[Effect of Aeration Density on Start-up of CANON Process].

The effect of aeration densities (3, 6, 12) on the CANON process start-up were investigated in R1, R2, and R3 inoculated mature anaerobic ammonium oxide granule sludge under the same conditions of aeration and aeration/anaerobic time ratio (1:1) at 25℃. The results showed that R1, R2, and R3 of the CANON process were initiated in 32, 29, and 23 d, respectively. A greater aeration density promoted the start-up of the CANON process. In the cycle test, the pH of R1, R2, and R3 decreased by 0.4, 0.55, and 1.06, respectively. R3 exhibited excellent denitrification performance due to its large aeration density and suitable time interval, which increased system efficiency in DO and better inhibited NOB activity. According to the denitrification route analysis, there were two denitrification pathways of ANA and SNA in the system. The proportion of SNA was 19.3%, 24.5%, and 33.6%, respectively. With the increase in aeration density, the contribution of SNA increased gradually.

[Effects of Different Substrate Concentrations on the Short-term Storage of ANAMMOX Bacteria].

Anaerobic ammonium oxidizing bacteria were stored under NH4+-N and NO2--N conditions (addition ratio 1:1) at a substrate concentration of 0, 60, and 120 mg·L-1at 15℃±1℃ for 15 days. The effect of different substrate concentrations on the short-term storage and recovery of anaerobic ammonia oxidation sludge was investigated. After a short period of storage, a recovery experiment was performed. The results show that the anaerobic ammonia oxidation activities in the reactors 1, 2, and 3 decrease by 41.8%, 17.4%, and 33.4%, respectively. Because of the excessive endogenous respiration and high substrate concentration, the activities of the bacteria in reactors 1 and 3 were inhibited, respectively. Therefore, the activities decreased greatly. Because the substrate concentration was relatively suitable in reactor No. 2, excessive endogenous respiration and high substrate concentration inhibition were avoided such that the activity of the bacteria species was maintained at the substrate concentration. Endogenous respiration occurred during the storage period. Subsequently, the organic matter in the three reactors was consumed. As a result, the EPS content decreased by 50.9%, 41.7%, and 23.7% and the particle size decreased by 31.6%, 16.7%, and 8.2%, respectively. This shows that endogenous respiration is maintained by the bacteria in the matrix-deficient period and the higher concentration of the substrate can to some extent delay the endogenous respiration. During the recovery period, the three reactors recover the denitrification performances after 15, 10, and 7 d respectively. This shows that the denitrification performance of the system has a faster recovery through enhanced strain activities compared with the proliferation of the strain.

Prediction of solvents extraction-the organochlorine pesticides in soil using solubility parameter.

Prediction of the optimal extraction solvent based on the solubility parameter to extract the typical organochlorine pesticides from Jiangxi red soil was reported in this paper. Hildebrand solubility parameters, including dispersion coefficient (delta(d)), polarity (delta(p)) and hydrogen bonding (delta(h)), of extraction solvents (including hexane, dichloromethane, hexane/methanol (4:1, v/v), hexane/acetone (1:1, v/v), hexane/dichloromethane (1:1, v/v) and organochlorine pesticides were calculated using group contribution method. The solvents, such as hexane/methanol (4:1, v/v) and hexane/acetone (1:1, v/v) were selected as ideal extraction solvents to extract o,p'-DDT o,p'-DDE and o,p'-DDD with high recoveries (>82%), furthermore, these solvents can be used to extract alpha-endosulfan, Endrin and HCB with the reliable recoveries (>75%). The estimated finding by solubility parameters was supported by the results of soxhlet extraction.