نیتروژن

Nitrate and orthophosphate in wastewater effluent have a considerable impact on the nutrient load of water bodies. Therefore, the discharging of nitrogenous and phosphorus compounds into water resources induces water pollution. The present study aimed to investigate the performance of natural materials in removing nitrate and orthophosphate from the effluent of a wastewater treatment plants. For this purpose, four laboratory-scale bioreactors with different combinations of filter materials, including woodchips (W), woodchips-beach sand (WS), woodchips-seashells (WSS), and woodchips-beach sand-seashells (WSSS) were applied to assess the performance of nitrate and orthophosphate removal in three hydraulic retention times of 12, 18 and 24 hr. The results showed that the highest removal performance of nitrate and orthophosphate belongs to the WSSS treatment by 92.19 and 96.57%, respectively. In addition, the retention time of 18 hr had the best performance in removing nitrate and orthophosphate in all bioreactors. The research findings revealed that the woodchips in combination with modifier materials have a excellent performance to remove nitrate and orthophosphate.

Earthworms have been used as adsorption markers to prove the biological availability of chemical fertilizers in soil. This study aimed to determine the amount of nutrient uptake in some earthworm species in an orchard soil. In this study, the uptake of nitrogen, phosphorus, potassium, zinc and iron by the application of different chemical fertilizers urea, ammonium sulfate, diammonium phosphate, solupotas, NPK compound fertilizer, NPK fertilizer with cow manure, zinc chelate and iron chelate in five Earthworm species were studied. Treatments were applied in three replications in a randomized complete block design and data were analyzed by ANOVA. Results showed that epigeic species were more active in the uptake of elements such as nitrogen and phosphorus. Meanwhile, E. fetida was more active in nitrogen uptake of urea (72%) and ammonium sulfate but was not active in uptake of phosphorus from diammonium phosphate fertilizer. On the other hand, the presence of organic matter in the fertilizer treatments caused less nitrogen and phosphorus uptake by the worms and under these conditions, the anecic species have performed poorly in the adsorption process. Chelating of nitrogen and phosphorus in organic compound molecules has reduced their adsorption power. In addition, E. fetida showed a higher tendency to adsorb iron (52%) and zinc (50%) in treated soil than control soil. In order to reduce the negative effects of chemical fertilizers on soil organisms, it is recommended to reduce their consumption in shallow soils.

Treating wastewaters containing nitrogenous compounds is an essential issue due to environmental hazards. New biological technologies such as simultaneous nitrification-denitrification (SND), ANAMMOX and SHARON were developed in the last decades. Such techniques are economical and more effective compared to conventional methods. The aim of this work was to investigate physico-chemical properties of SND process.

In this study, subsequent to constructing a comprehensive survey on papers published in the last two decades, the impacts of effective parameters such as temperature, pH, dissolved oxygen, organic carbon, floc size and sludge retention time (SRT) on SND process were investigated.

SND process reduces carbon source demand. Dissolved oxygen should be adjusted in a particular range to maintain an equilibrium between the nitrification and denitrification.  The process efficiency was higher in the basic pH. The optimum temperature for the growth of SND bacteria were 20-30 ℃. There was no linear correlation between efficiency of process and SRT.

The results of this research approved that new biological processes for nitrogen removal such as SND were promising owing to reducing the need for aeration and carbon source. By controlling the Physico-chemical conditions in process, good efficiencies can be achieved.

Azolla plants with the capability of fixing nitrogen, potassium and phosphorus, which are used as green manure and the nutrients in the compost, can be considered as a source of nutrition for plants. This study was designed to investigate the combined effects of Azolla with organic and inorganic fertilizers on soil NPK levels on study the growth index of Populous Deltoids. The Azolla were collected from ponds of Joibar city located in Mazandaran province. Azolla compost was used in combination with inorganic and organic materials and the amount of NPK in these compounds and its effects on growth parameters (height, stem diameter and leaf fresh weight) were investigated. The compost of Azolla 100% and straw 100% had the highest and the lowest NPK that resulted in significant increases in growth indices of Populus deltoides in comparison with control one. Growth Indices in the compost of Azolla 100% showed the significant increase in comparison to other fertilizer treatments (different percentages of Azolla, straw and urea). Also, the mixed manure of Azolla and organic compost (Azolla 50%+ straw 50%) (With 0.32% nitrogen, 0.02% phosphorus and 0.24% K) with inorganic fertilizer of urea was significantly increased growth parameters of plant than control. According to the results, compound fertilizer 50% Azolla +50% straw + urea and Azolla 100% compost were had the greatest impact on improving the soil and finaly, plants growth. Therefore, use of green manure and green manure combined with a combination of organic and inorganic fertilizers, according to the effects on soil chemical traits, resulted in fertility improvement and increase of crop and by reducing the use of chemical fertilizer in agriculture will prevent environmental pollution and its staggering costs and contribute to the sustainable development of agriculture.

