Phosphorus removal by ponds receiving polluted water from non-point sources

Phosphorus discharged into the water column of lakes, streams, reservoirs, and ponds is either assimilated by algae or retained by the sediment. A laboratory study was conducted using intact sediment-water columns obtained from three ponds to measure their capacity to assimilate P. Phosphorus retention by these systems was determined at two P levels (2 and 10 mg PL^–1 or equivalent to an area loading of 26 and 130 g cm^–2). The potential P removal rates were 20.4, 28.8 and 30.8 g P CM^–2 day^–1 for PSF (pond adjacent to septic fields), PP(pond adjacent to a pasture), and PAF (pond adjacent to agricultural farm land), respectively. Longer residence time was needed for P removal at high P loading (10 mg PL^–1) than at low P loading (2 mg P L^–1). At high P loading, 76–82% of the floodwater P was removed within 10 days. All sediments showed a greater sorption capacity under reduced conditions than under oxidized conditions. At the P levels evaluated, pond sediments functioned as net sinks for water column P.     

Quality of effluent water from earthern fish ponds in Hungary

The water quality of running water is determined mainly by the type of human activities within the catchment area, including fish culture. The introduction of polyculture, the intensive application of fertilizers, the use of manure and the development of fish-cum-duck culture have influenced water quality in fish ponds and in pond effluents in both the growing and harvesting seasons. Natural waters which serve as water supply for fish production systems are characterized by an increased nutrient load. Government order No. 3/1984.(11.7.) OVH, based on the Government order No. 32/1964. (XII. 13.) deals with the Water Utilization Act which is concerned with the state requirements on release of industrial effluents. This Act divides the area of the country into ‘zones o water quality protection’, and determines the limits of pollution load for each water quality zone including penalties in case the limits prescribed in the Act are exceeded. Fish farms are also included into this Act. In 1988, a 2-year research programme was started to analyse the effluents of extensive and intensive fish production systems from both environmental protection and economic standpoints. The goals of this research programme were: (1) to determine whether fish farm effluents meet the state requirements given under Government order No. 3/1984.(11.7.) OVH at all times of the growing season and what pollution is caused in the recipient; (2) to describe the changes of water quality in the inflow and the outflow waters and in the recipient during the rowing season and to collect data on possible water quality changes due to the seasonal drainage. These data should serve as a base for describing nutrient pathways in order to develop strategies for impact mitigation.     

Modeling of heavy metals removal from municipal landfill leachate using living biomass of water hyacinth

Water Hyacinth, Eichhornia crassipes, a fast-growing floating aquatic macrophyte; was used for the removal of heavy metals from a municipal landfill leachate. The leachate was spiked with different mixtures of five heavy metals (Cd, Cr, Cu, Pb and Ni), at a range of concentrations to cover the ranges reported in literature. The initial concentrations of the total heavy metals in leachate ranged from 0.06 to 5.5 mequiv L(-1). All experiments were carried out in batch reactors in a greenhouse environment. The water hyacinth plants showed a very promising ability to remove and accumulate these metals from the leachate (24% to 80% removal of total heavy metals). Generally, the reduction in concentration of total heavy metals followed two distinct patterns, a rapid initial decrease followed by a slower decrease. An exponential mathematical model was established to estimate the remaining concentration of total heavy metals in the leachate over time for the rapid initial decrease. Also, a linear relationship was established to estimate the concentration of total heavy metals over time for the slower decrease. In addition, Langmuir and Freundlich isotherms were applied to the observed data and the constants of each isotherm were obtained.     

Emissions of greenhouse gases from ponds constructed for nitrogen removal

Methane and carbon dioxide emission from three constructed ponds were monitored during an annual cycle. Water temperature was a good predictor of methane emission in all three ponds. In the most intensively studied pond, nitrate concentration in the bottom water could further explain the amount of methane emitted. When water temperature exceeded 15 °C between 1 and 54 mg, CH₄ m⁻² h⁻¹ was emitted on all occasions, while at temperatures below 10 °C, less than 0.6 mg CH₄ m⁻² h⁻¹ was emitted. The flux of carbon dioxide differed between the ponds and no consistent patterns were found. In a laboratory study at 20 °C, we showed that high, but naturally occurring, nitrate concentrations (8 and 16 mg NO₃⁻–N l⁻¹) constrained the production of methane compared to the treatment with no nitrate addition. Nitrous oxide production was positively correlated with nitrate concentration. Carbon dioxide production was highest at the highest nitrate concentration, which indicates that increased nitrate loading on ponds and wetlands will stimulate organic matter decomposition rates. Our conclusion is that these ponds constructed for nitrate removal emit greenhouse gases comparable to lakes in the temperate region.     

