Study On Treatment Of Nitrate-nitrogen Wastewater By Advanced Internal Electrolysis And A New Treatment Of Nitrate-nitrogen Process

Groundwater is always one of the main source of drinking water, but due to vast use of nitrogenous fertilizer and irrationally treatment or utilize of animal dejecta, domestic wastewater and Nitrogen-contained industrial wastewater, nitrate pollution of the groundwater was serious in many countries. In many uranium mines using in-situ leaching technology, the nitrate concentration in groundwater reached up to hundreds of milligram in a litra. For example, at a uranium mines of Xinjiang, the nitrate concentration in groundwater reached up to 770 mg/l, the water quality in the ore-bearing aquifers need to be improved, and required in accordance with the third national ground water quality sanitary standard. Based on the available information, technology effective in economy for high concentration nitrate treatment is lacking at the present time, the application of iron-carbine internal electrolysis methods treat the nitrate-contained wastewater is investigated in this paper.The research of nitrate reduce in the waste groundwater by strengthened internal electrolysis method is reported in this paper, reaction mechanism and basic reaction kinetics was discussed . Through the experiment of strengthened micro-electrolysis process and sedimentation-ion exchange process, a new process combination of Advanced internal Electrolysis-Precipitation-Ion replacement(AEPI) is designed.The results showed that in the best condition (internal electrolysis process: the reaction time is 90 min, carbon particle size is 2mm, dosage of Sulfamic Acid reagent is 5g/L, iron-carbon ratio is 15:1, catalyst–iron ratio is 25:1; precipitation: pH values in solution is 11,reaction time is 40min,ion-exchange: the hydraulic retention time is 5 min), the removal ratio of nitrate nitrogen reaches over 99%, and the concentration of NO2-N,NH3-N,NO3-N in the effluent is less than the third national ground water quality sanitary standard.Reduction of nitrates by internal electrolysis follows second-order dynamics model, and the reaction is a second-order reaction.AEPI is a completely new and practical technology of treating high-concentrate nitrate solution, includes the following strongpoint in contrast with the others:...