Department of Civil and Environmental Engineering, University of California , Berkeley, California 94720, United States.
Engineering Research Center for Re-inventing the Nation's Urban Water Infrastructure (ReNUWIt), Stanford, California, United States.
Environ Sci Technol. 2017 Feb 21;51(4):2373-2381. doi: 10.1021/acs.est.6b05816. Epub 2017 Feb 3.
Separate collection of urine, which is only 1% of wastewater volume but contains the majority of nitrogen humans excrete, can potentially reduce the costs and energy input of wastewater treatment and facilitate recovery of nitrogen for beneficial use. Ion exchange was investigated for recovery of nitrogen as ammonium from urine for use as a fertilizer or disinfectant. Cation adsorption curves for four adsorbents (clinoptilolite, biochar, Dowex 50, and Dowex Mac 3) were compared in pure salt solutions, synthetic urine, and real stored urine. Competition from sodium and potassium present in synthetic and real urine did not significantly decrease ammonium adsorption for any of the adsorbents. Dowex 50 and Dowex Mac 3 showed nearly 100% regeneration efficiencies. Estimated ion exchange reactor volumes to capture the nitrogen for 1 week from a four-person household were lowest for Dowex Mac 3 (5 L) and highest for biochar (19 L). Although Dowex Mac 3 had the highest adsorption capacity, material costs ($/g N removed) were lower for clinoptilolite and biochar because of their substantially lower unit cost.
尿液的单独收集，其体积仅占废水总量的 1%，但却包含了人类排泄的大部分氮，这可能会降低废水处理的成本和能源投入，并促进氮的回收利用，造福人类。本研究采用离子交换法从尿液中回收氮，以铵盐的形式作为肥料或消毒剂使用。本文比较了 4 种吸附剂（斜发沸石、生物炭、Dowex 50 和 Dowex Mac 3）在纯盐溶液、合成尿液和实际储存尿液中的阳离子吸附曲线。在合成尿液和实际尿液中，存在与钠离子和钾离子的竞争，但对任何吸附剂的铵吸附都没有显著降低。Dowex 50 和 Dowex Mac 3 的再生效率均接近 100%。从一个四口之家的尿液中捕获一周的氮所需的离子交换反应器体积，以 Dowex Mac 3（5 L）最小，生物炭（19 L）最大。尽管 Dowex Mac 3 的吸附容量最高，但由于其单位成本低，斜发沸石和生物炭的去除每克氮所需的材料成本（$/g N removed）较低。
