Study On Influencing Factors Of Desalination Performance And Its Control By Electrosorption Equipment In Wastewater Treatment

Urumqi city faces a huge shortage of water resources in China, Utilization of wastewater from Urumqi’s Sewage Disposal Factories is an important way to solve industrial water shortage. The major constraint in reclamation and reuse of wastewater is the salt content. Therefore, desalination technology is the key technology to be used in wastewater resources. Likewise, electrosorption is a new water processing technology, which is still in the research stage and needs more actual engineering practice. Urumqi High-tech Zone North recycling plant research on the bicarbonate alkalinity, total hardness, effluent flow and salinity, electrosorption equipment desalination, and TDS, Chloride ion, total hardness and HCO3-removal efficiency were analyzed, the main results are as follows:1. The influent HCO3-concentration is controlled in three conditions of170mg/L,260mg/L and440mg/L, electrosorption equipment continuous running of6cycles, in addition to TDS, Chloride ion and total hardness removal rates are low in the first cycle, removal rates of three ions and HCO3-are gradually downtrend in the remaining5cycles, when HCO3-concentration is440mg/L, the removal rate decreases significantly. In high bicarbonate alkalinity conditions, HCO3-interact with calcium and other hardness ions, leading to the scaling of electrode plate, thus affecting the desalting effect of electro-sorption equipment. In addition, basing on the scaling plate, bicarbonate of raw water with acidification stripping, equipment continuously running under the low influent HCO3-concentration can improve the desalting effect of electro-sorption equipment.2. The influent HCO3-concentration is controlled in the condition of80mg/L, total hardness is controlled in three conditions of340mg/L,770mg/L and1200mg/L, electro-sorption equipment continuous running of6cycles, except for HCO3-, the removal rates of TDS, Chloride ion and total hardness are relatively stable. When the influent HCO3-concentration increases at440mg/L, the removal rates of four show the tendency to decrease progressively, and the higher of total hardness, the removal rates of TDS, Chloride ion, and HCO3-decrease more significantly.3. Likewise water quality can be improved by using the electric adsortion method such as the increase of the influent flow, the removal rate of TDS, Chloride ion and total hardness decreased gradually, while the units of water energy consumption also decreases linearly; when the device is waterflow of0.5m3/h, the plate voltage of1.5V, the average water conductivity of1860μS/cm conditions, the average desalination rate of74.8%, energy consumption of1.42kWh/t; the average water conductivity is3862μS/cm conditions, the average desalination rate of72.4%, energy consumption of1.86kWh/t.Xinjiang’s sewage water has a higher hardness when compared to the Mainland. Therefore, the electrode surface of an electrosorption process is prone to fouling, resulting in lower efficiency of the electrosorption. One solution is to add acid in the pre-treatment process i.e. aeration measures, which removes bicarbonate alkalinity in the water, to prevent the generation of scaling phenomenon. The study proved electrosorption can be used for municipal wastewater reclamation and water desalination.