海水闭合循环系统生物滤器微生物特性研究

利用扫描电镜以察、荧光显微镜计数、氚化胸苷示踪等方法，研究了盐度为35的海水闭合系统生物滤器稳定成熟过程中，生物膜生物相的构建及系统中三态氮等水质指标的变化情况等。结果表明，海水闭合循环系统生物滤器可以建立完整的硝化作用，其稳定成熟过程与淡水及咸淡水生物滤器的情况相同，只是亚硝酸氧化滞后现象比较明显、细菌及其他牛物的变化与水化学指标的变化相吻合。试验系统达成熟状态需75d左右。     

不同用量的呼吸环和陶瓷环处理养殖废水中氨氮的效果

采用挂膜法在曝气式生物滤池中比较分析不同用量的呼吸环和陶瓷环处理养殖废水时NH_4~+-N,NO_2~--N的质量浓度变化,并构建浓度变化模型公式。结果表明,不同生物滤料、不同用量的NH_4~+-N质量浓度均随处理时间延长而逐渐下降,NO_2~--N质量浓度先上升至峰值然后下降。14%红色呼吸环、10%红色呼吸环NH_4~+-N和NO_2~--N处理效果最优,处理的第21~23天NH_4~+-N达最低值(0.056±0.014)mg·L~(-1),去除率为97.37%;处理的第10天NO_2~--N达到峰值(1.722±0.014)mg·L~(-1),第24~26天达最低值(0.024±0.009)mg·L~(-1)。不同比例不同生物滤料NH_4~+-N去除效果满足模型公式y=a/(1+be~(cx))+d,NO_2~--N去除效果满足模型公式y=x~ae~((b/x+cx))+d。     

抽屉式生物滤器在漠斑牙鲆循环水养殖中的效果研究

采用自行设计的抽屉式生物滤器应用于漠斑牙鲆(Paralichthys lethostigma)闭合循环水养殖系统,研究其对循环养殖水的处理效果及漠斑牙鲆的增重和饲料利用率的影响。结果表明:经过60 d的循环水养殖,漠斑牙鲆从初始时的(225.4±11.9)g增加到结束时的(337.5±10.3)g,增重率49.97%;试验饲料系数1.06,养殖密度24.1 kg/m3,成活率100%;抽屉式生物滤器对于NH4+-N、NO2--N和COD去除率分别为(10.61±1.88)%、(14.90±3.06)%和(16.11±1.70)%,可满足漠斑牙鲆养殖水体的水质要求。     

Degradation and effect of hydrogen peroxide in small‐scale recirculation aquaculture system biofilters

From an environmental point of view, hydrogen peroxide (HP) has beneficial attributes compared with other disinfectants in terms of its ready degradation and neutral by‐products. The rapid degradation of HP can, however, cause difficulties with regard to safe and efficient water treatment when applied in different systems. In this study, we investigated the degradation kinetics of HP in biofilters from water recirculating aquaculture systems (RAS). The potential effect of HP on the nitrification process in the biofilters was also examined. Biofilter elements from two different pilot‐scale RAS were exposed to various HP treatments in batch experiments, and the HP concentration was found to follow an exponential decay. The biofilter ammonia and nitrite oxidation processes showed quick recuperation after exposure to a single dose of HP up to 30 mg L^?1. An average HP concentration of 10–13 mg L^?1 maintained over 3 h had a moderate inhibitory effect on the biofilter elements from one of the RAS with relatively high organic loading, while the nitrification was severely inhibited in the pilot‐scale biofilters from the other RAS with a relatively low organic loading. A pilot‐scale RAS, equipped with two biofilter units, both a moving‐bed (Biomedia) and a fixed‐bed (BIO‐BLOK^®) biofilter, was subjected to an average HP concentration of ～12 mg L^?1 for 3 h. The ammonium‐ and nitrite‐degrading efficiencies of both the Biomedia and the BIO‐BLOK^® filters were drastically reduced. The filters had not reverted to pre‐HP exposure efficiency after 24 h, suggesting a possible long‐term impact on the biofilters.     

循环流水水产养殖系统接种商品硝化菌的试验研究

与接种成熟滤料等方法相比,利用商品硝化菌接种生物滤器来源广泛,操作简便。本文使用一种商业上已取得一定成功的商品硝化菌液接种循环流水水产养殖系统试验模型的生物滤器。试验开始时定期接人20mL菌液(细菌含量1.5×10~10CFU·mL~(-1))以处理400g饲料产生的4.27mg·L~(-1)氨氮(TAN),12d后TAN浓度低于0.05mg·L~(-1),20d后NO_2~- -N浓度降至同样水平。在为期30d的检验期中,系统内养殖2.15kg·m~(-3)淡水白鲳,日喂饲率2％。期间养殖池TAN最大值0.465mg-L~(-1),最小值0.393mg·L~(-1),平均值0.427±0.019mg·L~(-1);NO_2~- -N最大值0.062mg·L~(-1),最小值0.038mg·L~(-1),平均值0.052±0.007mg·L~(-1);EC呈线性上升状态,每周增加32.8 μs·cm~(-1);而pH呈线性下降,每周降低0.24。系统结束时生物滤器含细菌8.65×10~6CFU·mL~(-1),水质除TP超标外,其余指标均符合我国淡水水产养殖水质标准,在2.1％～1.4％的日喂饲率下淡水白鲳日增重为1.91g,饲料系数1.164。     

