Nitrite Nitrogen Concentrations Research Articles

Aerobic and anaerobic ammonium-oxidising bacterial enrichment from municipal solid waste

Leachate from the municipal solid waste (MSW) landfills contains high concentration of ammoniacal nitrogen that is a major toxic pollutant that has a great threat to environment. Among the processes available for the removal of ammoniacal nitrogen, one process is a combination of partial nitrification and anaerobic ammonium oxidation (anammox) process. It requires aerobic ammonium-oxidising bacteria (AOB) and anaerobic ammonium-oxidising bacteria (AnAOB). This paper presents the feasibility of enriching the AOB and AnAOB in 100-mL and 2.5-L batch reactors from fresh and mined MSW and leachate under aerobic and anaerobic conditions with varying feed-to-seed ratio. The AOB and AnAOB activity was monitored by measuring the intermediates such as hydroxylamine and hydrazine along with variations in ammoniacal nitrogen, nitrite nitrogen, and nitrate nitrogen concentrations in the reactor contents. The formation of intermediates such as hydroxylamine and hydrazine and ammoniacal nitrogen transformation data confirmed the enrichment of AOB and AnAOB. Further, AOB and AnAOB were validated by most probable number test and scanning electron microscopy analysis, respectively. DNA extraction, polymerase chain reaction amplification, and sequencing analysis authenticated the AnAOB as Candidatus Brocadia anammoxidans.

Fate of Nutrients in Secondary Treated Municipal Wastewater during Percolation through the Soil Media

The fate of nutrients (phosphorous and nitrogen species) was investigated in secondary treated municipal wastewater (STMWW) during percolation through soil media by using an experimental set‐up that consists of multiple soil columns. The columns were packed with silt loam soil samples and were operated under two different wetting and drying cycles to represent the typical operational conditions in a soil aquifer treatment (SAT) system. Dissolved oxygen, oxidation–reduction potential, ammonium nitrogen, nitrite nitrogen, nitrate nitrogen, total nitrogen, and phosphate phosphorus concentrations were measured in samples collected from different sampling ports along the columns. Average removal values of 62.8, 67.1, and 97.1% were achieved over 75 cm of effective soil depth over 25 weeks of operation for ammonium nitrogen, total nitrogen and phosphate phosphorus, respectively. The removal performance of nutrients typically increased by soil depth and no decrease in removal performance was observed up to end of the study. Consequently, SAT system can be considered to be an effective and low cost advanced treatment method for polishing residual nutrients in a STMWW.

Performance evaluation and bacteria analysis of AFB-MFC enriched with high-strength synthetic wastewater

In order to study the performance and bacterial communities of an anaerobic fluidized bed microbial fuel cell (AFB-MFC) system, the 16S rDNA gene sequencing was applied, and high-strength synthetic wastewater was treated by the AFB-MFC system. The high-strength synthetic wastewater, in which the concentrations of chemical oxygen demand (COD), nitrite nitrogen, and nitrate nitrogen were above 19,000, 2,516-3,871 and 927-1,427 mg/L, was treated by the AFB-MFC system. The removal efficiency of COD, nitrite nitrogen, and nitrate nitrogen reached 70-89, 98 and 98%, while the maximum voltage was 394 mV. The bacteria analysis revealed the presence of Alistipes putredinis, Carnobacterium sp., Victivallis vadensis, Klebsiella pneumoniae, Thauera sp., Parabacteroides merdae, Parvimonas micra, Parabacteroides sp., and Desulfomicrobium baculatum in the anode chamber. In addition, the Klebsiella pneumoniae was observed to have the capability of organic degradation and electricity generation, while the Thauera sp. has the capability of denitrification.

