Z. Sharifi; Mohammad Taaher Hossaini
Abstract
Introduction: the use of municipal solid waste (MSW) compost in agriculture as a soil conditioner is increasing day by day because of its positive effects on biological, physical, and chemical soil properties. However, some of the composts because of contamination with heavy metals and other impurities ...
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Introduction: the use of municipal solid waste (MSW) compost in agriculture as a soil conditioner is increasing day by day because of its positive effects on biological, physical, and chemical soil properties. However, some of the composts because of contamination with heavy metals and other impurities can have deleterious effects on groundwater quality, agricultural environment, food chain, plant growth and activity of soil microorganisms. Therefore, this study was conducted to investigate the physical and chemical properties, fertilizing potential and heavy metal polluting potential of two types of municipal solid waste composts with processing time between 4 to 8 years (type A) and between1 to 4 years (type B) produced in Sanandaj city with the aim of using it as an organic fertilizer.
Materials and Methods: Sanadaj city, the center of Kurdistan province, with a population of about 335,000 is located in the west of Iran. The current solid waste generation from the city is about 320 t/day, which are not separated at source of generation. About 200 t of the total produced wastes are composted using an open windrows system at the Sanandaj MSW Composting Plant, which is located in 10 km of Sanadaj-Kamiaran road and the rest are disposed at the landfill site. The compost manufactured by the composting plant has been collected around it in two different locations. The first belonges to the product of 2004-2008 (type A) and the second belonges to the product of 2009-2013 (type B). Till now, due to lack of quality information associated with these products, they have remained unused. Therefore, in this study, we sampled 3 samples composed of six subsamples (each containing 2 kg) from the products in March 2013. The samples were analyzed to determine the physical properties (including undesirable impurities, initial moisture content, particle size distribution, particle density, bulk density (ρb), porosity, and maximum water holding capacity), and the chemical properties (including organic carbon, ash content, pH and salinity) and total amounts of N, P, Ca, Mg, K, Na, Mn, Fe, Cr, Zn, Pb, Ni and Cd using standard methods.
Results and Discussion: The results showed that bulk density, ash content, and the amounts of elements based on the dry weight of compost increased with composting time, however particle size decreased. It is well known that dry bulk density increased with composting time as ash content increased and particle size decreased by decomposition, turning and screening. The decreases of particle size with composting time cause an enrichment of metals based on the dry weight of compost. It is likely due to solubilization of metals in waste by organic acid produced during the microbial decomposition of organic matter and their subsequent adsorption on finer particles due to the higher surface area and the higher ion exchangeable capacity. The evaluation of the fertilizing potential of the surveyed composts by comparing their properties with different standard sets showed that the both composts under test in this study were failed to meet the standard permissible limits with regard to glass content (on average, 21.7 times over the permissible limit), gravel content (on average, 1.4 times over the permissible limit), lead content (on average, 1.6 times over the permissible limit), and salinity content (on average, 1.4 times over the permissible limit). Furthermore, compost type B also failed to meet the standard permissible limits with regard to initial moisture content (on average, 1.4 times over the permissible limit) and ρb (0.2 gcm-3, less than permissible limit) for agricultural purposes. The results showed that excessive amount of glass impurity bigger than 2 mm, salinity and lead contents are the major problems in the use of the composts for agricultural purposes. It should be noted that according to the maximum permissible limit of lead (150-300 mg kg-1) for compost C1 quality class described by Australian standard; both the composts can be used as fertilizers or soil amendments. In order to eliminate glass impurity, remediation approaches such as fine milling and pelleting is needed to disguise the residual glasses and render it as relatively harmless. A feasible approach to eliminate these problems is probably physical fractionation of the studied composts. It allows us to assess the distribution of nutrients and contaminants values in the different physical fractions of the composts, which is useful to detect and to eliminate of the particle sizes which are the responsible for these impurities.