Cadmium tolerance and antibiotic resistance in Escherichia coli isolated from waste stabilization ponds

The incidence pattern of cadmium tolerance and antibiotics resistance by Escherichia coli was examined periodically from the samples of water, sludge and intestine of fish raised in waste stabilization ponds in a sewage treatment plant. Samples of water and sludge were collected from all the selected ponds and were monitored for total counts of fecal coliform (FC), total coliform (TC) and the population of Escherichia coli, which was also obtained from the intestine of fishes. Total counts of both FC and TC as well as counts of E. coli were markedly reduced from the facultative pond to the last maturation pond. Tolerance limit to cadmium by E. coli tended to decline as the distance of the sewage effluent from the source increased; the effective lethal concentration of cadmium ranged from 0.1 mM in split chamber to 0.05 mM in first maturation pond. E. coli isolated from water, sludge and fish gut were sensitive to seven out of ten antibiotics tested. It appears that holistic functions mediated through the mutualistic growth of micro algae and heterotrophic bacteria in the waste stabilization ponds were responsible for the promotion of water quality and significant reduction of coliform along the sewage effluent gradient.     

Treatment of oilfield produced water by waste stabilization ponds: Biodegradation of petroleum-derived materials

This study evaluated the biological treatability of produced water (PW), the water separated from oil at the wellhead which contains both dispersed oil and low levels of heavy metals, using waste stabilisation ponds (WSPs). We examined both chemical oxygen demand (COD) and oil and grease (O&G) removal using different process configurations (hydraulic retention time (HRT), aerobic and anaerobic conditions, oil skimming, effluent recycle) in a small (10 L) reactor being fed a synthetic PW (COD = 1050–1350 mg L⁻¹, O&G = 400–500 μL L⁻¹, 6 gNaCl/L). The reactor was operated for 6 months, and at a HRT of 6 days (8 with evaporation) COD removals were greater than 85%, and improved over time to >90%, while O&G removals (measured with a newly developed method) were greater than 82% and also improved with time. Operating with an anaerobic section, oil skimming and 300% recycling were all found to enhance COD removal.     

Effects of sewage waste stabilization lagoon effluent on stream invertebrates

The ecological impact of discharge to streams of domestic sewage waste stabilization lagoon effluent was investigated. Benthic invertebrates were compared upstream and downstream of discharges to eight New Zealand streams where effluent dilution ranged from 6- to 484-fold. The percentage of common invertebrate taxa whose density changed significantly (ANOVA, P<0.05) downstream declined in proportion with the log of the effluent dilution (r=-0.87) and increased with downstream increase in benthic respiration (r=0.91) and several intercorrelated indicators of organic enrichment (log biochemical oxygen demand, r=0.91; log suspended solids (SS), r=0.84). However, these changes in invertebrate densities did not always reflect degraded community structure. The nature and direction of changes suggests a subsidy-stress gradient of responses. Increases in SS of > 4 g m^-3 were associated with significant changes in density of > 50 percent of the common taxa and > 50 percent reduction of the densities of the sensitive Ephemeroptera, Plecoptera, and Trichoptera (EPT). However, EPT densities increased by up to 50 percent at lower organic solids loadings. No general relationships were found between relative densities of functional feeding groups and metabolic or water quality variables. These findings confirm that early warning of enrichment stress is more easily seen at the species level than at the functional level.     

Nutrient removal and biomass production in land treatment systems receiving domestic effluent

Land application of pre-treated wastewater is increasingly practiced to achieve both treatment and beneficial reuse of applied effluent. Vegetation is an important component of these systems, affecting hydraulic loading and nutrient uptake and hence treatment efficiency. This work investigated the effect of plant species (Acacia cyanophylla, Eucalyptus camaldulensis, Populus nigra and Arundo donax), on water requirements, nutrient removal, water use efficiency (WUE) and biomass production in land treatment systems (LTS) in which pre-treated wastewater was applied at rates to meet crop evapotranspiration. Vegetation had a strong effect on all the parameters monitored during this trial. A. cyanophylla produced the greatest amount of biomass and showed the highest irrigation requirements and WUE, followed by E. camaldulensis, A. donax and P. nigra. In addition, A. cyanophylla and A. donax achieved a higher leaf-N content compared to other species. As a result of the differences in tissue nutrient content and biomass, A. cyanophylla accumulated 23, 20, and 70% more N in hypergeous biomass than E. camaldulensis, A. donax and P. nigra, respectively. A. cyanophylla and E. camaldulensis accumulated 57 and 53% respectively more P than did P. nigra and A. donax. Therefore substantial improvement of the performance of the LTS in terms of nutrient removal can be achieved through the selection of appropriate plant species. Despite the enhanced growth rates observed in the study nutrient recovery by vegetation did not exceed 31 and 35% of the applied N and P, respectively. The relatively low percentages of removal are attributed to increased concentration of nutrients in effluent and the high ET rates prevailing in the study area. These findings suggest that additional practices are required to mitigate environmental impacts arising from excessive nutrient loads when effluent is applied at rates to meet crop water requirements.     

