Aerobic granulation of protein-rich granules from nitrogen-lean wastewaters.

Proteins (PN)-rich granules are stable in structure in long-term reactor operations. This study proposed to cultivate PN-rich granules with PN/polysaccharides (PS) >20 from nitrogen lean wastewater, with ammonia-nitrogen as sole nitrogen source at chemical oxygen demand (COD)/N of 153.8.

Drying and recovery of aerobic granules.

To dehydrate aerobic granules to bone-dry form was proposed as a promising option for long-term storage of aerobic granules. This study cultivated aerobic granules with high proteins/polysaccharide ratio and then dried these granules using seven protocols: drying at 37°C, 60°C, 4°C, under sunlight, in dark, in a flowing air stream or in concentrated acetone solutions. All dried granules experienced volume shrinkage of over 80% without major structural breakdown.

Strengthening aerobic granule by salt precipitation.

Structural stability of aerobic granules is generally poor during long-term operation. This study precipitated seven salts inside aerobic granules using supersaturated solutions of (NH4)3PO4, CaCO3, CaSO4, MgCO3, Mg3(PO4)2, Ca3(PO4)2 or SiO2 to enhance their structural stability. All precipitated granules have higher interior strength at ultrasonic field and reveal minimal loss in organic matter degradation capability at 160-d sequential batch reactor tests.

Magnesium carbonate precipitate strengthened aerobic granules.

Aerobic granules were precipitated internally with magnesium carbonate to enhance their structural stability under shear. The strengthened granules were tested in continuous-flow reactors for 220 days at organic loadings of 6-39 kg/m(3)/day, hydraulic retention times of 0.44-19 h, and temperatures of 10 or 28°C.

Degradation of cresols by phenol-acclimated aerobic granules.

High-strength cresol isomers were treated with phenol-acclimated granules in batch experiments. The aerobic granules effectively metabolized cresol isomers at concentrations up to 1,500 mg l(-1). The modified Haldane kinetic model, used to assess the kinetic behavior during cresol degradation by granule cells, yielded a high maximum specific growth rate (1.

Advances in aerobic granule formation and granule stability in the course of storage and reactor operation.

Aerobic granulation is drawing increasing global interest in a quest for an efficient and innovative technology in wastewater treatment. Developed less than two decades ago, extensive research work on aerobic granulation has been reported. The instability of the granule, which is one of the main problems that hinder practical application of aerobic granulation technology, is still to be resolved.

Functional consortia for cresol-degrading activated sludges: toxicity-to-extinction approach.

The conventional roll tube and plating techniques are typically time consuming and can culture in vitro only a small fraction of microbes in natural microflora. This study utilizes a novel, simple, and rapid method, the toxicity-to-extinction approach, to obtain the minimal functional consortium that can effectively degrade meta- (m-), para- (p-), and ortho- (o-) cresols. The original sludge had 16 major bands by denaturing gradient gel electrophoresis (DGGE).

Degrading high-strength phenol using aerobic granular sludge.

Aerobic granules were adopted to degrade high-strength phenol wastewater in batch experiments. The acclimated granules effectively degraded phenol at a concentration of up to 5,000 mg l(-1) without severe inhibitory effects. The biodegradation of phenol by activated sludge was inhibited at phenol concentrations >3,000 mg l(-1).

Biodegradation of phenol using Corynebacterium sp. DJ1 aerobic granules.

The single-culture Corynebacterium sp. DJ1 aerobic granules were cultivated and were utilized to degrade high-strength phenolic wastewater. These granules can degrade phenol at sufficient high rate without severe inhibitory effects up to phenol concentration of 2000 mg l(-1).