Components and processes

	Components
S_VFA	Volatile fatty acids (VFA)	Sumo1, Sumo2, Sumo2C, Sumo2S, Sumo4N	A fermented product representing a combination of acetate and other volatile fatty acids produced in an anaerobic environment from S_B. It is available for biological removal by OHOs, CASTOs (PAOs, GAOs), and AMETOs and chemical removal during HFO reduction.	g COD.m^-3
S_B	Readily biodegradable substrate (non-VFA)	Mini_Sumo, Sumo1, Sumo2, Sumo2S, Sumo4N	Non-VFA organic material that can be fermented to VFA, it represents a group of readily biodegradable organic material present in wastewater.	g COD.m^-3
S_B,mono	Readily biodegradable substrate as monomers (non-VFA)	Sumo2C	Small molecular weight substrate mainly consumed by AHOs in 1st stage of high-rate process.	g COD.m^-3
S_B,poly	Readily biodegradable substrate as polymers	Sumo2C	Readily biodegradable substrate that is not degraded in 1st stage of a high-rate process. Consumed by OHOs in 2nd stage.	g COD.m^-3
S_MEOL	Methanol (MEOL)	Sumo1, Sumo2, Sumo2C, Sumo2S, Sumo4N	A methyl alcohol or the simplest alcohol. A commonly used external carbon source for denitrification.	g COD.m^-3
C_B	Colloidal biodegradable substrate	Sumo1, Sumo2, Sumo2C, Sumo2S, Sumo4N	A biodegradable organic component, flocculates to form X_B. Analytically can be approximated by flocculation or filtration (larger than 0.1 micron but smaller than 1.2 micron)	g COD.m^-3
X_B	Slowly biodegradable substrate	Mini_Sumo, Sumo1, Sumo2, Sumo2C, Sumo2S, Sumo4N	High molecular weight particulates that are hydrolyzed by extracellular enzymes to release S_B. They are introduced directly from the influent and released during the bacterial decay process in death-regeneration concept models.	g COD.m^-3
S_U	Soluble unbiodegradable organics	Mini_Sumo, Sumo1, Sumo2, Sumo2C, Sumo2S, Sumo4N	A soluble organic material that is not degraded biologically or chemically in wastewater and leaves in the effluent. Typically, measured by performing a flocculated filtration test on the effluent of a nitrifying plant. It also has a nitrogen and phosphorus content. There is only one process, the Thermal Hydrolysis Process, which generates S_U from X_U in the model.	g COD.m^-3
C_U	Colloidal unbiodegradable organics	Sumo1, Sumo2, Sumo2C, Sumo2S, Sumo4N	A non-biodegradable organic material, flocculates to form X_U and leaves the plant in the WAS or cake. Analytically can be approximated by flocculation or filtration (larger than 0.1 micron but smaller than 1.2 micron)	g COD.m^-3
X_U	Particulate unbiodegradable organics	Mini_Sumo, Sumo1, Sumo2, Sumo2C, Sumo2S, Sumo4N	A non-biodegradable organic material that is larger than 1.2 micron. It is not hydrolysed and remains untransformed due to biological and chemical reactions. The thermal hydrolysis process model is the only unit that converts a portion of X_U to S_U.	g COD.m^-3
X_STO	Storage product of AHOs	Sumo2C	An internal cell storage organic material stored by AHOs in low SRT systems using S_B,mono and S_VFA. Its production doesn’t involve any energy and growth.	g COD.m^-3
X_PHA	Stored polyhydroxyalkanoates (PHA)	Sumo1, Sumo2, Sumo2C, Sumo2S, Sumo4N	Poly-hydroxy alkanoates considered as an internal organic cellular storage product of CASTOs (PAOs). The composition of alkanoates is represented as poly-β-hydroxybutyrate.	g COD.m^-3
X_GLY	Stored glycogen (GLY)	Sumo1, Sumo2, Sumo2C, Sumo2S, Sumo4N	Internal organic cellular storage product of CASTOs (GAOs).	g COD.m^-3
X_E	Endogenous decay products	Mini_Sumo, Sumo1, Sumo2, Sumo2C, Sumo2S, Sumo4N	An organic material released during cell lysis under aerobic and anoxic environment, it has an extremely slow conversion rate of 0.07 per day and it converts to X_B while releasing S_NHx and S_PO4. The X_E builds in a system with increasing SRT.	g COD.m^-3
X_E,ana	Anaerobic endogenous decay products	Sumo1, Sumo2, Sumo2C, Sumo2S, Sumo4N	An organic material released on cell lysis under anaerobic environment and hydrolysed in aerobic environment to release S_B, S_NHx, and S_PO4. This component is responsible for the additional VS destruction observed in a post aerobic digestion process.	g COD.m^-3
X_OHO	Ordinary heterotrophic organisms (OHO)	Mini_Sumo, Sumo1, Sumo2, Sumo2C, Sumo2S, Sumo4N	Generalist facultative ordinary hetrotrophic organisms that consume different soluble biodegradable organics including S_B, S_VFA, and X_MEOL and can perform biological removal under aerobic, anoxic, and anaerobic environments. They are also responsible for hydrolysis of the particulates. In MiniSumo and Sumo1, they perform one step denitrification, meaning from S_NOx to S_N2. In other models they follow two steps, S_NO3 reduction to S_NO2, and S_NO2 reduction to S_N2.	g COD.m^-3
X_CASTO	Carbon storing organisms (CASTO)	Sumo1, Sumo2, Sumo2C, Sumo2S, Sumo4N	A special group of carbon storing heterotrophic organisms representing a combination of both PAOs and GAOs. The process conditions dictate the ratio of PAO to GAO achieved in the process model. They are responsible for taking part in the EBPR process. They store PHA and/or GLY during the anaerobic conditions, and consume stored carbon during anoxic and aerobic environments to generate polyphosphate (X_PP). In Sumo1, they perform one step denitrification, meaning from S_NOx to S_N2. Is other models they follow two steps, S_NO3 reduction to S_NO2, and S_NO2 reduction to S_N2.	g COD.m^-3
X_MEOLO	Anoxic methanol utilizers (MEOLO)	Sumo1, Sumo2, Sumo2C, Sumo2S, Sumo4N	Specialist heterotrophic organisms responsible for removal of X_MEOL. Only found in systems with methanol addition and compete with OHOs during denitrification process. In Sumo1, they perform one step denitrification, meaning from S_NOx to S_N2. Is other models they follow two steps, S_NO3 reduction to S_NO2, and S_NO2 reduction to S_N2.	g COD.m^-3
X_AHO	Carbon adsorption heterotroph organisms (AHO)	Sumo2C	Heterotrophic organisms storing readily biodegradable small molecular weight components represented as S_B,mono and volatile fatty acids (S_VFA) into X_STO. The growth rate of AHOs is higher than that of the OHOs and outgrow them in a short SRT system of <2 days. They only carry out aerobic consumption of the X_STO and are expected to be seeded from the influent.	g COD.m^-3
X_NITO	Aerobic nitrifying organisms (NITO)	Mini_Sumo, Sumo1	Obligate aerobic autotrophic organism responsible for complete nitrification, from S_NHx to S_NOx. It represents a combination of AOBs and NOBs for simplification in the referred models.	g COD.m^-3
X_AOB	Aerobic ammonia oxidizers (AOB)	Sumo2, Sumo2C, Sumo2S, Sumo4N	Obligate aerobic autotrophic organism responsible for the first step in nitrification, from SNHx to SNO2.	g COD.m^-3
X_NOB	Nitrite oxidizers (NOB)	Sumo2, Sumo2C, Sumo2S, Sumo4N	Obligate aerobic autotrophic organism responsible for the second step in nitrification, from S_NO2 to S_NO3.	g COD.m^-3
X_AMX	Anammox organisms (AMX)	Sumo2, Sumo2C, Sumo2S, Sumo4N	A chemoautotrophic anaerobic bacteria that oxidizes ammonium with nitrite as the electron acceptor and with CO2 as the main carbon source. They are slow growers and have a long doubling time.	g COD.m^-3
X_AMETO	Acidoclastic methanogens (AMETO)	Mini_Sumo, Sumo1, Sumo2, Sumo2C, Sumo2S, Sumo4N	Anaerobic archea that consume S_VFA to produce S_CH4 and S_CO2 as a metabolic by-product and don’t grow under aerobic conditions.	g COD.m^-3
X_HMETO	Hydrogenotrophic methanogens (HMETO)	Mini_Sumo, Sumo1, Sumo2, Sumo2C, Sumo2S, Sumo4N	Anaerobic archea that consume S_H2 and S_CO2 to produce S_CH4 as a metabolic by-product and don’t grow under aerobic conditions.	g COD.m^-3
X_ASRO	Acidoclastic sulfate-reducing organisms (ASRO)	Sumo2S	A group of bacteria and archaea that perform anaerobic respiration utilizing S_SO4 and S_VFA, reducing it to S_H2S and generating S_CO2. They compete with AMETOs for S_VFA and negatively impact performance of a digester.	g COD.m^-3
X_HSRO	Hydrogenotrophic sulfate-reducing organisms (HSRO)	Sumo2S	A group of bacteria and archaea that perform anaerobic respiration utilizing S_SO4 and S_H2, reducing it to S_H2S. They compete with HMETOs for S_H2 consumption and negatively impact performance of a digester.	g COD.m^-3
X_SOO	Sulfur-oxidizing organisms (SOO)	Sumo2S	They oxidize S_H2S in two steps under aerobic and anoxic environments, first from S_H2S to X_S (elemental sulfur) and second from X_S to S_SO4.	g COD.m^-3
X_ALGAE	Photosynthetic organisms (ALGAE)	Mini_Sumo, Sumo1, Sumo2, Sumo2C, Sumo2S, Sumo4N	A group of photosynthetic organisms which grow, assimilate nutrients, S_CO2 and generate S_O2 in the presence of light. They consume S_O2 through respiration.	g COD.m^-3
S_NHx	Total ammonia (NH_x)	Mini_Sumo, Sumo1, Sumo2, Sumo2C, Sumo2S, Sumo4N	Total ammonia nitrogen is a sum of ammonium and free ammonia. An essential nutrient for the biokinetic growth reactions.	g N.m^-3
S_NH2OH	Hydroxylamine (NH₂OH)	Sumo4N	An intermediate product produced by AOB from S_NHx. It is then oxidized to S_NO under aerobic environments. It is also reduced to form S_N2O under anoxic environments.	g N.m^-3
S_NOx	Nitrate and nitrite (NO_x)	Mini_Sumo, Sumo1	A sum of nitrate and nitrite, and electron acceptor for anoxic reactions. In the referred Models it is considered nitrate for all COD conservation purposes.	g N.m^-3
S_NO2	Nitrite (NO₂)	Sumo2, Sumo2C, Sumo2S, Sumo4N	A sum of nitrous acid and nitrate ion and electron acceptor for anoxic reactions.	g N.m^-3
S_NO3	Nitrate (NO₃)	Sumo2, Sumo2C, Sumo2S, Sumo4N	An electron acceptor for anoxic reactions.	g N.m^-3
S_NO,AOB	Nitric oxide of AOB (NO)	Sumo4N	Nitric oxide generated by AOBs from S_NH2OH and either oxidized to S_NO2 and reduced to S_N2O. It is considered as an internal product.	g N.m-3
S_NO,OHO	Nitric oxide of OHO (NO)	Sumo4N	Nitric oxide generated by OHOs during S_NO2 reduction. It is considered as an internal product.	g N.m-3
S_N2O	Nitrous oxide (N₂O)	Sumo4N	Generated by OHOs from S_NO,OHO and by AOBs from S_NO,AOB.	g N.m-3
S_N2	Dissolved nitrogen (N₂)	Mini_Sumo, Sumo1, Sumo2, Sumo2C, Sumo2S, Sumo4N	Only nitrogenous product of denitrification except for in Sumo4N model and is subject to gas transfer.	g N.m^-3
S_N,B	Soluble biodegradable organic N (from SB)	Mini_Sumo, Sumo1, Sumo2, Sumo2C, Sumo2S, Sumo4N	A nitrogen containing soluble organic material (urea, amino acids, amines, and others) that releases nitrogen as total ammonia on ammonification in wastewater treatment. In the model it doesn’t have COD associated.	g N.m^-3
X_N,B	Particulate biodegradable organic N (from X_B)	Mini_Sumo, Sumo1, Sumo2, Sumo2C, Sumo2S, Sumo4N	A nitrogen containing particulate organic material (proteins and others) that releases S_N,B on hydrolysis in wastewater treatment. In the model it doesn’t have COD.	g N.m^-3
X_N,U	Particulate unbiodegradable organic N	Sumo1, Sumo2, Sumo2C, Sumo2S, Sumo4N	A nitrogen containing particulate organic material that is not biologically or chemically degraded in the plant and leaves with the cake solids. The only process that degrades X_N,U to S_NHx is the thermal hydrolysis process.	g N.m^-3
