SIDE–BY–SIDE COMPARISON OF MEMBRANE AND CONVENTIONAL FILTRATION TECHNOLOGIES WITH UV DISINFECTION TO MEET EXISTING AND FUTURE REGULATIONS

Pilot studies of different filtration/UV systems were conducted at the Sacramento Regional Wastewater Treatment Plant (SRWTP) to investigate the feasibility of a filtration/ultraviolet light (UV) system to meet existing and future discharge requirements. The phase 1 pilot study investigated continuous backwash sand filtration followed by UV, cloth (disk) filtration followed by UV, and microfiltration. The response of coliform bacteria in each of the filtration/microfiltration effluents to UV light was evaluated using a low pressure collimated beam apparatus. The comparison of the effectiveness of the different filtration/UV systems was measured by testing the following parameters: total and fecal coliform, enterococcus, cryptosporidium, giardia, TSS, COD, TDS, turbidity, total organic carbon, metals, trace organics, and endocrine disrupters. The phase 2 pilot study investigated the addition of chemical coagulants/flocculent upstream of continuous backwash sand filtration followed by UV, cloth (disk) filtration followed by UV, dual media filtration, and mono-media anthracite filtration. The response of coliform bacteria in each of the filter effluents to UV light was evaluated using a low pressure collimated beam apparatus. The comparison of the effectiveness of the different filtration/UV systems was measured by testing the following parameters: total and fecal coliform, TSS, UV transmittance at 254 nm, and turbidity. The effluent from the UV systems was tested for total and fecal coliform.