Conclusion: The assessment of MSW-based compost for use in agricultural soil as fertilizer or conditioner is a sustainable recycling practice owing to its nutrient content and its positive effects on soil physico-chemical properties. Thus, we evaluated the fertilizing potential of two MSW composts produced in Sanandaj city for agricultural purposes. Altogether, the results of the study showed that excessive amount of glass impurity bigger than 2 mm and salinity were the major problems in the use of the composts for agricultural purpose. As a result, the quality of the surveyed composts was not suitable for agricultural purposes without appropriate remediation of these restrictions.
A. Hemati; H. A. Alikhani; M. Rasapoor; H. Asgari Lajayer
Abstract
Introduction: Recycling organic wastes has vital roles in sustainable agriculture, reducing pollutants in the environment, and nutrient enrichment of soils. Compost is the product of recycling organic waste through anaerobic treatment, which can be a good alternative.Again the use of chemical fertilizers ...
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Introduction: Recycling organic wastes has vital roles in sustainable agriculture, reducing pollutants in the environment, and nutrient enrichment of soils. Compost is the product of recycling organic waste through anaerobic treatment, which can be a good alternative.Again the use of chemical fertilizers is inappropriate. Vinasse is brown material and it is a product of industrial production of alcohol from molasses. Vinasse, a by-product of ethanol production from molasses, is a highstrength effluent with a high content of organics, mainly organic acids, reducing substances, cultured matter and glycerol. The wastewater is characterized by high concentrations of potassium, calcium, chloride and sulphate ions, a high content of suspended solids, a high CoD (Chemical oxygen Demand) level and a high temperature at the moment of generation.Vinasse can be used as a supplement for enhancing compost fertilizer quality, because it has plenty of organic matter and minerals. This research was done with the purpose of surveying application of vinasse in different levels on indices of compost producing (temperature, microbial population, nitrogen, carbon, the ratio C/N, nitrate, pH and EC) and producing time in different phases (during the production and after compost production) for 5 months in the waste resumption complex of Aradkooh in Tehran.
Materials and Methods: The method used for compost production from solid waste material was ventilating the fixed mass. In this research, the volume of ventilation was 0.6 lit air for 1 lit waste material in a minute.Four different treatments (each three replicates ) were applied to the compost:C0 without vinasse (control), C1, C2 and C3, respectively 10, 20 and 30 ml vinasse per kg waste material. The following factors were measured during each phase: Total-N was measured by the Kjeldahl method and organic carbon was measured by the Walkley-Black method. Thermometers were used for temperature monitoring at different locations in the riff-raff. The microbial population size was obtained by the CFU method.Electrical conductivity and pH of the water extracts from the samples were determined by shaking the samples mechanically with distilled water at a solid-to-water ratio of 1:10 (w/v). Additionally, NO3–N was determined by spectrophotometric method.
Results and Discussion: At the beginning of this study, theresults showed that, after the formation of the riff-raff, temperature was increasing rapidly all over the riff-raff, which indicates a specified microbial activity. Minimum time to reach the thermophilic temperature, 30 ml per kilogram of vinasse raw materials, was for (C3) and maximum of them was for the control treatment (C0). Adding vinass in the second phase led to an increase in the compost mass temperature. Treatment C3 with the highest and treatment C0 has the lowest microbial populations. Total nitrogen content increased during composting of the waste materials in comparison with its initial concentration. In both phases treatment C3 has the highest and treatment C0 has the lowest total nitrogen content. According to results of the measurements of organic carbon in the first phase, at the beginning of composting process, most of the organic matter was in treatment C3and the lowest organic matter was in C0. However, with increasing the composting process, the vinass treatment had lost jts organic carbon with more gradient. In the second phase by adding vinass, the originally organic carbon increased because of the high levels of organic matter. But,with further vinass treatment, they lost their organic carbon more vigorously. During five months,changes in the ratio of carbon to nitrogen C/Nwas variable. In vinass treatment, the ratio ofC/N increased more vigorously until it reached one quarter and then it fell less sharply. In the first month, this ratio fell less sharply in the control group, and in the final months it fell with more intensity. In the second phase, decreasing the ratio of carbon to nitrogen was observed and the decrease treatment was more than the other treatments. The monthly analysis of riff-raff samples showed that the higher increase in pH mostly occurs in the first month, and in all cases the value of the electrical conductivity increased during composting. Until the second month of pH and EC treatment, C3 and C2 increased and decreased in the third to fifth months.In the second phase pH at vinasse treatment increased and pH at C0 treatment decreased. Maximum amount of nitrate was observed at C3 treatment and at Epsom salt phase nitrate has the maximum amount.
