Showing papers in "Japanese Journal of Water Treatment Biology in 2002"

Anaerobic Oxidation of Ammonium Confirmed in Continuous Flow Treatment Using a Non- woven Biomass Carrier

Abstract: Research was conducted to probe for useful applications of less commonly considered nitrogen bio-transformation processes including anaerobic ammonium oxidation (anammox) using continuous flow treatment with a non-woven biomass carrier for enrichment of slowly growing organisms. Reactors were seeded with sludge from an industrial denitrification unit process. Following seven weeks of operation under autotrophic anoxic conditions, disappearances of ammonium and nitrite with production of low levels of nitrate were evidenced at stoichiometric ratios approximating that of the anammox reaction documented at Delft University of Technology, The Netherlands. In subsequent loading rate studies, ammonium and total-nitrogen removal rates of 8.7 and 18.8 mg N l-1h-1, respectively, were achieved (hydraulic retention time, 9 h) . Furthermore a distinctly red biomass growth developed which is characteristic of the responsible microorganism (s) . The sequence of a 16S rDNA clone obtained from the red biomass matched that previously reported for the planctomycete firstly identified responsible for the reaction with a similarity score of 0.928 (99.1% sequence similarity) . To our knowledge, this constitutes the first substantiated confirmation of the biological anammox reaction outside of Europe.

Simultaneous Removal of TOC Compounds and NO3- in a Combined System of Chemical and Biological Processes for the Treatment of Wastewater from Rubber Thread Manufacturing.

Abstract: The inhibitory effects of 2-mercaptobenzothiazole (MBT), sulfur, stearic acid and Zn2+ contained in rubber thread wastewater on aceticlastic methanogens or nitrifyingbacteria were investigated. It was found that Zn2+ inhibited strongly the activity ofaceticlastic methanogens. After the pH of rubber thread wastewater was adjusted to 5, Zn2+ was removed to less than 5 mg l-1 by coagulation with addition of Na2S. After removal of Zn2+ in rubber thread wastewater, the TOC compounds and NH4+ were efficiently treated in anaerobic treatment followed by biological nitirification with recirculation. In this process, the TOC compounds and NO3- were simultaneously removed in the UAFP reactor. However, the TOC removal efficiency in the UAFP reactor decreased from 90% to 80% at the same TOC loading rate by recirculating the effluent from the nitirification reactor. Methane gas evolution rate also decreased proportionate to the decrease in the TOC removal efficiency. In addition, energy production of 19.5 kcal (l of rubber thread wastewater) -1 would be expected in the simultaneous treatment process.

Use of Hydrophilic Polytetrafluoroethylene (HPTFE) Membrane in Detecting Cryptosporidium Oocysts from Source Water

Abstract: A filtration and concentration method using hydrophilic polytetrafluoroethylene (HPTFE) membrane for detecting Cryptosporidium oocysts in source water is described. Ten liters of sample water spiked with approximately 115 or 230 oocysts, were filtered through 142 mm diameter HPTFE membrane with a pore size of 5.0μm. The oocysts captured on the filter were eluted by vortexing then concentrated by centrifugation. Subsequently, the oocysts in the suspension were purified by the immunomagnetic separation (IMS) method and stained with IFA. In addition, recovery efficiencies of the capsule filter filtration method using the IMS method were evaluated. The mean recovery efficiencies obtained were 48% for source water (n=37) and 20% for tap water (n=3) by the HPTFE membrane method, and 19% for source water (n=12) and 5% for tap water by the capsule filter filtration method (n=3) . The total processing (filtration and concentration) time for the HPTFE membrane method was 30 min. These findings demonstrated that the HPTFE method was simple, easy, economic, and rapid, with considerably high recovery efficiency.

Cassava Starch Processing Wastes: Potential Pollution and Role of Microorganisms

Abstract: As a result of agriculture, urban and industrial activities, wastes and residues are increasing and are causing environmental pollution. Current cassava starch industry processing, which is discharging voluminous amounts of solid waste and wastewater, is reappeared in this review. Potential pollutions of cassava starch processing (CSP) wastes including two major problems: high loading of organic compound and cyanide content in the exceeding limit are also indicated. The important role of microorganism reflected in the improvement of natural deficient properties of cassava products shows capacity of microorganisms in detoxification of cyanide as well as utilization of raw cassava starchas a substrate for growth and conversion. The information is collected as an evidence to confirm the feasibility of microorganism, particularly filamentous fungi, in the development of microbial treatment system for the reclaimation of the CSP wastes.