S_PO4	Orthophosphate (PO₄)	Mini_Sumo, Sumo1, Sumo2, Sumo2C, Sumo2S, Sumo4N	Soluble inorganic phosphorus, represents a combination of Phosphoric acid, Dihydrogen phosphate ion, Hydrogen phosphate ion, Phosphate ion. An essential nutrient for the biokinetic growth reactions.	g P.m^-3
X_PP	Stored polyphosphate (PP)	Sumo1, Sumo2, Sumo2C, Sumo2S, Sumo4N	Poly-phosphate considered as an internal inorganic cellular storage product of CASTOs (PAOs). The composition of X_PP is (Ca_0.1K_0.1Mg_0.35PO₃)_n.	g P.m^-3
S_P,B	Soluble biodegradable organic P (from SB)	Sumo1, Sumo2, Sumo2C, Sumo2S, Sumo4N	A phosphorus containing soluble organic material that releases phosphorus as S_PO4 in wastewater treatment. In the model it doesn’t have COD.	g P.m^-3
X_P,B	Particulate biodegradable organic P (from X_B)	Mini_Sumo, Sumo1, Sumo2, Sumo2C, Sumo2S, Sumo4N	A phosphorus containing particulate organic material that releases S_P,B on hydrolysis in wastewater treatment. In the model it doesn’t have COD.	g P.m^-3
X_P,U	Particulate unbiodegradable organic P	Sumo1, Sumo2, Sumo2C, Sumo2S, Sumo4N	A phosphorus containing particulate organic material that is not biologically or chemically degraded in the plant and leaves with the cake solids. The only process that degrades X_P,U to S_PO4 is the process model of thermal hydrolysis process.	g P.m^-3
S_O2	Dissolved oxygen (O₂)	Mini_Sumo, Sumo1, Sumo2, Sumo2C, Sumo2S, Sumo4N	Dissolved oxygen is major electron acceptor for aerobic system and is subjected to gas transfer.	g O₂.m^-3
S_CH4	Dissolved methane (CH₄)	Mini_Sumo, Sumo1, Sumo2, Sumo2C, Sumo2S, Sumo4N	Dissolved methane is the most reduced form of carbon and end product of methanogensis. They are subjected to gas transfer.	g COD.m^-3
S_H2	Dissolved hydrogen (H₂)	Mini_Sumo, Sumo1, Sumo2, Sumo2C, Sumo2S, Sumo4N	Dissolved hydrogen is generated during fermentation and transformed to S_CH4 during methanogensis. They are subjected to gas transfer.	g COD.m^-3
S_ALK	Alkalinity (ALK)	MiniSumo	Assumed to be bicarbonate and used for appropriate conversion of electric charges in the biokinetic reactions.	eq ALK.L^-1
S_CO2	Total inorganic carbon (CO₂)	Sumo1, Sumo2, Sumo2C, Sumo2S, Sumo4N	A sum of carbonic acid, bicarbonate ion, carbonate ion. It is end product of many biological reactions. As bicarbonate it is a substrate for nitrification and also consumed during methanogenesis.	g TIC.m^-3
X_INORG	Inorganics in influent and biomass	Mini_Sumo, Sumo1, Sumo2, Sumo2C, Sumo2S, Sumo4N	It represents the inorganic inerts present in influent and the biomass (0.11 g TSS.g COD^-1). It has a S_Na, S_Cl, S_Ca and S_Mg content.	g TSS.m^-3
S_CAT	Other strong cations (as Na⁺)	Sumo1, Sumo2, Sumo2C, Sumo2S, Sumo4N	Represented as sodium and is an essential element for biomass. It participates in pH and precipitation reactions.	g Na.m^-3
S_AN	Other strong anions (as Cl^-)	Sumo1, Sumo2, Sumo2C, Sumo2S, Sumo4N	Represented as chloride and is an essential element for biomass. It participates in pH and precipitation reactions.	g Cl.m^-3
S_Ca	Calcium	Sumo1, Sumo2, Sumo2C, Sumo2S, Sumo4N	An essential element for biomass and X_PPand participates in pH and precipitation reactions.	g Ca.m^-3
S_Mg	Magnesium	Sumo1, Sumo2, Sumo2C, Sumo2S, Sumo4N	An essential element for biomass and X_PP. It participates in pH and precipitation reactions.	g Mg.m^-3
S_K	Potassium	Sumo1, Sumo2, Sumo2C, Sumo2S, Sumo4N	An essential element for biomass and X_PP. It participates in pH and precipitation reactions.	g K.m^-3
S_H2S	Hydrogen sulfide (H₂S)	Sumo2S	Dissolved hydrogen sulfide gas, its subjected to gas transfer, biological and chemical reactions.	g S.m^-3
S_SO4	Sulfate (SO₄)	Sumo2S	An end product of S_H2S oxidation. It participates in pH determination	g S.m^-3
X_S	Particulate elemental sulfur (S)	Sumo2S	An intermediary product of partial S_H2S oxidation.	g S.m^-3
X_FeOH	Ferric hydroxide compounds (FeOH)	MiniSumo	Phosphorus-binding capacity of ferric hydroxides	g Fe.m^-3
X_FeP	Ferric phosphate compounds (FeP)	MiniSumo	This component results from binding phosphorus to the X_FeOH.	g Fe.m^-3
X_AlOH	Aluminium hydroxide compounds (AlOH)	MiniSumo	It stands for phosphorus-binding capacity of possible Al hydroxides	g Al.m^-3
X_AlP	Aluminium phosphate compounds (AlP)	MiniSumo	This component results from binding phosphorus to the X_AlOH.	g Al.m^-3
S_Fe2	Ferrous ion (Fe₂)	Sumo1, Sumo2, Sumo2C, Sumo2S, Sumo4N	Ferrous ion oxidized to ferric ion and then participates in X_HFO formation. It precipiates S_H2S to X_FeS and S_PO4 to X_Vivi under anaerobic environments.	g Fe.m^-3
X_HFO,H	Active hydrous ferric oxide, high surface (HFO,H)	Sumo1, Sumo2, Sumo2C, Sumo2S, Sumo4N	A ferric hydroxide with high surface area and high capacity to bind S_PO4. Higher mixing condition results in more X_HFO,H formation compared to X_HFO,L.	g Fe.m^-3
X_HFO,L	Active hydrous ferric oxide, low surface (HFO,L)	Sumo1, Sumo2, Sumo2C, Sumo2S, Sumo4N	A ferric hydroxide with low surface area and low capacity to bind S_PO4. Poor mixing condition results in more X_HFO,L formation compared to X_HFO,H.	g Fe.m^-3
X_HFO,old	Aged unused hydrous ferric oxide (HFO,old)	Sumo1, Sumo2, Sumo2C, Sumo2S, Sumo4N	When there is excess ferric addition and not much S_PO4 is available then X_HFO,H and X_HFO,L formed age into X_HFO,old. These are incapable of removing S_PO4.	g Fe.m^-3
X_HFO,H,P	P-bound hydrous ferric oxide, high surface (HFO,H,P)	Sumo1, Sumo2, Sumo2C, Sumo2S, Sumo4N	The Fe-S_PO4 complex formed with X_HFO,H.	g Fe.m^-3
X_HFO,L,P	P-bound hydrous ferric oxide, low surface (HFO,L,P)	Sumo1, Sumo2, Sumo2C, Sumo2S, Sumo4N	The Fe-S_PO4 complex formed with X_HFO,L.	g Fe.m^-3
X_HFO,H,P,old	Aged P-bound hydrous ferric oxide, high surface (HFO,H,P,old)	Sumo1, Sumo2, Sumo2C, Sumo2S, Sumo4N	Aged form of X_HFO,H,P.	g Fe.m^-3
X_HFO,L,P,old	Aged P-bound hydrous ferric oxide, low surface (HFO,L,P,old)	Sumo1, Sumo2, Sumo2C, Sumo2S, Sumo4N	Aged form of X_HFO,L,P.	g Fe.m^-3
X_HAO,H	Active hydrous aluminium oxide, high surface (HAO,H)	Sumo1, Sumo2, Sumo2C, Sumo2S, Sumo4N	Aluminium hydroxide with high surface area and high capacity to bind S_PO4. Higher mixing condition results in more X_HAO,H formation compared to X_HAO,L.	g Al.m^-3
X_HAO,L	Active hydrous aluminium oxide, low surface (HAO,L)	Sumo1, Sumo2, Sumo2C, Sumo2S, Sumo4N	Aluminium hydroxide with low surface area and low capacity to bind S_PO4. Poor mixing condition results in more X_HAO,L formation compared to X_HAO,H.	g Al.m^-3
X_HAO,old	Aged unused hydrous aluminium oxide (HAO,old)	Sumo1, Sumo2, Sumo2C, Sumo2S, Sumo4N	When there is excess X_HAO and not much S_PO4 is available then XHAO and X_HAO,L formed age into X_HAO,old. These are incapable of removing S_PO4.	g Al.m^-3
X_HAO,H,P	P-bound hydrous aluminium oxide, high surface (HAO,H,P)	Sumo1, Sumo2, Sumo2C, Sumo2S, Sumo4N	The Al-S_PO4 complex formed with X_HAO,H.	g Al.m^-3
X_HAO,L,P	P-bound hydrous aluminium oxide, low surface (HAO,L,P)	Sumo1, Sumo2, Sumo2C, Sumo2S, Sumo4N	The Al-S_PO4 complex formed with X_HAO,L.	g Al.m^-3
X_HAO,H,P,old	Aged P-bound hydrous aluminium oxide, high surface (HAO,H,P,old)	Sumo1, Sumo2, Sumo2C, Sumo2S, Sumo4N	Aged form of X_HAO,H,P.	g Al.m^-3
X_HAO,L,P,old	Aged P-bound hydrous aluminium oxide, low surface (HAO,L,P,old)	Sumo1, Sumo2, Sumo2C, Sumo2S, Sumo4N	Aged form of X_HAO,L,P.	g Al.m^-3
X_CaCO3	Calcium carbonate (CaCO₃)	Sumo1, Sumo2, Sumo2C, Sumo2S, Sumo4N	Essential chemical for pH control - a precipitate that forms readily	g TSS.m^-3
X_ACP	Amorphous calcium phosphate (ACP)	Sumo1, Sumo2, Sumo2C, Sumo2S, Sumo4N	Elemental composition of Ca₃(PO₄)₂ * 4H₂O.	g TSS.m^-3
X_BSH	Brushite (BSH)	Sumo1, Sumo2, Sumo2C, Sumo2S, Sumo4N	Elemental composition of CaHPO₄ * 2H₂O. Forms at lower pH values than Struvite	g TSS.m^-3
X_STR	Struvite (STR)	Sumo1, Sumo2, Sumo2C, Sumo2S, Sumo4N	Formed under anaerobic environments and has an elemental composition of MgNH₄PO₄ * 6H₂O.	g TSS.m^-3
X_Vivi	Vivianite (Vivi)	Sumo1, Sumo2, Sumo2C, Sumo2S, Sumo4N	Formed under anaerobic environments and has an elemental composition of Fe₃(PO₄)₂ * 8H₂O.	g TSS.m^-3
X_FeS	Iron sulfide (FeS)	Sumo2S	Formed under anaerobic environments and is a precursor for pyrite formation.	g TSS.m^-3
H	Enthalpy	Mini_Sumo, Sumo1, Sumo2, Sumo2C, Sumo2S, Sumo4N	An energy-like property that is used to calculate temperature of a system. It flows from the influent unit to the plant.	MJ.m^-3
S_ALPHA	Alpha indicator	Mini_Sumo, Sumo1, Sumo2, Sumo2C, Sumo2S, Sumo4N	A surrogate representing the surfactant composition in the wastewater.	unitless
S_ORPswitch	ORP driver for CASTO activity switches	Sumo1, Sumo2, Sumo2C, Sumo2S, Sumo4N	A surrogate switch to calculate the activity of CASTOs.	unitless
G_CO2	Carbon dioxide gas (CO₂)	Sumo1, Sumo2, Sumo2C, Sumo2S, Sumo4N	Gaseous form represented in bubbles of wastewater system.	g TIC.m^-3
G_CH4	Methane gas (CH₄)	Mini_Sumo, Sumo1, Sumo2, Sumo2C, Sumo2S, Sumo4N	Gaseous form represented in bubbles of wastewater system.	g COD.m^-3
G_H2	Hydrogen gas (H₂)	Mini_Sumo, Sumo1, Sumo2, Sumo2C, Sumo2S, Sumo4N	Gaseous form represented in bubbles of wastewater system.	g COD.m^-3
G_O2	Oxygen gas (O₂)	Mini_Sumo, Sumo1, Sumo2, Sumo2C, Sumo2S, Sumo4N	Gaseous form represented in bubbles of wastewater system.	g O₂.m^-3
G_NH3	Ammonia gas (NH₃)	Sumo1, Sumo2, Sumo2C, Sumo2S, Sumo4N	Gaseous form represented in bubbles of wastewater system.	g N.m^-3
G_N2	Nitrogen gas (N₂)	Mini_Sumo, Sumo1, Sumo2, Sumo2C, Sumo2S, Sumo4N	Gaseous form represented in bubbles of wastewater system.	g N.m^-3
G_NO	Nitric oxide gas (NO)	Sumo4N	Gaseous form represented in bubbles of wastewater system.	g N.m^-3
G_N2O	Nitrous oxide gas (N₂O)	Sumo4N	Gaseous form represented in bubbles of wastewater system.	g N.m^-3
G_H2S	Hydrogen sulfide gas (H₂S)	Sumo2S	Gaseous form represented in bubbles of wastewater system.	g S.m^-3
G_CO2,atm	Carbon dioxide gas (CO2)	Sumo1, Sumo2, Sumo2C, Sumo2S, Sumo4N	Gaseous form represented in the atmosphere around wastewater systems.	%v/v
G_CH4,atm	Methane gas (CH₄)	Mini_Sumo, Sumo1, Sumo2, Sumo2C, Sumo2S, Sumo4N	Gaseous form represented in the atmosphere around wastewater systems.	%v/v
G_H2,atm	Hydrogen gas (H₂)	Mini_Sumo, Sumo1, Sumo2, Sumo2C, Sumo2S, Sumo4N	Gaseous form represented in the atmosphere around wastewater systems.	%v/v
G_O2,atm	Oxygen gas (O₂)	Mini_Sumo, Sumo1, Sumo2, Sumo2C, Sumo2S, Sumo4N	Gaseous form represented in the atmosphere around wastewater systems.	%v/v
G_NH3,atm	Ammonia gas (NH3)	Sumo1, Sumo2, Sumo2C, Sumo2S, Sumo4N	Gaseous form represented in the atmosphere around wastewater systems.	%v/v
G_N2,atm	Nitrogen gas (N₂)	Mini_Sumo, Sumo1, Sumo2, Sumo2C, Sumo2S, Sumo4N	Gaseous form represented in the atmosphere around wastewater systems.	%v/v
G_NO,atm	Nitric oxide gas (NO)	Sumo4N	Gaseous form represented in the atmosphere around wastewater systems.	%v/v
G_N2O,atm	Nitrous oxide gas (N₂O)	Sumo4N	Gaseous form represented in the atmosphere around wastewater systems.	%v/v
G_H2S,atm	Hydrogen sulfide gas (H₂S)	Sumo2S	Gaseous form represented in the atmosphere around wastewater systems.	%v/v
S_MM,index	Methyl mercaptan production index	Sumo2S	A surrogate for indicating the potential for odor generation at a wastewater facility.	Unitless

