Algorithm 1a. UWWTP: Treatment required#

Overview#

First decision step in determining what wastewater treatment level is legally “required” for a given plant, based on:

How big the plant’s connected agglomerations are (population equivalent load)
What type of water body the discharge goes into (e.g., freshwater, coastal, sensitive area)
Special deadlines for compliance to one or more articles of the 1991 UWWTD (Articles 3, 4, 5)
Whether the plant is active and connected to an agglomeration

Simplified Logic#

1. Low load case#

If load < 2000 →
- result_required = Appropriate
- exit_leaf = 01-A-02

2. If receiving area dependent cases#

If receiving area in {SA, CSA, A54, A58, A58523, A523, A5854}#

Call Algorithm 1b

If receiving area = NA#

If water in {ES, FW, LF} →
- result_required = Secondary
- exit_leaf = 01-A-03
Else if water in {LC, CW} →
- If load < 10000 →
  - result_required = Appropriate
  - exit_leaf = 01-A-04
- Else →
  - result_required = Secondary
  - exit_leaf = 01-A-05

If receiving area = LSA#

If water in {ES, LF} →
- If 2000 ≤ load ≤ 10000 →
  - result_required = Primary
  - exit_leaf = 01-A-06
- Else →
  - result_required = Secondary
  - exit_leaf = 01-A-07
Else if water in {LC, CW} →
- If load ≥ 150000 →
  - result_required = Secondary
  - exit_leaf = 01-A-08
- Else if load ≥ 10000 →
  - result_required = Primary
  - exit_leaf = 01-A-09
- Else →
  - result_required = Appropriate
  - exit_leaf = 01-A-10

Decision Tree#

        graph TB
ROOT["If number of discharge points > 0 (except BG and HR in 2018) and at least one agglomeration is connected"]

ROOT --> Y1((YES)) --- B1["If biggest agglomeration generated load < 2000p.e"]
ROOT --> N1((NO)) --- B2["Required = NR"]
B2 -.- ID01(["01-A-01"])

B1 --- Y2((YES)) --- C1["Required = Appropriate"]
C1 -.- ID02(["01-A-02"])

B1 --- N2((NO)) --- C2["Check receiving area type: If number of discharge points > 1 choose the most constraining (SA, CSA, A58>NA>LSA), if number of discharge points =0, use NA of type FW"]

C2 --- TYPE1["SA, CSA, A54 and/or A58"]
C2 --- TYPE2["NA"]
C2 --- TYPE3["LSA"]

%% SA, CSA, A54 branch
TYPE1 --- ALG1["see separate algorithms 1b and 1c"]

%% NA branch
TYPE2 --- WB1["Check waterbody type"]
WB1 --- WB1_1["ES, FW or LF"]
WB1 --- WB1_2["LC or CW"]

WB1_1 --- REQ1["Required = Secondary"]
REQ1 -.- ID03(["01-A-03"])

WB1_2 --- LOAD1["If biggest agglomeration generated load < 10000p.e"]
LOAD1 --- Y3((YES)) --- REQ2["Required = Appropriate"]
REQ2 -.- ID04(["01-A-04"])
LOAD1 --- N3((NO)) --- REQ3["Required = Secondary"]
REQ3 -.- ID05(["01-A-05"])

%% LSA branch
TYPE3 --- WB2["Check waterbody type"]
WB2 --- WB2_1["ES or LF"]
WB2 --- WB2_2["LC or CW"]

WB2_1 --- LOAD2["If biggest agglomeration generated load >= 2000 and <= 10000p.e"]
LOAD2 --- Y4((YES)) --- REQ4["Required = Primary"]
REQ4 -.- ID06(["01-A-06"])
LOAD2 --- N4((NO)) --- REQ5["Required = Secondary"]
REQ5 -.- ID07(["01-A-07"])

WB2_2 --- LOAD3["If biggest agglomeration generated load >= 150 000p.e"]
LOAD3 --- Y5((YES)) --- REQ6["Required = Secondary"]
REQ6 -.- ID08(["01-A-08"])
LOAD3 --- N5((NO)) --- LOAD4["If biggest agglomeration generated load >= 10000p.e"]

LOAD4 --- Y6((YES)) --- REQ7["Required = Primary"]
REQ7 -.- ID09(["01-A-09"])
LOAD4 --- N6((NO)) --- REQ8["Required = Appropriate"]
REQ8 -.- ID10(["01-A-10"])

%% 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 reference;
class Y1,Y2,Y3,Y4,Y5,Y6 yesBox;
class N1,N2,N3,N4,N5,N6 noBox;

Algorithm 1a. UWWTP: Treatment required#

Overview#

Simplified Logic#

1. Low load case#

2. If receiving area dependent cases#

If receiving area in {SA, CSA, A54, A58, A58523, A523, A5854}#

If receiving area = NA#

If receiving area = LSA#

Decision Tree#

Pseudocode#