Wastewater type: Thiourea-containing wastewater
Target compound: Thiourea, CS(NH2)2
Technology: electrochemical oxidation
Test scale: Laboratory module
Treatment time: 1 hour
Primary targets: Thiourea and COD
1. TREATMENT CHALLENGE
Thiourea-containing wastewater presents a dual treatment challenge: removal of the specific sulfur- and nitrogen-containing organic compound and reduction of the overall oxidizable organic load measured as COD.
The supplied laboratory test evaluated whether electro-oxidation could rapidly destroy thiourea while simultaneously lowering COD.
2. Electro Oxidation Treatment Approach
An electrochemical oxidation trial module treated the wastewater for one hour. Influent and effluent COD and thiourea concentrations were measured, together with total electricity consumption per cubic meter of wastewater.
Operating parameters such as pH, current/current density, electrode substrate, electrode area, temperature, flow rate and conductivity were not stated in the worksheet.
3. REPORTED RESULTS
Parameter Influent Effluent Reported Removal
COD 8,000 mg/L 1,040 mg/L 87%
Thiourea, CS(NH2)2 4,580 mg/L 255 mg/L 94.4%
Energy consumption — — 1.1 kWh/m3
Treatment time — — 1 hour
The reported thiourea reduction corresponds closely to the concentration change from 4,580 mg/L to 255 mg/L.
4. PERFORMANCE INTERPRETATION
Within one hour, BDD electro-oxidation removed 94.4% of thiourea and reduced COD by 87%.
The higher thiourea removal percentage relative to total COD suggests that the target compound was oxidized very effectively, while some oxidizable organic material or oxidation intermediates remained in the treated water. Additional analytical data would be required to identify the residual COD species.
The combination of rapid target-compound destruction and major COD reduction makes this test particularly relevant for concentrated specialty-chemical wastewater where a specific refractory compound must be controlled.
5. INDUSTRIAL RELEVANCE
Electro-oxidation could be considered for:
– Direct destruction of thiourea in concentrated batch wastewater.
– Pretreatment before biological treatment.
– Final polishing where thiourea-specific limits apply.
– Treatment of difficult specialty-chemical side streams.
– Hybrid systems combining BDD with downstream biological, adsorption or membrane treatment.
6. ENGINEERING NOTES AND DATA LIMITATIONS
The very low reported electricity consumption of 1.1 kWh/m3 is retained exactly as provided in the source worksheet. Because current, electrode area, reactor volume and other operating parameters are not provided, this value should be confirmed during engineering validation before being used for full-scale operating-cost estimates.
No data are provided for sulfur species, nitrogen transformation products, toxicity, by-products or mineralization beyond COD.
7. KEY TAKEAWAY
A one-hour BDD laboratory test reduced thiourea from 4,580 mg/L to 255 mg/L (94.4% removal) and COD from 8,000 mg/L to 1,040 mg/L (87% removal), with reported energy consumption of 1.1 kWh/m3.