Phototrophic bacteria for nutrient recovery from domestic wastewater

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• 作者：Tim H眉lsen ; Damien J. Batstone ; J眉rg Keller
• 关键词：Purple non-sulphur bacteria ; Domestic wastewater ; COD ; Nutrient recovery ; Assimilation
• 刊名：Water Research
• 出版年：1 March, 2014
• 年：2014
• 卷：50
• 期：Complete
• 页码：18-26
• 全文大小：1122 K

文摘

The organics and nutrients in industrial and domestic wastewater are increasingly being regarded as a valuable resource for energy and nutrient recovery. Emerging concepts to redesign wastewater treatment as resource recovery systems include the use of different bacteria and algae to partition carbon and nutrients to the particulate phase through assimilation or bio-accumulation. This study evaluates the use of purple phototrophic bacteria (PPB) (also known as purple non-sulphur bacteria or PNSB) for such a biological concentration process through a series of batch tests. The key objectives are to (a) demonstrate consistent selection and enrichment of PPB using infrared light in a non-sterile medium, and (b) achieve effective partitioning of soluble organics, ammonium and phosphate into the PPB culture. PPB were successfully enriched from pre-settled domestic wastewater within 2-3 days and identified as members of the order Rhodobacterales. Under anaerobic conditions with infrared irradiation the enrichment culture was able to simultaneously remove COD (63聽卤聽5%), NH₄-N (99.6%-0.12聽卤聽0.03聽mgN聽L^鈭?) and PO₄-P (88%-0.8聽卤聽0.6聽mgP聽L^鈭?) from primary settled domestic wastewater in 24聽h. In this experiment, acetate was added as an additional carbon source to demonstrate the maximal nitrogen and phosphorous elimination potential. Almost all the COD removed was assimilated into biomass rather than oxidised to CO₂, with the total COD actually increasing during the batch experiments due to phototrophic synthesis. NH₄-N and PO₄-P were also assimilated by the biomass rather than removed through destructive oxidation or accumulation. The process offers the opportunity to concentrate organics and macronutrients from wastewater in one solids stream that can be anaerobically digested to generate energy and recover nutrients from the concentrated digestate. Technical challenges include the design of a continuous reactor system, as well as efficient delivery of electrons, either through light or chemical sources.