Nitrogen removal from animal waste treatment water by anammox enrichment

The aim of this work was to examine the applicability of the anaerobic ammonium oxidation (anammox) process to three kinds of low BOD/N ratio wastewaters from animal waste treatment processes in batch mode. A rapid decrease of NO(2)(-) and NH(4)(+) was observed during incubation with wastewaters from AS and UASB/trickling filter and their corresponding control artificial wastewaters. This nitrogen removal resulted from the anammox reaction, because the ratio of removed NO(2)(-) and NH(4)(+) was close to the theoretical ratio of the anammox reaction. Comparison of the inorganic nitrogen removal rate of the actual wastewater and that of control artificial wastewater showed that these two kinds of wastewater were very suitable for anammox treatment. Incubation with wastewater from RW did not show a clear anammox reaction; however, diluting it by half enabled the reaction, suggesting the presence of an inhibitory factor. This study showed that the three kinds of wastewater from animal waste treatment processes were suitable for anammox treatment.     

Enzyme immobilized reactor design for ammonia removal from waste water

Removal of nitrogen compound from waste, water is essential and often accomplished by biological process. To prevent washout and to develop an efficient bioreactor, immobilization of suitable microorganisms could be sensible approach. Strains and permeabilized cells encapsulated in cellulose nitrate microcapsules and immobilized on polystyrene, films were prepared by the method described in the previous study. In the wastewater, treatment system, nitrification of ammonia component is generally known as rate controlling step. To enhance the rate of nitrification, firstly nitrifying strainsNitrosomonas europaea (IFO 14298), are permeabilized chemically, and immobilized on polystyrene, films and secondly oxidation rates of strain system and permeabilized strain system are compared in the same condition. With 30 minute permeabilized cells, it took about 25 hours to oxidize 70% of ammonia in the solution, while it took about 40 hours to treat same amount of ammonia with untreated cells. All the immobilization procedures did not harm to the enzyme activity and no mass transfer resistance through the capsule wall was shown. In the durability test of immobilized system, the system showed considerable activity for the repeated operation for 90 days. With these results, the system developed in this study showed the possibility to be used in the actual waste water treatment system.     

Sunlight inactivation of fecal indicator bacteria and bacteriophages from waste stabilization pond effluent in fresh and saline waters

Sunlight inactivation in fresh (river) water of fecal coliforms, enterococci, Escherichia coli, somatic coliphages, and F-RNA phages from waste stabilization pond (WSP) effluent was compared. Ten experiments were conducted outdoors in 300-liter chambers, held at 14C (mean river water temperature). Sunlight inactivation (k(S)) rates, as a function of cumulative global solar radiation (insolation), were all more than 10 times higher than the corresponding dark inactivation (k(D)) rates in enclosed (control) chambers. The overall k(S) ranking (from greatest to least inactivation) was as follows: enterococci > fecal coliforms greater-than-or-equal E. coli > somatic coliphages > F-RNA phages. In winter, fecal coliform and enterococci inactivation rates were similar but, in summer, enterococci were inactivated far more rapidly. In four experiments that included freshwater-raw sewage mixtures, enterococci survived longer than fecal coliforms (a pattern opposite to that observed with the WSP effluent), but there was little difference in phage inactivation between effluents. In two experiments which included simulated estuarine water and seawater, sunlight inactivation of all of the indicators increased with increasing salinity. Inactivation rates in freshwater, as seen under different optical filters, decreased with the increase in the spectral cutoff (50% light transmission) wavelength. The enterococci and F-RNA phages were inactivated by a wide range of wavelengths, suggesting photooxidative damage. Inactivation of fecal coliforms and somatic coliphages was mainly by shorter (UV-B) wavelengths, a result consistent with photobiological damage. Fecal coliform repair mechanisms appear to be activated in WSPs, and the surviving cells exhibit greater sunlight resistance in natural waters than those from raw sewage. In contrast, enterococci appear to suffer photooxidative damage in WSPs, rendering them susceptible to further photooxidative damage after discharge. This suggests that they are unsuitable as indicators of WSP effluent discharges to natural waters. Although somatic coliphages are more sunlight resistant than the other indicators in seawater, F-RNA phages are the most resistant in freshwater, where they may thus better represent enteric virus survival.     

