Principles of municipal waste management in Poland and selected regions of Europe
High level of production and consumption in member-countries of the European Union is connected with generating a considerable amount of waste. In individual EU member-countries various methods aiming at decreasing the amount of generated waste are implemented. The current situation in Poland, and the best practical solutions introduced in some European regions have been presented in the paper. These solutions were put in place, mainly to fulfill the EU or country's regulations. The priority of municipal waste management measures is to prevent and minimize its generation. Decisions on preventing waste generation should be made as early as at the stage of product designing and manufacturing. The basic principle of proper municipal waste management is to create a system of regional solutions, which includes all the elements of waste management and relates them to the local conditions.
The European Union produces about 18 million tons of waste from meat industry per year. The real danger of the BSE disease caused a necessity of looking for a new alternative solution of meat waste management. The proposed solution of meat industry waste management would create meat production waste free with the use of the cleaner production method. Cleaner production includes: pollution prevention, reduction of the source, recovery of materials and energy (for example: the recovery of blood plasma and protein hydrolisate from bone sludge) and their recycling. The thermal processing of meat industrial waste (bone sludge, meat-bone meal and odour) is anticipated, too. Ashes from meat calcining have the phosphorus content close to its concentration, of the typical phosphoric raw materials. That confirmed the possibility of using such ashes as the substitute of phosphoric raw materials. The target model of waste free meat waste management included the results of the implemented and current research.
Obtaining protein hydrolysates with chemical and enzymatic methods
The goal of our research was to work up a method of hydrolisates protein production using as raw material fresh pork meat-bone tissue after dismantling the process of half carcasses. Actually this raw material was practically all utilized as waste. The results of laboratory research and an industrial test allowed to state that is possible to produce hydrolysates containing 8 - 10% of proteins, and the most advantageous parameters of the chemical process are: the reaction time ~105 min., temperature 120°C, pressure 3.0 bars. With the use of enzymes (Protamex and Flavourzyme), it is possible to obtain a non-gelling protein hydrolysate with a high degree of clarity and light cream colour. The best results were achieved with the following parameters: the meat-bone feedstock to the water ratio from 1:1 to 1:2, the temperature of 40 - 45°C, the time of the process 3 h, pH ~6.
Manufacturing of phosphoric acid from hydroxyapatite, contained in the ashes of the incinerated meat-bone wastes
The results of the investigations concerning phosphoric acid manufacturing, by the extraction method, from the ashes containing hydroxyapatite, obtained through the thermal treatment of bone sludge have been presented. The incinerated bone sludge with ~ 16% P content and the minimal amount of impurities can be an alternative source for phosphoric acid production. The process consists in two stages. In the 1st stage, reaction of hydroxyapatite with phosphoric acid resulting in monocalcium phosphate formation in the solution obtained is carried out. The tests revealed that overall hydroxyapatite dissolution in phosphoric acid takes place when the concentration is 37% H3PO4. In the 2nd stage monocalcium phosphate is converted into calcium sulphate using concentrated sulphuric acid at the recommended temperature of 95°C. The principles of the technological idea of the process of phosphoric acid manufacturing from HA-containing ashes, obtained by bone wastes incineration, as well as a preliminary economic analysis for the production of 10 000 t/year of food-grade phosphoric acid have been developed.
A chemical method of the production of "heavy" sodium tripolyphosphate with the high content of Form I or Form II
Sodium tripolyphosphate STPP is used in laundry detergent as a detergent "builder". The paper presents the chemical method of obtaining "heavy", i.e. with higher bulk density granulated sodium tripolyphosphate. The bulk density of sodium tripolyphosphate was increased by preparing a mixture of the dried sodium phosphates, the recycled subgrain of STPP and water in specific proportions and calcining this mixture for 1 hour at 400°C and 550°C (to obtain a proper STPP form) in the chamber kiln. This method allows producing the granular sodium tripolyphosphate with high bulk density (1.04-1.07 kg/dm3) and a high content of Form I or Form II, respectively.
