A　synergistic　partial　denitrification,　anaerobic　ammonium　oxidation　(Anammox),　and　in-situ　fermentation　(SPDAF)　system　was　established　to　solve　problems　of　wastewater　treatment　plants　(WWTPs)　in　combined　treatment　of　domestic　sewage,　and　nitrate　wastewater　discharged　from　industrial　areas.　The　SPDAF　system　was　started　up　at　decreasing　temperatures　(26.8-18.9　celcius),　and　remained　robust　at　abrupt　temperature　drop　and　drastic　temperature　fluctuations　(20.7-14.1　celcius).　The　influent　and　effluent　total　inorganic　nitrogen　(TIN)　were　97.0　+/-　3.7　mg/L　and　10.3　+/-　4.0　mg/L,　respectively.　In-situ　fermentation　supplemented　electron　donors　for　NO3-N　reduction.　A　high　TIN　removal　efficiency,　of　89.5　+/-　3.9%　was　obtained.　Specifically,　Anammox　contributed　90.9　+/-　5.2%　to　TIN　removal.　Furthermore,　the　abundances　of　hydrolysis　and　acidogenesis　bacteria　were　14.02%　and　29.47%　in　the　low　and　high　zones,　respectively,　which　promoted　fermentation　and　the　use　of　complex　organics.　This　study　provided　novel　insights　for　actual　operation　of　WWTPs.