Biological processes	Concepts description
Aerobic growth on VFA, O₂	Growth on S_VFA under aerobic conditions. Requires S_O2, nutrients (S_NHx, S_PO4, S_CAT, S_AN, S_Ca, S_Mg). Bell shape inhibition function on pH: BellinhpH.
Anoxic growth on VFA, NO₂^-	Growth on S_VFA under anoxic conditions. This is the second step of denitrification in Sumo2, Sumo2C and Sumo2S), S_NO2 is reduced into S_N2. This process is not described in Sumo1 and MiniSumo. Requires S_NO2, nutrients (S_NHx, S_PO4, S_CAT, S_AN, S_Ca, S_Mg). Bell shape inhibition function on pH: BellinhpH.
Anoxic growth on VFA, NO₃^-	Growth on S_VFA under anoxic conditions. This is the denitrification process in Sumo1 and MiniSumo: S_NO3 is reduced in S_N2. This is the first step of denitrification in Sumo2, Sumo2C and Sumo2S): S_NO3 is reduced into S_NO2. Requires S_NO3, nutrients (S_NHx, S_PO4, S_CAT, S_AN, S_Ca, S_Mg). Bell shape inhibition function on pH: BellinhpH.
Aerobic growth on S_B, O₂	Growth on S_B under aerobic conditions. Requires S_O2, nutrients (S_NHx, S_PO4, S_CAT, S_AN, S_Ca, S_Mg). Bell shape inhibition function on pH: BellinhpH
Anoxic growth on S_B, NO₂^-	Growth on S_B under anoxic conditions. This is the second step of denitrification in Sumo2, Sumo2C and Sumo2S), S_NO2 is reduced into S_N2. This process is not described in Sumo1 and MiniSumo. Requires S_NO2, nutrients (S_NHx, S_PO4, S_CAT, S_AN, S_Ca, S_Mg). Bell shape inhibition function on pH: BellinhpH
Anoxic growth on S_B, NO₃^-	Growth on S_B under anoxic conditions. This is the denitrification process in Sumo1 and MiniSumo: S_NO3 is reduced in S_N2. This is the first step of denitrification in Sumo2, Sumo2C and Sumo2S): S_NO3 is reduced into S_NO2. Requires S_NO3, nutrients (S_NHx, S_PO4, S_CAT, S_AN, S_Ca, S_Mg). Bell shape inhibition function on pH: BellinhpH.
S_B fermentation with high VFA (OHO growth, anaerobic)	Growth on S_B under anaerobic conditions. OHO Fermenters have different growth rate of 0.3 d^-1 and digesters have different K_SB,ana of 350 mgCOD/L Produce S_VFA as fermentation product and S_H2. Under high S_VFA concentration, the yield of S_H2 production is higher (less S_VFA produced). Requires nutrients (S_NHx, S_PO4, S_CAT, S_AN, S_Ca, S_Mg). Bell shape inhibition function on pH: BellinhpH.
S_B fermentation with low VFA (OHO growth, anaerobic)	Growth on S_B under anaerobic conditions. OHO Fermenters have different growth rate of 0.3 d^-1 and digesters have different K_SB,ana of 350 mgCOD/L Produce S_VFA as fermentation product and S_H2. Under low S_VFA concentration, the yield of S_H2 production is lower (more S_VFA produced). Requires nutrients (S_NHx, S_PO4, S_CAT, S_AN, S_Ca, S_Mg). Bell shape inhibition function on pH: BellinhpH.
Aerobic growth on S_MEOL, O₂	OHO aerobic growth on methanol in order to consum any residual methanol from anoxic carbon dosage for denitrification. Requires S_O2, nutrients (S_NHx, S_PO4, S_CAT, S_AN, S_Ca, S_Mg). Bell shape inhibition function on pH: BellinhpH.
OHO decay	OHO decay process under anoxic and aerobic conditions. This process release X_B and X_E (death-regeneration concept).
OHO anaerobic decay	OHO decay process under anaerobic conditions. This process release X_B and X_E,ana (death-regeneration concept).