Culture of yellowtail kingfish (Seriola lalandi) in a marine recirculating aquaculture system (RAS) with artificial seawater

The development of new species is a high priority for the diversification of the Chilean aquaculture sector. The yellowtail kingfish (Seriola lalandi) is a promising candidate for commercial production in recirculating aquaculture systems (RAS). This paper presents data on the culture of yellowtail kingfish in a marine RAS working for 488 days using artificial sea water. Growth performance, feed conversion, feeding rate, condition factor and mortality were determined for fish having an average initial weight (±S.D.) of 0.7±0.2g up to a final average weight of 2006±339.0g. The RAS configuration (drum filter, protein skimmer with ozone, biological nitrification and denitrification, carbon dioxide removal and oxygenation) showed performance stability under the conditions assayed (low water renewal rate). Total ammonia nitrogen and nitrite-nitrogen concentration averaged 0.74±0.42mg/L and 0.21±0.24mg/L respectively. After installation, the denitrification reactor kept nitrate-nitrogen concentrations below 40mg/L. Nitrate-nitrogen was totally reduced at oxidation reduction potential values between −150 and −250mV. Water temperature averaged 22.6±1.4°C and oxygen was maintained close to saturation levels. Carbon dioxide concentration was in average 8.3±2.47mg/L and pH 7.5±0.1. Water renewal rate was 0.45% of the total system volume per day. The system proved the capability to maintain optimal water quality and secured animal welfare.

Impact of Shallow Groundwater Quality Evolution in Kunming Urban by Human Activities

Chemical components of the groundwater change with time and space due to the influence of environmental geological conditions and human activities, where the human activity is one of the main factors which cause the deterioration of groundwater quality. In this paper, the monitoring data of shallow groundwater in Kunming urban has been collected and analyzed. The results indicates that with the acceleration of the industrialization and urbanization process, the chemical characteristics of groundwater have been changed, such as the total dissolved solid (TDS) and nitrogen, including ammonium nitrogen, nitrite nitrogen, and nitrate nitrogen concentration increase gradually. TDS and ammonium nitrogen can be used as indicators that reflect the influence of human activities on the shallow groundwater quality in Kunming urban and characterize obvious pollution of groundwater quality respectively. Based on the reason analysis for TDS increase in groundwater, basic mechanism of the influence of human activities on groundwater quality in the study areas are discussed, which is expected to provide scientific basis for pollution prevention and control of shallow groundwater quality in Kunming urban.

A benchmark simulation to verify an inhibition model on decay stage for nitrification

Activated Sludge Models (ASMs) are widely used for biological wastewater treatment plant design, optimisation and operation. In commonly used ASMs, the nitrification process is modelled as a one-step process. However, in some process configurations, it is desirable to model the concentration of nitrite nitrogen through a two-step nitrification process. In this study, the benchmark datasets published by the Water Environment Research Foundation (WERF) were used to develop a two-step nitrification model considering the kinetics of Ammonium Oxidising Bacteria (AOB) and Nitrite Oxidising Bacteria (NOB). The WERF datasets were collected from a chemostat reactor fed about 1,000 mg-NH3-N/L synthetic influent with at different sludge retention times of 20, 10 and 5-d, whereas the pH in the reactor varied in the range of 5.8 and 8.8. Supplemental laboratory batch experiments were conducted to assess the toxicity of nitrite-N on nitrifying bacteria. These tests suggested that 500 mg-N/L of nitrite at pH 7.3 was toxic to NOB and resulted in continuous decrease in bulk oxygen uptake rate. To model this phenomenon, a poisoning model was used instead of the traditional Haldane-type inhibition model. The poisoning model for NOB and AOB with different threshold poisonings for unionised NO2-N and NH3-N concentrations could successfully reproduce the three WERF datasets.

