Wastewater Treatment Plant Upgrades (WWT / Renseanlæg)¶

Summary¶

Upgrades to municipal wastewater treatment plants to achieve higher N and P removal. Four upgrade levels, each a step up from the previous. Binary decision per plant per level — only one level can be chosen.

Upgrade levels¶

Code	Name	Description
MBN	Biological N removal	Basic biological nitrification/denitrification
MBNDK	MBN + denitrification	Enhanced denitrification
MBNDKF	MBNDK + phosphorus removal	+ chemical P precipitation
MBNDKFe	MBNDKF + extended	Most intensive treatment level

Each level's effects and costs are plant-specific, loaded from .inc files.

Decision variable¶

WWTx(p,j) ∈ {0,1} — binary for each plant p and upgrade level j. Constraint: Sum(j$ww(j), WWTx(p,j)) ≤ 1 — at most one upgrade level per plant.

N Effect¶

WWTNeff(p,"MBN")     = MBNNeff(p)
WWTNeff(p,"MBNDK")   = MBNDKNeff(p)
WWTNeff(p,"MBNDKF")  = MBNDKFNeff(p)
WWTNeff(p,"MBNDKFe") = MBNDKFeNeff(p)

Applied with plant-specific retention:

WWTkr(k) = Σ_p Σ_j (1 − WWTRetention(p)/100) × WWTNeff(p,j) × WWTx(p,j) / 1000

P Effect¶

WWTPeff(p,"MBN")   = MBNPeff(p)
WWTPeff(p,"MBNDK") = MBNDKPeff(p)
WWTPeff(p,"MBNDKF")= MBNDKFPeff(p)
* MBNDKFe P effect not defined in code — check MBNDKFePeff.inc

WWT P reductions aggregate at up_lakecatch level:

WWT_P_Red(up_lakecatch) = Σ_p Σ_j WWTPeff(p,j) × WWTx(p,j)

Cost¶

WWTCost(p,"MBN")     = MBNcost(p)
WWTCost(p,"MBNDK")   = MBNDKcost(p)
WWTCost(p,"MBNDKF")  = MBNDKFcost(p)
WWTCost(p,"MBNDKFe") = MBNDKFecost(p)

All plant-specific from .inc files.

Data sources¶

Costs: MBNCost.inc, MBNDKCost.inc, MBNDKFCost.inc, MBNDKFeCost.inc
N effects: MBNNeff.inc, MBNDKNeff.inc, MBNDKFNeff.inc, MBNDKFeNeff.inc
P effects: MBNPeff.inc, MBNDKPeff.inc, MBNDKFPeff.inc
Retention: WWTRetention.inc
Spatial linkage: Set_p.inc, Set_KP.inc (plant–catchment assignment)

Open questions¶

Is MBNDKFe P effect defined anywhere? Not visible in main .gms.
How many WWT plants are in the model? What is the typical cost and effect range?
WWTRetention(p) — is this the in-stream retention between the plant and the coast, or within the plant itself?