Enhancing methane production in the UK WWTP via co-digestion of microalgae and sewage sludge

摘要: The study investigated the possible integration of microalgal digestion into existing WWTP configurations to benefit from infrastructure. This was with overall aim increasing energy production. In particular, it aimed at plants that utilise advance anaerobic thermal hydrolysis process (THP) in place, as this is hypothesized enhance algal degradability and CH4 yield while simultaneously producing biomass suitable for co-digestion sewage sludge. The effect THP studied on Chlorella vulgaris adopted results showed a 35% increase methane 0.265 0.357L /g VS added suggesting possibility approach upgrade microalgae competitive standard likes food waste FYM. It then proposed first time, pre-treated sludge thus, several co-digestions (0%, 25:75, 50:50, 75:25 100%) alga: respectively were studied. Results addition alga had linear relationship obtained up ratio 75% algae corresponding 0.369L added. Based this, laboratory scale CSTR developed identify operational parameters challenges can favour be encountered during continuous running these substrates. A an OLR 4 g L-1d-1 HRT 20 days produced highest 0.434L balance between substrate thus favouring methanogenic activities. The goes further investigate alternative biofuel production using carboxylate under which influence iodoform, pre-treatment retention time VFA During study, optimum iodoform complete inhibition order avoid conversion gas reported 10mg/L. Experiments carried out respective research platform experiment, peak concentrations ranged 6.01 6.94 g/L, concentration 50:50 (alga:sludge) fermenter 0.992 total acid/g fed 11 , seconded by 25:75 0.952 varying 17days. Comparing both approaches proved significant over AD experiments 92 166% all tested ratio. Conclusively, could inferred fermentation WAS ratios produce VFAs may alternate option While most optimal experiments, effective Retention however days. facilities installed presents positive about size Esholt UK, serving population 700,000 currently treating 80 tonnes dry daily, where each tonne digested within system would gain 1926 MJ (535 kWh). Not only will implementation technology help additional revenue extra biogas produced, also expected offset some expended wastewater treatment via utilization nutrients digestate reducing nutrient load being recycled back treatment. products such acetic acid ethanol modified lead profit 3536 MJ/tonne (982 kWh) 6654 (1848 per ton microalgae, improvement 1.8 – 3.4 times concludes areas recommended achieve full exploitation techniques/resources commercial level.