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

The United States Marine Shrimp Farming Program (USMSFP) introduced a new technology for shrimp farming called recirculating raceway system. This is a zero-water exchange system capable of producing high-density shrimp yields. However, this system produces wastewater characterized by high levels of ammonia, nitrite, and nitrate due to 40% protein diet for the shrimp at a high density of 1,000 shrimp per square meter. The high concentrations of nitrate and nitrite (greater than 25 ppm) are toxic to shrimp and cause high mortality. So treatment of this wastewater is imperative in order to make shrimp farming viable. One simple method of treating high-nitrogen wastewater is the use of a sequencing batch reactor (SBR). An SBR is a variation of the activated sludge process, which accomplishes many treatment events in a single reactor. Removal of ammonia and nitrate involved nitrification and denitrification reactions by operating the SBR aerobically and anaerobically in sequence. Initial SBR operation successfully removed ammonia, but nitrate concentrations were too high because of carbon limitation in the shrimp production wastewater. An optimization study revealed the optimum carbon to nitrogen (C:N) ratio of 10:1 for successful removal of all nitrogen species from the wastewater. The SBR operated with a C:N ratio of 10:1 with the addition of molasses as carbon source successfully removed 99% of ammonia, nitrate, and nitrite from the shrimp aquaculture wastewater within 9 days of operation.     

Modeling nitrogen removal for a denitrification biofilter

Nitrous oxide (N₂O) is a major greenhouse gas, heavily contributing to global warming. N₂O is emitted from various sources such as wastewater treatment plants, during the nitrification and denitrification steps. ASM models, which are commonly used in wastewater treatment, usually consider denitrification as a one-step process (NO₃ ⁻ directly reduced to N₂) and are as such unable to provide values for intermediate products of the reaction like N₂O. In this study, a slightly modified ASM1 model was implemented in the GPS-X™ software to simulate the concentration of such intermediate products (NO₂ ⁻, NO and N₂O) and to estimate the amounts of gaseous N₂O emitted by the denitrification stage (12 biofilters) of the Seine-Centre WWTP (SIAAP, Paris). Simulations running on a 1-year period have shown good agreements with measured effluent data for nitrate and nitrite. The calculated mean value for emitted N₂O is 4.95 kgN–N₂O/day, which stands in the typical range of estimated experimental values of 4–31 kgN–N₂O/day. Nitrous oxide emissions are usually not measured on WWTPs and so, as obtained results show, there is a certain potential for using models that quantify those emissions using traditionally measured influent data.     

Repeated removal of cadmium and zinc from an industrial effluent by waste biomass Sargassum sp.

Waste biomass Sargassum sp. biosorbed 100% of Cd²⁺ and 99.4% of Zn²⁺ from a 3 and 98 mg l^–1 solution (pH 4.5), respectively, at the end of four serial experiments. Of the five desorbents studied in consecutive adsorption/desorption cycles, CaCl₂ 0.05 M eluted nearly 40% of both metals and decreased the biosorption in only 8% and 17% of Cd²⁺ and Zn²⁺, respectively. Although NaOH desorbent improved the heavy metal uptake from the second cycle onwards, it did not elute metals from the pre-loaded biomass.     

Oxygen balance in micro stabilization ponds

Summary In a continuous flow of domestic sewage, the effect of various environmental conditions on the oxygen balance of an algal-bacterial culture was studied in 2 microponds in series. The relation between the size of the algal population and the amount of photosynthetic oxygen was discussed.The efficiency of the symbiotic system in relation to photosynthetic oxygenation was elucidated in terms of two oxygenation factors. One is concerned with the consumption of oxygen by the existing flora and the other with the BOD of the influent substrate.Prof. of Botany, Fac. of Science.Lecturer in Sanitary Biol., Fac. of Engineering.     