Distributions and transport of typical contaminants in different urban stormwater runoff under the effect of drainage systems

In recent years, the pollution of receiving water induced by urban stormwater runoff has gained considerable attention. Meanwhile, rainwater is also a potential and valuable water resource, which may effectively mitigate the increasing water shortage. In the present study, the distributions and transport of nutrients and heavy metals in different stormwater runoff of two residential communities (site A and B) under the effect of drainage systems were discussed in detail. Site A with combined drainage system was located in old district featured with a lot of big manufacturing and chemical factories in suburb. Differently, site B with separate system was situated in new district occupied by small shops and residential quarters. The results indicated that air quality was a significant influence factor and reference index in the decision-making of rainwater harvesting and reuse. For nutrients, the anthropic activities contributed adequately ammonia nitrogen and total phosphorus to the road runoff(RD) and sewer overflows, especially in site A with combined drainage system. However, the roof runoff (RF) presented the highest event mean concentrations (EMC) of nitrate and nitrite nitrogen, probably due to the high runoff coefficient of roof and low interference from human activities on dry deposition. Zn(II), Cu(II), and Pb(II) concentrations showed a similar variation pattern, although there were some small differences owing to the erosion of metal materials from rooftops and street lamps. Compared with the “Standards for Drinking Water Quality” in China, the direct rainfall and RF in site B could be harvested and utilized for potential drinking water supply from the perspective of the studied parameters. For site A, at least 33.8% of NH4+-N and 50.8% of NO3--N in RF must be removed before reuse. The results obtained in this research would provide an important assistance and support in urban rainwater reuse as well as runoff pollution control.

English

The aims of this study were to help the development of the models describing denitrification in the recirculation aquaculture systems and to contribute to the knowledge on the role of heterotrophic bacteria in aquaculture nutrient removal systems in mudflats along the coast. Six aerobic denitrifying strains were isolated by bromothymol blue (BTB) plate technique from the fish farm sediments in mudflat along the coast. The strain DF-1 was selected for the aerobic denitrification studies as it was highly effective in removing nitrite compared with other strains; it lowered the nitrite nitrogen (nitrite-N) concentration from 10 mg/L to zero in 20 h. The aerobic denitrification by the strain DF-1 occurred at significantly higher rates of nitrite-N degradation than the positive controls (sterile screening media) under different pH, temperature, and various concentrations of nitrite and salinity. The rate of nitrite-N degradation was 99.3, 97.7, 99.5, 96.5, and 91.8% when sucrose, glucose, sodium acetate, sodium succinate and potassium sodium tartrate, respectively, were used as the carbon source. The strain DF-1 contained the nirK gene as indicated by the amplification of nitrite reductase. The strain DF-1 was identified asKlebsiella oxytoca by the morphological observation and 16SrRNA gene analysis.   Key words: Coastal pollution, high nitrogen risk, aerobic denitrification, Klebsiella oxytoca, nitrite nitrogen degradation rate, aquaculture.

Nitrate removal from groundwater using solid-phase denitrification process without inoculating with external microorganisms

Denitrification of groundwater was studied using a laboratory-scale reactor packed with biodegradable snack ware served as both carbon source and biofilm support for microorganisms. The complete removal of 50 mg/L of nitrate-nitrogen was achieved in a 23-day-old reactor with 2.1 h of hydraulic retention time without inoculating with any external microorganisms, which indicates that indigenous microorganisms in groundwater proliferate readily and result in stable biofilm formation onto biodegradable snack ware. Accumulation of nitrite and nitrate residue was detected when hydraulic retention time was lower than 2.1 h. The breakthrough of nitrate-nitrogen up to over 10 mg/L in the effluent water was observed with nitrate removal efficiency reducing to about 75 % when hydraulic retention time was lowered to 1.4 h. The highest rate of denitrification was observed with 1.5 h of hydraulic retention time. Dissolved organic carbon concentration in the effluent water ranged between 10 and 20 mg/L during the stable operation of the reactor, and nitrite-nitrogen concentration was never higher than 0.09 mg/L. Considering its relatively low price and high denitrification rate, biodegradable snack ware can become a good alternative for denitrification process.

