Application of UASB-reactors to industrial waste-water treatment; performance data and results in granulation control

Several types of high organic matter pollutants containing (COD‐range: 3–50 kg · m−3) industrial waste waters were treated in laboratory scale (1.2–23 dm3) sludge blanket (UASB) and UASB‐fixed bed hybrid (UBF) reactors. In most cases higher than 80% of COD‐removal efficiency has been attained. The CO2 content of the biogas developed was mainly influenced by the neutralization (base to acid) ratio related to feed pH. Cell immobilization by granule formation was considered as a change in microbial population: enrichment and aggregate formation of Methanotrix‐like filamentous microorganisms. Based on physiological and physical indexes of microbial selection and with regard to the different sensitivities of microorganisms to substrate inhibition, a new start‐up method was developed for rapid (40–45 days) granulation of raw digested sludge.