Conclusion: Eventually, it is recognized that treatment C3 and C2it is adequate to add context of organic waste and this treatment decreases the production time of compost up to two months.The second phase was not suitable compared with the first phase due to the inability of increasing nitrate-nitrogen and pH.
H. Emami; A.R. Astaraei; A. Fotovat
Abstract
Soil quality is important for evaluating the soil fertility and physical condition. Soil physical and chemical indicators should be regarded for determining the soil quality. This research was conducted to study the effect of organic matter on quantitative value of soil quality. Three level (15, 30, ...
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Soil quality is important for evaluating the soil fertility and physical condition. Soil physical and chemical indicators should be regarded for determining the soil quality. This research was conducted to study the effect of organic matter on quantitative value of soil quality. Three level (15, 30, and 60 ton/ha) of different organic compounds including municipal waste compost, sewage sludge, cattle manure, and wheat straw to gether with control treatment in three replications were applied into loamy soil. The treated soils were kept for 6 months at 70% of field capacity moisture in greenhouse condition. Then soil quality determined based on non-linear score function by using of 14 physical and chemical indicators. The results showed that the score of control treatment was 52.7, which it belong to class 4, i.e. low quality. Addition of different organic matter into studied soil led to improve soil quality score and soil quality class was increased one to 2 degrees. Among the studied treatments, the highest score of soil quality was obtained in 60 ton/ha sewage sludge and 30 and 60 ton/ha compost. Also, addition the other organic treatments cause to increase the quantitative soil quality score in relation to control, and soil quality class increased one degree. Among the studied indicators, iron (Fe), Manganese (Mn), zinc (Zn) micro-nutrients, aeration porosity (AC), and mean weight diameter of aggregates (MWD) were the important limiting indictors in degrading the soil quality in control treatment, and applying the compost and sewage sludge increased their scores.
Ahmad Gholamalizadeh Ahangar; B. Kermanizadeh; S.K. Sabbagh; A. Sirousmehr
Abstract
This investigation was conducted in order to evaluate the direct effects of organic and bio - fertilizers on yield components of two native wheat cultivars, Bolani and cross - Bolani. The experiment conducted as a factorial in a completely randomized design with three replications. Treatment includes ...
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This investigation was conducted in order to evaluate the direct effects of organic and bio - fertilizers on yield components of two native wheat cultivars, Bolani and cross - Bolani. The experiment conducted as a factorial in a completely randomized design with three replications. Treatment includes fertilizer factor: vermicompost (F1), vermicompost + compost (F2), vermicompost + mycorrhiza (F3), compost + vermicompost + mycorrhiza (F4), compost (F5), mycorrhiza + compost (F6), mycorrhiza (F7) and control (no fertilizer application F8) and cultivar factor includes two cultivar Bolani (C1) and cross - Bolani (C2). The results showed that the interaction effect of combined treatments (F7C2) of high yield (1.13 g.pot-1) obtained. The treatment combination (F7C2) of (0.355) was highest harvest index. The high correlation between weight per plant with plant height, spike length, grain yield and harvest index were observed. Generally the combined application of vermicompost and mycorrhiza cultivar cross - Bolani is more suitable for grain production.
