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 ...
Read More
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.
