###############################################################################
# WaterTAP Copyright (c) 2021, The Regents of the University of California,
# through Lawrence Berkeley National Laboratory, Oak Ridge National
# Laboratory, National Renewable Energy Laboratory, and National Energy
# Technology Laboratory (subject to receipt of any required approvals from
# the U.S. Dept. of Energy). All rights reserved.
#
# Please see the files COPYRIGHT.md and LICENSE.md for full copyright and license
# information, respectively. These files are also available online at the URL
# "https://github.com/watertap-org/watertap/"
#
###############################################################################
"""
This module contains a zero-order representation of a sedimentation unit
operation.
"""
from pyomo.environ import Constraint, units as pyunits, Var
from idaes.core import declare_process_block_class
from watertap.core import build_sido, constant_intensity, ZeroOrderBaseData
# Some more information about this module
__author__ = "Adam Atia"
[docs]@declare_process_block_class("SedimentationZO")
class SedimentationZOData(ZeroOrderBaseData):
"""
Zero-Order model for a Sedimentation unit operation.
"""
CONFIG = ZeroOrderBaseData.CONFIG()
[docs] def build(self):
super().build()
self._tech_type = "sedimentation"
build_sido(self)
constant_intensity(self)
# TODO: Does it really make sense for this to be indexed by time?
self.basin_surface_area = Var(
self.flowsheet().config.time,
units=pyunits.ft**2,
doc="Surface area of sedimentation tank",
)
self.settling_velocity = Var(
self.flowsheet().config.time,
units=pyunits.m / pyunits.s,
doc="Particle settling velocity",
)
self._fixed_perf_vars.append(self.settling_velocity)
self._perf_var_dict["Basin Surface Area (ft^2)"] = self.basin_surface_area
self._perf_var_dict["Settling Velocity (m/s)"] = self.settling_velocity
def rule_basin_surface_area(b, t):
return b.basin_surface_area[t] == pyunits.convert(
b.properties_in[t].flow_vol / b.settling_velocity[t],
to_units=pyunits.ft**2,
)
self.basin_surface_area_constraint = Constraint(
self.flowsheet().time, rule=rule_basin_surface_area
)
if self.config.process_subtype == "phosphorus_capture":
self.phosphorus_solids_ratio = Var(
self.flowsheet().config.time,
units=pyunits.dimensionless,
doc="Mass fraction of phosphorus in settleable solids",
)
self._fixed_perf_vars.append(self.phosphorus_solids_ratio)
self._perf_var_dict[
"Phosphorus-Solids Ratio (kg/kg)"
] = self.phosphorus_solids_ratio
# This subtype is intended to be used explicitly for phosphorous capture.
# If the user provides TSS, the amount of settled phosphate would be determined based on
# an assumed fraction of phosphate in TSS. Alternatively, the user could provide phosphates
# as the species, and the amount of solids + phosphate settled would be reported.
# However, the user cannot provide both TSS and phosphates.
if (
"phosphates" in self.config.property_package.solute_set
and "tss" in self.config.property_package.solute_set
):
raise KeyError(
"tss and phosphates cannot both be defined in the solute_list. "
"Please choose one."
)
elif "phosphates" in self.config.property_package.solute_set:
self.final_solids_mass = Var(
self.flowsheet().config.time,
units=pyunits.kg / pyunits.s,
doc="Solids mass flow in byproduct stream",
)
@self.Constraint(
self.flowsheet().time,
doc="Solids mass flow in byproduct stream constraint",
)
def solids_mass_flow_constraint(b, t):
return (
b.final_solids_mass[t]
== b.properties_byproduct[t].flow_mass_comp["phosphates"]
/ b.phosphorus_solids_ratio[t]
)
self._perf_var_dict[
"Final mass flow of settled solids (kg/s)"
] = self.final_solids_mass
elif "tss" in self.config.property_package.solute_set:
self.final_phosphate_mass = Var(
self.flowsheet().config.time,
units=pyunits.kg / pyunits.s,
doc="Phosphate mass flow in byproduct stream",
)
@self.Constraint(
self.flowsheet().time,
doc="Phosphate mass flow in byproduct stream constraint",
)
def phosphate_mass_flow_constraint(b, t):
return (
b.final_phosphate_mass[t]
== b.properties_byproduct[t].flow_mass_comp["tss"]
* b.phosphorus_solids_ratio[t]
)
self._perf_var_dict[
"Final mass flow of settled phosphate (kg/s)"
] = self.final_phosphate_mass
else:
# Raise this error in case the user is intended to make use of the subtype but entered
# the wrong component names.
raise KeyError(
"One of the following should be specified in the solute_list: "
"tss or phosphates"
)