Using residual water from a marine shrimp farming BFT system. part I: nutrient removal and marine microalgae biomass production

Abstract

Microalgae have great biotechnological potential but the high cost of traditional formulae culture media is one of the limiting factors to their commercial cultivation. As an alternative, the use of residual water from other activities has been proposed as a culture medium. The goal of this study was to produce Chaetoceros muelleri, Nannochloropsis oculata and Tetraselmis chuii biomass using residual water from an intensive Litopenaeus vannamei biofloc cultivation system and to verify the ammoniacal nitrogen, nitrite, nitrate and orthophosphate consumption. The microalgae cultures were developed until the second day of their stationary phase in the following treatments: 100% f/2 culture media; 100% residual water; residual water diluted 50% with marine water. T. chuii and N. oculata presented the best relative biomass average (576 mg L−1; 474 mg L−1)(P > 0.05). All the species completely assimilated the orthophosphate in 2 days. In 10 days, T. chuii and N. oculata assimilated 87% and 85% of nitrate respectively. It can be concluded that residual water from an L. vannamei biofloc cultivation system can be used as an alternative culture medium for T. chuii and N. oculata biomass production. Moreover, the microalgae biomass proved to be very effective in recycling the dissolved nutritive salts.

Using residual water from a marine shrimp farming BFT system. Part II: Artemia franciscana biomass production fed microalgae grown in reused BFT water

“…The higher final biomass explains the lower volume of T. chuii culture necessary for the daily 10 mg L −1 microalgae supply during the experiment. The difference in biomass production from these three microalgae species when grown in residual water from biofloc cultivation systems was also verified by Magnotti, Lopes, Derner & Vinatea (). These authors cultivated these three microalgae species for 10 days, with the same type of residual water and obtained final dried biomass of 702 ± 120 mg L −1 , 589 ± 89 mg L −1 and 170 ± 30 mg L −1 de T. chuii , N. oculata and C. Muelleri , respectively, without addition of sodium silicate for the diatom cultivation.…”

“…Therefore, this lower biomass gain may be associated to other residual water characteristics, not only the silicate privation as discussed by Magnotti et al . ().…”

“…Due to the small biomass gain, Magnotti et al . () do not recommend C. muelleri for biofloc residual water‐based cultivations, at least without the addition of silicate to the culture medium, and further studies are needed.…”

Growth of Chlorella vulgaris using wastewater from Nile tilapia (Oreochromis niloticus) farming in a low-salinity biofloc system

“…Regarding the removal of the nitrogen and phosphorus compounds, the values of our study may seem considerably lower when compared to some of the values described in literature, as in some studies they were up to 100% for nitrogen and phosphorus (e.g. Martinez, Sanchez, Jimenez, El Youfi, & Munoz, 2000;Magnotti, Lopes, Derner, & Vinatea, 2016). Even so, it is important to emphasize that the cultures in these studies were initially stocked with different densities, which causes faster assimilations and larger amounts when inoculated in higher density.…”

Fish farm effluents are suitable growth media for Nannochloropsis gaditana, a polyunsaturated fatty acid producing microalga

“…Biotreatment of aquaculture wastewaters with microalgae is an attractive approach for simultaneous costeffective microalgal mass production and sustainable wastewater remediation [21]. In fact, aquaculture effluents can be an excellent medium for algal growth [21][22][23][24][25][26], although these wastes contain residual organic compounds and other micropollutants. For instance, shrimp farm wastewater containing phosphorus, nitrogen and total and volatile suspended solids in high concentrations [21,27], is a suitable medium for microalgae cultivation [26].…”