Effective bio-treatment of fresh leachate from pretreated municipal solid waste in an expanded granular sludge bed bioreactor

The effect of calcium on the treatment of fresh leachate in an expanded granular sludge bed bioreactor

“…Note that in Table 1 the influent pH was stabilized in 4.0-4.8 while that in the effluent was increased to 6.8-7.5. This demonstrates that the anaerobic fermentation results in an increase of solution pH, largely due to the formation of more NH 3 -N as the metabolites (Liu et al, 2010). Fig.…”

“…The schematic diagram of the EGSB bioreactor was shown in the early paper (Liu et al, 2010). Temperature of the bioreactor was controlled with the thermostat and heating resistor at 35-37°C and the liquid up-flow velocity (Vup) was kept at 3.2 m/h.…”

“…The expanded granular sludge bed (EGSB) bioreactor, modified from the up-flow anaerobic sludge blanket (UASB) reactor, has been used to treat the fresh leachate (Liu et al, 2010). A very often observed phenomenon in this treatment is scaling on the EGSB/ UASB bioreactor wall and along effluent pipes, as reported also by Kim et al (2003Kim et al ( , 2004 and van Langerak et al (1998), attributed to the high concentration of calcium in the leachate.…”

Emerging perspectives on environmental burden minimisation initiatives from anaerobic digestion technologies for community scale biomass valorisation

“…increase the scale of operation [51]; to manage complex waste; to prevent the release of offensive odour [46], etc. The variations in pre-treatment approaches are geared to treating different characteristics of feedstocks, involving efficient processing of the input feedstock [13,14,23,52] and/or, innovative mechanical/bio-chemical/ thermal/radiative treatments [15,44,53], the latter particularly useful for digesting longer chain lignocellulosic biomass and wooden fractions [54,55]. However, any pre-treatment makes use of some form of energy (pressure, translational, rotational, thermal, or electrical) and/or chemicals and both resources can have diverse environmental implications.…”

“…For example, there is a scope to improve/ fasten the degradation of the waste feedstock characterised by high volatile solids and low total solids (especially food waste -including raw fruit and vegetables and cooked food) through adequate hydrolysis and addition of alkaline buffer to enhance digestion [23,52]; recirculation of a proportion of leachate into the digestion process (up to 50%, recommended in the literature [13]); recirculation of effluent (process water) [14,42]. However, process water must be recycled with care (with appropriate treatment) to avoid the accumulation of soluble inhibitory compounds such as ammonia and salt.…”