Biological processes	Concepts description
MEOLO growth, NO₂	Growth on SMEOL under anoxic conditions. This is the second step of denitrification in Sumo2, Sumo2C and Sumo2S), S_NO2 is reduced into S_N2. This process is not described in Sumo1 and MiniSumo. Requires S_NO2, nutrients (S_NHx, S_PO4, S_CAT, S_AN, S_Ca, S_Mg). Bell shape inhibition function on pH: BellinhpH
MEOLO growth, NO₃	Growth on SMEOL under anoxic conditions. This is the denitrification process in Sumo1 and MiniSumo: S_NO3 is reduced in S_N2. This is the first step of denitrification in Sumo2, Sumo2C and Sumo2S): S_NO3 is reduced into S_NO2. Requires S_NO3, nutrients (S_NHx, S_PO4, S_CAT, S_AN, S_Ca, S_Mg). Bell shape inhibition function on pH: BellinhpH.
MEOLO decay	MEOLO decay process under anoxic and aerobic conditions. This process release X_B and X_E (death-regeneration concept).
MEOLO anaerobic decay	MEOLO decay process under anaerobic conditions. This process release X_B and X_E,ana (death-regeneration concept).

Biological processes	Concepts description
NITO growth	NITO growth process, using S_NHx as electron donor. S_NHx is oxidized in S_NO3 in one step. S_CO2 is used as carbon source. Requires S_O2, nutrients (S_NHx, S_PO4, S_CAT, S_AN, S_Ca, S_Mg). Bell shape inhibition function on pH: BellinhpH.
NITO decay	NITO decay process under anoxic and aerobic conditions. This process release X_B and X_E.
NITO anaerobic decay	NITO decay process under anaerobic conditions. This process release X_B and X_E,ana .

Biological processes	Concepts description
AOB growth	AOB growth process, using S_NHx as electron donor. This is the first step of nitrification: S_NHx is oxidized in S_NO2 S_CO2 is used as carbon source. Requires S_O2, nutrients (S_NHx, S_PO4, S_CAT, S_AN, S_Ca, S_Mg). Bell shape inhibition function on pH: BellinhpH.
AOB decay	AOB decay process under anoxic and aerobic conditions. This process release X_B and X_E.
AOB anaerobic decay	AOB decay process under anaerobic conditions. This process release X_B and X_E,ana .

Biological processes	Concepts description
NOB growth	NOB growth process, using S_NO2 as electron donor. This is the second step of nitrification: S_NO2 is oxidized in S_NO3 S_CO2 is used as carbon source. Requires S_O2, nutrients (S_NHx, S_PO4, S_CAT, S_AN, S_Ca, S_Mg). Bell shape inhibition function on pH: BellinhpH.
NOB decay	NOB decay process under anoxic and aerobic conditions. This process release X_B and X_E.
NOB anaerobic decay	NOB decay process under anaerobic conditions. This process release X_B and X_E,ana .

Biological processes	Concepts description
Growth	AMX growth process, using S_NHx as electron donor and S_NO2 as electron acceptor. S_NO3 and S_N2 are produced by the reaction. The stoichiometry is described above. S_CO2 is used as carbon source. Requires S_NHx, S_NO2, nutrients (S_NHx, S_PO4, S_CAT, S_AN, S_Ca, S_Mg). Bell shape inhibition function on pH: BellinhpH.
Decay	AMX decay process under anoxic and aerobic conditions. This process release X_B and X_E.
Anaerobic decay	AMX decay process under anaerobic conditions. This process release X_B and X_E,ana .

