Experiment on influence of ferrous and manganese ions in groundwater on recharge of groundwater source heat pump system

For the chemical clogging problem by ferrous and manganese ions in recharge of groundwater source heat pump system, studies the influence of different ferrous and manganese ion contents and ratios on the chemical clogging in intermittent recharge conditions. Taking the urban area of Shenyang as an example, conducts the laboratory test of simulative recharge process with different recharge water samples, and contrasts the SEM pictures of porous medium surface before and after recharge. The results show that Fe²⁺ is one of the important factors of influencing clogging degree. The higher the concentration of Fe²⁺ is, the earlier the clogging occurs and the more severe the degree of clogging is. There is not obvious impact on clogging with the sample that only has Mn²⁺ in it. Mn²⁺ has not obvious impact on clogging except in the synergy of Fe²⁺. Intermittent recharge can bring in a lot of oxygen. That accelerates the precipitation of ferrous and manganese oxidation reaction and leads to aggravated clogging phenomena. Therefore, Fe²⁺ content must be controlled preferentially and strictly in the recharge process. The area with high ferrous content or high concentration of ferrous and manganese ions should be avoided during the consideration of site construction. In addition, the possibility to contact with oxygen during the process must be reduced, which can increase the recharge efficiency and reduce the times of washing wells.