by an OLR increase from 0.55 to 1.11 kg CODm−3 on day 83, whichwas maintained for 6 days.
Feeding was therefore stopped for about 23 days and resumed with an OLR of 0.46 kg CODm−3 on day 112 for 11 days followed by 0.63 kg CODm−3 on day 123 for 9 days corresponding to a
HRT of 90 days due to the decreased volume of feed.
The alkalinity in the digester was within the range of 1800–2900mg CaCO3 L−1 as shown in Fig. 5. A gradual increase in