digester. |
