Pretreatment Of Urotropine Production Wastewater By Microelectrolysis/Fenton Process And Iron Sludge Recycling Technology

Urotropine is widely used as fuel in military,pesticide in agriculture,preservative in food,urinary infective agent in medicine,curing agent in paint and so on.It is difficult to be degraded by microbe with its stable chemical structure,resulting in low biodegradability.Therefore,a pretreatment process is usually added to deal with such pharmaceutical wastewater,while a single water treatment technology is difficult to achieve emission standards.In this paper,the degradation of simulated and actual urotropine wastewater was carried out by Fenton method and iron-carbon micro-electrolysis-Fenton method.Besides,the sludge produced by the Fenton process was resourced.?1?Simulating urotropine wastewater was degraded by Fenton reaction.The removal rate of COD and TOC was the highest,reaching 67.4% and 63.2% respectively,under the conditions of H₂O₂/Fe²⁺ of 6,H₂O₂ dosage of 77.7 g/L,p H of 4 and reaction time of 1 h.The urotropine wastewater was degraded by iron-carbon microelectrolysis-Fenton reaction.The iron-carbon micro electrolysis reaction was carried out for 2 h with p H value of 3,and then the Fenton reaction was carried out for 3 h with p H value of 4 and H₂O₂ dosage of 33.3 g/L.The removal rate of COD and TOC reached 65% and 60.3%,resulting in the the highest treatment efficiency and biodegradability.?2?Actual urotropine wastewater was degraded by Fenton reaction.The removal rate of COD and TOC was the highest,reaching 88% and 76% respectively,under the conditions of H₂O₂/Fe²⁺ of 4,H₂O₂ dosage of 15.1 g/L,p H of 7 and reaction time of 2 h.The actual urotropine wastewater was treated by iron-carbon microelectrolysis—Fenton reaction.The iron-carbon micro electrolysis reaction was carried out for 2 h with p H value of 3,and then the Fenton reaction was carried out for 3 h with p H value of 4 and H₂O₂ dosage of 3.2 g/L.The removal rate of COD and TOC reached 92% and 79%.The actual urotropine wastewater treated by the Fenton process and the iron-carbon micro-electrolysis—Fenton has reached the biodegradable range.?3?The main components of Fenton sludge are Fe OOH,organic matter and some inorganic salts.The Fenton sludge was used as a raw material,and after calcination at 400°C for 3 h in a muffle furnace,the iron was present in the form of Fe2O3.And the organic matter has been completely oxidized.At this time,the sludge was used as raw material,and it was calcined in a tube furnace.After calcination at 700°C for 2 h,the sludge was basically in the form of Fe3O4.At this time,Fe3O4 was separated by magnetic separation technique to complete the resource utilization of Fenton sludge.