Biodegradation of 2,6-Naphthalenedisulfonic Acid by a Floc-Forming Bacterium, Pigmentiphaga sp. NDS-1.

Abstract: Two 2, 6-naphthalenedisulfonate (2, 6NDS) degrading bacteria were isolated from the activated sludge of a wastewater treatment plant and designated NDS-1 and NDS-2. Only strain NDS-1 showed a floc-forming ability in such media as synthetic wastewater. Sequence analysis of the partial 16S ribosomal DNA (rDNA) sequence of strain NDS-1 revealed that it is a strain closely related to Pigmentiphaga kullae, which was recently established in the family Alcaligenaceae, and that the sequence was in perfect agreement with that of strain NDS-2. Strain NDS-1 could mineralize 2, 6NDS and 1, 6-naphthalenedisulfonate (1, 6NDS) with sulfate ion release, but showed no assimilating or desulfonating activity on 8 other sulfonated naphthalenes, indicating that it has a very narrow substrate specificity. 2, 6NDS-induced NDS-1 cells exhibited a high oxygen uptake for 2, 6NDS, while non-induced cells showed a very low oxygen uptake, demonstrating that 2, 6NDS oxidation is inducible in strain NDS-1.

Novel Nitrogen Removal Process Using Attached Activated Sludge

Abstract: In a conventional activated sludge aeration tank, organic nitrogen was almost completely converted to ammonium but very little was converted to oxidized forms of nitrogen (nitrite and nitrate) . Nitrification and denitrification in the aerated unit process, though, was achieved by using three submerged cells with porous sides consisting of nonwoven materials for retention of biomass. When synthetic wastewater with nitrogen only in organic form was fed directly into a cell (as opposed to the surrounding aeration tank), T-N decreased from 42 to 30 mg/l and TOC levels, from 110 to 10 mg/l. Because virtually all activated sludge was attached to cell walls, there was essentially no excess sludge wastage over 100 days of operation. Denitrification efficiency using the novel apparatus was shown to be effected by TOC and alkalinity in the influent wastewater as well as dissolved oxygen levels and the method of influent feed. When wastewater was fed simultaneously into two cells, versus only one, the T-N removal efficiency improved from 34% to 45%. Effluent T-N was shown to decrease with a decrease in DO in the aeration tank and careful control of TOC and alkalinity levels in the wastewater feed allowed for nitrogen removal efficiencies as high as 75%.

Biodegradation of Estrogens Using a Nitrifying Activated Sludge

Abstract: In this paper, the biodegradability of estrogens; estrone (E1), 17β-estradiol (E2), and ethynylestradiol (EE2) ; was evaluated using a nitrifying activated sludge (NAS) . NAS could degrade E1, E2, EE2 with the biodegradation rate constants, i.e.0.035h-1, 0.056h-1, 1.3h-1 respectively, indicating that E2 was the most biodegradable among the three estrogens.It should be noted that biodegradation of E2 produced E1, which was confirmed by a spike test on a reversed phase high performance liquid chromatography equipped with an electrochemical detector (HPLC-ECD) . An sequential reaction analysis where it was assumed that E2 was biodegraded to an unknown compound via E1 showed that E1 was firstly produced by biodegradation of E2. As for the unknown intermediates of E1 and EE2 were detected by HPLC-ECD. Based on the result that these electrochemically detectable compounds were eluted faster than the parent compounds, i.e. E1 and EE2, On the HPLC-ECD, it was suggested that more polar compounds containing phenolic group than the three estrogens were produced by NAS. Because significant decrease of the peak area of these compounds on the HPLC-ECD chromatogram was observed during biodegradation of E1 and EE2, it was suggested that NAS could cleavage phenolic group of E1 and EE2.

The Use of Green Tea Powder and Green Tea Polyphenols for Treatment of Vibrio-Infected Shrimp Culture Water.

