Sludge Thickening

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._sludge_thickening.BeltThickener(ID='', ins: Sequence[AbstractStream] | None = None, outs: Sequence[AbstractStream] | None = (), thermo=None, init_with='WasteStream', sludge_moisture=0.96, solids=(), max_capacity=100, power_demand=4.1)

Gravity belt thickener (GBT) designed based on the manufacture specification data sheet. [1]

The 0th outs is the water-rich supernatant (effluent) and the 1st outs is the solid-rich sludge.

Key parameters include:

  • Capacity: 80-100 m3/h.

  • Influent solids concentration: 0.2-1%.

  • Sludge cake moisture content: 90-96%.

  • Motor power: 3 (driving motor) and 1.1 (agitator motor) kW.

  • Belt width: 2.5 m.

  • Weight: 2350 kg.

  • Quote price: $3680 ea for three or more sets.

The bare module (installation) factor is from Table 25 in Humbird et al. [2] (solids handling equipment).

The following components should be included in system thermo object for simulation: Water.

Parameters:

  • sludge_moisture (float) – Moisture content of the thickened sludge, [wt% water].

  • solids (Iterable(str)) – IDs of the solid components. If not provided, will be set to the default solids attribute of the components.

  • max_capacity (float) – Maximum hydraulic loading per belt thickener, [m3/h].

  • power_demand (float) – Total power demand of each belt thickener, [kW].

References

property N_thickener

[int] Number of required belt thickeners.

line: str = 'Belt thickener'

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

class qsdsan.sanunits._sludge_thickening.SludgeCentrifuge(ID='', ins: Sequence[AbstractStream] | None = None, outs: Sequence[AbstractStream] | None = (), thermo=None, init_with='WasteStream', include_construction=True, sludge_moisture=0.8, solids=(), centrifuge_type='scroll_solid_bowl')

Sludge Centrifuge with material usage.

The 0th outs is the water-rich supernatant (effluent) and the 1st outs is the solid-rich sludge.

The following components should be included in system thermo object for simulation: Water.

Parameters:

  • sludge_moisture (float) – Moisture content of the thickened sludge, [wt% water].

  • solids (Iterable(str)) – IDs of the solid components. If not provided, will be set to the default solids attribute of the components.

References

[1] https://dolphincentrifuge.com/wastewater-centrifuge/ (accessed 12-4-2022).

line: str = 'Sludge centrifuge'

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

class qsdsan.sanunits._sludge_thickening.SludgeSeparator(ID='', ins: Sequence[AbstractStream] | None = None, outs: Sequence[AbstractStream] | None = (), thermo=None, init_with='WasteStream', split=None, settled_frac=None, **kwargs)

For sludge separation based on Trimmer et al., note that no default cost or environmental impacts are included.

The following components should be included in system thermo object for simulation: Water.

Parameters:

  • ins (Iterable(stream)) – Waste for treatment.

  • outs (Iterable(stream)) – Liquid, settled solids.

  • split (float or dict) – Fractions of material retention in the settled solids. Default values will be used if not given.

  • settled_frac (float) – Fraction of influent that settles as solids. The default value will be used if not given.

Examples

bwaise systems

References

[1] Trimmer et al., Navigating Multidimensional Social–Ecological System Trade-Offs across Sanitation Alternatives in an Urban Informal Settlement. Environ. Sci. Technol. 2020, 54 (19), 12641–12653. https://doi.org/10.1021/acs.est.0c03296.

line: str = 'Sludge separator'

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

property settled_frac

[float] Fraction of influent that settles as solids.

property split

[float] or [dict] Fractions of material retention in the settled solids before degradation. If a single number is provided, then it is assumed that retentions of all Components in the WasteStream are the same.

Note

Set state variable values (e.g., COD) will be retained if the retention ratio is a single number (treated like the loss stream is split from the original stream), but not when the ratio is a dict.

class qsdsan.sanunits._sludge_thickening.SludgeThickening(ID='', ins: Sequence[AbstractStream] | None = None, outs: Sequence[AbstractStream] | None = (), thermo=None, init_with='WasteStream', sludge_moisture=0.96, solids=(), disposal_cost=0.13778891386554848)

A generic class for concentrating (i.e., thickening) of sludge from wastewater treatment processes based on Shoener et al.

The 0th outs is the water-rich supernatant (effluent) and the 1st outs is the solid-rich sludge.

Two pumps (one for the supernatant and one for sludge) are included.

Separation split is determined by the moisture (i.e., water) content of the sludge, soluble components will have the same split as water, insolubles components will all go to the retentate.

Note that if the moisture content of the incoming feeds are smaller than the target moisture content, the target moisture content will be ignored.

The following components should be included in system thermo object for simulation: Water.

Parameters:

  • ins (Iterable(stream)) – Dilute sludge stream.

  • outs (Iterable(stream)) – Water/bulk-liquid-rich stream, concentrated sludge.

  • sludge_moisture (float) – Moisture content of the sludge, [wt% water].

  • solids (Iterable(stream)) – IDs of the solid components. If not provided, will be set to the default solids attribute of the components.

  • disposal_cost (float) – Disposal cost of the dewatered solids. [$/kg].

References

[1] Shoener et al., Design of Anaerobic Membrane Bioreactors for the Valorization of Dilute Organic Carbon Waste Streams. Energy Environ. Sci. 2016, 9 (3), 1102–1112. https://doi.org/10.1039/C5EE03715H.

auxiliary_unit_names: tuple[str, ...] = ('effluent_pump', 'sludge_pump')

class-attribute Name of attributes that are auxiliary units. These units will be accounted for in the purchase and installed equipment costs without having to add these costs in the baseline_purchase_costs dictionary. Heat and power utilities are also automatically accounted for.

line: str = 'Sludge thickening'

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