Biological treatment of shrimp production wastewater

Abstract

Over the last few decades, there has been an increase in consumer demand for shrimp, which has resulted in its worldwide aquaculture production. In the United States, the stringent enforcement of environmental regulations encourages shrimp farmers to develop new technologies, such as recirculating raceway systems. This is a zero-water exchange system capable of producing high-density shrimp yields. The system also produces wastewater characterized by high levels of ammonia, nitrate, nitrite, and organic carbon, which make waste management costs prohibitive. Shrimp farmers have a great need for a waste management method that is effective and economical. One such method is the sequencing batch reactor (SBR). A SBR is a variation of the activated sludge biological treatment process. This process uses multiple steps in the same reactor to take the place of multiple reactors in a conventional treatment system. The SBR accomplishes equalization, aeration, and clarification in a timed sequence in a single reactor system. This is achieved through reactor operation in sequences, which includes fill, react, settle, decant, and idle. A laboratory scale SBR was successfully operated using shrimp aquaculture wastewater. The wastewater contained high concentrations of carbon and nitrogen. By operating the reactors sequentially, namely, aerobic and anoxic modes, nitrification and denitrification were achieved as well as removal of carbon. Ammonia in the waste was nitrified within 4 days. The denitrification of nitrate was achieved by the anoxic process, and 100% removal of nitrate was observed within 15 days of reactor operation.

Effect of carbon to nitrogen (C:N) ratio on nitrogen removal from shrimp production waste water using sequencing batch reactor

“…Bacteria in the sludge include Nitrosomonas, Nitrobacter, and Pseudomonas spp. [5], and this sludge provided microorganisms for nitrification and denitrification reactions in the SBR.…”

Evaluating effects of biobased 2,5‐furandicarboxylate esters as plasticizers on the thermal and mechanical properties of poly (vinyl chloride)

“…Moreover, unlike phthalates, furan compounds are metabolized during the Krebs cycle. 35,36 In this study, three FDCA esters, dibutylfuran-2,5-dicarboxylate (DBF), diisoamylfuran-2,5-dicarboxylate (DIAF), and di-(2-ethylhexyl)furan-2,5-dicarboxylate, were synthesized and used to plasticize PVC from 10 to 50 parts per hundred (phr). Fourier transform infrared (FTIR) spectroscopy, mechanical testing, scanning electron microscopy (SEM), differential scanning calorimetry (DSC), DMTA, thermogravimetric analysis (TGA), melt flow rate (MFR) measurement, and migration measurements were used to investigate the comprehensive properties of the blended products.…”

Characterization of Nitrifying Bacterial Community in a Mariculture Wastewater Treatment Using SBR System

“…However, in some cases the costly equipment and complex operations sometimes discourage extensive use of these systems. To attempt to solve these issues, a SBR system was introduced for shrimp wastewater treatment initially in Thailand (Paungfoo et al 2007) and subsequently in South Carolina (Boopathy et al 2009;Fontenot et al 2007;Roy et al 2010). The use of one tank with multiple reaction steps considerably lowered the running costs and complexity of the system.…”

“…However, the functional nitrifying bacteria in the systems were not thoroughly studied, the sludge carrier material was either absent or carried with air stones, and the processing time was relatively long, i.e. about 3.5-8 d of hydraulic retention time (HRT) (Paungfoo et al 2007;Boopathy et al 2009 ;Fontenot et al 2007;Roy et al 2010). In this study, a four sequential step SBR system was developed to treat mariculture wastewater and the effects of local nitrifying bacteria was identified with molecular and microscopy techniques.…”