As the proof-of-concept study for the 3DPEC, we analysed the detection linearity and LODs for Nimesulide, an anti-inflammatory drug, in real industrial sewage. The 3DPCE allowed to obtain ultralow LOD = 1 nM when the analysis is carried out after industrial sewage 1:10 (v/v) dilution in PBS, a result competitive to, or surpassing, most other state-of-art electrochemical sensors. Consecutive electroanalyses result in gradual electrode fouling by chemisorbed species, where electrode regeneration is possible through repeated activation rather than just washing with PBS. The 3DPEC can be fabricated on demand and used for on-site measurements. Importantly, composite modifications, such as catalytically active composite additives or surface modifications, may further lower the LOD.