Enhanced combined assimilative and bound phosphorus uptake in concurrence with nitrate removal in pre-anoxic cyclic sequencing batch reactor

Needless to specify, controlling nitrogen and phosphorus discharge from wastewater treatment plants is synonymous with the prevention of eutrophication of surface waters, as one of the major issues related to water security. The present study investigates the performance of a pre-anoxic sequencing batch reactor (SBR) working on the basis of intermittent aeration, operated at varied carbon (bCOD) to nitrogen (C/N) ratio of 3, 7.5, and 10, and readily biodegradable (rbCOD) to slowly biodegradable (sbCOD) ratio of 0.1, 0.25, and 0.5. The findings revealed that an enhanced nitrogen removal was observed, together with higher C/N and rbCOD to sbCOD ratios. The results also show a consistent increase in total phosphorus removal with an increase in nitrogen removal. The phosphorus uptake of sludge varied from 0.02 – 0.045 mgP/mgVSS (avg. 0.031 ± 0.004), which resulted in enrichment levels of 0.88 – 1.68 times the stoichiometric value of 0.0267 mgP/mgVSS (avg. 1.45 ± 0.14). On an average basis, the assimilative total phosphate (TP) content was increased by 0.008 gTP/gNO -/3 -N removal rate. The excess phosphorus removal was due to the formation of poorly soluble polyvalent phosphate compounds, which was found based on dry analysis, which persisted as bound phosphate in the sludge

Dynamic simulation and 3E optimization with an environmental assessment of an efficient energy plant for generation of fresh water by humidification-dehumidification technology and green power and H2

© 2022Buildings, mainly residential complexes, can benefit significantly from integrated district generating systems because of their flexibility, increased energy efficiency, and reduced emissions. The energy requirements of a building in Beijing, China, are investigated in this work using dynamic modeling software. The use of solar energy, including photovoltaic thermal panels and collectors, desalination systems, which include humidification and dehumidification units, and hydrogen generation systems, which include alkaline and proton exchange membrane electrolyzer, as well as heating and cooling systems, is suggested and examined transiently. The TRNSYS software works by simulating a situation from a thermodynamic and environmental point of view. According to the findings, we receive solar radiation on our solar panels for more than half the year, with a maximum output of 16.2 kWh. Additionally, it was found that more hydrogen and freshwater were produced during the year's warmer seasons, with the maximum hydrogen production rate reaching 2 kg per hour. The hydrogen tank, therefore, had a higher state of charge during the hotter months. The power and heating produced were also calculated on the hottest and coldest days of the year. The findings showed that power generation is roughly-four times higher on the year's hottest day than the coldest. Furthermore, since freshwater and hydrogen production rates rise during hot weather, the overall efficiency is higher during warm months. After optimization was completed, the best-case scenario saw 0.7 kg of hydrogen produced for 17.45 $/GJ. Environmentally, using solar energy can be reduced CO2 emissions compared with fossil fuels