Litter decomposition is the most important way of nutrient entering to soil and soil nutrient availability is highly related to dynamics of nutrients and litter decomposition in the forest ecosystems. This study aimed to evaluate the dynamics of nutrients and litter decomposition in the northern Zagros forests using litterbag technique for 180 days in the Khul Hoare forests located in Baneh city. The litter bags were collected at intervals of 30, 60, 120 and 180 days and the rate of leaf litter decomposition and chemical compounds such as nitrogen, carbon, phosphorus, potassium and calcium were measured. The results showed there was no significant correlation between the rate of decomposition and the initial composition of nutrients and also C: N and C: P ratios. Due to the qualification of leaf litter based on the amount of nitrogen in this study, the average amount of nitrogen in Quercus libani was 1.37%. So Lebanon oak can be classified in the average group and it can be considered as a soil improver species. In the studied litter, phosphorus and nitrogen had a similar performance and their concentration increased over time (7.27 and 30.38 mg/g respectively). While concentration of elements such as calcium, potassium and magnesium was decreased. The nutrient concentration of Quercus libani leaf litter was Ca>N>P>K> Mg.

Water quality trading (WQT) is an economically incentive-based strategy that focuses on finding the optimal discharge permit market for surface water quality management. The amounts of traded discharge permits determine the interactions of emission sources in the market. Pollutantsthat are able to provide extra permits can satisfy the demands of other participants for credits. Finding appropriate permit sellers and buyers depends on their marginal costs, enthusiasm for participating in the market and the impacts on the quality of checkpoint for waste load allocation (WLA). It was recommended that the feasibility and cost-effectiveness of WQT should be analyzed in advance for practice. This needsto estimate the projected loads, environmental standard limits, the incremental and total abatement costs, and finally to optimize WLA. In addition, the assignment of total maximum daily loads (TMDLs) is required. This can be carried out through the simulation methods. However, TMDLs and WLAs with focus on limiting total nitrogen (TN) may be different to the phosphorous or biochemical oxidation demand (BOD). Therefore, the outcomes of WQT may be dependent on different factors such as the spatial location of pollutants, discharge loads, river self remediation, and economical and environmental conditions. All emphasizes on this fact that WLA using WQT requires analytical studies in different cases. This research primarily aims atfinding the optimal WLA in the downstream of Sefidrud in which the trading discharge permits (TDP) based on TN may qualify the pollutantsfor market interactions. It intends to assess the feasibility of WQT policy and compares the analytical results to the case of Gharesoo River. Finally, the effectiveness of integrating wastewater reclamation with TDP is introduced as a solution and compared with the results of Gharesoo River.
The study area is limited to the downstream catchment of Sefidrud in which it starts at the spillway of Sangar Reservoir at headwater. This ends up to the Caspian Sea after 55 km length. Here, the main pollutantsare identified as domestic, agricultural and industrial sources. This area receives the effluents of 10 point sources and rice farm lands. The flow rates and the projected TN load (kg/day) discharged to the surface water are estimated using the export coefficients, typical concentrations of TN and the statistical reports of their discharges as for the Gharesoo River. These were simulated by Qual2kw and the terminus point is the checkpoint. TMDLs are calculated by limiting TN to 4.5 mg/L at checkpoint. The impacts of discharge load reduction incurred by emission sources are also determined through the sensitivity analysis and normalized as previous studies.
This research addressesthe feasibility of nitrogen discharge permit market in Sefidrud and compares its effectiveness to the Gharesoo River. For this purpose, in the first scenario, the outcomes of conventional TDP policy are calculated and in the second scenario, its integration of wastewater reclamation market is examined.
The simulation results reveal that the concentrations of total and organic nitrogen can be reduced from 10 and 6.6 mg/L at checkpoint to 4.5 and 1.4 mg/L, respectively. This is conducted using the TMDL policy. This improvement may totally cost 70 billion Rials in a year in the catchment. In this regard, if the wastewater treatment operators appropriately use the secondary units, it can be expected that the classification of river based on water quality index promotes one degree.
