.. index:: pair: watertap.unit_models.dewatering;dewatering
The main assumptions of the implemented model are as follows:
- Single liquid phase only
- Steady state only
- Has no volume
Dewatering is a process commonly used in wastewater treatment plants to separate water from solids using centrifugal motion and/or vacuums. In doing so, the dewatering unit reduces the sludge volume, which improves system operation and mitigates costs related to storage, processing, disposal, etc. This implementation of the dewatering unit is based on the IDAES separator unit.
The degrees of freedom in a dewatering unit model are the inlet feed state variables:
- temperature
- pressure
- component mass compositions
The dewatering unit model does not use ControlVolumes, and instead writes a set of material, energy and momentum balances to split the inlet stream into two outlet streams. Dewatering models have a single inlet Port (named inlet) and two outlet Ports (named overflow and underflow).
Description | Symbol | Indices |
---|---|---|
Time | t | [0] |
Phases | p | ['Liq'] |
Particulate Components | j | ['X_I', 'X_S', 'X_P', 'X_BH', 'X_BA', 'X_ND'] |
Non-particulate Components | j | ['H2O', 'S_I', 'S_S', 'S_O', 'S_NO', 'S_NH', 'S_ND', 'S_ALK'] |
NOTE: These components are defined in the ASM1 Property Package documentation.
Description | Symbol | Variable Name | Index | Value | Units |
---|---|---|---|---|---|
Percentage of suspended solids in the underflow | p_{dewat} | p_dewat | None | 0.28 | \text{dimensionless} |
Percentage of suspended solids removed | TSS_{rem} | TSS_rem | None | 0.98 | \text{dimensionless} |
Description | Equation |
---|---|
Suspended solid concentration | C_{TSS} = 0.75 (C_{X_{I}} + C_{X_{IP}} + C_{X_{BH}} + C_{X_{BA}} + C_{X_{S}}) |
Dewatering factor | f_{dewat} = p_{dewat} (\frac{10}{C_{TSS}}) |
Remove factor | f_{q_{du}} = \frac{TSS_{rem}}{100 * f_{dewat}} |
Overflow particulate fraction | split_{particulate} = 1 - TSS_{rem} |
Overflow soluble fraction | split_{soluble} = 1 - f_{q_{du}} |
.. currentmodule:: watertap.unit_models.dewatering
.. autoclass:: DewateringUnit :members: :noindex:
J. Alex, L. Benedetti, J.B. Copp, K.V. Gernaey, U. Jeppsson, I. Nopens, M.N. Pons, C. Rosen, J.P. Steyer & P. A. Vanrolleghem Benchmark Simulation Model no. 2 (BSM2)