Evaluation of ozone disinfection from view points of inactivation disinfection effects and byproducts formation. Hatatatsu, Toshika; Suzuki, Yutaka. Advanced Wastewater Treatment Division, Public Works Research Institute, Ministry of Construction, Tsukuba, Ibaraki, Japan. WEFTEC 2000, Annu. Conf. Expo. Water Qual. Wastewater Treat., 73rd (2000), 4273-4287.
Abstract:
O3 has strong disinfecting power, but it might produce toxic byproducts, such as aldehydes and bromate ions. Inactivation effects and byproducts formation by O3 disinfection when O3 was used for wastewater disinfection were examd. There were few problems with residual O3 or ozonation byproducts and their toxicity, even if the inactivation level was as high as -4 log to -5 log coliform group survival ratio. Byproduct concns. increased and toxicity was higher when seawater was added. The presence of Br- is the key factor which causes O3 disinfection to form toxic byproducts.
Toxicity of ozonated sea water to Penaeus chinensis and Paralichthys olivaceus. Jiang, Guoliang; Liu, Yun; Yang, Dong; Lu, Yan. College of Marine Life Sciences, Ocean University of Qingdao, Tsingtao, Peop. Rep. China. Haiyang Kexue (2001), 25(3), 11-13.
Abstract:
The toxicity of ozonized sea water to the Penaeus chinensis and Paralichthys olivaceus was studied. The results showed that the tolerance of shrimp for residual ozone levels was much higher than that of the fish, the shrimp would live 48 h in ozone water ? 1mg/L, while fish could not live more than 3 h. Concn. lethal to 50% of sample fish of Bastard halibut for 48 h was 0.13 mg/L. Compared with other disinfecting method, the ozonation is a good treatment method for intensive aquaculture with suitable level.
Effect of seawater treated with ozone on content of protein, amino acid and carbohydrate in Chlorella sp. Wang, Chenggang; Tang, Xuexi; Zheng, Bo; Tang, Xiaohua. Shandong Marine Science and Technology Academy, Tsingtao, Peop. Rep. China. Haiyang Kexue (2001), 25(2), 15-17, 23.
Abstract:
The effects of seawater treated by ozone on contents of protein, amino acids, and carbohydrate were studied in Chlorella sp. at the different growth stages. The results showed as follows: a certain dosage of ozone treatment could increase the content of protein and amino acids, but decrease the content of carbohydrate. The proportion of necessary amino acids for fish to the total amino acids in the microalgae did not exhibit significant change compared with control group. Ozone treatment of Chlorella sp. could promote the whole nutrient level.
Effects of ozone-produced oxidants on ventilation of the pearl oyster, Pinctada fucata martensii. Yamamoto, Ken-Ichi; Kondo, Masakazu; Handa, Takeshi; Nakamura, Masatoshi. National Fisheries University, Shimonoseki, Yamaguchi, Japan. Suisan Zoshoku (2000), 48(3), 509-516.
Abstract:
To evaluate the effect of ozone-produced oxidants (OPO) on the ventilation of the pearl oyster, Pinctada fucata martensii, the ventilation vol. (Vg), the gill cilia movement (SP) and the surface structure of gills were examd. after exposure to ozonized seawater for 24 h. Vg was examd. every 3 h during exposure to the seawater of OPO 0.70 mg O3/L. Also the day when Vg recovered to the level of the control after exposure (DY) was examd. In the 24 h, Vg and SP decreased with an increase in the OPO concn., and showed zero at 0.58 mg O3/L or more. DY was under 23 days at 0.42 mg O3/L or below, and 10-80 days at 0.58-0.70 mg O3/L. However, at 0.58-0.70 mg O3/L, 20% of the individuals used for the expt. died 5-76 days later. Every 3 h, Vg decreased with time. DY was under 23 days within 12 h and 25-80 days at 24 h. The damages of the gills were postulated to progress in the order: the frontal cilia disappeared, the lateral cilia disappeared, the ciliary disk collapsed, and the gill filaments disappeared from the tip.
Analysis of residual ozone (in fresh water) or residual oxidants (in seawater) by spectrophotometry with DPD reagent. Anon. UK. Res. Discl. (2000), 438(Oct.), P1800-P1801.
A couple of good things for fish
Abstract:
Adaptation of a spectrophotometric method for the detn. of free chlorine in water to the detn. of O3 and other oxidants is described. The method uses N,N-diethyl-p-phenylenediamine in the presence of KI as the reagents. The detn. limit of the method is 0.014 mg O3/L.
Surface disinfection of Atlantic halibut Hippoglossus hippoglossus eggs with ozonated sea-water inactivates nodavirus and increases survival of the larvae. Grotmol S; Totland G K Department of Aquaculture, Institute of Marine Research, Bergen, Norway.
[email protected] DISEASES OF AQUATIC ORGANISMS (2000 Jan 14), 39(2), 89-96.
Abstract:
Disinfection by ozonation of sea-water may reduce the risk of transmission of nodavirus, a major fish pathogen, via Atlantic halibut Hippoglossus hippoglossus eggs. In the present study, eggs at 4 d prior to hatching were exposed to nodavirus and then to ozonated sea-water using different concentrations (0.3 to 10 mg l-1) and exposure times (0.5 to 10 min). None of the larvae from virus-exposed eggs washed with ozonated sea-water developed viral encephalopathy and retinopathy (VER), which was detected in all dead larvae from eggs exposed to nodavirus but not washed with ozonated sea-water. In the non-treated control group about 20% of the dead larvae developed the disease. This suggests that the halibut eggs taken from a large-scale production facility were already contaminated with nodavirus. The egg groups which had been treated with 4 mg O3 l-1 for 0.5 min or with lower total ozone exposures had a higher survival and no adverse effects on the development of the larvae after hatching were observed. Although a slight delay in hatching was found, after 2 d the cumulative hatching had normalised. In the egg groups with high total exposure (4 mg O3 l-1 for 1 min or higher total ozone exposures) a pronounced negative effect on hatching was observed. Our results indicate that the egg surface may be important in the transfer of nodavirus and that nodavirus associated with the surface of the egg may be inactivated by ozonated sea-water.