Biological processes	Concepts description
CASTO growth on PHA and GLY, O₂	PHA/GLY → CASTO Requires O₂. Kinetic parameters µ_CASTO: Maximum specific growth rate of CASTOs K_STC: Half-saturation of PHA and GLY for CASTOs K_O2,CASTO,AS: Half-saturation of O₂ for CASTOs (AS) Kinetic rate limitation/inhibitions Monod ratio saturation function on substrate: MRsat_{XSTC,XCASTO,KSTC} Monod saturation function on electron acceptor: O₂ → Msat_{SO2,KO2,CASTO} Monod saturation functions on nutrients: NH_x, PO₄, cations, anions, calcium and magnesium: Msat_{SNHx,KNHx,OHO}, Msat_{SPO4,KPO4,BIO}, Msat_SCAT,KCAT, Msat_SAN,KAN, Msat_SCa,KCa,PAO, Msat_SMg,KMg,PAO Bell shape inhibition function on pH: Bellinh_pH
CASTO growth on PHA and GLY, NO_x/NO₂/NO₃	PHA/GLY → CASTO Requires NO_x/NO₂/NO₃. Kinetic parameters µ_CASTO: Maximum specific growth rate of CASTOs η_CASTO,anox: Reduction factor for anoxic growth of CASTOs on NO_x K_STC: Half-saturation of PHA and GLY for CASTOs K_NOx,CASTO,AS/K_NO2,CASTO,AS/K_NO3,CASTO,AS: Half-saturation of NO_x/NO₂/NO₃ for CASTOs (AS) K_O2,CASTO,AS: Half-saturation of O₂ for CASTOs (AS) Kinetic rate limitation/inhibitions Monod ratio saturation function on substrate: MRsat_{XSTC,XCASTO,KSTC} Monod saturation function on electron acceptor: NO_x → Msat_{SNOx,KNOx,CASTO} (Mini_Sumo, Sumo1) NO₂ → Msat_{SNO2,KNO2,CASTO} (Sumo2, 2C, 2S) NO₃ → Msat_{SNO3,KNO3,CASTO} (Sumo2, 2C, 2S) Monod inhibition function on O₂: Minh_{SO2,KO2,CASTO} Monod inhibition function on NO₂: Minh_{SNO2,KNO2,CASTO} (Sumo2, 2C, 2S) Monod saturation functions on nutrients: NH_x, PO₄, cations, anions, calcium and magnesium: Msat_{SNHx,KNHx,OHO}, Msat_{SPO4,KPO4,BIO}, Msat_SCAT,KCAT, Msat_SAN,KAN, Msat_SCa,KCa,PAO, Msat_SMg,KMg,PAO Bell shape inhibition function on pH: Bellinh_pH
PAO polyphosphate storage, O₂	S_PO4 → X_PP Requires O₂. Kinetic parameters q_PAO,PP: Maximum polyphosphate uptake rate of PAOs K_O2,CASTO,AS: Half-saturation of O₂ for CASTOs (AS) K_PO4,PAO,AS: Half-saturation of PO4 for PAOs (AS) Ki_PP,PAO,max: Half-inhibition of maximum PP content of PAOs Kinetic rate limitation/inhibitions Monod saturation function on electron acceptor: O₂ → Msat_{SO2,KO2,CASTO} Logistic saturation function on substrate: Logsat_{SPO4,KPO4,PAO} Logistic inhibition function on product: Loginh_XPP,XPAO,max Monod saturation functions on nutrients as calcium, magnesium and potassium: Msat_SCa,KCa,PAO, Msat_SMg,KMg,PAO, Msat_SK,KK,PAO Bell shape inhibition function on pH: Bellinh_pH
PAO polyphosphate storage, NO_x/NO₂/NO₃	S_PO4 → X_PP Requires NO_x/NO₂/NO₃. Kinetic parameters q_PAO,PP: Maximum polyphosphate uptake rate of PAOs η_CASTO,anox: Reduction factor for anoxic growth of CASTOs K_NOx,CASTO,AS/K_NO2,CASTO,AS/K_NO3,CASTO,AS: Half-saturation of NO_x/NO₂/NO₃ for CASTOs (AS) K_O2,CASTO,AS: Half-saturation of O₂ for CASTOs (AS) K_PO4,PAO,AS: Half-saturation of PO₄ for PAOs (AS) Ki_PP,PAO,max: Half-inhibition of maximum PP content of PAOs Kinetic rate limitation/inhibitions Monod saturation function on electron acceptor: O₂ → Msat_{SO2,KO2,CASTO} Logistic saturation function on substrate: Logsat_{SPO4,KPO4,PAO} Logistic inhibition function on product: Loginh_XPP,XPAO,max Monod inhibition function on O₂: Minh_{SO2,KO2,CASTO} Monod inhibition function on NO₂: Minh_{SNO2,KNO2,CASTO} (Sumo2, 2C, 2S) Monod saturation functions on nutrients as calcium, magnesium and potassium: Msat_SCa,KCa,PAO, Msat_SMg,KMg,PAO, Msat_SK,KK,PAO Bell shape inhibition function on pH: Bellinh_pH
PAO growth on PHA, O₂; PO₄ limited	PHA/GLY → CASTO Requires O₂ and PP. Kinetic parameters µ_PAO,lim: Maximum specific growth rate of CASTOs under P limited K_PHA: Half-saturation of PHA for PAOs K_O2,CASTO,AS: Half-saturation of O₂ for CASTOs (AS) Ki_PO4,lim,AS: Half-inhibition of PO4 for PAOs under PO4 limitation (AS) K_PP,lim: Half-saturation of PP (nutrient) for PAOs under PO₄ limitation (AS) Kinetic rate limitation/inhibitions Monod ratio saturation function on substrate: MRsat_{XPHA,XPAO,KPHA} Monod saturation function on electron acceptor: O₂ → Msat_{SO2,KO2,CASTO} Monod inhibition function on PO₄: Minh_{SPO4,KiPO4,lim} Monod saturation function on X_PP: Msat_XPP,KPP,lim Monod saturation functions on nutrients: NH_x, cations, anions, calcium and magnesium: Msat_{SNHx,KNHx,OHO}, Msat_SCAT,KCAT, Msat_SAN,KAN, Msat_SCa,KCa,PAO, Msat_SMg,KMg,PAO Bell shape inhibition function on pH: Bellinh_pH
PAO growth on PHA, NO_x/NO₂/NO₃; PO₄ limited	PHA/GLY → CASTO Requires NO_x/NO₂/NO₃ and PP. Kinetic parameters µ_PAO,lim: Maximum specific growth rate of CASTOs under P limited K_PHA: Half-saturation of PHA for PAOs K_O2,CASTO,AS: Half-saturation of O₂ for CASTOs (AS) Ki_PO4,lim,AS: Half-inhibition of PO4 for PAOs under PO4 limitation (AS) K_PP,lim: Half-saturation of PP (nutrient) for PAOs under PO₄ limitation (AS) Kinetic rate limitation/inhibitions Monod ratio saturation function on substrate: MRsat_{XPHA,XPAO,KPHA} Monod saturation function on electron acceptor: NO_x → Msat_{SNOx,KNOx,CASTO} (Mini_Sumo, Sumo1) NO₂ → Msat_{SNO2,KNO2,CASTO} (Sumo2, 2C, 2S) NO₃ → Msat_{SNO3,KNO3,CASTO} (Sumo2, 2C, 2S) Monod inhibition function on O₂: Minh_{SO2,KO2,CASTO} Monod inhibition function on NO₂: Minh_{SNO2,KNO2,CASTO} (Sumo2, 2C, 2S) Monod inhibition function on PO₄: Minh_{SPO4,KiPO4,lim} Monod saturation function on X_PP: Msat_XPP,KPP,lim Monod saturation functions on nutrients: NH_x, cations, anions, calcium and magnesium: Msat_{SNHx,KNHx,OHO}, Msat_SCAT,KCAT, Msat_SAN,KAN, Msat_SCa,KCa,PAO, Msat_SMg,KMg,PAO Bell shape inhibition function on pH: Bellinh_pH
PAO's PHA storage from VFAs and PO₄ release	VFA → PHA and X_PP → S_PO4 Kinetic parameters q_PAO,PHA: Rate of VFA storage into PHA for PAOs K_VFA,CASTO,AS: Half-saturation of VFA storage for CASTOs (AS) K_PP: Half-saturation of PP for PAOs Ki_PHA,PAO,max: Half-inhibition of maximum PHA content of PAOs Kinetic rate limitation/inhibitions Monod saturation function on VFA: Msat_{SVFA,KVFA,CASTO} Monod ratio saturation function on PP: MRsat_XPP,XPAO,KPP Logistic inhibition function on product: Loginh_{XPHA,XPAO,max}
GAO's GLY storage from VFAs	PHA → CO₂ and GLY → CO₂ Kinetic parameters q_GAO,GLY: Rate of VFA storage into GLY for GAOs K_VFA,CASTO,AS: Half-saturation of VFA storage for CASTOs (AS) Ki_GLY,GAO,max: Half-inhibition of maximum GLY content of GAOs Kinetic rate limitation/inhibitions Monod saturation function on VFA: Msat_{SVFA,KVFA,CASTO} Logistic inhibition function on product: Loginh_{XGLY,XGAO,max}
CASTO aerobic maintenance	PHA → CO₂ and GLY → CO₂ Requires O₂. Kinetic parameters b_STC: Rate of CASTOs maintenance on PHA and GLY K_O2,CASTO,AS: Half-saturation of O₂ for CASTOs (AS) K_STC: Half-saturation of PHA and GLY for PAOs Kinetic rate limitation/inhibitions Monod saturation function on electron acceptor: O₂ → Msat_{SO2,KO2,CASTO} Monod ratio saturation function on STC: MRsat_{XSTC,XCASTO,KSTC}
CASTO anoxic maintenance, NO_x/NO₂/NO₃	PHA → CO₂ and GLY → CO₂ Requires NO_x/NO₂/NO₃. Kinetic parameters b_STC: Rate of CASTOs maintenance on PHA and GLY η_bSTC,anox: Reduction factor for anoxic maintenance of CASTOs on PHA and GLY K_O2,CASTO,AS: Half-saturation of O₂ for CASTOs (AS) K_NOx,CASTO,AS/K_NO2,CASTO,AS/K_NO3,CASTO,AS: Half-saturation of NO_x/NO₂/NO₃ for CASTOs (AS) K_STC: Half-saturation of PHA and GLY for PAOs Kinetic rate limitation/inhibitions Monod inhibition function on O₂: Minh_{SO2,KO2,CASTO} Monod inhibition function on NO₂: Minh_{SNO2,KNO2,CASTO} (Sumo2, 2C, 2S) Monod saturation function on electron acceptor: NO_x → Msat_{SNOx,KNOx,CASTO} (Mini_Sumo, Sumo1) NO₂ → Msat_{SNO2,KNO2,CASTO} (Sumo2, 2C, 2S) NO₃ → Msat_{SNO3,KNO3,CASTO} (Sumo2, 2C, 2S) Monod ratio saturation function on STC: MRsat_{XSTC,XCASTO,KSTC}
GAO anaerobic maintenance	GLY → VFA Kinetic parameters b_STC: Rate of CASTOs maintenance on PHA and GLY η_bGLY,ana: Reduction factor for anoxic maintenance of CASTOs on PHA and GLY K_O2,CASTO,AS: Half-saturation of O₂ for CASTOs (AS) K_NOx,CASTO,AS/K_NO2,CASTO,AS/K_NO3,CASTO,AS: Half-saturation of NO_x/NO₂/NO₃ for CASTOs (AS) K_STC: Half-saturation of PHA and GLY for PAOs Kinetic rate limitation/inhibitions Monod inhibition function on O₂: Minh_{SO2,KO2,CASTO} Monod inhibition function on: NO_x → Minh_{SNOx,KNOx,CASTO} (Mini_Sumo, Sumo1) NO₂ → Minh_{SNO2,KNO2,CASTO} (Sumo2, 2C, 2S) NO₃ → Minh_{SNO3,KNO3,CASTO} (Sumo2, 2C, 2S) Monod ratio saturation function on STC: MRsat_{XSTC,XCASTO,KSTC}
PP cleavage for maintenance	PP → PO₄ Rate expression covers the aerobic, anoxic and anaerobic PP cleavage as follows (Sumo1, MODEL sheet, row 27, column CB): r24 = b_PP,ana,T * X_PAO * Logsat_XPP,KPO4,PAO * (η_bPP,aer * MR_{inhXPHA,XPAO,KPHA,cle} * Msat_{SO2,KO2,CASTO} + ηb_PP,anox * Minh_{SO2,KO2,CASTO} * Msat_{SNOx,KNOx,CASTO} + Minh_{SO2,KO2,CASTO} * Minh_{SNOx,KNOx,CASTO}) Kinetic parameters b_PP,ana: Rate of PAOs maintenance under anaerobic conditions (PP cleavage) η_bPP,aer: Reduction factor for aerobic maintenance of PAOs on PP η_bPP,aer: Reduction factor for aerobic maintenance of PAOs on PP η_bPP,anox: Reduction factor for anoxic maintenance of PAOs on PP K_PO4,PAO,AS: Half-saturation of PO4 for PAOs (AS) K_PHA,cle: Half-saturation of PHA for PAOs at PP cleavage K_O2,CASTO,AS: Half-saturation of O₂ for CASTOs (AS) K_NOx,CASTO,AS/K_NO2,CASTO,AS/K_NO3,CASTO,AS: Half-saturation of NO_x/NO₂/NO₃ for CASTOs (AS) Kinetic rate limitation/inhibitions Logistic saturation function on substrate: Logsat_XPP,KPO4,PAO Monod ratio inhibition function on PHA: MRinh_{XPHA,XPAO,KPHA,cle} Monod saturation function on O₂: Msat_{SO2,KO2,CASTO} Monod saturation function on: NO_x → Msat_{SNOx,KNOx,CASTO} (Mini_Sumo, Sumo1) NO₂ → Msat_{SNO2,KNO2,CASTO} (Sumo2, 2C, 2S) NO₃ → Msat_{SNO3,KNO3,CASTO} (Sumo2, 2C, 2S) Monod inhibition function on O₂: Minh_{SO2,KO2,CASTO} Monod inhibition function on: NO_x → Minh_{SNOx,KNOx,CASTO} (Mini_Sumo, Sumo1) NO₂ → Minh_{SNO2,KNO2,CASTO} (Sumo2, 2C, 2S) NO₃ → Minh_{SNO3,KNO3,CASTO} (Sumo2, 2C, 2S)
S_B fermentation with high VFA (PAO growth, anaerobic)	SB → VFA + CASTO Kinetic parameters µ_FERM,PAO: Fermentation growth rate of PAOs Activity limitation act_FERM,PAO,ORP: Fermentation activity switch for ORP Kinetic rate limitation/inhibitions Logistic saturation function on VFA: Logsat_{SVFA,KVFA,FERM} Monod saturation function on S_B: Msat_SB,KSB,ana Monod saturation functions on nutrients: NH_x, PO₄, cations, anions, calcium and magnesium: Msat_{SNHx,KNHx,BIO}, Msat_{SPO4,KPO4,BIO}, Msat_SCAT,KCAT, Msat_SAN,KAN, Msat_SCa,KCa, Msat_SMg,KMg Bell shape inhibition function on pH: Bellinh_pH
S_B fermentation with low VFA (PAO growth, anaerobic)	SB → VFA + CASTO Kinetic parameters µ_FERM,PAO: Fermentation growth rate of PAOs Activity limitation act_FERM,PAO,ORP: Fermentation activity switch for ORP Kinetic rate limitation/inhibitions Logistic inhibition function on VFA: Loginh_{SVFA,KVFA,FERM} Monod saturation function on S_B: Msat_SB,KSB,ana Monod saturation functions on nutrients: NH_x, PO₄, cations, anions, calcium and magnesium: Msat_{SNHx,KNHx,BIO}, Msat_{SPO4,KPO4,BIO}, Msat_SCAT,KCAT, Msat_SAN,KAN, Msat_SCa,KCa, Msat_SMg,KMg Monod saturation functions on CO₂: Msat_{SCO2,KCO2,BIO} Bell shape inhibition function on pH: Bellinh_pH
CASTO decay	CASTO → X_B and X_E under anoxic and aerobic conditions. Kinetic parameters b_CASTO: Decay rate of CASTOs η_bCASTO,anox: Reduction factor for anoxic decay of CASTOs K_STC: Half-saturation of PHA and GLY for PAOs K_O2,CASTO,AS: Half-saturation of O₂ for CASTOs (AS) K_NOx,CASTO,AS/K_NO2,CASTO,AS/K_NO3,CASTO,AS: Half-saturation of NO_x/NO₂/NO₃ for CASTOs (AS) K_PP: Half-saturation of PP for PAOs Kinetic rate limitation/inhibitions Monod ratio inhibition function on STC: MRinh_{XSTC,XCASTO,KSTC} Monod saturation function on O₂: Msat_{SO2,KO2,CASTO} Monod ratio inhibition function on PP: MRinh_XPP,XPAO,KPP Monod saturation function on: NO_x → Msat_{SNOx,KNOx,CASTO} (Mini_Sumo, Sumo1) NO₂ → Msat_{SNO2,KNO2,CASTO} (Sumo2, 2C, 2S) NO₃ → Msat_{SNO3,KNO3,CASTO} (Sumo2, 2C, 2S) Monod inhibition function on O₂: Minh_{SO2,KO2,CASTO} Monod inhibition function on: NO_x → Minh_{SNOx,KNOx,CASTO} (Mini_Sumo, Sumo1) NO₂ → Minh_{SNO2,KNO2,CASTO} (Sumo2, 2C, 2S) NO₃ → Minh_{SNO3,KNO3,CASTO} (Sumo2, 2C, 2S)
CASTO anaerobic decay	CASTO → X_B and X_E under anaerobic conditions. Kinetic parameters b_CASTO: Decay rate of CASTOs η_bCASTO,ana: Reduction factor for anaerobic decay of CASTOs K_O2,CASTO,AS: Half-saturation of O₂ for CASTOs (AS) K_NOx,CASTO,AS/K_NO2,CASTO,AS/K_NO3,CASTO,AS: Half-saturation of NO_x/NO₂/NO₃ for CASTOs (AS) K_PP: Half-saturation of PP for PAOs K_GLY: Half-saturation of glycogen for GAOs (AS) m_tox,ana,max: Toxicity factor of aerobes under anaerobic conditions (maximum) Kinetic rate limitation/inhibitions Monod ratio inhibition function on GLY: MRinh_{XGLY,XCGAO,KGLY} Monod ratio inhibition function on PP: MRinh_XPP,XPAO,KPP Monod inhibition function on O₂: Minh_{SO2,KO2,CASTO} Monod inhibition function on: NO_x → Minh_{SNOx,KNOx,CASTO} (Mini_Sumo, Sumo1) NO₂ → Minh_{SNO2,KNO2,CASTO} (Sumo2, 2C, 2S) NO₃ → Minh_{SNO3,KNO3,CASTO} (Sumo2, 2C, 2S) First order toxicity: X_CASTO * m_tox,ana