Comparison of the treatment performance of bio-substrate based and meadow brown soil based subsurface infiltration systems for domestic wastewater treatment

To foster the practical development of subsurface wastewater infiltration (SWI) systems in China, two systems were implemented on the campus of Shenyang University. The bio-substrate filled SWI (BSWI) and meadow brown soil filled SWI (MSWI) system operated under the same operation mode. According to the 12-month experimental results, the bio-substrate had much higher potential to be a good substrate as compared to the meadow brown soil. The maximum adsorbing capability for NH(4)(+)-N of the bio-substrate was 0.724 mg/g, while for the meadow brown soil, the maximum value was 0.471 mg/g. The amounts of nitrifying and denitrifying bacteria of the BSWI were one order of magnitude higher than that for the MSWI. Ammonia, nitrite and nitrate nitrogen concentrations implied nitrification-denitrification process went well in the BSWI. Moreover, the BSWI system maintained efficient pollutants removal, the mean removal efficiencies were 92.3 ± 1.5%, 96.5 ± 3.1%, 90.0 ± 2.1%, 78.6 ± 1.2%, 91.2 ± 1.1% and 99.7 ± 1.0% for COD, BOD(5), NH(4)(+)-N, TN, TP and SS, respectively. As compared with the MSWI system, pollutant removal efficiencies improved by 26.8 ± 2.3% for NH(4)(+)-N, 33.8 ± 1.7% for TN, 22.4 ± 1.4% for COD, 26.0 ± 3.5% for BOD(5) and 14.7 ± 2.9% for TP, respectively.

Effects of complex probiotics on water quality and microbial communities in grass carp(Ctenopharyngodon idellus)culture

This experiment was conducted to study the effects of complex probiotics on water quality and microbial community structure in grass carp culture.The results of water quality determination showed that compared with the control group,the concentration of ammonia nitrogen,nitrite nitrogen and total nitrogen in treatment group was lower in the whole experiment,respectively;On 18th d,the concentration of nitrate nitrogen in treatment group was decreased by 54.49%(P0.05).On 15th d,the concentration of total inorganic nitrogen in treatment group was decreased by 28.75%(P0.05).Orthophosphate and total phosphorus had no difference between the two groups.The 454-Pyrosequencing results showed that the composition of bacterial communities was highly variable between control and treatment groups,and microbial diversity of treatment was higher than that of control.Firmicutes and Proteobacteria decreased by 91.21%(P0.01)and 21.75%(P0.01)respectively.Bacteroidetes,Actinobacteria and Cyanobacteria increased by 288%(P0.01),435%(P0.01)and 848%(P0.01)respectively.Among Proteobacteria,Alphaproteobacteria and Betaproteobacteria was elevated by 318%(P0.01)and 18% respectively,while Gammaproteobacteria was reduced by 78.82%(P0.01).

A Depth Wise Diversity of Free Living N<sub>2</sub> Fixing and Nitrifying Bacteria and Its Seasonal Variation with Nitrogen Containing Nutrients in the Mangrove Sediments of Sundarban, WB, India

Mangrove provides a unique ecological niche to different microbes which play various roles in nutrient recycling as well as various environmental activities. The highly productive and diverse microbial community living in mangrove ecosystems continuously transforms dead vegetation and recycle nitrogen, phosphorus, sulphur and other nutrients that can later be used by the plants. Mangrove ecosystems are rich in organic matter, and however, in general, they are nutrient-deficient ecosystems, especially of nitrogen and phosphorus. The present study investigated depth wise variation of Nitrifying bacteria, Nitrogen fixing bacteria, total bacterial population along with nitrate-nitrogen, nitrite-nitrogen and other physicochemical parameters of soil during pre-monsoon, monsoon and post-monsoon periods at three different sampling stations of mangrove sediments viz. deep forest region, rooted region and unrooted region. The microbial population was also found maximum in the deep forest sediment relative to the other two sites. Populations of cultureable microbes were found maximum in surface soil and decreased with increase in depth in Sundarban mangrove environment. A decreasing trend of total microbial load, nitrifying and nitrogen fixing bacteria with increase in depth were recorded throughout the year. Present study revealed the relationship among depth integrated variations of physicochemical components (viz. soil temperature, pH, salinity, nitrite nitrogen and nitrate nitrogen concentration) and total microbial load, nitrifying and nitrogen fixing bacteria microbial populations.