Abstract: The anti-microbial activity of green tea (GT) and green tea polyphenols (GTPP) on Vibrio harveyi was investigated under different growth conditions: nutrient rich medium (325 agar mixed with GT and GTPP) and low nutrient conditions (sterile seawater) . Studies of its effects on the bacterial microflora in shrimp hepatopancreas were also explored. Both GT and GTPP were found to be effective against V. harveyi. The growth of V. harveyi was inhibited at 400 ppm GTPP and 1, 000 ppm GT on 325 agar plates. Under low nutrient conditions in saline environment simulating the natural habitat for Vibrio species, growth of V. harveyi was inhibited at 300 GTPP and 800 GT. The susceptibilities of bacteria isolated from shrimp hepatopancreas varied with the type of strain at different concentrations of GT and GTPP.

The Effect of Manganese Released from Lake Sediment on the Growth of Cyanobacterium Microcysitis aeruginosa

Abstract: In order to clarify the effect of the manganese released from lake sediment on the growth of M. aeruginosa, the cyanobacterium was cultured with leachate obtained by column leaching experiments which used lake sediment in Lake Kasumigaura Japan. The growth of M. aeruginosa in the leachate of sediment at St.1 and St.9 reached the density higher than 1.2×106 cells⋅ml-1, and was larger than those at the other points. The corresponding manganese concentrations of these leachates were also more than 10 times higher than the other points. That is why, it was considered that manganese might promote the growth of M. aeruginosa. Furthermore, in order to clarify the relation between manganese and the growth of M. aeruginosa, it was cultured with the addition of manganese into leachates of sediment and artificial medium. From the results, the addition of manganese or EDTA in all leachates of sediment except those for St.l and St.9, also accelerated the growth of M. aeruginosa. Moreover, it was obvious that manganese only promoted the growth of M. aeruginosa in the presence of EDTA, according to the results of experiments with artificial medium. A comparison of the results of experiments with leachate of sediment and artificial medium indicated that manganese complexing-agents like EDTA were included in the leachate of sediment. The relation between manganese and complexing-agents released from sediment is thus important for controlling the growth of M. aeruginosa in eutrophic lake.

Anaerobic Degradation of Terephthalic Acid and Aniline by Methanogenic Consortia.

Abstract: The biodegradability of eight aromatic compounds; benzyl alcohol, phenol, toluene, terephthalic acid, aniline, benzensulfonic acid, 2, 4, 6-trichlorophenol and m-nitrophenol; was evaluated under methanogenic conditions. Benzyl alcohol and phenol were termed as readily biodegradable aromatic compounds based on the net gas production. Toluene, terephthalic acid, aniline, an benzenesulfonic acid were termed as persistent compounds. 2, 4, 6-trichlorophenol and m-nitrophenol were caused a toxicity response of the methanogenesis. All compounds, which were suggested to be toxicity compounds by the biodegradability test, showed toxicity to aceticlastic methanogens. The anaerobic continuous treatments of synthetic wastewaters with aniline or terephthalic acid as the carbon sources were carried out. Glucose or acetic acid, used as co-substrates, showed stimulatory effect on the degradation of aniline or terephthalic acid. The degradation efficiency of aniline and terephthalic acid were more than 80% and 90%, respectively, in the treatments of synthetic wastewaters with acetic acid and aniline or terephthalic acid at the mole ratio (acetic acid / aniline or terephthalic acid) over 10.0 at a TOC loading rate of 0.5g/l⋅d.

