The enhanced ettringite formation process (EEFP), a technology developed at the Energy & Environmental Research Center, is a process for the treatment of waste streams containing difficult-to-remove and potentially toxic trace elements such as boron and selenium. This easily implemented technology, based on the mineral ettringite, a calcium aluminosulfate hydroxide hydrate (Ca6Al2[SO4]3[OH]l2.26H2O), has possible applications for a suite of potentially hazardous trace elements, including but not limited to arsenic, boron, chromium, molybdenum, selenium, and vanadium. The EEFP has been optimized to reduce boron and selenium concentrations (including selenate and selenite) up to two orders of magnitude using a simple process that incorporates the problematic trace elements from a large volume of contaminated water into a relatively small mass of ettringite. The EEFP has been used successfully in laboratory experiments to treat boron- and selenium-containing wastes from industrial process streams. Key in this treatment option is that it is not sensitive to the selenium redox state as is the case with some other treatment options such as iron precipitation. Additionally, the process may reduce sulfate concentrations and sometimes aluminum and calcium concentrations as well. The treated water can often meet drinking water standards. This process is an important addition to currently available waste treatment options, many of which are either not economical or effective for these key elements of concern. The EEFP has been developed sufficiently for use in a field demonstration leading ultimately to a marketable commercial technology for the treatment of some of the most difficult-to-treat aqueous waste streams. This technology has been patented.