  Due to the growing amount of data from in-situ sensors in wastewater systems,
it becomes necessary to automatically identify abnormal behaviours and ensure
high data quality. This paper proposes an anomaly detection method based on a
deep autoencoder for in-situ wastewater systems monitoring data. The
autoencoder architecture is based on 1D Convolutional Neural Network (CNN)
layers where the convolutions are performed over the inputs across the temporal
axis of the data. Anomaly detection is then performed based on the
reconstruction error of the decoding stage. The approach is validated on
multivariate time series from in-sewer process monitoring data. We discuss the
results and the challenge of labelling anomalies in complex time series. We
suggest that our proposed approach can support the domain experts in the
identification of anomalies.