In order to study the feasibility of conventional TDP, the WLA is determined using the typical procedure outlined by previous studies. Allocation ofabatement duties to the pollutantswith lower marginal costs as permit sellers may decrease the annual TN abatement costs about 1340 million Rials. It only saves 2% in comparison with TMDL approach and may not receive significant outcomes. In contrary, the results of TDP in Gharesoo River approved its economical efficiency. Here, total savings may exceed 35%. This is discussed as a matter of difference in the total nitrogen discharged between the domestics and agricultural users. The ratios of nitrogen loads in domestic effluent to the agricultural drainage are, respectively, 0.58 and 0.71 for Sefidrud and Gharesoo Rivers. This ratio is introduced as an index to compare the feasibility of nitrogen discharge permit market. Since the point sources are typically assigned as permit sellers to supply credits for non-point sources, this index may imply that whether the trading has sufficient permits. Studying these two cases for nitrogen permit market indicatedthat in lower ratios, the market may find more limits to supply credits. In this regard, it is concluded that the success of market does not rely on the expansion of catchments. It mainly depends on the existence of centralized point-sources and the agricultural land uses. It is also confirmed that the balance between permit demand and supply is the key of a successful trade.
In the second scenario, this study introduces an integration of TDP and wastewater reclamation market. This intends to find an economical solution to increase the credits for trading. If the reclaimed water is used for irrigation of crop lands, about 15 credits may be added to the conventional trading. In addition, the necessity of nitrogen removal would be reduced. This is due to the fact that the agricultural users require the nutrient contents of reclaimed water and simultaneously domestic wastewater treatment plants prefer not to remove nitrogen to sell their effluents with higher values. Consequently, marginal nitrogen abatement costs are dramatically reduced. In this regard, total cost savings would be increased to 57% and 63% in Sefidrud and Gharesoo catchments, respectively. It shows that the integration of markets not only provides more flexibility to the system but also makes markets promising as an economical solution.
In the first scenario, the primary price of permits can only be determined on 150 thousands Rials. Some stakeholders and dischargers may lose their economical incentives for participation in TDP. As a result, they would leave the market and make the predicted interactions fail. In order to increase the robustness of conventional market, it is recommended that point-sources should use discount factor about 15 to 25% for credits. In this condition, the equity in benefits may increase and make market more stable. However, the shadows of unstable and breakable market turn this strategy into a challenging solution. Therefore, in the second scenario, the integration market is introduced. Regarding the analytical results, it is understood that market would be changed into a more flexible strategy that no longer is dependent on the permit price for stability. In contrary to the first scenario, the point sources are not obliged to use the discount factor. However, they would freely reduce the permit price to increase the economical incentives of the permit buyer (non-point source). It is claimed that in this scenario, the permits can be sold about 99% cheaper than the first scenario and simultaneously all sellers may use the maximum benefits obtained. These results have similarly been achieved in Gharesoo River as well.
Finally, it can be discussed that using the integrated reclaimed water and discharge permit market depends on the capabilities of wastewater treatment plants to supply permits enough in regard. In other words, a highly populated city is required in the study area to provide the secondary treated wastewater and its related permits for the integrated market. Therefore, some recent studies have introduced approaches in which they may find further flexibility and economical savings in the market. For example, using artificial aeration is recommended for small areas with permanent streams in which the dissolved oxygen and BOD concentration are the major quality problems of water. Here, the integrated market is able to fill the blanks for nitrogen control and reduce more abatement costs. The second approach is to identify the amounts of tradable permits through index like dissolved oxygen where multiple pollutants such as BOD and nitrogen have to be controlled simultaneously. For example, the dischargers who are not able to provide nitrogen limits should abate more BOD in their effluents to address DO limits instead. In TDP program, this approach can increase the flexibility for pollution abatement but has high uncertainty and complexity. This is recommended to be used only in small areas with limited non-point sources. Meanwhile, the integrated market can be associated with this approach and increase its outcomes. Third approach points to the fact that in trading between point-non point sources, the seasonal demands and supplies should be considered. Therefore, in large watersheds with high non point sources, using seasonal WLA may reduce the overall abatement costs and increase the equity. However, this depends on that wastewater treatment plants should be practically able to obey various WLA policies through different seasons. Consequently, designing operationally flexible tertiary treatment units is a key factor for successful seasonally integrated discharge permit and reclaimed water market. Therefore, it can be outlined that the integrated market can be combined with different technical or management based approaches but needsto be studied in advance. The selection of optimal alternative and also permit pricing mat require an analysis based on game theory approach.