虹鳟鱼在双层浮球式生物滤器封闭循环水系统中的养殖试验

本文介绍了虹鳟鱼在双层浮球式生物滤器封闭循环式养殖系统中的养殖试验。该养殖系统主要包括射流暴气增氧、沉淀分离和双层浮球生物过滤器过滤,过滤悬浮物能力达到90％,氨氮处理能力达到149~(gm-3.d-1)(在养殖水体15度条件下),利用臭氧催化氧化法完成杀菌、消毒及二次去除氨氮作用。在8个养殖水体为1m~3的养殖池,放养1015尾平均体重240g虹鳟鱼的循环水养殖系统中,应用动力为0．75kW、处理能力为20 T/h的BAF—20型双层浮球生物过滤设备进行循环养殖水体的处理。在养殖试验过程中,对养殖水体的pH、DO、COD、悬浮物、氨氮、亚硝酸盐、硝酸盐等水化学指标进行了监测,并对虹鳟鱼在养殖过程中不同阶段的生长情况进行了测量。结果表明,在水体循环周期为2次/h,换水周期为一次/每两周的条件下COD≤15mg/l、氨氮≤1mg/l、亚硝酸盐≤0．13mg/l、硝酸盐≤24mg/l,经对比养殖试验表明,没有循环鱼池的水体和经过浮球式生物滤器封闭循环系统的循环水体的各项指标具有明显的差别。试验表明浮球式生物滤器封闭循环水系统完全满足虹鳟鱼工厂化养殖生产的要求,确保虹鳟鱼养殖水体的水质和鱼类生长环境,达到良好养殖效果。     

生物过滤器在农业臭气处理中的应用

针对当前集约化养殖引起的环境污染问题,提出用生物过滤器处理农业臭气。介绍了欧美国家用生物过滤器处理废气的发展情况及用前景;概述了生物过滤器处理废气的机理、流程和主要设备;讨论了生物过滤器在处理废气方面的发展趋势,特别是在农业生产方面的发展趋势。     

复合生物滤池与人工湿地组合工艺处理农村生活污水工程实例

以苏州太湖流域衙甪里村为例,介绍了复合式生物滤池与人工湿地组合工艺对农村生活污水处理的工程实例应用。运行结果表明:该村生活污水经复合式生物滤池与人工湿地组合工艺处理后,其COD、NH3-N、TN和TP指标均达到《GB18918—2002城镇污水处理厂污染物排放标准》一级B标准,部分指标达到一级A标准要求,运行稳定且成本低廉,说明复合式生物滤池与人工湿地组合工艺适宜在太湖流域农村地区推广应用。     

Productive performance of juvenile freshwater prawns Macrobrachium rosenbergii in biofloc system

The aim of this study was to compare two rearing systems for freshwater prawn Macrobrachium rosenbergii: one with use of a recirculating aquaculture system with biofilters (RAS) and another with use of microbial flocs (F). Thirty postlarvae of freshwater prawn with an initial average weight of 0.13 ± 0.05 g were randomly stocked in six experimental units with 0.20 m² and volume of 50 L. The experiment lasted thirty days. Dissolved oxygen, temperature and pH were monitored daily; ammonia concentration was determined three times per week; nitrite concentration, alkalinity and hardness were measured weekly. For the formation of microbial floc, molasses was used to keep the ammonia concentrations within safe levels for prawn farming. The variables of water quality remained within the suitable range for the production of the species, except for ammonia concentrations at the F treatment, which exceeded the safe levels. At the end of the experiment, the following parameters were evaluated: survival, specific growth rate, weight gain and feed conversion rate. Differences were found only in feed conversion rate with better values on RAS treatment. The microorganisms present in the RAS and F treatment were also evaluated. The densities of rotifers, amoebas and total bacteria were higher at the F treatment although the same organisms were found at the RAS treatment. The results of this study showed the possibility of rearing M. rosenbergii in biofloc system technology.     

Use of a field-scale biofilter for the degradation of the organophosphate insecticide coumaphos in cattle dip wastes

Insecticide wastes generated from livestock dipping operations are well suited for biodegradation processes since these wastes are concentrated, contained, and have no other significant toxic components. A field-scale biofilter capable of treating 15000-litre batches of dip waste containing the acaricide coumaphos was used to reduce the coumaphos concentration in two successive 11000-litre batch trials from 2000 mg litre^-1 to 10 mg litre^-1 in approximately 14 days at 25–29°C. Removal of coumaphos from the biofilter effluent is a function of both physical filtration and biodegradation by the biofilter. However, stoichiometric increases in chloride levels in the effluent as coumaphos concentrations decreased confirmed that coumaphos was being degraded by the biofilter rather than just being filtered out. In subsequent 5500-litre batch experiments, the addition of a vitamin supplement to the biofilter-treated dip resulted in a further decrease in coumaphos concentration to approximately 1 mg litre^-1. Results from incubations of two representative Texas soils with biofilter-treated dip spiked with [benzo-U-¹⁴C] coumaphos revealed that 32–36% of the spiked [¹⁴C] coumaphos was mineralized in the soils after 110 days at 30°C. © 1998 SCI.