Search

Effectiveness of macroalgae was investigated for enhancing wastewater treatment processes. Bioremediation using macroalgae could remove nitrate and phosphate contaminants in the water where algae assimilate nitrogen and phosphorus and convert them to biomass. This study evaluates the effects of high nitrate concentration on the kinetics of cell growth during nitrate and phosphate removal by a macroalga Cladophora glomerata. The algal growth and nitrate removal from media containing initial nitrate concentrations of 5mg/L to 400 mg/L were monitored in batch growth, whereas control media has no additional nitrate. Light exposure was kept for 12 and 20 hours. The purpose of this research was to find out the effect of various nitrate concentrations on nitrate and phosphate removal with macroalgal growth. Maximum growth kinetic reaches ?=0.075/day in 20 hours light exposure with 100 mg/L initial nitrate concentration. Nitrate and phosphate reach about 90% removal rates on the fifth day. Nitrate concentration was not significantly affected by biomass growth (Pearson correlation: 0.295). But, phosphate concentration has a moderate correlation with macroalgae biomass (Pearson correlation: 0.533).

Abstract Characterization and removal of natural organic matter, which is contained in the effluent of slow sand filters, was observed by alum coagulation under various dosages. In addition to non-purgedable dissolved organic carbon (NPDOC), trihalomethanes formation potential (THMFP) and haloacetic acid formation potential (HAAFP) measurement, high-performance size-exclusion chromatography (HPSEC) with ultraviolet/visible and dissolved organic carbon (DOC) detectors was used to characterize the various organic fractions contained in the water before and after coagulation. The results show that alum coagulation could effectively remove hydrophobic aromatic, which forms mainly humic substances. The reduction in THMFP was found to be higher than that of NPDOC and HAAFP under specific alum dosage, and the former was also found to be proportional to the corresponding reduction in the area of hydrophobic aromatic fraction, mostly humic subtances, as obtained from HPSEC chromatogram with peak-fitting.

Microalgae is a microscopic plant that has chlorophyll for carrying out photosynthesis. Chlorella sp. is one of the most easily found microalgae in the aquatic. Chlorella sp needs some nutrients such as nitrate and total phosphate for growing. There are many ways to develop microalgae, and an algae reactor is more effective on a large scale. Algae reactor has the same concept with oxidation ditch by using different microorganisms. This study applied an oxidation ditch reactor filled with microalgae Chlorella sp for treating domestic wastewater in terms of nitrate and phosphate concentration. Variation of rotational speed airbrush (45 and 60 rpm) and ratio volume of waste to microalgae (3:1, 4:1, 5:1, 6:1) were performed. The sample was collected for 5 days and measured for nitrate and phosphate concentration. The result shows that the optimum removal of nitrate and total phosphate is about 63.64% and 66.15%, respectively, with an under-speed variation of 60 rpm and a volume ratio of 3: 1. This study concludes that oxidation ditch reactor-filled microalgae Chlorella sp had performed an effective process in removing nitrate and total phosphate under optimum speed rotation and a low ratio of waste microalgae. [ABSTRACT FROM AUTHOR]

Wastewater treatment with microalgae such as oxidation ditch algae reactor (ODAR) could reduce organic matter, however, the process might produce by-products that are toxic when dissolved in water. Effluent organic matter and algae organic matter are by-products of the microalgae process, that are released as well in ODAR system. The presence of these compounds in water can be a precursor for the formation of disinfection by-products (DBPs). The aim of this study is to determine the characteristics of effluent organic matter contained in domestic ODAR using the microalgae Chlorella sp. under variations of oxic and oxic-anoxic conditions. Novelty of this study is oxidation ditch combined with microalgae and the effect of aeration and intermittent aeration in the quality of wastewater effluent. Microalgae were applied in ODAR under oxic for 24 hours of aeration and oxic-anoxic through a brush aerator on for 7 hours and off for 3 hours with a ratio of waste volume to microalgae 1:1 with sampling time up to 5 hours. The results showed that BOD concentration tends to decrease up to 45% and 67% for oxic-anoxic and oxic, respectively. The UV254 value increased up to 110% and 147% for oxic-anoxic and oxic, respectively. Further, fluorescence excitation-emission matrix (FEEM) analysis identified the changing of four organic fractions as measured by the fluorescence regional index (FRI). The results indicate a decrease of aromatic protein-like significantly up to 62% and a decrease in soluble microbial products up to 30%. While humic acid-like and fulvic acid-like tends to increase by about 25-29% and 44-46%. [ABSTRACT FROM AUTHOR]

