Algorithm 9. Agglomeration: Article 5 only#

Overview#

Determine compliance of an agglomeration with Article 5 of the 1991 urban wastewater treatment directive, which focuses on nitrogen (N) and phosphorus (P) removal but also other more stringent parameters such as disinfection or specific treatments required for the purpose of the implementation of other EU Directives, and treatment stringency.

Compliance depends on:

  • Agglomeration size.

  • Applicability of Article 5(4).

  • RCA removal rates.

  • Load discharged without treatment.

  • Load entering treatment plants.

  • Treatment level of connected plants.

  • Deadline for Article 5 relative to reporting year.

Simplified Logic#

1. Agglomeration < 10,000 p.e.#

  • → NR

  • (exit_leaf = 09-01)

2. Agglomeration ≥ 10,000 p.e.#

  • If Art.5(4) applies and N & P removal ≥ 75% →

    • C

    • (exit_leaf = 09-02)

  • Else, if Art.5(4) applies and N or P removal < 75% →

    • NC

    • (exit_leaf = 09-13)

  • Else, if no more stringent treatment required →

    • NR

    • (exit_leaf = 09-03)

3. Check load discharged without treatment#

If ≤ 2% and ≤ 2000 p.e.:#

  • If any plant NC and load entering NC > 1% & ≥ 2000 →

    • NC

    • (exit_leaf = 09-06)

  • Else, if any plant PD →

    • PD

    • (exit_leaf = 09-07)

  • Else, if any plant C →

    • C

    • (exit_leaf = 09-08)

  • Else →

    • NR

    • (exit_leaf = 09-09)

Else (load > thresholds):#

  • Check Article 5 deadline vs reporting date:

    • If aggDateArt5 ≤ repSituationAt →

      • NC

      • (exit_leaf = 09-04 or 09-11)

    • If aggDateArt5 > repSituationAt →

      • PD

      • (exit_leaf = 09-05 or 09-12)

Decision Tree#

        graph TB
ROOT["Agglomeration is <10.000pe"]

%% Left Branch
ROOT --> Y1((YES)) --- C_NR_01["Compliance Article 5 = NR"]
C_NR_01 -.- ID01(["09-01"])

%% Main NO Branch
ROOT --> N1((NO)) --- ART5["Article 5(4) applies"]

%% Art 5(4) YES
ART5 --- Y2((YES)) --- RCA["rca removal rate N<75% and removal rate P<75%"]

RCA --- Y3((YES)) --- C_NC_13["Compliance Article 5 = NC"]
C_NC_13 -.- ID13(["09-13"])

RCA --- N2((NO)) --- C_C_02["Compliance Article 5 = C"]
C_C_02 -.- ID02(["09-02"])

%% Art 5(4) NO
ART5 --- N3((NO)) --- MORE_STR["At least one plant has treatment required = more stringent"]

%% More stringent NO
MORE_STR --- N4((NO)) --- C_NR_03["Compliance Article 5 = NR"]
C_NR_03 -.- ID03(["09-03"])

%% More stringent YES
MORE_STR --- Y4((YES)) --- LOAD_DIS["Load discharged without treatment <=2% of generated load and <= 2000p.e"]

%% Load discharged NO
LOAD_DIS --- N5((NO)) --- DL5A["Deadline of article 5 is before or equal to reporting reference year"]

DL5A --- Y5((YES)) --- C_NC_04["Compliance article 5=NC"]
C_NC_04 -.- ID04(["09-04"])

DL5A --- N6((NO)) --- C_PD_05["Compliance article 5=PD"]
C_PD_05 -.- ID05(["09-05"])

%% Load discharged YES
LOAD_DIS --- Y6((YES)) --- SUM_LOAD["(Sum of load entering for all plants with treatment in place = primary or secondary or NI or compliance for article 5 = NC) <=1% and < 2000p.e."]

%% Sum load YES
SUM_LOAD --- Y7((YES)) --- COND_NC["At least one compliance for Article 5 = NC AND (Sum of load entering for all plants with compliance for article 5 = NC) >1% or >= 2000p.e."]

COND_NC --- Y8((YES)) --- C_NC_06["Compliance article 5 = NC"]
C_NC_06 -.- ID06(["09-06"])

COND_NC --- N7((NO)) --- COND_PD["At least one compliance for Article 5 = PD"]

COND_PD --- Y9((YES)) --- C_PD_07["Compliance article 5 =PD"]
C_PD_07 -.- ID07(["09-07"])

COND_PD --- N8((NO)) --- COND_C["At least one compliance for Article 5 = C"]

COND_C --- Y10((YES)) --- C_C_08["Compliance article 5 = C"]
C_C_08 -.- ID08(["09-08"])

COND_C --- N9((NO)) --- C_NR_09["Compliance article 5 = NR"]
C_NR_09 -.- ID09(["09-09"])

%% Sum load NO
SUM_LOAD --- N10((NO)) --- DL5B["Deadline of article 5 is <> (null or NR or NI or ?)"]

DL5B --- N11((NO)) --- C_NR_10["Compliance article 5=NR"]
C_NR_10 -.- ID10(["09-10"])

DL5B --- Y11((YES)) --- DL5C["Deadline of article 5 is before or equal to reporting reference year"]

DL5C --- Y12((YES)) --- C_NC_11["Compliance article 5=NC"]
C_NC_11 -.- ID11(["09-11"])

DL5C --- N12((NO)) --- C_PD_12["Compliance article 5=PD"]
C_PD_12 -.- ID12(["09-12"])


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

%% Class Assignments
class ID01,ID02,ID03,ID04,ID05,ID06,ID07,ID08,ID09,ID10,ID11,ID12,ID13 reference;
class Y1,Y2,Y3,Y4,Y5,Y6,Y7,Y8,Y9,Y10,Y11,Y12 yesBox;
class N1,N2,N3,N4,N5,N6,N7,N8,N9,N10,N11,N12 noBox;

Pseudocode#

Show python code
 
A = (aggC1 * aggGenerated) * 0.01 
 
if aggGenerated < 10000: 
    return "NR", "09-01" 
 
if np_54 > 0: 
    if remN_remP_75 > 0: 
        return "C", "09-02" 
    else: 
        return "NC", "09-13" 
 
if np_treat_more_str == 0: 
    return "NR", "09-03" 
 
# Check load discharged without treatment 
if (aggPercWithoutTreatment <= 2.0 and (aggGenerated * aggPercWithoutTreatment * 0.01) <= 2000): 
    if np_5NC > 0 and sp_load_enter_5NC > A * 0.01 and sp_load_enter_5NC >= 2000: 
        return "NC", "09-06" 
    elif np_5PD > 0: 
        return "PD", "09-07" 
    elif np_5C > 0: 
        return "C", "09-08" 
    else: 
        return "NR", "09-09" 
        
else: 
    # Check Article 5 deadline 
    if aggDateArt5 is None: 
        return "NR", "09-10" 
    elif aggDateArt5 <= repSituationAt: 
        return "NC", "09-04"  # or 09-11 depending on branch 
    else: 
        return "PD", "09-05"  # or 09-12 depending on branch