This study concluded that water quality trading strategy is not necessarily an efficient and promising practice to manage all surface waters. It depends on how much stakeholders attain economical benefits to participate in this voluntary strategy;otherwise, it would be failed. In this case, for nitrogen discharge permit market, it is recommended that the reclaimed water is used for irrigation withhigh content of nutrients. Therefore, the obligations tohigh nitrogen abatement and its managementcosts would be decreased. This makes the conventional market change into a more flexible strategy that is almost independent onprimary permit price. As a consequence, the market shape turns into a free interaction with the lowest monitoring requirements. However, it requires further studies to analyze the details of interactions with respect to the variations of permit demands in time. In addition, the combination of different qualitative parameters such as BOD, TN and DO may change the economical outcomes.

In order to study the quantitative and qualitative characteristics of sunflower (Alestar hybrid) under the effects of bio fertilizer and winter wheat as a green manure in combination with the integrated nitrogen sources (chemical-farmyard manure, FYM), an experiment was carried out on experimental farm at faculty of agriculture, Tarbiat Modares University, Tehran, Iran in 2008. The experimental design was a split plot in a randomized complete blocks with three replications, in which seven fertilizer treatments including F1 (100% FYM), F2 (75% FYM + 25% chemical), F3 (50% FYM + 50% chemical), F4 (25% FYM + 75% chemical), F5 (100% chemical), F6 (50% FYM + 50% chemical + green manure), F7 (75% FYM + 25% chemical + green manure) were randomized to the main plot units and two levels of bio fertilizer I1 (inoculation) and I0 (control) to the sub plot units. The results revealed that grain and biological yield, yield components in integrated systems was significantly more than organic and chemical systems. The highest grain yield (3034.5 kg/ha), head weight (90.06 g), head diameter (19.40 cm). 1000 seed weight (67.99 g) and seed number in head (925.5) were obtained in F6 treatment (F6>F3>F4>F7>F2>F5>F1). Inoculation of bio fertilizer improved the grain yield and yield components, oil and protein content and the oil quality of sunflower compared with untreated plants. Saturated fatty acids decreased significantly, while unsaturated fatty acids (linoleic acid and oleic acid) increased in response to raising the organic manure and using bio fertilizer.

The aims of our study were to compare the effectiveness of different nutrition systems and fungi Piriformospora indica on yield and the concentration of elements in shoot and grain of fennel (Foeniculum Valgare Mill). A field study was conducted in 2009 in the Tehran region and the type of design was a randomized complete block with a factorial arrangement and three replications. Five levels of manure (without organic manure، 100% cattle manure، 100% spent mushroom compost and 50% cattle manure with 50% spent mushroom compost and 100% N) along with two levels of inoculation and not-inoculation of the plant with Piriformospora indica. Results showed that different nutrition systems impacted significantly on yield، dry matter، harvest index and nitrogen concentration of plant and grain. The result also showed that fungi significantly affected all of the measured traits except for the potassium concentration of plant and grain. Also، the interaction effects of fungi ´ nutrition systems was not significant in all measured traits except the harvest index. The result showed that the highest (1559 kg/ha) and the least (632 kg/ha) grain yield was produced in chemical systems Piriformospora indica and fertilization systems respectively.

