Photovoltaic wastewater treatment based on a combined heterotrophic and sulfur-based autotrophic denitrification technology
MA Hang1,2, LI Xiang1,2, HUANG Yong1,2, WEI Fan-kai1,2
1. School of Environmental Science and Engineering, Suzhou University of Science and Technology, Suzhou 215002, China; 2. Institute of Environmental Biotechnology, Suzhou University of Science and Technology, Suzhou 215002, China
Abstract：Photovoltaic wastewater was used as the influent of a combined heterotrophic and sulfur-based autotrophic denitrification reactor. When the influent F- concentration was 800mg/L, NO3--N concentration was 350mg/L, TOC/N was 0.7, the nitrogen removal rate and denitrification efficiency of the reactor reached 2.0~2.5kg/(m3·d) and 90% above without pH adjustment. Defluorination experiments indicated that F- concentration of photovoltaic wastewater was decreased to 800mg/L by adding calcium oxide. Meanwhile, the pH of the wastewater was raised to 7.68, which met the pH(7.5~8.5) requirement of the combined denitrification. The remaining F- and generated SO42- in combined denitrification were removed effectively by secondary defluorination. Photovoltaic wastewater containing high F- concentration (800mg/L above) could be treated by preliminary defluorination, combined denitrification and secondary defluorination. In terms of the cost of denitrification in photovoltaic wastewater treatment, the combined denitrification could save 0.82yuan/t compared with unit cost of the heterotrophic denitrification.
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