Clarifier

QSDsan: Quantitative Sustainable Design for sanitation and resource recovery systems

This module is developed by:

This module is under the University of Illinois/NCSA Open Source License. Please refer to https://github.com/QSD-Group/QSDsan/blob/main/LICENSE.txt for license details.

class qsdsan.sanunits._clarifier.FlatBottomCircularClarifier(ID='', ins: Sequence[AbstractStream] | None = None, outs: Sequence[AbstractStream] | None = (), thermo=None, init_with='WasteStream', underflow=2000, wastage=385, surface_area=1500, height=4, N_layer=10, feed_layer=4, X_threshold=3000, v_max=474, v_max_practical=250, rh=0.000576, rp=0.00286, fns=0.00228, isdynamic=True, **kwargs)

A flat-bottom circular clarifier with a simple 1-dimensional N-layer settling model. [1]

Parameters:

  • ID (str) – ID for the clarifier. The default is ‘’.

  • ins (WasteStream) – Influent to the clarifier. Expected number of influent is 1.

  • outs (WasteStream) – Treated effluent and sludge.

  • underflow (float, optional) – Designed recycling sludge flowrate (RAS), in [m^3/d]. The default is 2000.

  • wastage (float, optional) – Designed wasted sludge flowrate (WAS), in [m^3/d]. The default is 385.

  • surface_area (float, optional) – Surface area of the clarifier, in [m^2]. The default is 1500.

  • height (float, optional) – Height of the clarifier, in [m]. The default is 4.

  • N_layer (int, optional) – The number of layers to model settling. The default is 10.

  • feed_layer (int, optional) – The feed layer counting from top to bottom. The default is 4.

  • X_threshold (float, optional) – Threshold suspended solid concentration, in [g/m^3]. The default is 3000.

  • v_max (float, optional) – Maximum theoretical (i.e. Vesilind) settling velocity, in [m/d]. The default is 474.

  • v_max_practical (float, optional) – Maximum practical settling velocity, in [m/d]. The default is 250.

  • rh (float, optional) – Hindered zone settling parameter in the double-exponential settling velocity function, in [m^3/g]. The default is 5.76e-4.

  • rp (float, optional) – Flocculant zone settling parameter in the double-exponential settling velocity function, in [m^3/g]. The default is 2.86e-3.

  • fns (float, optional) – Non-settleable fraction of the suspended solids, dimensionless. Must be within [0, 1]. The default is 2.28e-3.

References

property A_settle

[float] The surface area for settling in m^2, i.e., the area of the clarifier’s flat bottom.

property N_layer

[int] The number of layers into which the clarifier is divided in the settling model.

property V_settle

[float] Total volume modeled for settling in m^3, calculated based on surface area and height.

property X_t

[float] Threshold suspended solid concentration, in g/m^3.

property feed_layer

[int] The feed layer counting from top to bottom.

property fns

[float] Non-settleable fraction of the suspended solids

property h_layer

[float] The height of each layer in the settling model, in m.

line: str = 'Flat bottom circular clarifier'

class-attribute Name denoting the type of Unit class. Defaults to the class name of the first child class

property rh

[float] Hindered zone settling parameter in the double-exponential settling velocity function, in m^3/g.

property rp

[float] Flocculant zone settling parameter in the double-exponential settling velocity function, in m^3/g.

set_init_TSS(arr)

set the initial TSS [mg/L] in each layer of the clarifier.

set_init_sludge_solids(**kwargs)

set the initial concentrations [mg/L] of solids in the underflow sludge.

set_init_solubles(**kwargs)

set the initial concentrations [mg/L] of solubles in the clarifier.

property underflow

[float] The designed recycling sludge flow rate in m3/d.

property v_max

[float] Maximum theoretical (i.e. Vesilind) settling velocity, in m/d

property v_max_p

[float] Maximum practical settling velocity, in m/d

property wastage

[float] The designed wasted sludge flow rate in m3/d.

class qsdsan.sanunits._clarifier.IdealClarifier(ID='', ins: Sequence[AbstractStream] | None = None, outs: Sequence[AbstractStream] | None = (), thermo=None, sludge_flow_rate=2000, solids_removal_efficiency=0.995, sludge_MLSS=None, isdynamic=False, init_with='WasteStream', F_BM_default=None, **kwargs)
line: str = 'Ideal clarifier'

class-attribute Name denoting the type of Unit class. Defaults to the class name of the first child class

property sludge_flow_rate

[float] The designed sludge flow rate (wasted + recycled) in m3/d.