Anzali wetland on the south west of Caspian Sea is a unique ecosystem was registered as Ramsar site at 1975. Anzali wetland was deteriorated due to numerous disorder and poor water quality. The riverin input were strongly affective in the process of eutrophication where the eastern and central region was more degraded. The first survey on the eutrophication process was conducted at 1969, since then several other investigations reported too. This survey was conducted on several study sites at period from 1991 to 2000. For evaluating eutrophication degree the trophic model of chlorophyll-a, total phosphorous and nitrogen also total phosphate to total nitrogen index were used. The result showed that the mean Chlorophyll-a concentration is above of 25 µg/l. and the nitrogen and phosphorous concentration were between 0.15-1.5 mg/l and 0.17-0.05 mg/l. respectively. On the based of trophic level of chlorophyll-a, total phosphorous and total nitrogen 87-100 % of wetland is eutroph however at early years about 46-90 % of the surface area were eutroph indicating that the trend of eutrophication increasing. Trophic models of phosphate to nitrogen shows the most part of Anzali wetland is in the extreme mesotrophic level close to entropic zone. The average entropic index value was 46 with respect to other characteristic of wetland appear to be low. According to TSI (PN) less than 5.2% surface area of Anzali wetland is entropic state status. Anzali wetland does not have enough capacity to reduce all anthropogenic loads from its watershed area therefore the first effective activity is to prevent nutrient load input of wetland. The restoration of Anzali wetland is suggested base on previous investigation recommendations and with revising some of them.

Residue management is one of the optimistic options for sustaining agroecosystems. In order to investigate NO3 and NH4 dynamism with the application of soybean and cotton residues incorporated with a silty-clay-loam soil (0-30 cm), an aerobic incubation experiment was carried out using three residue treatments (including cotton residue, soybeanresidue and cotton residue+urea to eliminate immobilization). The residue amount was determined in order to provide 150 Kg ha-1 of Kjeldahl nitrogen after incorporation with soil (this was done using the nitrogen factor method).The samples were incubated for 175 days under a controlled environment at 25 ˚C. The NO3 and NH4 concentration and bacteria, fungi and Actinomycete populations were measured 7, 14, 28, 67, 109 and 175 days after incubation began. The results confirmed microbial activity dynamism during time. Cotton residues revealed a non significant prevalence on soybean residue with respect to cumulative nitrate and ammonia, which were released during the incubation period. In all cases, the cotton + urea treatment was better than both other treatments. These results were not interpretable based on the C:N ratio and the results showed that the lignin content is probably more important than the C:N ratio (lignin percentage of cotton and soybean residues are equal to 0.7-1.6% and 14%, respectively). In this study, the relationship between nitrate and ammonia dynamism with microbial communities have been analyzed.

Formal environmental education is very important and necessary for sustainable learning in each society. Therefore, sudents’ books must include environmental subject. In most of countries, Perception of educational planners and teachers toward environmental issues in students’ books play key role in development of this kind of education. The aim of this study is exploring perception of educational planners to environmental education in curriculum of guidance schools. A survey instrument is used to measure constructs of perception and attitudes.

In order to study the effect of Iranian zeolite application namely clinoptilolite in animal manure, on yield and yield component of sunflower under different irrigationregimes, an experiment was conducted during 2005- 2006 year, at Research Field of Tarbiat Modares University, Faculty of Agriculture, located at 16 KM Tehran-Karaj Highway, as spilt plot arrangement in randomize complete block design with four replications. Irrigation regimes including: irrigation after consuming 35% of available soil moisture (W1), irrigation after consuming 70% of available soil moisture (W1) that were randomized to the main plot units and subplots were different fertilizer treatments including: providing 100% N of plant requirement from urea chemical fertilizer (F1), providing 60% and 40% N plant requirement from urea chemical fertilizer and animal manure respectively (F2), providing 60% and 40% plant requirement N from urea chemical fertilizer and animal manure compost respectively accompany with zeolite in amount of 5% of animal manure weight (F3), providing 60% and 40% plant requirement N from urea chemical fertilizer and animal manure compost respectively accompany with zeolite in amount of 5% of animal manure weight (F4), providing 60% and 40% plant requirement N from urea chemical fertilizer and animal manure compost respectively accompany with zeolite in amount of 5% of animal manure weight (F5). Result showed that different irrigation regimes and fertilizer levels and their interactions significantly affected on grain yield, oil percent and yield, protein percent, 1000 seed weight, head diameter, grain number in head, final dry matter and leaf chlorophyll content at flowering stage. The highest grain yield was obtained from F4 and F5 treatments in W1 irrigation regime with of 2641.6 and 2602.4 kg/ha respectively. Therefore the best treatments in this experiment were W1F4 and W1F5.