Anaerobic Treatment of Sugary Wastewater by the UASB Process

Abstract: High strength sugary wastewater was continuously treated in a 12.5l UASB reactor operated at 37°C for 440 days. This included 350 days of loading rate study during which volumetric loading rate (VLR) was increased from 0.3 to 24 g-TOC/l·d and 90 days of investigation at a stable loading rate of 8 g-TOC/l·d. The UASB reactor achieved 80-98% TOC reduction at VLRs up to 16 g-TOC/l·d. Mass balance calculations revealed that 46% and 49% of TOC removed was converted to CO2 and CH4, respectively while the rest was converted to biomass with an average observed sludge yield of 0.094 g-VSS/g-TOC. The C: N: P ratio in the wastewater, pH, volatile fatty acid (VFA) concentration of the effluent and hydraulic retention time (HRT) were all correlated with the removal efficiency of the reactor. For achievement of effective TOC removal efficiencies, these parameters must be maintained at C: N: P=350: 10: 2; pH, 6.8-7.2; VFAs, less than 1000mg/l; and HRT, greater than 12 hr. The microbial structure of the granules was elucidated and microorganisms resembling the Methanobacterium and Methanobrevibacter genera were found to be dominant in the granular sludge cultivated during the period of loading rate increases. However, Methanothrix-like methanogens were found to be dominant in granular sludge cultivatedduring the period with a stable loading rate of 8 g-TOC/l·d. And loading rate is a majoroperational parameter in a UASB reactor for selection of granular sludge with better characteristics such as granule size, settling velocity, MLSS and VSS concentration.

Development of Phosphorus Removal Process of On-site Domestic Wastewater Treatment Systems Using Dripping Method of Thick Iron Solution

Abstract: An advanced technique of dripping the thick iron solution was developed and applied to on-site domestic wastewater treatment systems. The thick iron solution was obtained by heating and melting FeCl3⋅6H2O crystals.By using the new technique, the T-P concentration of the treated water decreased to less than 1mg·l-1 when the thick iron solution was added at an Fe/P molar ratio of 1.75. The addition of thick iron solution did not affect the removal of BOD, COD, SS and T-N.The T-P concentration of the treated water increased when coagulated sludge containing ferric phosphate was in contact with the anaerobic sludge in the tank for along time. This problem could be solved by improving the process to prevent such contact. It was also shown that the addition of thick iron solution increased the volume of sludge by about 30%.

Production of Cyanobacterial Hepatotoxin Microcystin in a Nutrient-limited Culture of Microcystis viridis.

Abstract: The production of microcystin by a nutrient-starved Microcystis viridis culture with a nutrient gradient was examined. The specific production rate of microcystin increased with increasing nitrate and phosphate concentrations. The specific production rates of nitrate-starved cultures after nitrate supply were higher than those of phosphate-starved cultures after phosphate supply showing that nitrogen is a more important nutrient for microcystin production than phosphorus. The time course of microcystin production by nitrate-starved M.viridis after nitrate supply was evaluated at 2h intervals. The microcystin-RR content increased to more than 2-fold within 24 hrs. An increase in dry weight was not observed within 24 hrs, showing microcystin was produced prior to cell growth for nitrogen-starved M. viridis. The specific production rate of microcystin-RR seemed to increase with increasing nitrate cell quota, which suggested that the nitrogen cell quota might regulate the rate of production of microcystin in lakes and reservoirs.

Effects of Phosphate on Nitrifying Activity in a Water Treatment Plant at Low Temperature

Abstract: Nitrification by autotrophic bacteria is sensitive to low temperature and nitrification efficiency decreases in winter, however, the activity can be maintained when phosphate, which is eliminated through a coagulation-sedimentation process in potable water treatment plants, is amended prior to sand and GAC filtration. We examined seasonal changes in the population of nitrifying bacteria during the water treatment process and the effect of phosphate amendment in the laboratory. The population densities of nitrifying bacteria in the biofilm attached to sand and GAC observed in winter were of the same order as those in other seasons. The potential nitrifying activity in winter was about 0.5-to 1.8-fold that in summer when examined at 30°C. Filter sand seemed to be more sensitive to low temperatures than GAC as seasonal deviations in nitrifying activities were larger in sand. The immediate effect of phosphate addition was confirmed using a sand column and the population of ammonia-oxidizing bacteria did not increase significantly after 3 weeks of incubation. Phosphate addition enhanced ammonia-elimination rate more than nitrification products accumulation rate. When nitrifying activity was inhibited by the addition of allylthiourea, the respiration in phosphate-amended culture was more active than in culture without phosphate. Thus a possibility remained that addition of phosphate might have enhanced ammonification by heterotrophic bacteria in the biofilm resulting in an increase in nitrifying activity.