The paper presents the results of the calcining process of deproteinised and defatted bone pulp called bone sludge. The calcining process was performed in two stages. The first step of the calcining process was realized at the temperature of 600°C in a rotary kiln. In the second stage the obtained bone ashes were calcined at five different temperatures from 650°C to 950°C for 2 hours in a chamber kiln and in air atmosphere. The products of the calcining process were characterized by the XRD method. Calcium content was determined by titration whereas the contents of total phosphorus and acid-soluble phosphorus - by the spectrophotometric method. The X-ray analysis confirmed that hydroxyapatite is the main component of the calcining products. Calcium and phosphorus contents were kept at the level of 40% and 17.5%, respectively, which corresponded to the Ca/P ratio of not stechiometric hydroxyapatite. In vitro studies, in the simulated body fluid, Ringer liquid and distilled water were realised. The measurements of pH value of SBF and Ringer fluid were realized. Additionally electrical conductivity as well as pH for distilled water where conducted. The goal of these tests was to evaluate chemical durability of dense hydroxyapatite materials.
Evaluation of the biomedical properties of hydroxyapatite obtained from bone waste
The method of obtaining hydroxyapatite by thermal treatment of deproteinised and defatted bone pulp called bone sludge was presented. The products of the calcining process were characterized with X-ray diffraction (XRD) and Fourier transformed infrared spectroscopy (FT-IR). The calcium content was determined with titration, whereas the contents of total phosphorus - with a spectrophotomertric method. X-ray investigations confirmed that hydroxyapatite was the main component of the calcining products in the calcining process. The FT-IR spectra confirmed that all organic substances were removed during the calcining process. On the basis of the research into physiological liquids the propensity to resorption of hydroxyapatite bioceramic was evaluated.
The results of a research related to the physico - chemical properties of the mixture of bone - waste and their ingredients have been presented. The mixtures was made up from waste: bovine bones, pork bones, bone sludge and bone meal. The content of the individual waste in the mixtures was selected on the basis of the heat of the combustion of the mixture and the amount of the waste produced in a meat processing plant. The heat of the combustion has been determined by the calorimeter, the content of phosphorus by spectrophotometric method, calcium by titration and phase composition by X - ray diffraction.
The investigations confirmed that pork bones have the highest heat of the combustion 17 MJ/kg because of a big amount of fats. The analyzed waste has contained on average 16.5 wt % phosphorus and above 30 wt % calcium. X - ray diffraction method has proved that in bone waste one phase - hydroxyapatite occurs.
Analysis of sodium tripolyphosphate production processes with a cumulative calculation method
Sodium tripolyphosphate - one of the condensed phosphates is an important ingredient in various types of cleaning substances and a food additive. The paper presents a comparison of different variants of STPP production with the application of the cumulative calculation method. The material balances of the processes were taken as the basis of the analysis. The method of the process analysis as shown in the cumulative calculation determines the influence of the emissions of dust and gas pollutions originating from a particular production process, as well as wastewater and solid wastes resulting from it, upon the natural environment. It was proved that the solution of the production STPP with the dry one-step method has the lowest impact on the environment among the three assessed solutions.
In the study, sodium tripolyphosphate (STPP) was obtained according to the one-stage method. Batch mixes with varied degrees of soda ash neutralization were produced using thermal or wet processing phosphoric acid and/ or recycled STPP calcined in a laboratory rotary kiln. Chromatographic analysis of the phosphate forms showed that products containing as much as 94.73% of a single component were produced. At STPP recycling rates of 2.5 and 5, products with a low bulk density ranging between 0.437-0.547 kg/dm3 were obtained. The recycling of STPP reduces the insoluble substance content, which affects the properties of the product. The phase composition of the products largely depends on the type of recycled phase of sodium tripolyphosphate (phase I and/or phase II) and the calcining temperature.