Biological processes	Concepts description
AMETO growth	Substrate is S_VFA and produce S_CH4. Too much S_VFA results in a Haldane S_VFA inhibition Free ammonia inhibition Requires nutrients (S_NHx, S_PO4, S_CAT, S_AN, S_Ca, S_Mg). Bell shape inhibition function on pH: BellinhpH.
AMETO decay	AMETO decay process under anoxic and aerobic conditions. This process release X_B and X_E (death-regeneration concept).
AMETO anaerobic decay	AMETO decay process under anaerobic conditions. This process release X_B and X_E,ana (death-regeneration concept).

Biological processes	Concepts description
HMETO growth	Substrate H2 and produce S_CH4. Requires nutrients (S_NHx, S_PO4, S_CAT, S_AN, S_Ca, S_Mg). Bell shape inhibition function on pH: BellinhpH.
HMETO decay	HMETO decay process under anoxic and aerobic conditions. This process release X_B and X_E (death-regeneration concept).
HMETO anaerobic decay	HMETO decay process under anaerobic conditions. This process release X_B and X_E,ana (death-regeneration concept).

Biological processes	Concepts description
AHO storage of S_B,mono	Storage of S_B,mono into X_STO without any energy required
AHO storage of S_VFA	Storage of S_VFA into X_STO without any energy required
AHO growth on X_STO, O₂	Requires O₂, X_STO and nutrients. This is the AHO growth process.
AHO decay	Decay process of AHO under anoxic and aerobic conditions, resulting in X_B, C_B and X_E release. X_STO is also considered to be released in the proportion of X_STO/X_AHO.
AHO anaerobic decay	Decay process of AHO under anaerobic conditions, resulting in X_B, C_B and X_E,ana release. X_STO is also considered to be released in the proportion of X_STO/X_AHO.

Biological processes	Concepts description
ASRO growth - SO₄ reduction with S_VFA	ASRO growth process on S_VFA, using S_SO4 as electron acceptor. S_H2S is produced. Requires S_SO4 and nutrients (S_NHx, S_PO4, S_CAT, S_AN, S_Ca, S_Mg). Bell shape inhibition function on pH: BellinhpH.
ASRO decay	ASRO decay process under anoxic and aerobic conditions. This process release X_B and X_E (death-regeneration concept).
ASRO anaerobic decay	ASRO decay process under anaerobic conditions. This process release X_B and X_E,ana (death-regeneration concept).

Biological processes	Concepts description
HSRO growth - SO₄ reduction with S_H2	HSRO growth process on S_H2, using S_SO4 as electron acceptor. S_H2S is produced. Requires S_SO4 and nutrients (S_NHx, S_PO4, S_CAT, S_AN, S_Ca, S_Mg). Bell shape inhibition function on pH: BellinhpH.
HSRO decay	HSRO decay process under anoxic and aerobic conditions. This process release X_B and X_E (death-regeneration concept).
HSRO anaerobic decay	HSRO decay process under anaerobic conditions. This process release X_B and X_E,ana (death-regeneration concept).

Biological processes	Concepts description
SOO growth on H₂S, O₂	SOO aerobic growth, using S_H2S as electron donor. S_H2S is oxidised into elemental sulfur X_S with S_O2 as electron acceptor. Requires S_H2S, S_O2 and nutrients (S_H2S, S_NHx, S_PO4, S_CAT, S_AN, S_Ca, S_Mg).
SOO growth on H₂S, NO₂	SOO anoxic growth, using S_H2S as electron donor. S_H2S is oxidised into elemental sulfur X_S with S_NO2 as electron acceptor. Requires S_H2S, S_NO2 and nutrients (S_H2S, S_NHx, S_PO4, S_CAT, S_AN, S_Ca, S_Mg).
SOO growth on H₂S, NO₃	SOO anoxic growth, using S_H2S as electron donor. S_H2S is oxidised into elemental sulfur X_S with S_NO2 as electron acceptor. Requires S_H2S, S_NO2 and nutrients (S_H2S, S_NHx, S_PO4, S_CAT, S_AN, S_Ca, S_Mg).
SOO growth on S°, O₂	SOO aerobic growth, using elemental sulfur X_S as electron donor. X_S is oxidised into sulfate S_SO4 with S_O2 as electron acceptor. Requires X_S, S_O2 and nutrients (S_H2S, S_NHx, S_PO4, S_CAT, S_AN, S_Ca, S_Mg).
SOO growth on S°, NO₂	SOO anoxic growth, using elemental sulfur X_S as electron donor. X_S is oxidised into sulfate S_SO4 with S_NO2 as electron acceptor. Requires X_S, S_NO2 and nutrients (S_H2S, S_NHx, S_PO4, S_CAT, S_AN, S_Ca, S_Mg).
SOO growth on S°, NO₃	SOO anoxic growth, using elemental sulfur X_S as electron donor. X_S is oxidised into sulfate S_SO4 with S_NO3 as electron acceptor. Requires X_S, S_NO3 and nutrients (S_H2S, S_NHx, S_PO4, S_CAT, S_AN, S_Ca, S_Mg).
SOO decay	SOO decay process under anoxic and aerobic conditions. This process release X_B and X_E (death-regeneration concept).
SOO anaerobic decay	SOO decay process under anaerobic conditions. This process release X_B and X_E,ana (death-regeneration concept).