Performance of sequencing microbead biofilters in a recirculating aquaculture system

Biological filtration, or biofiltration, is the key technology in recirculating aquaculture systems. Sequencing microbead biofilters, in which the media maintains a continuous up-and-down movement, are based on traditional microbead filters but offer superior filtration properties. The performance characteristics of a sequencing microbead biofilter installed in a recirculating aquaculture system for rearing Barcoo perch at 29±1°C were examined. The total ammonia-nitrogen (TAN) concentrations and the nitrite-nitrogen concentrations during a 52-day culture period were maintained blow 1.6mg/L and 0.9mg/L. In order to ensure efficient biofiltration, the optimal actual application of hydraulic retention time was determined to be approximately 3–5min. The water flow produced by the reciprocating motion of the media served to wash away suspended solids, ensuring the occurrence of optimal nitrification processes. Additionally, the reciprocating motion of the media enhanced ammonia treatment efficiency significantly by improving the transport of nutrients and nitrification activity. Compared to a static situation the ammonia removal rate increased by 27% based on the application of up-and-down reciprocating movement. The biofilm on the microbead forms as a compact, complex, and homogeneous structure, consisting of numerous microscopic thin sheets. Additionally, a multitude of pores, interstitial voids, and vertical channels were widely observed to convey obviously advantageous properties in support of fluid passage, thus enhancing mass transfer and ultimately contributing to biofiltration effectiveness. The optimum biofilm thickness for providing efficient biofiltration was determined to be approximately 70μm for this filter.

Method to identify potential phosphorus rate-limiting conditions in post-denitrification biofilm reactors within systems designed for simultaneous low-level effluent nitrogen and phosphorus concentrations

Water-quality standards requiring simultaneous low level effluent N and P concentrations are increasingly common in Europe and the United States of America. Moving bed biofilm reactors (MBBRs) and biologically active filters (BAFs) have been used as post-denitrification biofilm reactors in processes designed and operated for this purpose (Boltz et al., 2010a). There is a paucity of information describing systematic design and operational protocols that will minimize the potential for phosphorus rate-limited conditions as well as a lack of information describing the interaction between these post-denitrification biofilm reactors and unit processes that substantially alter phosphorus speciation (e.g., chemically enhanced clarification). In this paper, a simple mathematical model for estimating the threshold below which P becomes rate-limiting, and the model is presented and evaluated by comparing its predictions with operational data from post-denitrification MBBRs and BAFs. Ortho-phosphorus (PO4–P), which is the dissolved reactive component of total phosphorus, was a primary indicator of P rate-limiting conditions in the evaluated post-denitrification biofilm reactors. The threshold below which PO4–P becomes the rate-limiting substrate is defined: SPO4–P:SNOx–N = 0.0086 g P/g N and SPO4–P:SM = 0.0013 g P/g COD. Additional analyses indicate JNOx−Navg=0.48g/m2/d when SPO4–P:SNOx–N > 0.0086, and JNOx−Navg=0.06g/m2/d when SPO4–P:SNOx–N < 0.0086. Effluent nitrate–nitrogen plus nitrite–nitrogen concentration (SNOx–N) from the evaluated post-denitrification biofilm reactors began to rapidly increase when SPO4–P:SNOx–N was 0.01, approximately (consistent with the rate-limitation threshold of SPO4–P:SNOx–N < 0.0086 predicted by the mathematical model described in this paper). Depending on the processes used at a given WWTP, optimizing chemically enhanced clarification to increase the amount of PO4–P that remains in the clarifiers effluent stream, dosing phosphoric acid in the MBBR or BAF influent stream, and/or optimizing secondary process EBPR may overcome phosphorus rate-limitations in the biofilm-based post-denitrification process.

