Modelling chlorine wall decay in a full-scale water supply system

Figures & data

Table 1. Characterization of pipes and flow in the case study

Pipe	Diameter (mm)	L (m)	Min Re(-)	Max Re(-)	Average Re(-)	Min water age (h)	Max water age (h)	Average water age (h)
WTP-1	1500	504	390 000	840 000	626 272	1.2	1.3	1.2
1–2	800	1 446	120 000	368 000	255 527	1.8	2.5	2.0
2-A	400	1 054	0	45 000	23 077	4.1	11	5.8
2–3	800	1 575	120 000	352 000	243 834	2.9	4.4	3.4
3-B	400	2 302	76 000	128 000	114 130	4.6	7.0	5.4
3–4	700	6 828	91 000	329 000	213 976	8.3	12	9.7
4-C	250	1 028	0	132 500	381 166	9.2	16	12
4–5	700	3 748	91 000	294 000	200 225	11	14	13
5-D	100	11	8 000	47 000	22 030	12	16	14
5–6	700	2 720	91 000	294 000	197 367	14	18	16
6-E	350	501	0	409 500	135 423	16	22	18
6–7	450	3 265	139 500	364 500	272 183	16	20	18
7-F	250	249	2 500	130 000	45 577	16	26	20
7-G	450	2 967	130 500	301 500	247 234	17	21	19

Figure 1. Case study scheme

Figure 2. Bulk decay model (2 R) fitting to bottle test results

Figure 3. Correlation plot for the bulk decay model (2 R)

Figure 4. Average chlorine consumption in the system (from the inlet to each monitored node) and percentage of wall decay to overall chlorine demand

Figure 5. Correlation plots for the (a) EXPBIO and the (b) FO models

Figure 6. Measured and simulated chlorine concentration over time at node D by FO and EXPBIO models

Figure 7. Correlation plots for EXPBIO model when parameters A and B vary by a factor of 10

Figure 8. EXPBIO model predictions for node D by (a) decreasing A to 0.01 dm/h, (b) increasing A to 2 dm/h, (c) decreasing B to 5.2 L/mg and (d) increasing B to 7.2 L/mg