Biological processes	Concepts description
OHO growth with NO₃	Reduction NO₃^-→NO₂^- Kinetic parameters µ_OHO: Maximum specific growth rate of OHOs η_OHO,NO3: Reduction factor for anoxic growth of OHOs on NO₃ K_VFA,NO3,AS: Half-saturation of VFA for OHOs on NO₃ (AS) K_SB,NO3,AS: Half-saturation of readily biodegradable substrate for OHOs on NO₃ (AS) K_{O2,OHO,NO3,AS}: Half-saturation of O₂ for OHOs on NO₃ (AS) K_NO3,OHO,AS: Half-saturation of NO₃ for OHOs (AS) Kinetic rate limitation/inhibitions Monod saturation function on substrate: Msat_VFA,KVFAor Msat_SB,KSB*Minh_SVFA,KVFA Monod saturation function on electron acceptor: NO₃ => Msat_{SNO3,KNO3,OHO} Monod inhibition function on O₂: Minh_{SO2,KO2,OHO,NO3} Monod saturation functions on nutrients: NH_x, PO₄, cations, anions, calcium and magnesium: Msat_{SNHx,KNHx,OHO}, Msat_{SPO4,KPO4,BIO}, Msat_SCAT,KCAT, Msat_SAN,KAN, Msat_SCa,KCa, Msat_SMg,KMg Bell shape inhibition function on pH: BellinhpH
OHO growth with NO₂	Reduction NO₂^-→NO_,OHO (NO considered as cell-internal intermediate) Inhibited by NO Kinetic parameters µ_OHO: Maximum specific growth rate of OHOs η_OHO,NO2: Reduction factor for anoxic growth of OHOs on NO₂ K_VFA,NO2,AS: Half-saturation of VFA for OHOs on NO₂ (AS) K_SB,NO2,AS: Half-saturation of readily biodegradable substrate for OHOs on NO₂ (AS) K_NO2,OHO,AS: Half-saturation of NO₂ for OHOs (AS) K_{O2,OHO,NO2,AS}: Half-saturation of O₂ for OHOs on NO₂ (AS) Ki_{NO,OHO,NO2,AS}: Half-inhibition of NO for OHOs denitrification of NO₂ (AS) Kinetic rate limitation/inhibitions Monod saturation function on substrate: Msat_VFA,KVFAor Msat_SB,KSB*Minh_SVFA,KVFA Monod saturation function on electron acceptor: NO₂ => Msat_{SNO2,KNO2,OHO} Monod inhibition function on O₂: Minh_{SO2,KO2,OHO,NO2} Monod inhibition function on NO: Minh_{SNO,KiNO,OHO,NO2} Monod saturation functions on nutrients: NH_x, PO₄, cations, anions, calcium and magnesium: Msat_{SNHx,KNHx,OHO}, Msat_{SPO4,KPO4,BIO}, Msat_SCAT,KCAT, Msat_SAN,KAN, Msat_SCa,KCa, Msat_SMg,KMg Bell shape inhibition function on pH: BellinhpH
OHO growth with NO	Reduction NO_,OHO→N₂O (NO considered as cell-internal intermediate) Inhibited by NO Kinetic parameters µ_OHO: Maximum specific growth rate of OHOs η_OHO,NO: Reduction factor for anoxic growth of OHOs on NO K_VFA,NO,AS: Half-saturation of VFA for OHOs on NO (AS) K_SB,NO,AS: Half-saturation of readily biodegradable substrate for OHOs on NO (AS) K_NO,OHO,AS: Half-saturation of NO for OHOs (AS) K_O2,OHO,NO,AS: Half-saturation of O₂ for OHOs on NO (AS) Ki_NO,OHO,NO,AS: Half-inhibition of NO for OHOs denitrification of NO (AS) Kinetic rate limitation/inhibitions Monod saturation function on substrate: Msat_VFA,KVFAor Msat_SB,KSB*Minh_SVFA,KVFA Haldane functions on electron acceptor: NO => Hsat_SNO,KNO,OHO Monod inhibition function on O₂: Minh_{SO2,KO2,OHO,NO2} Monod saturation functions on nutrients: NH_x, PO₄, cations, anions, calcium and magnesium: Msat_{SNHx,KNHx,OHO}, Msat_{SPO4,KPO4,BIO}, Msat_SCAT,KCAT, Msat_SAN,KAN, Msat_SCa,KCa, Msat_SMg,KMg Bell shape inhibition function on pH: BellinhpH
OHO growth with N₂O	Reduction N₂O→N₂ Inhibited by NO Kinetic parameters µ_OHO: Maximum specific growth rate of OHOs η_OHO,N2O: Reduction factor for anoxic growth of OHOs on N₂O K_VFA,N2O,AS: Half-saturation of VFA for OHOs on N₂O (AS) K_SB,N2O,AS: Half-saturation of readily biodegradable substrate for OHOs on N₂O (AS) K_N2O,OHO,AS: Half-saturation of N₂O for OHOs (AS) K_{O2,OHO,N2O,AS}: Half-saturation of O₂ for OHOs on N₂O (AS) Ki_{NO,OHO,NO2,AS}: Half-inhibition of NO for OHOs denitrification of N₂O (AS) Kinetic rate limitation/inhibitions Monod saturation function on substrate: Msat_VFA,KVFAor Msat_SB,KSB*Minh_SVFA,KVFA Monod saturation function on electron acceptor: N₂O => Msat_{SN2O,KN2O,OHO} Monod inhibition function on O₂: Minh_{SO2,KO2,OHO,NO2} Monod inhibition function on NO: Minh_{SNO,KiNO,OHO,N2O} Monod saturation functions on nutrients: NH_x, PO₄, cations, anions, calcium and magnesium: Msat_{SNHx,KNHx,OHO}, Msat_{SPO4,KPO4,BIO}, Msat_SCAT,KCAT, Msat_SAN,KAN, Msat_SCa,KCa, Msat_SMg,KMg Bell shape inhibition function on pH: BellinhpH

Biological processes	Concepts description
AOB NH_x oxidation to NH₂OH	Requires O₂. The Monod term in the original model (Pocquet et al, 2016) is on free ammonia. It has been replaced by a term on total ammonia for more stability of the model under normal pH range. Kinetic parameters The maximum rate is the maximum specific growth rate of AOBs divided by the AOB yield (µ_AOB/Y_AOB) to keep the same substrate utilization rate than for the AOB growth process (AOB NH₂OH oxidation to NO process) µ_AOB: Maximum specific growth rate of AOBs K_{O2,NHx,AOB,AS}: Half-saturation of O₂ for NH_x oxydation by AOBs (AS) K_{O2,NHx,AOB,Sidestream}: Half-saturation of O₂ for NH_x oxydation by AOBs (Sidestream) K_{NHx,NH2OH,AOB,AS}: Half-saturation of NH_x to NH₂OH for AOBs (AS) Kinetic rate limitation/inhibitions Monod saturation functions on electron acceptor: O₂ => Msat_{SO2,KO2,NHx,AOB} Monod saturation functions on electron donor: NHx => Msat_{SNHx,KNHx,NH2OH,AOB}
AOB NH₂OH oxidation to NO	Requires O₂. This is the AOB growth process. Kinetic parameters µ_AOB: Maximum specific growth rate of AOBs K_{O2,NH2OH,AOB,AS}: Half-saturation of O₂ for NH₂OH oxidation by AOBs (AS) K_{O2,NH2OH,AOB,sidestream}: Half-saturation of O₂ for NH₂OH oxidation by AOBs (Sidestream) K_NH2OH,AOB,AS: Half-saturation of NH₂OH for AOBs (AS) K_{NHx, AOB,AS}: Half-saturation of NH_x for AOBs (AS) Kinetic rate limitation/inhibitions Monod saturation functions on electron donor: NH₂OH => Msat_{SNH2OH,KNH2OH,AOB} Monod saturation functions on electron acceptor: O₂ => Msat_{SO2,KO2,NH2OH,AOB} Logistic switch on bicarbonates, pH dependent: LogsatpH_CO2,AOB Monod saturation functions on nutrients: NH_x, PO₄, cations, anions, calcium and magnesium: Msat_{SNHx,KNHx,AOB}, Msat_{SPO4,KPO4,BIO}, Msat_SCAT,KCAT, Msat_SAN,KAN, Msat_SCa,KCa, Msat_SMg,KMg Bell shape inhibition function on pH: BellinhpH
AOB NO oxidation to NO2	Requires O₂. Kinetic parameters The maximum rate is the maximum specific growth rate of AOBs divided by the AOB yield (µ_AOB/Y_AOB) to keep the same substrate utilization rate than for the AOB growth process (AOB NH₂OH oxidation to NO process) µ_AOB: Maximum specific growth rate of AOBs K_{O2,NH2OH,AOB,AS}: Half-saturation of O₂ for NH₂OH oxidation by AOBs (AS) K_{O2,NH2OH,AOB,sidestream}: Half-saturation of O₂ for NH₂OH oxidation by AOBs (Sidestream) K_{NO,NO2,AOB,AS}: Half-saturation of NO to NO₂ for AOBs (AS) Kinetic rate limitation/inhibitions Monod saturation functions on electron acceptor: O₂ => Msat_{SO2,KO2,NH2OH,AOB} Monod saturation functions on electron donor: NO => Msat_{SNO,KNO,NO2,AOB}
AOB NO reduction to N2O (NN pathway)	Direct pathway of N₂O production (or NN pathway): NO reduction to N₂O by the enzyme “Nor” coupled with the hydroxylamine oxidation to nitrite Kinetic parameters The maximum rate is the maximum specific growth rate of AOBs divided by the AOB yield (µ_AOB/Y_AOB), reduced by a reduction factor for NO reduction to N₂O by AOBs (NN pathway) (ƞ_AOB,NO,N2O) µ_AOB: Maximum specific growth rate of AOBs ƞ_AOB,NO,N2O: Reduction factor for NO reduction to N₂O by AOBs (NN pathway) K_NH2OH,AOB,AS: Half-saturation of NH₂OH for AOBs (AS) K_{NO,N2O,AOB,AS}: Half-saturation of NO to N2O for AOBs (AS) Kinetic rate limitation/inhibitions Monod saturation functions on electron donor: NH2OH => Msat_{SNH2OH,KNH2OH,AOB} Monod saturation functions on electron acceptor: NO => Msat_{SNO,KNO,N2O,AOB}
AOB HNO2 reduction to N2O (ND pathway)	Indirect pathway of N₂O production (or ND pathway): HNO₂ reduction to N₂O coupled with NH₂OH oxidation to nitrite. Originally this ND pathway considers 2 steps: NO₂ reduction to NO (NirK enzyme), then NO reduction to N₂O (Nor enzyme) (Mampaey et al., 2013; Ni et al., 2011). These two processes are merged in this single one to avoid the NO loop with the AOB NO oxidation to NO₂ process (Pocquet et al., 2016). the Haldane-type term on O2 is replaced with a simple Monod inhibition term. This results in a limitation of this process under anoxic conditions with hydroxylamine, what is observed by some authors (Domingo-Félez and Smets, 2016) Stoichiometric parameters Y_AOB: Yield of AOBs on NH_x Kinetic parameters The maximum rate is the maximum specific growth rate of AOBs divided by the AOB yield (µ_AOB/Y_AOB), reduced by a reduction factor for HNO₂ reduction to N₂O by AOBs (ND pathway) (ƞ_AOB,NO2,N2O) µ_AOB: Maximum specific growth rate of AOBs ƞ_AOB,NO2,N2O: Reduction factor for HNO2 reduction to N2O by AOBs (ND pathway) K_NH2OH,AOB,AS: Half-saturation of NH₂OH for AOBs (AS) K_HNO2,AOB,AS: Half-saturation of HNO₂ for AOBs (AS) K_iO2,AOB,AS: Half-inhibition of O₂ for N₂O production by AOBs (AS) Kinetic rate limitation/inhibitions Monod saturation functions on electron donor: NH₂OH => Msat_{SNH2OH,KNH2OH,AOB} Monod saturation functions on electron acceptor: HNO₂ => Msat_{SHNO2,KHNO2,AOB} This process contribution increase at low DO: Monod inhibition term on O₂ => Minh_SO2,KiO2,AOB