Ammonium removal pathways and microbial community in GAC-sand dual media filter in drinking water treatment

A GAC-sand dual media filter (GSF) was devised as an alternative solution for drinking water treatment plant to tackle the raw water polluted by ammonium in place of expensive ozone-GAC processes or bio-pretreatments. The ammonium removal pathways and microbial community in the GSFs were investigated. The concentrations of ammonium, nitrite and nitrate nitrogen were monitored along the filter. Total inorganic nitrogen (TIN) loss occurred during the filtration. For 1 mg ammonium removal, the TIN loss was as high as 0.35 mg, DO consumption was 3.06 mg, and alkalinity consumption was 5.55 mg. It was assumed that both nitrification and denitrification processes occur in the filters to fit the TIN loss and low DO consumption. During the filtration, nitritation, nitrification and nitritation-anaerobic ammonium oxidation processes probably occur, while traditional nitrification and denitrification and simultaneous nitrification and denitrification processes may occur. In the GSFs, Nitrosomonas and Nitrospira are likely to be involved in nitrification processes, while Novosphingobium, Comamonadaceae and Oxalobacteraceae may be involved in denitrification processes.

Effects of carbohydrate addition on Litopenaeus vannamei intensive culture in a zero-water exchange system

The present study investigated the effects of carbohydrate addition on the water quality, carbon/nitrogen ratios, densities of total bacteria, nitrogen cycle bacteria and zooplankton, and shrimp growth performance in a zero-water exchange system for Litopenaeus vannamei intensive culture. Sucrose was added as the carbohydrate into the water at five levels, i.e., 0, 25%, 50%, 75% and 100% of the theoretical adding quantity. Our results demonstrated that carbohydrate addition, especially 75% and 100% of the theoretical quantity significantly reduced the concentrations of total ammonia nitrogen and nitrite nitrogen during the late culture period in the water (P<0.05). In addition, carbohydrate addition significantly increased carbon/nitrogen ratios and total bacterial densities of the water (P<0.05), whereas did not affect those of the sediment on the whole. We also found that the densities of nitrogen cycle bacteria (ammonia-oxidizing, nitrite-oxidizing and denitrifying bacteria) in both the water and the sediment of the carbohydrate-added treatments were obviously affected compared to those of the control treatments. Zooplankton densities in the water were determined to be significantly increased by carbohydrate addition (P<0.05). The parameters for shrimp growth performance including the yield, survival and feed conversion ratio demonstrated that 75% of the theoretical quantity was more suitable for L. vannamei culture. Conclusively, carbohydrate addition into zero-water exchange systems for L. vannamei intensive culture can effectively improve the water quality, bacterial activities and zooplankton growth, consequently resulting in the better growth performance.

In Situ Destruction of Perchlorate and Nitrate Using Gaseous Electron Donor Injection Technology

Perchlorate and nitrate in vadose‐zone soil can be continuing sources of groundwater contamination and technologies for remediation of these sources are limited. Gaseous electron donor injection technology (GEDIT) is an in situ approach that was demonstrated at a site in California. A mixture of hydrogen, carbon dioxide, liquefied petroleum gas (LPG), and nitrogen was injected into the vadose zone over a period of 5 months followed by 3 months of LPG alone. Perchlorate and nitrate plus nitrite nitrogen concentrations were reduced by over 90% and both were capable of being reduced to nondetectable concentrations. Hydrogen was required for perchlorate destruction, although concentrations as low as 0.5% were effective. Hydrogen was not required for nitrate destruction. Contaminant destruction was observed in both fine‐grained and coarse‐grained soils ranging from clay to gravel. Hydrogen was an effective electron donor because of its low molecular weight and high diffusivity which likely promoted its penetration into low‐permeability formations. Contaminant destruction was also observed in moisture contents ranging from 6.8% to 36% demonstrating that GEDIT was effective in low‐ and high‐moisture soils. The radius of influence (ROI) for perchlorate destruction was approximately 3.0 to 4.6 m while that for nitrate was greater than 17 m. The ROI was limited by use of a single injection location. Use of a grid injection system is anticipated to greatly increase efficiency. This research represents the first demonstration of GEDIT for treatment of contaminants in the vadose zone.

