Bioluminescence-Based Method for Measuring Assimilable Organic Carbon in Pretreatment Water for Reverse Osmosis Membrane Desalination

Abstract

A bioluminescence-based assimilable organic carbon (AOC) test was developed for determining the biological growth potential of seawater within the reverse osmosis desalination pretreatment process. The test uses Vibrio harveyi, a marine organism that exhibits constitutive luminescence and is nutritionally robust. AOC was measured in both a pilot plant and a full-scale desalination plant pretreatment.In the desalination industry, reverse osmosis (RO) membrane fouling from biological growth, i.e., biofouling, causes loss of productivity and increases operating and maintenance costs. Given that RO has generally been used in warm water, because of geography or colocation with power plants, biological growth has been considered "the Achilles heel of membrane processes" (2). Heterotrophic biological growth can be reduced by limiting energy sources, i.e., organic carbon, through coagulation and/or biofiltration. Having a straightforward measurement tool available will enhance an operator's control of limiting substrate during treatment. This article presents a marine AOC test for determining the biological growth potential of water within the RO desalination pretreatment process.The method has been adapted from a previously published freshwater AOC assay (5), except that the saltwater test uses the marine test organism Vibrio harveyi. The principle of the AOC test is based on the observed growth of a nutritionally diverse organism in the water sample. The amount of biomass produced can be directly related to the easily assimilable organic substrate. Because V. harveyi (ATCC 700106; American Type Culture Collection, Manassas, VA) exhibits constitutive luminescence, the amount of light produced can be directly related to biomass, which can be correlated to the AOC in the water.Bacteria were recovered from stocks frozen at Ϫ80°C in marine broth and 10% glycerol by streaking onto marine agar containing (per liter) 10 g peptone, 5 g yeast extract, 15 g agar (BD and Co., Sparks, MD), and 20 g sodium chloride (EMD Chemicals, Gibbstown, NJ) and incubated (30°C) overnight. To prepare the refrigerated stock, a single colony was inoculated into a saline buffer (1ϫ M9 salts [BD and Co., Sparks, MD] in 1,000 ml Milli-Q water with 2% sodium chloride, 0.1 mM CaCl 2 , and 1.0 mM MgSO 4 and adjusted to pH 7.2) fortified with 2 mg of acetate-carbon/liter. The inoculated buffer was incubated for 7 days at 30°C, and then the stock was stored at 4°C for up to 30 days for the inoculation of water samples. The bacterial titer was monitored by performing serial dilutions onto marine agar and was generally close to 7 ϫ 10 6 CFU/ml. AOC-free glassware preparation and sample collection have been described previously (5). A high-sensitivity, automated, and programmable photon-counting luminometer was used (SpectraMax L luminescence microplate reader; Molecular Devices Inc., Sunnyvale, CA) in conjunction with very-lowcross-talk 96-well white polystyrene microtiter plates (manufacturer catalog no. 7571; Thermo Scientific Corporation, Milford, MA). ...

Assimilable Organic Carbon (AOC) in Soil Water Extracts Using Vibrio harveyi BB721 and Its Implication for Microbial Biomass

“…A recent work [24] showed the feasibility of using the naturally occurring luminous strain, V. harveyi BB721, in AOC assays for saline water samples. The strength of luminescence signals of the microbial biomass yielded were significantly related to the amount of organic carbon added.…”

A review research of assimilable organic carbon bioassay

“…It was in the studies on the regions where microbial growth in drinking waters was regulated by the content of phosphorus, rather than organic carbon [52][53][54] was developed. In the studies on reclaimed water and desalination of seawater, Weinrich et al [31] built the AOC bioassay with the bioluminescent derivatives of P17 and NOX as inoculum for reclaimed water and another AOC bioassay [30] with V. harveyi suitable for sea water. Moreover, further developments [9,41,55] have demonstrated that at these low AOC concentrations the attached bacterial (biofilms) growth occurs at very short contact times.…”

“…According to Hammes' [19] study, total cell count with fluorescence staining and flow cytometry replaced plate count method can be used to establish complete growth curves for a natural microbial consortium growing on AOC. Weinrich et al [30] used Vibrio harveyi, a marine organism that exhibits constitutive luminescence suitable for sea water and is nutritionally robust as AOC bioassay inoculum without construction of Table 3 The AOC values of water samples from three methods (cited from the paper of Liu [ bioluminescent AOC assay strains. Especially, the use of V. harveyi expanded the application field of AOC from freshwaters to seawater.…”

“…The international development of AOC bioassays[1,2,[18][19][20][21][22][23][29][30][31][32]35] Symbols: y year, d day, BGM bacterial growth measurement, IM indigenous microorganism, BM bioluminescent mutants, SPC spread plate count, TM turbidity measurement, ATP-L adenosine tri-phosphate luminescence, L luminescence, BL bioluminescence, TCC-FCM total cell count with fluorescence staining and flow cytometry.…”

Biofouling in capillary and spiral wound membranes facilitated by marine algal bloom

“…A common species of marine bacteria, Vibrio harveyi was used as model seawater bacteria. This species has been used as a standard bacterium for measuring assimilable organic carbon (AOC) in seawater (Weinrich et al, 2011). A pure strain of the bacteria (NCCB 79042) was inoculated in sterilised saline (34 g/L) medium for lucibacterium and incubated at 30 o C until the concentration reach ~100 million cells/ml.…”