Immobilized periphytic cyanobacteria for removal of nitrogenouscompounds and phosphorus from shrimp farm wastewater

Abstract

IntroductionAquaculture has grown rapidly over the last couple of decades due to significant increases in the demand for fish and seafood throughout the world. This intense development has resulted in the generation of large quantities of wastewater, which includes dissolved inorganic nitrogen and phosphorus (Kamilya et al., 2006). Nitrogenous compounds and phosphorus are major contaminants in aquaculture wastewater and their release into surrounding water bodies can cause eutrophication (Kamilya et al., 2006). It is imperative that this wastewater be treated by employing environmentally friendly and cost-effective methods.A number of techniques have been developed to control nitrogenous substances in aquaculture systems (Yusoff et al., 2011;Devaraja et al., 2013). Some of these processes tend to be either highly sophisticated or extremely complicated and expensive (Hoffmann, 1998). Several authors have demonstrated the use of cyanobacteria in treating wastewater from dairy (Boominathan and Manoharan, 2008), dye (Vijayakumar et al., 2005), and sewage (Manoharan and Subramanian, 1992), indicating that it may be a feasible option. This may be due to the fact that cyanobacteria have simple growth requirements and do not need energy-rich compounds like other nonphotosynthetic microorganisms. In addition, many cyanobacteria combine photosynthesis and nitrogen fixation, which is an advantage over other eukaryotic photosynthetic organisms (Vijayakumar, 2012).Most wastewater treatments describe microalgae growing in suspension, and there are reports of planktonic microalgae being used for removal of nitrogenous compounds from wastewater (Shelknanloymilan et al., 2012;Sriram and Seenivasan, 2012). However, one of the major limitations of this technology is the difficulty encountered in separating suspended biomass from the treated water discharge. As such, there has been an increased interest in using immobilized cyanobacteria to Abstract: Cyanobacteria can be used to remove nitrogenous compounds from wastewater, but a major bottleneck in the process is the separation of cyanobacterial biomass from the treated water discharge, which may cause eutrophication. The current study assessed the suitability of three periphytic cyanobacteria (Geitlerinema sp., Gloeotrichia sp., and Lyngbya sp.) isolated from shrimp ponds. These cyanobacteria were immobilized by self-adhesion to polyvinyl chloride sheets, forming mats, and were screened for their efficacy to reduce nitrogenous compounds and phosphorus. Among the three isolates, Geitlerinema sp. showed the highest reduction rate (98%) and was further tested using shrimp pond wastewater. The results showed that initial wastewater concentrations (mg L -1 ) of total ammonia nitrogen (5.0), nitrite nitrogen (2.9), and soluble reactive phosphorus (2.5) were significantly (P < 0.05) reduced within 7 days in tanks containing wastewater + Geitlerinema sp. mats (0.1, 0.2, and 0.8) compared to wastewater + substrate only (4.3, 2.7, and 2.3) or wastewater only (4.4, 2.8, and 2.4). In addition...

Potential of Synechococcus elongatus UTEX 2973 as a feedstock for sugar production during mixed aquaculture and swine wastewater bioremediation

“…Photosynthetic microorganisms such as algae and cyanobacteria (also known as blue-green algae) have been increasingly used in recent decades to treat different types of wastewaters such as aquaculture [ [27] , [28] , [29] , [30] , [31] ], swine [ 32 ], and sewage wastewater [ 33 , 34 ] to reduce inorganic nutrients, total dissolved solids, biological oxygen demand, and other harmful material. They can effectively uptake atmospheric carbon dioxide and nutrients from wastewater and convert them to cellular storage materials such as carbohydrates, lipids, and proteins in their biomass.…”

The usage of Cyanobacteria in wastewater treatment: prospects and limitations

“…showed the maximum reduction rate (98%), and wastewater concentrations and total ammonia nitrogen, nitrite nitrogen and soluble reactive phosphorus were reduced (Banerjee et al . 2015).…”