Characteristics of corrosion sales and biofilm in aged pipe distribution systems with switching water source

Abstract

Red water has occasionally been observed in the water distribution system of Beijing following a change in the city's water source. Aged cast iron pipes from both affected and unaffected areas were used to establish experimental drinking water distribution systems under different disinfection conditions. The scale deposits formed under different conditions were characterized by X-ray diffraction and scanning electron microscopy, and the bacterial characteristics of the corrosion scales were determined using several molecular methods. The water quality changed less in pipe samples from the unaffected areas than pipes from the affected areas. The pipe samples from the unaffected area included predominantly α-FeOOH, Fe 3 O 4 , and γ-FeOOH, and 24.2% nitrate-reducing bacteria (NRB) were predominant with fewer ironoxidizing bacteria (IOB) being observed. The composition of corrosion products did not exhibit large variation over time although their crystallinity exhibited a slight decrease throughout the duration of the experiment. In contrast, in the pipe samples from the affected, α-FeOOH was the main compound with less γ-FeOOH and Fe 3 O 4 , and 3.3% IOB and 12% NRB with few IRB were observed. However, after transporting surface water containing disinfectants, the Fe 3 O 4 and dense corrosion layer formed, inhibiting the release of iron. Moreover, IRB and NRB became dominant. 22.6% and 34.3% NRB appeared in the pipes after chlorination and chloramination, respectively. The synergistic interaction of IRB and NRB with the corrosion layer played a large role in the release of iron from a cast iron pipe following changes in water quality.

The bacterial community significantly promotes cast iron corrosion in reclaimed wastewater distribution systems

“…Goethite (FeOOH) was identified as the predominant crystalline phase in the corrosion scale of the black layers during the entire experimental period regardless of disinfection methods. This was consistent with previous studies, i.e., goethite was the dominant crystalline phase of the cast iron corrosion scale in both drinking water and reclaimed wastewater distribution pipelines [3, 5]. However, in addition to goethite, magnetite, siderite, lepidocrocite, and calcite were also detected in the cast iron corrosion scales, reported by Wang et al [3] and Zhu et al [10], but these crystalline phases did not appear in our study.…”

“…As shown in Additional file 1: Figure S12, Proteobacteria was the most abundant phylum in all the samples collected from both the yellow layers and black layers, accounting for 53.8 ~ 94.2% of the total bacterial community. This is consistent with the analytical results of the bacterial community in the cast iron corrosion scale of RWDS [8] and DWDS [5], in which Proteobacteria accounted for 56.7% and 64.0% on average. Another interesting phenomenon is that the relative abundance of Proteobacteria in black layers was significantly higher than that in the corresponding yellow layers under different disinfection conditions.…”

Microbiologically Influenced Corrosion of a Pipeline in a Petrochemical Plant

“…From an engineering point of view, the importance of microorganisms' nature is that they have quite a large variation in size. They are also homogeneously distributed, potentially very fast-growing, and they have significantly grown with perceivable restraints in nutrient availability induced by an overpopulating of microorganisms [11,17]. Figure 7 represents a closer look at the biofilm in the outer surface in which microorganisms are distributed.…”

“…MIC, in any form, starts with the formation of a biofilm on the metal substrate [1], within which planktonic cells get attached to the substrate of steel, where they grow, reproduce, consume nutrients and produce an extracellular polymer substance (EPS) in addition to other metabolic products that generate a localized corrosion cell and collectively build the biofilm. It is also well known that microorganisms can use chemicals as nutrient sources and oxidize them [10][11][12]. Microbial corrosion of steel is divided into aerobic and anaerobic corrosions, with the latter known to induce a higher corrosion rate, while the former is associated with a lower corrosion rate [13].…”

Simulation Model of Contamination Threat Assessment in Water Network Using the Epanet Software

“…Previous studies conducted in different operating water supply systems pay attention to the significant effect of the potential safety loss resulting from the failure [9][10][11][12][13][14]. Identification of the dependence between the damage and losses arising from failure is an important aspect of everyday operation water supply system, examples of such studies taking into account the analysis of aforementioned parameters of failure, are among others [15][16][17][18][19][20][21].…”