Effect of aluminum (Al3+) on granulation in upflow anaerobic sludge blanket reactor treating low-strength synthetic wastewater.

The effect of aluminum on agglomeration in the sludge bed and chemical oxygen demand (COD) removal efficiency in laboratory-scale upflow anaerobic sludge blanket (UASB) reactors treating low-strength synthetic wastewater (approximately 665 to 738 mg/L of COD) was investigated. Continuous application of aluminum chloride (200 mg/L) caused poor COD removal, less sludge density, and adversely affected agglomeration in the sludge bed. An adverse effect on granulation also was observed when 300 mg/L aluminum chloride was added only during the startup, and the effect continued even after it was discontinued.

Influence of extrinsic factors on granulation in UASB reactor.

The aim of this mini-review is to synthesize and analyze information on how the process of granulation is affected by environmental and operational conditions in the reactor. The factors reviewed are temperature, pH, alkalinity, organic loading rate, upflow velocity, nature and strength of substrate, nutrients, multivalent cations and heavy metals, microbial ecology of seed sludge, exo-cellular polymer, and addition of natural and synthetic polymers. Careful temperature control and adequate alkalinity is required for generation and maintenance of granules.

Enhanced granulation by natural ionic polymer additives in UASB reactor treating low-strength wastewater.

Effect of natural ionic polymer additives on granulation in lab-scale UASB reactors treating low-strength synthetic wastewater (COD 750-850 mg/L) was examined. The organic loading rate was 1.477+/-0.

Enhanced granulation in UASB reactor treating low-strength wastewater by natural polymers.

Reetha (Sapindus trifoliata) seed extract and Chitosan were used as additives in the sludge bed of a UASB reactor treating low strength wastewater to enhance granulation. Five parallel laboratory scale UASB reactors were operated for 250 days with synthetic wastewater feed containing COD in the range of 600-800 mg/L. The reactors were seeded with spent sludge from a full-scale 5MLD UASB treatment plant at Jajmau, Kanpur, India.