Abstract: A method and equipment for secondary sewage treatment by anaerobic treatment of sewage after the sewage has passed from a septic tank or other primary treatment device. The effluent from the primary treatment device is directed to the lower annular volume of the wrap-around anaerobic filter. The outer side wall boundaries of the wrap-around filter are defined by a permeable or impermeable earth retention cloth while the inner boundary is defined by the primary treatment device. The anaerobic filter is composed of gravel or other surface contact media. After the effluent reaches the lower annular volume, the effluent is directed through the void spaces of the anaerobic wrap-around upflow filter. Having passed through the filter the effluent is delivered to the drain field or other final treatment facility.