OBTAINING FERTILIZERS BASED ON FOOD WASTE AND STUDYING SOME OF THEIR PROPERTIES

ABSTRACT

During the research, samples of organic and mineral fertilizers were obtained from food waste, economizing local and natural raw materials. At this time, food waste was exposed to initial mechanical processing, and then the fertilizer was obtained by enriching its composition with nutrients. Some properties specific to fertilizers were studied in the obtained samples. Their water solubility, pH value, the content of nitrogen and phosphorus in its composition were determined. These samples are not inferior to fertilizers known in the industry in terms of nitrogen and phosphorus content. Using the obtained fertilizer samples as nitrogenous and phosphorous fertilizers is considered effective.

АННОТАЦИЯ

В ходе исследований были получены образцы органических и минеральных удобрений из пищевых отходов с экономией местного и природного сырья. В это время пищевые отходы подвергались первичной механической обработке, а затем получали удобрение, обогащая его состав питательными веществами. В полученных образцах изучены некоторые свойства, характерные для удобрений. Определены их растворимость в воде, значение рН, содержание азота и фосфора в его составе. Эти образцы не уступают известным в промышленности удобрениям по содержанию азота и фосфора. Эффективным считается использование полученных образцов удобрений в качестве азотных и фосфорных удобрений.

Keywords: food waste, reuse, fertilizer samples.

Ключевые слова: пищевые отходы, повторное использование, образцы удобрений.

In recent years, the industry development of and population growth have led to a sharp increase in the amount of waste. Entering the environment as a chemical and biological preparation, waste becomes a source of danger for living beings. Protecting the environment and minimizing these environmental problems is one of the main tasks of modern chemistry [1-2]. 42% of waste is generated by households, 39% by food industry, and 5% by distribution. Waste thrown into the natural environment poses a threat to the health and life of the population. For this purpose, collection, disposal, efficient use of food waste is considered urgent [1-3].

The objective of our research is to restore the soil-to-soil food chain by recycling this waste. At the same time, the core objective is to reduce the amount of residual waste by disposing of waste, form a cheap raw material market by reducing raw material consumption, and re-synthesize fertilizer based on this waste. These fertilizers are used instead of chemical fertilizers. Thus, in this way, the negative impact of synthetic fertilizers on the environment, as well as the impact of throwing vegetable food waste into landfills, will be reduced.

As it is known, nutritional components are important for plants. The most important nutritional components are N, K, P.  Mg, Ca, S, B and Fe, etc. are also nutritional components that differ in their effects on the plant [4-5]. Various daily household wastes were used as a source of phosphorus (e.g. egg shell), as a source of nitrogen, phosphorus and potassium (fruit, vegetable peels, potatoes) [3].

Experımental part

Samples of environmentally friendly fertilizers were obtained under laboratory conditions based on food waste like potato peels, apples, egg shells. Food waste is enriched with N-, P-, and S. Calcium-based waste, household waste, and ammonium salts and nitric acid and its salts as the N-component, and phosphate and hydrophosphate salts as P-component were taken in certain ratios as an initial component. The components waste: N-component: P-component were taken according to the calculated ratios of 2:1:1 - 5:1:1 (table 1).

Household waste was used as raw material when conducting the research. As a nitrogen source, vegetable peel-potato, apple waste, and as a calcium source eggshell were taken for the green component mixture. The waste was dried and ground in a grinder. It was weighed on an analytical balance with an accuracy of 0,001 g.

Table 1.

Waste: Mass ratios of N:P components

Note: E/S - egg shells, P/P - potato peels, AHP - ammonium hydrophosphate, AN - ammonium nitrate, NaP - sodium orthophosphate

The taken components were mixed at room temperature of 50°C for 15-20 minutes under laboratory conditions. The process is carried out through a mixer until a homogeneous mass is obtained.

The obtained homogeneous mass was dried at a temperature of 100-110°C in an oven of POL-EKO-APARATURA SP.J brand. As a result, a powdered mass was obtained.

Results and discussion

Some properties of the samples obtained under laboratory conditions, water solubility, moisture, pH, nitrogen and phosphorus content, were studied according to the methodology [6-7]. The samples were weighed on an analytical scale with an accuracy of 0,001 g and their moisture content was determined according to the proper method (tables 2, 3).

All samples were obtained in the form of viscous solid mass. These samples were dried at a temperature of 100-110℃ for 2 hours. The amount of mass obtained in the form of powder was measured on an analytical balance. The moisture content in the samples obtained on the basis of waste was determined according to the methodology. Indicators are presented in table 2. As a result of the conducted analyses, the moisture content of the sample of 8.93 g containing egg shells was determined to be 0,031 g. In contrast to the other egg shell, the moisture content in the egg shell of 3.31 g is 0.0217g.

The weights of the samples containing potato peels were 16,2 g and 4,82 g. Both had a moisture content of 0,014 g and 0,021 g, respectively.

In the sample containing apple waste, the moisture content of the apple of 10,87g was determined to be 0,028 g, and the moisture content of the apple sample containing 2,77 g was determined to be 0,03 g. A graph is constructed according to the table, (fig.1).

Table 2.

Changes in the mass obtained during the moisture determination in the samples

As a continuation of the research, it is planned to eliminate hygroscopicity in these samples.

Figure 1. Moisture content determined in the obtained samples

The samples were measured with a pH meter of HI83141 brand under laboratory conditions.

When the ratio of components was 2:1:1, pH of potato peels was 5,34, when it was 5:1:1, pH was 2,82, and pH of egg shells was 5,17 in the ratio of 2:1:1, pH was 6,51 in the ratio of 5:1:1, and in the ratios of 2:1:1 and 5:1:1 of apple waste, pH was 4,31 and 2,12, respectively (table 3).

Table 3.

Quality indicators of the samples obtained on the basis of food waste

Note: P/P- potato peel, E/S- egg shell,  A/W- apple waste

The amount of nitrogen in the samples was in the range of 13,2-21%, and the amount of phosphorus was in the range of 11-14%.

The application of organic and mineral fertilizers obtained in laboratory conditions on the basis of waste in the research work can play a positive role in solving environmental problems, reducing the amount of waste, saving raw materials, and increasing the productivity of plant growth. The use of the samples with a high acid number in saline soils is considered appropriate.

Conclusion

The process of obtaining environmentally friendly fertilizers based on waste was developed by saving natural raw materials. The waste selected as a source of nitrogen and phosphorus was enriched with both micro and macro components in the process of obtaining fertilizers. The process was carried out at a temperature of 18-25℃ for 5-10 minutes. pH value, moisture content, nitrogen and phosphorus content of the obtained samples were studied according to the proper method.

Apple waste was 2.8 - 3%, depending on the amount of components taken in the used sample. 2.1-1.4% moisture was observed when using potato peel waste, and 3-0.022% moisture was observed when using egg shell waste. The formation of moisture is partly due to the hygroscopicity of the taken components.

pH value of the samples was in the range of 6,51-2,2, the moisture content was in the range of -1.4-3%, the amount of nitrogen was in the range of 13,2-25%, and the amount of phosphorus was in the range of 9-21%.

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