This module contains all wastewater treatment systems and associated unit operations. The main interface to create a wastewater treatment system is the create_wastewater_treatment_system() function. Please checkout each submodule for additional details on the available wastewater treatment systems.

create_wastewater_treatment_system(*args, kind=None, **kwargs)[source]#

Create a wastewater treatment system. Two configurations are available: conventional and high-rate. The conventional configuration is based on the process described in Humbird et al., while the high-rate process is based on the one described in Li et al. Both configurations are designed to use biological processes to remove organics in the wastewater, and use reverse osmosis to remove the ions, after which the treated water is recycled as process water to be used in the biorefinery.

The main differences between the configurations is that the conventional process uses large anaerobic and aerobic basins for organic removal, which has a very low organic loading (grams COD/L/d). While the high-rate process uses high-rate anaerobic technologies including internal circulation and anaerobic membrane bioreactor with a much higher organic loading (>10X of the conventional ones). With the much higher organic loading rate (smaller reactor and physical footprint) and the use of two anaerobic unit operations (anaerobic process does not need aeration therefore saves electricity), the high-rate process is expected to have lower CAPEX/OPEX with lower environmental impacts (see the example for MESP comparison for the corn stover biorefinery).



Calculate the minimum ethanol selling price of the corn stover biorefinery with either the conventional or high-rate wastewater treatment configurations:

>>> import biosteam as bst
>>> from biorefineries import cornstover as cs
>>> bst.settings.set_thermo(cs.create_chemicals())
>>> def get_MESP(**WWT_kwargs):
...     bst.main_flowsheet.set_flowsheet(WWT_kwargs['kind'])
...     # WWT_kwargs will be passed to the wastewater treatment system creator
...     sys = cs.create_system(WWT_kwargs=WWT_kwargs)
...     sys.simulate()
...     tea = cs.create_tea(sys)
...     ethanol = sys.get_outlet('ethanol')
...     MESP = tea.solve_price(ethanol) * cs.ethanol_density_kggal
...     print(f"{WWT_kwargs['kind']} MESP: ${MESP:.1f}/gal")
>>> # With the conventional WWT process
>>> get_MESP(kind='conventional')
conventional MESP: $2.1/gal
>>> # With the high-rate WWT process
>>> get_MESP(process_ID=6, kind='high-rate')
high-rate MESP: $1.4/gal


[1] Li et al., Design of a High-Rate Wastewater Treatment Process for Energy and Water Recovery at Biorefineries. ACS Sustainable Chem. Eng. 2023, 11 (9), 3861–3872. https://doi.org/10.1021/acssuschemeng.2c07139.

[2] Humbird et al., Process Design and Economics for Biochemical Conversion of Lignocellulosic Biomass to Ethanol: Dilute-Acid Pretreatment and Enzymatic Hydrolysis of Corn Stover; Technical Report NREL/TP-5100-47764; National Renewable Energy Lab (NREL), 2011. https://www.nrel.gov/docs/fy11osti/47764.pdf

[3] Davis et al., Process Design and Economics for the Conversion of Lignocellulosic Biomass to Hydrocarbon Fuels and Coproducts: 2018 Biochemical Design Case Update; NREL/TP-5100-71949; National Renewable Energy Lab (NREL), 2018. https://doi.org/10.2172/1483234