Biological contact oxidation technology was used to remediate the polluted river water in Hanyang, China. The purification effect of the polluted river water in three simulated rivers was investigated using two different carriers, i.e., AquaMats made in USA and semi flexible supports made in China. The results showed that when the hydraulic loading rate increased, purification effect in terms of CODMn decreased. Moreover, the removal efficiency of total nitrogen (TN) increased when AquaMats support was used, however it decreased when semi flexible support was used, in comparison with the control experiment. The removal ability of total phosphorus (TP) was strengthened by using different carriers.

A cyanophage capable of infecting Anabaena floaquae was isolated by traditional dilution and plating techniques from a eutrophicated freshwater lake, Dianchi Lake, in Yunnan Province, China, and designated as F1. Morphologically, cyanophage F1 is similar to the bacteriophage T4, and it should belong to Myoviridae. Cyanophage F1 could effectively lyses Anabaena flosaquae cells both on the cyanobacterium plates and in liquid cultures. In microcosm experiments, inoculation of cyanophage F1 could clear the artificial Anabaena flosaqua water blooms within three days. The results could provide important information on the cyanobacterial/phage interactions in the field, and suggested that cyanophage F1 could be a promising bio-control agent in the control of cyanobacterial blooms.

Microorganisms capable of degrading Di-n-Butyl Phthalate (DBP) were isolated by acclimation and enrichment techniques. The adaptation of microorganisms to DBP was investigated. The microbial cells were immobilised onto the ceramic honeycomb supports. The DBP degradation was performed in a novel kind of bioreactor using ceramic honeycomb support as carrier for microbial immobilisation. The experimental results showed that the biomass adsorbed onto the ceramic support could reach 95 mg dry weight/g carrier. The immobilised microbial cells were used for the treatment of wastewater containing DBP. The results demonstrated that the DBP concentration of the outlet reached the stationery-state level of less than 1.0 mg/L within three days at inlet DBP concentration of 100 mg/L and 12 h of hydraulic retention time.

The microbial immobilization method using polyvinyl alcohol (PVA) gel as an immobilizing material was improved and used for entrapment of activated sludge. The oxygen uptake rate (OUR) was used to characterize the biological activity of immobilized activated sludge. Three kinds of PVA-immobilized particles of activated sludge, that is, PVA-boric acid beads, PVA-sodium nitrate beads and PVA-orthophosphate beads were prepared, and their biological activity was compared by measuring the OUR value. The bioactivity of both autotrophic and heterotrophic microorganisms of activated sludge was determined using different synthetic wastewater media (containing 250 mg/L COD and 25 mg/L NH4(+)-N). The experimental results showed that the bioactivity and stability of the three kinds of immobilized activated sludge was greatly improved after activation. With respect of the bioactivity and the mechanical stability, the PVA-orthophosphate method may be a promising and economical technique for microbial immobilization.

A helical filamentous cyanobactericidal bacterium was isolated from Dianchi Lake, a eutrophic freshwater lake in Kunming City of the Yunnan Province in China using a special solid medium. This species was designated strain PdY3. This bacterium was identified as a novel Saprospira sp. on the basis of its morphological characteristics and 16S rDNA sequence. Strain PdY3 showed apparent group behavior on the solid medium, forming orderly, bundle-like group structures. These bundles moved as groups. Individuals in a bundle responded to the bundle as a whole. PdY3 also showed group behavior and formed a three-dimensional reticular structure when co-cultured with Anabaena in liquid media. This helical bacterium lysed cyanobacteria through direct contact and its group behavior greatly accelerated the cyanobactericidal process. Our experiments showed that PdY3 caused lysis of 64% of Anabaena cells within 1 day and that its cyanobactericidal range was broad. These results underscore potential application of Saprospira on the control of blooms of cyanobacteria. PdY3 group behavior might allow a more efficient capture of bacterial prey.