School of Earth and Environment, Leeds University, UK; Charney School of Marine Sciences, Haifa University, Israel.
The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel.
Water Res. 2014 Jun 1;56:109-21. doi: 10.1016/j.watres.2014.02.049. Epub 2014 Mar 11.
Simultaneous removal of nitrogen and phosphorus by microbial biofilters has been used in a variety of water treatment systems including treatment systems in aquaculture. In this study, phosphorus, nitrate and sulfate cycling in the anaerobic loop of a zero-discharge, recirculating mariculture system was investigated using detailed geochemical measurements in the sludge layer of the digestion basin. High concentrations of nitrate and sulfate, circulating in the overlying water (∼15 mM), were removed by microbial respiration in the sludge resulting in a sulfide accumulation of up to 3 mM. Modelling of the observed S and O isotopic ratios in the surface sludge suggested that, with time, major respiration processes shifted from heterotrophic nitrate and sulfate reduction to autotrophic nitrate reduction. The much higher inorganic P content of the sludge relative to the fish feces is attributed to conversion of organic P to authigenic apatite. This conclusion is supported by: (a) X-ray diffraction analyses, which pointed to an accumulation of a calcium phosphate mineral phase that was different from P phases found in the feces, (b) the calculation that the pore waters of the sludge were highly oversaturated with respect to hydroxyapatite (saturation index = 4.87) and (c) there was a decrease in phosphate (and in the Ca/Na molar ratio) in the pore waters simultaneous with an increase in ammonia showing there had to be an additional P removal process at the same time as the heterotrophic breakdown of organic matter.
微生物生物滤池同时去除氮和磷已应用于各种水处理系统，包括水产养殖处理系统。在这项研究中，通过对消化池污泥层的详细地球化学测量，研究了零排放、循环海水养殖系统厌氧循环中的磷、硝酸盐和硫酸盐循环。由于微生物在污泥中的呼吸作用，高浓度的硝酸盐和硫酸盐（约 15 mM）在覆盖水中循环，导致硫化物积累高达 3 mM。对表面污泥中观察到的 S 和 O 同位素比值的模拟表明，随着时间的推移，主要的呼吸过程从异养硝酸盐和硫酸盐还原转变为自养硝酸盐还原。与鱼粪相比，污泥中无机 P 的含量要高得多，这归因于有机 P 向自生磷灰石的转化。这一结论得到了以下几点的支持：(a) X 射线衍射分析表明，积累了一种不同于粪便中发现的 P 相的磷酸钙矿物相；(b) 计算表明，污泥的孔隙水对羟基磷灰石高度过饱和（饱和度指数为 4.87）；(c) 同时存在磷酸盐（以及 Ca/Na 摩尔比）的减少和氨的增加，表明在异养分解有机物的同时，必须有一个额外的 P 去除过程。