Rules	pH Specification (option available in configure mode for influents)	Input variables	Variables solved	Targets
pHSet	Input pH and alkalinity	pH S_ALK	S_CAT,NET IS S_CO2	Chargebalanceerror ISerror SCO2error
NonpHSet	Input ions and CO₂	S_CO2 S_CAT S_AN	pH IS	Chargebalanceerror ISerror

Name	Value	Unit
IS	9.97E-05	ISunit
S_CO2	0.53	mg TIC/L
S_ALK	0.5	mg CaCO₃/L
S_{CAT_NET}	-0.090	mmol/L
S_CAT	0.00	mmol/L
S_AN	0.090	mmol/L
S_NHx	1.4	g N/m³
[NH₄⁺]	0.100	mmol/L
[NH₃]	0.00039	mmol/L
chargebalanceerror	4E-15	eq.L^-1
ISerror	2E-15	ISunit
SCO2error	-2E-10	mg CaCO₃/L

Name	Value	Unit
pH	9.79	pHunit
IS	2.89E-05	ISunit
S_CO2	0	mg TIC/L
S_ALK	5.0	mg CaCO₃/L
S_CAT	0.000	mmol/L
S_AN	0.000	mmol/L
S_NHx	1.4	g N/m³
[NH₄⁺]	0.029	mmol/L
[NH₃]	0.071	mmol/L
chargebalanceerror	-2E-13	eq.L^-1
ISerror	-2E-13	ISunit
SCO2error	nd	mg CaCO₃/L

Symbol	Name	Formula
X_CaCO3	Calcium carbonate (CaCO₃)	CaCO₃
X_STR	Struvite (STR)	MgNH₄PO₄ * 6H₂O
X_BSH	Brushite	CaHPO₄ * 2H₂O
X_ACP	Amorphous calcium phosphate (ACP)	Ca₃(PO₄)₂ * 4H₂O
X_Vivi	Vivianite (Vivi)	Fe₃(PO₄)₂* 8H₂O
X_FeS	Iron sulfide (FeS) (only in Sumo2S)	FeS

Y_AMX,NO2	Yield of AMX on NO₂	1.32	mol NO2/mol NH4
Y_AMX,NO3	Yield of AMX on NO₃	0.26	mol NO3/mol NH4

2	r2	OHO growth on VFAs, NO₃
3	r3	OHO growth on VFAs, NO₂
4	r4	OHO growth on VFAs, NO
5	r5	OHO growth on VFAs, N₂O
7	r7	OHO growth on S_B, NO₃
8	r8	OHO growth on S_B, NO₂
9	r9	OHO growth on S_B, NO
10	r10	OHO growth on S_B, N₂O

	Cations and anions calculation revised	Type(Equilibrium)
Symbol	Name	Expression
S_CAT	Cations concentration	If((S_CAT_0 + S_CAT,NET) > 0; S_CAT_0 + S_CAT,NET; S_CAT_0)
S_AN	Anions concentration	If((S_CAT_0 + S_CAT,NET) > 0; S_AN_0; S_AN_0 - S_CAT,NET)

Symbol	Name	Default	Unit
S_Fe_M	Fe(OH)₃	0.0	mg.L^-1
G	Average velocity gradient in mixing tank	50	s^-1
K_G	Half saturation coefficient for G value	10	s^-1

HFO,H => HFO,L	non-used active hydrous aluminium oxide, high surface is turned into active hydrous aluminium oxide, low surface
HFO,H,P=>HFO,H,P,old	P-bound hydrous aluminium oxide, high surface is turned into aged P-bound hydrous aluminium oxide, high surface

¶ Introduction

¶ Components in Sumo models

¶ Biological processes

¶ BOD removal

¶ Biomasses involved in BOD removal

¶ Ordinary heterotrophic organisms, XOHO

¶ Anoxic methanol utilizers, XMEOLO

¶ Nitrogen removal

¶ Nitrification model

¶ Biomasses involved in nitrification

¶ Aerobic nitrifying organisms, XNITO

¶ Aerobic ammonia oxidizers, XAOB

¶ Nitrite oxidizers, XNOB

¶ Anammox organisms, XAMX

¶ Impact of operating conditions and design on nitrification

¶ Sidestream and mainstream nitrification

¶ Measuring specific growth rate

¶ Denitrification model

¶ Impact of operating conditions and design on denitrification

¶ Model specifications under anoxic conditions

¶ Key model details of the denitrification process

¶ Phosphorus removal

¶ Enhanced biological phosphorus removal (EBPR) processes

¶ Biomass involved in BioP: Carbon storing organisms, XCASTO

¶ Chemical phosphorus removal

¶ Anaerobic digestion processes

¶ Methanogenesis

¶ Acidoclastic methanogens, XAMETO

¶ Hydrogenotrophic methanogens, XHMETO

¶ Biological conversions

¶ Flocculation

¶ Hydrolysis

¶ Ammonification

¶ Biological phosphorus conversion

¶ Endogenous products conversion

¶ Anaerobic methanol conversion

¶ Nitrate/Nitrite assimilative reduction

¶ Photosynthesis processes

¶ Mechanisms of focus models

¶ Sumo2C

¶ Carbon absorption heterotroph organisms, XAHO

¶ Sumo2S

¶ General sulfur and iron model

¶ FeS precipitation and iron interaction

¶ Reduction of Fe3+, sulfide as electron donor

¶ Reduction of Fe3+, organic matter as electron donor

¶ FeS precipitation

¶ Oxidation of Fe2+

¶ Reduction of sulfate

¶ Oxidation of sulfide

¶ Biological oxidation

¶ Chemical oxidation

¶ Biomasses involved in sulfur reactions

¶ Acidoclastic sulfate-reducing organisms, XASRO

¶ Hydrogenotrophic sulfate-reducing organisms, XHSRO

¶ Sulfur-oxidizing organisms, XSOO

¶ Sumo4N

¶ 4-step denitrification: Anoxic growth of OHOs from Hiatt&Grady (2008, only for OHO denitrification on SB and SVFA)

¶ 4-step AOB nitrification: From Pocquet et al. 2016

¶ Physico-chemical processes

¶ pH and alkalinity

¶ Components definition

¶ Speciation expressions

¶ Dissociation and acidity constants

¶ Speciation calculation

¶ Charge balance, ionic strength and alkalinity calculation

¶ Charge balance calculation

¶ Ionic strength calculation

¶ Alkalinity calculation

¶ Resolution of charge balance, ionic strength and alkalinity

¶ Input pH and alkalinity (pH Set)

¶ Input ions and CO2 (NonpHSet)

¶ Chemical phosphorus removal with metal salts addition (iron or aluminium)

¶ HFO precipitation

¶ Phosphorus binding on HFO

¶ Phosphorus desorption

¶ HFO aging

¶ Phosphorus dissolution

¶ Chemical precipitation reactions

¶ Ordinary heterotrophic organisms, X_OHO

¶ Anoxic methanol utilizers, X_MEOLO

¶ Aerobic nitrifying organisms, X_NITO

¶ Aerobic ammonia oxidizers, X_AOB

¶ Nitrite oxidizers, X_NOB

¶ Anammox organisms, X_AMX

¶

Key model details of the denitrification process

¶ Biomass involved in BioP: Carbon storing organisms, X_CASTO

¶ Acidoclastic methanogens, X_AMETO

¶ Hydrogenotrophic methanogens, X_HMETO

¶ Carbon absorption heterotroph organisms, X_AHO

¶ Reduction of Fe³⁺, sulfide as electron donor

¶ Reduction of Fe³⁺, organic matter as electron donor

¶ Oxidation of Fe²⁺

¶ Acidoclastic sulfate-reducing organisms, X_ASRO

¶ Hydrogenotrophic sulfate-reducing organisms, X_HSRO

¶ Sulfur-oxidizing organisms, X_SOO

¶ 4-step denitrification: Anoxic growth of OHOs from Hiatt&Grady (2008, only for OHO denitrification on S_B and S_VFA)

¶ Input ions and CO₂ (NonpHSet)