Zygmunt Kowalski

Treatment of chromic tannery wastes

Abstract The new method for treatment of waste waters from tanneries containing chrome and large amounts of other inorganic compounds has been studied. It was found that the addition of cement at suitable temperature and pH results in a decrease of Cr(III) and Fe(III) contents. The method has been verified in practice in five tanneries. It is very simple, cheap and effective in all cases with very different composition of tannery chrome-containing wastes.

A review of municipal solid waste composition and quantities in Poland.

A review of results of the research involving the quantitative and composition analyses of household waste conducted in Poland in recent years is presented in this paper. For these analyses various methodologies have been employed, as there is not one obligatory methodology how to characterise municipal solid waste. The results of the research in large Polish cities indicate great variability, which is difficult to be reasonably explained. This situation is affected by a number of factors, such as various methods and places for sample collection, various methods for tests, fractional character of most of the studies (studies carried out only in some periods during a year). Consequently, it is neither possible to measurably compare their results, nor to generalise them. Hence, within this article only individual data for large cities is provided. It is therefore necessary to standardise methodology for such analyses in Europe, taking into account local variability (such as different housing patterns, climate and waste collection schemes) to allow comparison of results. Reported yearly household waste generation in Polish cities varies from 238 to 309 kg per inhabitant. Biodegradable waste is a strongly dominated fraction in household waste from Polish cities, followed by paper/cardboard and plastics. Historical data shows that waste composition has undergone profound changes, the most significant being an increase of the share of plastics and decrease of fine fraction. The presented data indicates that waste composition strongly depends on the type of housing and its heating system. In the new multi-family buildings with central heating the share of paper and plastics is higher than in old houses with individual heating. In the latter ones the share of fine fraction is higher.

Assessment of waste management technology using BATNEEC options, technology quality method and multi-criteria analysis.

Best Available Techniques Not Entailing Excessive Costs (BATNEEC) options, technology quality method and multi-criteria analysis were proposed as means of developing indices for evaluating municipal waste management systems. The proposed indices can be treated as a tool for ranking the system taking into account technical, environmental, economic, social and other objectives, bearing in mind specific features of the area involved. The analysis was made for three different incineration plants (Spittelau in Vienna, Warsaw and Tarnobrzeg) together with alternative waste disposal versions (with or without biogas burning and with MBP Mechanical-Biological Process) and the waste management infrastructure. The results showed that incineration of waste is much more beneficial than disposal. These results conform to the waste hierarchy identified in EU Directive 2008/98, but the indices created are easy to interpret and useful as a tool for communicating with the public, which is often a crucial factor in determining the location of investment.

Environmental evaluation of the effects of using chromic waste in the production of chromium compounds

Abstract The extreme of the quality indicator WJ was determined as a measure of the difference between the quantity of chromic waste introduced into the process and that obtained from it. It was determined for the elaborated technological alternatives of the sodium chromate production process which uses chromic waste as a substitute for natural raw materials. The technological process quality TJ was defined; it evaluates each of the technological alternatives taking into consideration the environmental figures. The most advantageous alternative is characterised by a negative balance of chromic waste—40% more chromic waste is introduced into the process than is obtained from it. Also, the consumption of chromium-containing raw materials decreases by 63% and process efficiency increases by 16.1% in comparison to the standard dolomite method.

Model of technological alternatives of production of sodium chromate (VI) with the use of chromic wastes

This article presents a mathematical model which describes the sodium chromate (VI) production process with the use of chromic waste as a substitution of natural raw materials. This model is a function of selected process parameters common for all of the examined alternatives and based on equations of material balance. Optimization of the elaborated technological alternatives of the production process with use of recycling of chromic waste has been evaluated by determining the extreme value of the quality indicator WJ. This indicator defines the quantity of waste created in the process. Optimization results enabled the selection of the optimal technological solution from all of the alternatives possible for use in industrial practice. Negative values of the indicator prove that there is the possibility of introducing to the process a larger quantity of waste than the one obtained in the process and transported to the storage heaps.

From sewage sludge ash to calcium phosphate fertilizers

Our work presents the results of the research on the utilization of ashes after sewage sludge combustion comprising phosphorus recovery in the form of useful products. The investigations were divided into three parts: selecting the combustion parameters of sewage sludge, examining ash leaching with mineral acids (nitric and phosphoric) to high phosphorus selectivity assuring a low content of iron and heavy metals in the extracted solutions and precipitation of CaHPO4 .2H2O. Suitable temperature of a sewage sludge combustion enables selective extraction of phosphorus compounds from ash because of hematite phase forming, insoluble in mineral acids. The extracts from phosphoric acid leaching, where the extraction of phosphorus compounds was 96.1%, have very good properties for its further use as the initial solution for CaHPO4 .2H2O with 6% lime milk. The obtained product is characterized by high purity and phosphorus availability compatible even with the feed phosphate standard.

Principles of municipal waste management in Poland and selected regions of Europe

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 countrys 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.

Manufacturing of phosphoric acid from hydroxyapatite, contained in the ashes of the incinerated meat-bone wastes

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.

Thermal utilization of mixtures of bone waste

Thermal utilization of mixtures of bone waste 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.

The Possibilities of Obtaining Hydroxyapatite from Meat Industry

The goal of this work was investigation of physical and chemical properties of calcining products obtained from bone sludge. The calcining process was carried out at the temperatures of 873–1223 K, in chamber kilns in air atmosphere. X-ray investigations of phase composition confirmed that hydroxyapatite is the main component of calcining products. The phosphorus content in these products was close to the level of concentration of this element in typical phosphoric raw materials which proved right using waste materials from meat industry as a substitute for phosphoric raw materials. Studies of morphology of ashes obtained at different temperatures showed that the calcining temperature did not affect the product properties in essential manner. In all cases fine-crystalline products, with a similar shape and size of grain were obtained. Only ashes calcined at 1223 K were characterized by slightly melted crystallites.