Impact of total organic carbon and chlorine to ammonia ratio on nitrification in a bench-scale drinking water distribution system

Nitrification occurs in chloraminated drinking water systems and is affected by water quality parameters. The aim of this study was to investigate the impact of total organic carbon and chlorine to ammonia ratio on nitrification potential in a simulated drinking water distribution system as during chloramination. The occurrence of nitrification and activity of nitrifying bacteria was primarily monitored using four rotating annular bioreactors (RAB) with different chlorine to ammonia ratios and total organic carbon (TOC) levels. The results indicated that nitrification occurred despite at a low influent concentration of ammonia, and a high concentration of nitrite nitrogen was detected in the effluent. The study illustrated that reactors 1(R1) and 3 (R3), with higher TOC levels, produced more nitrite nitrogen, which was consistent with the ammonia-oxidizing bacteria (AOB) counts, and was linked to a relatively more rapid decay of chloramines in comparison to their counterparts (R2 and R4). The AOB and HPC counts were correlated during the biofilm formation with the establishment of nitrification. Biofilm AOB abundance was also higher in the high TOC reactors compared with the low TOC reactors. The chlorine to ammonia ratio did not have a significant impact on the occurrence of nitrification. Bulk water with a high TOC level supported the occurrence of nitrification, and AOB development occurred at all examined chlorine to ammonia dose ratios (3:1 or 5:1).

Limnological characterization of freshwater systems of the Thomas Point Oasis (Admiralty Bay, King George Island, West Antarctica)

Hydrochemical research into the small, shallow water bodies and wetland areas around the Henryk Arctowski Polish Antarctic Station (King George Island) is presented. Concentrations of nitrite, nitrate, ammonium, and total nitrogen in these waters were determined, as were those of reactive and total phosphorous, inorganic carbon, organic carbon, total carbon, silicate, and chloride and sulfate ions. Conductivity and pH were also measured. Average concentrations ranged widely, e.g., total nitrogen 0.176–29.21 mg L −1, total phosphorus 0.022–18.35 mg L −1, total carbon 1.38–26.90 mg L −1, Cl − 30.17–850 mg L −1, and SO 4 2– 2.11–236 mg L −1. The trophic status was influenced by influxes of nitrogen and phosphorus from penguin rookeries. Selected water bodies supported 31 taxa of algae and 11 invertebrate taxa, with Euglenophyta dominating in waters with high concentrations of ammonium–nitrogen, whereas diatoms characterized Lake Wujka, with low ammonium concentrations. All water bodies studied had rotifers, but crustaceans were only represented in Lake Wujka.

Investigation of the Organic Pollution and Contaminants' Biological Destruction of the River Kamchiya

ABSTRACTThe subject of the present work is an investigation of the water quality of the river Kamchiya with regard to the organic pollution and contaminants' biodegradability. Nutrients content (ammonium nitrogen, nitrite nitrogen, nitrate nitrogen, phosphate), Dissolved oxygen (DO), Biochemical Oxygen Demand (BOD), Chemical Oxigen Demand (COD) were analyzed in 10 monitoring stations downstream for three years period. The river was characterized with good oxygen status. The nitrates corresponded to the national water quality standards. Concentrations of ammonium nitrogen, nitrite nitrogen and phosphates over the threshold limits were determined in most of the monitoring stations. The average annual concentrations of nitrite pollution at the nearest to the river mouth monitoring stations Poda exceeded the threshold limits 4 times for 2006, 9 times for 2007 and 5 times for 2008 year. The highest concentration measured at this station during June 2007 year was 0, 91 mg/dm3 at 0,04 mg/dm3 threshold limit. The highest levels of ammonia and nitrites exhibited disturbance of the nitrification processes. The coefficient of conservatism of the organic pollutants was calculated by the correlation between BOD and COD values. In most of the cases the coefficient value was under 0,5 which determined the organic pollutants as highly conservative with regard to biological destruction.