Evaluation of Anaerobic Filter Bed-Biological Filtration Process with Physicochemical Phosphorus Removal Methods

Abstract: A simultaneous removal of nitrogen and phosphorus technology in small-scale domestic wastewater treatment was developed. Physicochemical phosphorus removal systems such as the coagulation method, electrolysis of iron method and electrolysis of aluminum method were combined with anaerobic filter bed-biological filtration process and removal efficiencies of organic matter, nitrogen and phosphorus as well as sludge generation were investigate.It was demonstrated that these systems improved the organic matter and phosphorus removal efficiencies. Moreover, the denitrification rate improved, which could contribute to stabilizing the nitrogen removal efficiency in this process, as well as reducing the volume of the anaerobic filter bed tank. The water quality of the effluent was less than BOD10mg⋅l-1, T-N10mg⋅l1 and T-P1 mg⋅l1. To achieve this efficiency with the coagulation method, it was necessary to closely manage the generated sludge. With the electrolysis of iron method, a high phosphorus removal efficiency was achieved under the general maintenance and management of generated sludge. With the electrolysis of aluminum method, although an extremely high removal efficiency was achieved, it was necessary to investigate the conditions for controlling the elution of aluminum ion to stabilize the phosphorus removal efficiency. These findings clarified that by incorporating the physicochemical phosphorus removal system with anaerobic filter bed-biological filtration process, the simultaneous nitrogen and phosphorus removal system could be established.

Bacterial Populations and Degradation of Sludge Components in a Modified Two-Series Digestion Process Including Sludge Liquefaction

Abstract: Distributions of bacterial populations and degradation of sewage sludge components in a two-series digestion process with liquefaction of thickened surplus sludge (hereinafter called the modified two-series digestion) and in a conventional mono-phase digestion (hereinafter called the conventional digestion) process were investigated. A high level of 2.7 × 1010 MPN/ml acidogenic bacteria in the thermophilic liquefaction reactor of the modified two-series digestion was observed at a volatile suspended solid (VSS) volumetric loading rate of 14 g/l⋅d. This count was three orders of magnitude higher than that of all other anaerobic bacteria enumerated in the reactor. At a VSS loading rate of 6 g/l⋅d, the levels of hydrogenotrophic and aceticlastic methanogens in the mesophilic digestor of the modified two-series digestion were 1.2 × 108 and 1.9 × 107 MPN/ml, respectively, which were 3 and 1.5 times higher than those in the reactor of the conventional digestion. In the modified two-series digestion, the degradation efficiencies of lipid, protein, carbohydrate and lignin in the sludge were 69.8%, 57.7%, 46.8% and 24.5%, respectively, at a VSS loading rate of 3 g/l⋅d. These values were over 10% higher than those of the conventional digestion at the same loading rate, except for lignin which was only 5% higher. The specific resistances of sludges after treatment by the modified two-series and conventional digestions were 4.58 × 1011 m/kg and 6.15 × 1011 m/kg, respectively. The modified two-series digestion process demonstrated performance superior to the conventional digestion process.

Experimental Study on the Behavior of Fecal Contamination Indicators on Surface Water Sampled at Hanbara Intake Station.

Abstract: The behaviors of Enterobacter spp., Escherichia coli, and Enterococcus faecalis in surface water samples were studied. The number of coliform bacteria such as Enterobacter spp. and Escherichia coli increased in water samples from Hanbara Intake Station that is located downstream from Miyagase Reservoir. The coliform bacteria counts for samples taken from the Hayato River, which is located upstream of Miyagase Reservoir, remained constant. However, the counts of the same bacteria inoculated insaline solution (0.85%) declined. Consequently, it was concluded that coliform bacteria have growth potential in the environment prevailing at Miyagase Reservoir. Furthermore, the study suggested that the observed increase in coliform bacteria might be related to changes in quality of dammed water as well as the natural lakes. On the other hand, E.faecalis did not proliferate in the surface water samples obtained from the Hanbara Station and the Hayato River which were inoculated. In order to adequately assess associated fecal health risks, this study recommends that the detection of colifbrm bacteria in water samples be followed by the detection of Enterococcus spp.

Comparison of the Multi-well Filtration ELISA, MPN and FISH Methods for Quantifying Ammonia Oxidizing bacteria in Activated Sludge.

