Samuelsson Oscar, Björk Anders, Zambrano Jesús, Carlsson Bengt
IVL Swedish Environmental Research Institute, Stockholm, Sweden E-mail:
Mälardalens Högskola, Västerås, Sweden.
Water Sci Technol. 2018 Oct;78(5-6):1034-1044. doi: 10.2166/wst.2018.350.
Biofilm fouling is known to impact the data quality of sensors, but little is known about the exact effects. We studied the effects of artificial and real biofilm fouling on dissolved oxygen (DO) sensors in full-scale water resource recovery facilities, and how this can automatically be detected. Biofilm fouling resulted in different drift direction and bias magnitudes for optical (OPT) and electrochemical (MEC) DO sensors. The OPT-sensor was more affected by biofilm fouling compared to the MEC-sensor, especially during summer conditions. A bias of 1 mg/L was detected by analysing the impulse response (IR) of the automatic air cleaning system in the DO sensor. The IR is an effect of a temporal increase in DO concentration during the automatic air cleaning. The IRs received distinct pattern changes that were matched with faults including: biofilm fouling, disturbances in the air supply to the cleaning system, and damaged sensor membrane, which can be used for fault diagnosis. The results highlight the importance of a condition-based sensor maintenance schedule in contrast to fixed cleaning intervals. Further, the results stress the importance of understanding and detecting bias due to biofilm fouling, in order to maintain a robust and resource-efficient process control.
已知生物膜污染会影响传感器的数据质量，但具体影响尚不清楚。我们研究了人工和实际生物膜污染对全尺寸水资源回收设施中溶解氧（DO）传感器的影响，以及如何自动检测这种影响。生物膜污染导致光学（OPT）和电化学（MEC）溶解氧传感器出现不同的漂移方向和偏差幅度。与MEC传感器相比，OPT传感器受生物膜污染的影响更大，尤其是在夏季条件下。通过分析溶解氧传感器中自动空气清洁系统的脉冲响应（IR），检测到1 mg/L的偏差。IR是自动空气清洁过程中溶解氧浓度随时间增加的一种效应。所获得的IR呈现出明显的模式变化，这些变化与包括生物膜污染、清洁系统空气供应干扰以及传感器膜损坏等故障相匹配，可用于故障诊断。结果凸显了基于状态的传感器维护计划相对于固定清洁间隔的重要性。此外，结果强调了理解和检测生物膜污染导致的偏差的重要性，以便维持稳健且资源高效的过程控制。