Aquatic organic matters refer to chemical compounds that result from natural processes in the environmental including algae metabolic reactions and decomposition of organic matter. The removal of NOM is the most effective effort to minimize the generation of disinfection by-products (DBPs). Aims of this research are to compare various treatments in controlling aquatic organic matters, which caused the formation of the carcinogenic compound. Combination processes of pre-chlorination, coagulation with alum and FeCl3 and adsorption with powdered activated carbon (PAC) was applied under different dosage. TOC and UV254 were measured to quantify organic matters, Fourier Transform Infrared (FTIR) was applied to identify organics properties, and CHCl3 was measured to know carcinogenic concentration. The results showed that pre-chlorination only caused the formation of lower molecular weight, pre-chlorination followed by coagulation combined with adsorption showed a better result than coagulation-adsorption only. FeCl3 coagulant is more effective than alum. Aromatic compounds are a precursor for the formation of CHCl3, since removal UV254 along with CHCl3 concentration. [ABSTRACT FROM AUTHOR]

Surface water is mainly used as source water after treatment process to produce drinking water or clean water. The existence of natural organic matter (NOM) in surface water caused some problems in water treatment, instead of taste and aesthetic issues. Preoxidation and prechlorination are oxidation processes that have been used widely for different purposes in water treatment process. The objective of the study was to compare performance of permanganate preoxidation and prechlorination in removing NOM and to know the changing of NOM in term of its functional group properties by using Fourier-Transform Infrared (FTIR). TOC concentration and UV210 value were used to represent NOM parameter. The results showed that prechlorination has a higher performance to treat NOM in water than permanganate preoxidation. Further, prechlorination could be considered as pretreatment of coagulation in order to improve its performance in removing TOC concentration and aromatic compounds. FTIR could be applied to track the changing of NOM functional groups, and organic properties in prechlorination followed by alum coagulation have the lowest percentage transmittance. [ABSTRACT FROM AUTHOR]

Implementation of microalgae has been considered for enhancing effluent wastewater quality. However, it can cause environmental issues due to the release of extracellular and algal organic matter in the biological process. This study aimed to investigate the characteristics of dissolved effluent as algae- and bacteria-derived organic matter during the oxidation ditch process. Furthermore, experiments were conducted under three combinations filled by Spirulina platensis, Chlorella vulgaris, and without microalgae. The results showed that dissolved effluent organic matter was more aromatic and hydrophobic than before treatment. Fluorescence spectroscopy identified two components—aromatic protein–like and soluble microbial product–like components—at excitation/emission of 230/345 nm and 320/345 nm after treatment, instead of fulvic acid–like at 230/420 nm and humic acid–like at 320/420 nm in raw wastewater. These components were fractionated based on the average of molecular weight cut-offs (MWCOs), and high (MWCOs > 50,000 Da), medium (MWCOs 50,000–1650 Da), and low molecular weights (MWCOs < 1650 Da) were reported. Biological oxidation ditch under symbiosis algal bacteria generated humic and fulvic acid with a higher MWCOs than the process without algal. The quality and quantity of dissolved effluent organic matter in an oxidation ditch reactor were significantly affected by algal-bacteria symbiotic. [ABSTRACT FROM AUTHOR]

Combination of constructed wetland with activated sludge (AS) is one of the application of sustainable development for dealing with environmental pollution. The objective of this study was to compare the performance of three system of domestic wastewater treatment, namely AS, combination AS with constructed wetland containing Canna lily (AS‐CWC), combination AS with constructed wetland containing Cyperus papyrus (AS‐CWP) for treating domestic wastewater. Mini pilot scale of treatment system was built under continuous flow. Samples were taken at outlet in each unit for measuring water quality parameters, such as BOD, TSS, PO43−, NH4+‐N and NO3−‐N. The results indicated that AS‐CWC performed a higher removal of BOD, PO43− and TSS than AS‐CWP and AS. AS‐CWC and AS‐CWP showed a statistically insignificant difference removal of NH4+‐N and NO3‐‐N, though the former performed a higher removal than the later. This study revealed that TOC increased in the highest percentage in AS and the lowest increasing in AS‐CWP. Constructed wetlands should be integrated with primary treatment to enhancing effluent quality and reduce organic matter, a precursors of carcinogenic compound. [ABSTRACT FROM AUTHOR]

