Regulation of water quality and growth characteristics of indoor raceway culture of Litopenaeus vannamei

Two modes of regulating the water quality of experimental ponds in indoor raceway culture of Litopenaeus vannamei were evaluated using simple water treatment facilities. A self-made water purifying net, aeration stone, composite microbe preparation, and Ceratophyllum demersum were placed in the experimental ponds and the culture water was circulated along the raceway inside the pond using a paddle wheel aerator. In addition, the water quality in the experimental pond was improved by draining effluent from the pipeline at the bottom of ponds 7 and 8 （mode I） and exchanging the circulating water in pond 10 （mode Ⅱ） with the reservoir water in pond 9 using a pump and pipeline. The water quality in the experimental ponds was similar in response to regulation using mode Ⅰ or mode Ⅱ. Water quality parameters in the experimental ponds were controlled within a suitable range by simple facilities during culture period without using any chemical treatments. The rich content of dissolved oxygen was maintained by the circular flow and continuous aeration of the pond water. The respective average values of the main water parameters in experimental ponds 7 and 10 in response to regulation of the water quality using modes Ⅰ and Ⅱwere as follows： pH 8.17 and 7.99; DO 5.16 mg/L and 5.97 mg/L; CODMn18.45 and 12.61 mg/L; TAN （NH3-N） 0.854 mg/L （0.087 mg/L） and 0.427 mg/L （0.012 mg/L）; NO2-N 0.489 mg/L and 0.337 mg/L. Moreover, the average body length and body weight of harvested shrimp of pond 7 and pond l0 were 7.56 cm and 8.99 cm, 5.10 g and 8.33 g, respectively. Furthermore, the survival rate, average biomass yield and average condition factor of the shrimp harvested were 70% and 60%, 2.54 kg/m2 and 2.14 kg/m2, and 0.675 g/cm and 0.927 g/cm, respectively. Linear equations describing the relationship between body length and culture time and cubic or power functions describing the relationship between body weight and body length were obtained based on evaluation of the growth data of shrimps throughout the culture period.

Chang Gao Brand Water Purifier & Mineralizer

People are making excessive demands for their drinking water as they pay more and more attentions to the quality of life. Mineral water contains more calcium, magnesium and lots of trace elements than the running water, and therefore it is good for the digestion, promotion of metabolism, prevention of cardiovascular diseases and osteoporosis, and promotion of Children growth. It has become a favourite drink for many people.

Guanyin Water Purifier

The Beijing Guanyin Water Purifying Technical Co. Ltd. is a manufacturing company, specialized in producing water purifying equipment, with water purifying technology imported from the United States and its combination of specific resources from China. The said company produces Guanyin water purifier which is a kind of renovated and high efficiency family water purifier of the water tap type. It is fitted with dual water outlets and a multi-stage filtering device, which helps prolong its service life. Different to other makes,

Sensitive Determination of Five Priority Haloacetic Acids by Electromembrane Extraction with Capillary Electrophoresis

A method for sensitive determination of five priority haloacetic acids in drinking water has been developed for the first time based on electromembrane extraction(EME)prior to CZE with capacitively coupled contactless conductivity detection(CZE-C^(4)D).The target analytes were extracted from 10 mL of the sample solution(donor phase),through the supported liquid membrane(using a polypropylene membrane supporting 1-octanol),and into 10μL of 50 mmol/L NaAc solution(acceptor phase).The extracted solution was directly analyzed by CZE-C^(4)D without de-rivatization.Several factors that affect separation,detection and extraction efficiency were investigated.Under the optimum conditions,five haloacetic acids(monochloroacetic acid,dichloroacetic acid,trichloroacetic acid,mono-bromoacetic acid,and dibromoacetic acid)could be well separated from other components coexisting in water samples within 23 min,exhibiting a linear calibration over two orders of magnitude(r≥0.9943);the enrichment factors at 430-671 were obtained in a 30 min of extraction,and the limits of detection were in the range of 0.17-0.61 ng/mL.The intraday relative standard deviations for peak areas investigated at 10 ng/mL were between 1.2%and 9.7%for the combined EME-CZE-C^(4)D procedure.This approach offers an attractive alternative to the officially proposed method for purified drinking water analysis,which requires derivatization procedure prior to gas chromatography analysis.