Metabolic removal of phosphate from sewage effluent

Eutrophication, or fertilization, has become a major water pollution problem associated with the discharge of mineral-rich sewage eflluent. A metabolic process to remove dissolved phosphate from sewage through the action of sewage microorganisms is under development. The process, unlike other proposed solutions to the problem, would not require tertiary treatment of the sewage. Laboratory studies have produced promising data. Early reports from municipal sewage treatment plants confirm the expectation that the process may be feasible for widespread use.     

Peroxidase-catalyzed color removal from bleach plant effluent

Effluent from the caustic extraction stage of a bleach plant is highly colored due to the presence of dissolved products from lignin chlorination and oxidation. Color removal from the effluent by hydrogen peroxide at neutral pH was catalyzed by addition of horseradish peroxidase. The catalysis with peroxidase (20 mg/L) was observed over a wide range of peroxide concentrations (0.1mM-500mM), but the largest effect was between 1mM and 100mM. The pH optimum for catalysis was around 5.0, while the basal rate of noncatalyzed peroxide color removal simply increased with pH within the range tested (3-10). Peroxidase catalysis at pH 7.6 reached a maximum at 40 degrees C in 4 h assays with 10mM peroxide, and disappeared above 60 degrees C. Compared with mycelial color removal by Coriolus versicolor, the rate of color removal by peroxide plus peroxidase was initially faster (first 4 h), but the extent of color removal after 48 h was higher with the fungal treatment. Further addition of peroxidase to the enzyme-treated effluent did not produce additional catalysis. Thus, the peroxide/peroxidase system did not fully represent the metabolic route used by the fungus.     

Enhancing biological nitrogen removal from tannery effluent by using the efficient Brachymonas denitrificans in pilot plant operations

Summary Laboratory scale and pilot plant reactors were inoculated with an efficient denitrifier, Brachymonas denitrificans(CCUG 45880), in order to evaluate whether a bio-augmentation approach can be used to enhance biological nitrogen removal from tannery effluents. To determine the effectiveness of the introduced strain, denitrifying activity in the activated sludge was monitored by nitrate uptake rate (NUR) measurement of NO₃-N. Fluorescent in situ hybridization (FISH) technique was used to monitor the growth of the augmented species. The laboratory scale nitrate removal efficiency with the introduced B. denitrificans (3.7±0.6 mg NO₃-N gVSS ⁻¹ h ⁻¹) was higher than that of the activated sludge without the addition of the bacteria (3.5±0.7 mg NO₃-N gVSS ⁻¹ h ⁻¹); the NUR in the pilot plant after and before the introduction of the strain was also of the magnitude of 12.0±1.4 and 10.6±1.4 mg NO₃-N gVSS ⁻¹ day ⁻¹ , respectively. In situ hybridization results revealed that the introduced denitrifying bacteria significantly facilitated the development of a dense denitrifying bacterial population in the activated sludge, which enhanced in situ denitrification activity. FISH data indicated that once introduced, B. denitrificans remained abundant throughout the experimental period. The ability to seed a bioreactor with bacterial strain capable of removing target pollutants from tannery effluents in a mixed microbial community suggests that this approach could have commercial applications.     

High-rate nitrogen removal from waste brine by marine anammox bacteria in a pilot-scale UASB reactor

Applied Microbiology and Biotechnology - The goal of this study was to develop a startup strategy for a high-rate anaerobic ammonium oxidation (anammox) reactor to treat waste brine with high...     

Phytoremediation of landfill leachate waste contaminants through floating bed technique using water hyacinth and water lettuce

Abstract

In the present study, the effectiveness of water hyacinth and water lettuce was tested for the phytoremediation of landfill leachate for the period of 15?days. Fifteen plastic containers were used in experimental setup where aquatic plants were fitted as a floating bed with the help of thermo-pole sheet. It was observed that both plants significantly (p?<?0.05/p?<?0.01/p?<?0.001) reduce the physicochemical parameters pH, TDS, BOD, COD and heavy metals like Zn, Pb, Fe, Cu and Ni from landfill leachate. Maximum reduction in these parameters was obtained at 50% and 75% landfill leachate treatment and their removal rate gradually increased from day 3 to day 15 of the experiment. The maximum removal rate for heavy metals such as for Zn (80–90%), Fe (83–87%) and Pb (76–84%) was attained by Eichhornia crassipes and Pistia stratiotes. Value of bioconcentration and translocation factor was less than 1 which indicates the low transport of heavy metals from roots to the above-ground parts of the plants. Both these plants accumulate heavy metals inside their body without showing much reduction in growth and showing tolerance to all the present metals. Therefore, results obtained from the study suggest that these aquatic plants are suitable candidate for the removal of pollution load from landfill leachate.