Effectiveness of macroalgae was investigated for enhancing wastewater treatment processes. Bioremediation using macroalgae could remove nitrate and phosphate contaminants in the water where algae assimilate nitrogen and phosphorus and convert them to biomass. This study evaluates the effects of high nitrate concentration on the kinetics of cell growth during nitrate and phosphate removal by a macroalga Cladophora glomerata. The algal growth and nitrate removal from media containing initial nitrate concentrations of 5mg/L to 400 mg/L were monitored in batch growth, whereas control media has no additional nitrate. Light exposure was kept for 12 and 20 hours. The purpose of this research was to find out the effect of various nitrate concentrations on nitrate and phosphate removal with macroalgal growth. Maximum growth kinetic reaches µ=0.075/day in 20 hours light exposure with 100 mg/L initial nitrate concentration. Nitrate and phosphate reach about 90% removal rates on the fifth day. Nitrate concentration was not significantly affected by biomass growth (Pearson correlation: 0.295). But, phosphate concentration has a moderate correlation with macroalgae biomass (Pearson correlation: 0.533). [ABSTRACT FROM AUTHOR]

Integrated constructed wetland into activated sludge process has a potential in improving treated wastewater with high organic loading. However, biological activities on those processes will generate microbial by-products from substrate metabolism and cell lysis. The presence of those compounds in effluent of wastewater treatment causes problems in source water. This study combines fluorescence excitation emission matrices (FEEM) with high-performance size exclusion chromatography with fluorescence detector (HPSEC-FLD) to characterize molecular weight–based fluorescent of organic matter and its removal in combination of constructed wetland with activated sludge process. The results show that three components of fluorescence organic: fulvic acid–like (Ex/Em 250/440 nm), SMP-like (Ex/Em 280/350 nm), humic acid–like (Ex/Em 340/420 nm), have been identified in all samples by the FEEM. Further, the HPSEC-FLD, which was set up based on chosen fluorescence wavelength, revealed two different apparent molecular weight (AMW) fractions: high molecular weight (HMW)/biopolymer (50,000 Da) and medium molecular weight (MMW)/humic substance–like (3000–650 Da). Peak-fitting determines that the area of MMW is higher than the area of HMW of all fluorescence organic components, and the area of HMW of fluorescence fulvic acid–like is comparable with the area of SMP-like, and no HMW of humic acid–like detected. Humic acid–like and fulvic acid–like were removed during treatment, while metabolite by-product were released as shown by increasing fluorescence SMP-like and TOC concentration. This method gives new insight to characterize organic matter for assessing effluent of wastewater quality and determining the appropriate water treatment. [ABSTRACT FROM AUTHOR]

CO2 emissions resulting from human activities are relatively higher concentrations that disrupt the equilibrium system in the air and ultimately damage the environment and human well-being. One environmentally friendly solution for CO2 gas removal is to use microalgae (Chlorella sp.). Chlorella sp. in photobioreactors has the ability to biofixate CO2 gas. Chlorella sp. was chosen because of the most numerous in freshwater and seawater. The purpose of this study was to determine the kinetic model of the effect of adding substrate concentrations and flow rate variations on the growth and development rates of Chlorella sp. due to exposure to pure CO2 gas emissions. This study uses pure CO2 gas with a flow rate of 0.02 L/min, 0.04 L/min, 0.06 L/min, 0.08 L/min, 0.1 L/min and a substrate of 350 mg/L, 500 mg/L, 650 mg/L, 800 mg/L, 950 mg/L on a laboratory scale. The results showed that the most optimum growth rate occurred at the addition of substrate concentrations of 800 mg/L with a flow rate of 0.08 L/min. [ABSTRACT FROM AUTHOR]

In this study, natural organic matter (NOM) in source water, as well as the treated water after coagulation with or without potassium permanganate (KMnO4) preoxidation, was characterized by using high performance size exclusion chromatography with organic carbon detector (HPSEC-OCD) and fluorescence excitation emission matrices (F-EEMs) with parallel factor (PARAFAC) analysis. Bulk parameters, such as dissolved organic carbon (DOC) and ultraviolet light absorbance at 254 nm (UV254), were also analyzed. The results show that KMnO4preoxidation caused the breakdown of high molecular weight (MW) organics into low MW organics. All organics, whether those that existed in the source water or those generated by KMnO4preoxidation, could be partly removed by coagulation. Combining the derived organic fractions obtained from HPSEC-OCD with peak-fitting and from F-EEMs with PARAFAC on the same sample, humic substances have been specified as the main organic composition. Further, the predictive models for trihalomethanes formation potential (THMFP) and haloacetic acids formation potential (HAAFP) based on organic fractions from HPSEC-OCD have higher accuracy than those based on the components from PARAFAC modeling. These models provide useful tools to specify the organic fractions from HPSEC-OCD and F-EEMs that constitute active precursors towards trihalomethanes (THMs) or haloacetic acids (HAAs) formation in water. Further, by knowing the major organic precursors, it would facilitate choosing the appropriate water treatment process for disinfection by-products (DBPs) control. [ABSTRACT FROM PUBLISHER]