Abstract: MPN (most probable number) method has been used to quantify nitrifiers in activated sludge, and it was very useful for enumerating nitrifying activity. However, it takes about one month to get the results and requires a complicated operation. Consequently, in last decade, several immunological and molecular methods such as ELISA (Enzyme-Linked Immunosorbent Assay) and FISH (Fluorescence in situ hybridization) methods have been developed to quantify nitrifiers rapidly. In this study, to enumerate ammonia oxidizing bacteria (AOB) population in activated sludge more rapidly, a new quantification method, multi-well filtration ELISA using a monoclonal antibody against Nitrosomonas europaea was developed. The threshold of the calibration curve using N. europaea with multi-well filtration ELISA method was about 4.0×105 cells⋅ml-1, which was lower than that of normal ELISA. This means that the quantification range of AOB was extended. Furthermore, by using the multi-well filtration ELISA method, the bestowing time for biomass enumerating was decreased to 5 hours.According to comparison of multi-well filtration ELISA, MPN and FISH methods, the property of multi-well filtration ELISA was more interrelated with that of MPN than that of FISH method when quantify AOB in activated sludge under practical conditions. Furthermore, multi-well filtration ELISA took results the most quickly among them.

Removal Characteristics of Suspended Solids and Organic Compounds in Anaerobic Filter Process of Small-Scale Domestic Wastewater Treatment Facilities (Gappei-shori johkasou)

Abstract: Domestic wastewater treatment facilities, being called ‘Gappei-shori johkasou’, play an important role in the wastewater countermeasures of Japan. In small-scale gappei-shori johkasous for less than 50 persons'use, anaerobic filter process has been usually adopted as a primary treatment. Removal characteristics of organic compounds in this process have been reported, but the greater part of these results cannot be applied to the operation of johkasous as a practical matter, because of using artificial wastewater in the laboratory work. In this paper, therefore experimental investigations were carried out to make clear the removal characteristics of suspended solids, in addition to organic compounds, in this process of the actual johkasous.The results showed that high SS removal ratio was achieved when netlike plates filter medium with a dimension of 100 mm×70 mm and ball-like skeleton filter medium were used in the 1st chamber and 2nd chamber of anaerobic filter tank, respectively. The BOD removal rate in this tank can be expressed by a linear reaction. Compared to a sedimentation/separation tank in which there is no filter medium, low molecule-ization of organic compounds in anaerobic filter tank progressed faster even though the HRT is three-fifth of that in sedimentation/separation tank. Most of the VFA in anaerobic filter tank was found to be decomposed into acetic acid and propyonic acid.

Cavitation Control as a Means of Reducing Algal Biomass in Pond Waters

Abstract: This is a first report of the use of cavitation treatment, an innovative method, to suppress phytoplankton biomass. It was found that cavitation treatment immediately kil1ed some algal cells in pond waters; about 75% of Peridinium sp. died when exposed to cavitation for one minute at 1800 rpm of the shaft rotation in a cylinder. The effectiveness of cavitation for causing algal death varied with different species. These results showed the possibility of using cavitation treatment to suppress algal biomass for a short time. Experiments combining different cavitation powers and treatment times with different species are required if we are to develop an effective system for suppressing specific algal blooms in particular bodies of water.

Evaluation of a Granular Sludge USB Process for Denitrification of Groundwaters with Low Hardness Including Polluted Field Samples.

Abstract: Research was conducted to further evaluate a denitrifying upflow sludge-blanket (USB) unit process for treatment of soft groundwater amended to a high pH as previously shown to be essential for effective granulation. From kinetic studies, a saturation constant of 15 mg-N/l was determined reflecting a high affinity of the granular sludge for the ethanol-nitrate substrate. The influence of carbon loading during the course of continuous treatment runs demonstrated that nitrite persisted in the effluent at carbon to nitrogen ratios below 1.1. Groundwater samples polluted with nitrate were obtained from two towns in Kumamoto Prefecture and used in continuous treatment experiments. Influent nitrate as high as 29 mg-N/l was completely removed at a HRT of only 30 min. The characteristics of these groundwaters without chemical additions (other than pH adjustment) were well suited for subsistence of granular sludge with good retention characteristics. Discussion was offered to establish protocol for progressing to actual treatment in the field, which should be possible for groundwaters of low hardness common to Japan with only minimal chemical adjustments (e.g., pH) at the treatment site.