Study On The Characteristic Of Filamentous Bulking Under The Condition Of Co-metabolic Biodegradation Of Benzene Derivative Pollutants From Regenerated Papermaking Wastewater

A class of refractory organic pollutants exists in regenerated papermaking wastewater, which is not conducive to improve wastewater treatment rate.How to translate benzene into non-toxic pollutants or make it completely degrade by microbial co-metabolism has become a research hotspot in recent years, but filamentous bulking phenomena occurs in engineering applications, which has a negative impact on effluent quality. In this research co-metabolism degradation of refractory organic pollutants, the impact refractory organic pollutants on microorganism and filamentous bulking phenomena were studied so that they can provide a theoretical basis for engineering practice.By increasing the influent COD and fixing hydraulic retention time to start the reactor, it can bring good start effect after 34 days.Effluent quality was stabile;COD average removal rate was 88%; dibutyl phthalate degradation rate gradually increased from 49% to 75%; xylene degradation rate gradually increased from 55% to 78%.COD removal rate was 96.5%;DBP removal rate was 87.6%;xylene removal rate was 90.2% with glucose and formic acid as a carbon source.The removal rate was better than glucose and formic acid as a carbon source alone.With glucose and formic acid as a carbon source,there was 103mg/gMLVSS polysaccharide at anaerobic phase and 89mg/gMLVSS polysaccharide at first anoxic phase.With glucose and formic acid as a carbon source alone, there was 89mg/gMLVSS polysaccharide at anaerobic phase and 97mg/gMLVSS polysaccharide at first anoxic phase.Polysaccharide decreased as COD reduced.With glucose and formic acid as a carbon source, there was 13mg/gMLVSS protein at anaerobic phase and 21mg/gMLVSS protein at first anoxic phase.The change of protein was smaller than that of polysaccharide as current.When the xylene concentration was lower than 40mg/L,its inhibition rate of microbial dehydrogenated activity was less than 25%,a mild degree;while it was more than 80mg/L, its inhibition of dehydrogenated activity translated a moderate degree into a mild degree.And comparing to xylene, dibutyl phthalate had more serious inhibition on the microorganisms. Macromolecular organic acidification mainly occurred in 24 hours.In the first two days,the inhibition rate of oxygen consumption was higher, but as dibutyl phthalate and xylene degradation,its inhibition rate of oxygen consumption gradually decreased.While HRT was 8h, pH decreased to 4.7 in first anoxic phase and filamentous bulking occurred.Biofilm ecosystem was out of balance at low pH value and biological phase changed. Some filamentous micro-organisms which adapted to low pH value grew rapidly, while other microbes which did not adapt to a low pH value grew slowly. Zoogloea disintegrated and filamentous bulking occurred. The predominant bulking causing filamentous microorganism in the paper mill effluent treatment system was identified.Fungi spp.was found to be the predominant filamentous microorganisms.The kinetics study revealed that the pH was a critical factor affecting the excessive growth of Fungi spp.The limiting percentage of filamentous is higher than that of floc-forming bacteria. The increase rates of floc-forming bacteria and filamentous were highest when glucose and formic acid were provided together. The increase rate of floc-forming bacteria while glucose was provided was higher than that while formic acid was provided, but the increase rate of filamentous while formic acid was provided was higher than that while glucose was provided.