(algorithm4)=
# Algorithm 4. Agglomeration: Article 3 Compliance

## Overview

This procedure checks whether an agglomeration ≥ 2000 p.e. has an adequate wastewater collection system by deadline date.

* If **<2000 p.e.** → not relevant (**NR**).
* If deadline not reached → pending (**PD**).
* If deadline reached → several branches:
  * Very small untreated load → compliant (**C**).
  * Too much untreated load → non-compliant (**NC**).
  * In-between → compliant but flagged with extra QC:
    * **QC** when a load is addressed by IAS (<=2% and <=1000 p.e.)
    * **AddQC** when significant load is addressed by IAS (>2% or >1000 p.e. of the generated load of the agglomeration)

## Simplified Logic

### 1. Low load case

* If **aggGenerated < 2000** →
  * compliance = **NR** for Art 3, 4, 5, 6
  * (`alg4_exit_leaf = 04-01`)

### 2. Agglomeration ≥ 2000

#### Deadline of Article 3 passed or unknown (`aggDateArt3 <= repSituationAt`)

1. If
   * (**wastewater not collected + wastewater treated in IAS**) ≤ 2000 p.e.
   * AND (**% not collected + % treated in IAS**) ≤ 2%  
     →
   * compliance = **C**
   * (`alg4_exit_leaf = 04 02`)

2. Else:
   * If (**% not collected > 2 OR sum not collected > 2000 p.e.**) →
     * compliance = **NC**
     * (`alg4_exit_leaf = 04-05`)

   * Else:
     * If (**wastewater treated in IAS > 2% OR sum treated in IAS > 1000 p.e.**) →
       * compliance = **C + AddQC**
       * (`alg4_exit_leaf = 04-06`)

     * Else →
       * compliance = **C + QC**
       * (`alg4_exit_leaf = 04-03`)

#### Deadline of Article 3 not yet passed

* compliance = **PD**
* (`alg4_exit_leaf = 04-04`)

## Decision Tree

```{mermaid}
graph TB
ROOT["Check agglomeration generated load"]

ROOT --> L1(("< 2000p.e")) --- LT2000["Compliance art3 = NR Compliance art4 = NR Compliance art5 = NR Compliance art6 = NR"]
LT2000 -.- ID01(["04-01"])

ROOT --> L2((">= 2000p.e")) --- GE2000["Deadline of Article 3 is before or equal to reporting reference date"]

GE2000 --- N1((NO)) --- ART3_PD["Compliance art3 = PD"]
ART3_PD -.- ID04(["04-04"])

GE2000 --- Y1((YES)) --- COND1["If ((sum of wastewater not collected in collecting system and not addressed by IAS) + sum of wastewater treated in IAS) <= 2000p.e AND ((% of wastewater not collected in collecting system and not addressed by IAS) + % of wastewater treated in IAS) <= 2%"]

COND1 --- Y2((YES)) --- ART3_C["Compliance art3 = C"]
ART3_C -.- ID02(["04-02"])

COND1 --- N2((NO)) --- COND2["If (sum of wastewater not collected in collecting system and not addressed by IAS) > 2000p.e OR (% of wastewater not collected in collecting system and not addressed by IAS) > 2%"]

COND2 --- Y3((YES)) --- ART3_NC["Compliance art3 = NC"]
ART3_NC -.- ID05(["04-05"])

COND2 --- N3((NO)) --- COND3["If addressed by IAS >2% or >1000pe"]

COND3 --- Y4((YES)) --- ART3_C_ADDQC["Compliance art3 = C Additionnal compliance art3: AddQC"]
ART3_C_ADDQC -.- ID06(["04-06"])

COND3 --- N4((NO)) --- ART3_C_QC["Compliance art3 = C Additionnal compliance art3= QC"]
ART3_C_QC -.- ID03(["04-03"])

%% Styles
classDef reference stroke:#00a2ff,color:#00a2ff;
classDef yesBox fill:#4CAF50,color:white,stroke:#2E7D32;
classDef noBox fill:#F44336,color:white,stroke:#C62828;
classDef routeBox fill:#E0E0E0,color:black,stroke:#9E9E9E;

%% Class Assignments
class ID01,ID02,ID03,ID04,ID05,ID06 reference;
class Y1,Y2,Y3,Y4 yesBox;
class N1,N2,N3,N4 noBox;
class L1,L2 routeBox;
```

## Pseudocode

```{dropdown} Show python code
```python
if aggGenerated < 2000: 
    setCompliance(agg_id, art3="NR", art4="NR", art5="NR", art6="NR", exit="04-01") 
 
else: 
    if aggDateArt3 <= repSituationAt: 
        # deadline reached 
        untreated_load = (aggGenerated * aggPercWithoutTreatment) / 100 
        ias_load = (aggGenerated * aggC2) / 100 
 
        if untreated_load + ias_load <= 2000 and (aggPercWithoutTreatment + aggC2) <= 2: 
            setCompliance(agg_id, art3="C", exit="04-02") 
 
        elif untreated_load > 2000 or aggPercWithoutTreatment > 2: 
            setCompliance(agg_id, art3="NC", exit="04-05") 
 
        else: 
            # borderline, check IAS 
            if aggC2 > 2 or ias_load > 1000: 
                setCompliance(agg_id, art3="C", add_art3="AddQC", exit="04-06") 
            else: 
                setCompliance(agg_id, art3="C", add_art3="QC", exit="04-03") 
 
    else: 
        # deadline not reached 
        setCompliance(agg_id, art3="PD", exit="04-04") 
```