Barbara Tchórzewska-Cieślak

The use of activated carbons for removing organic matter from groundwater

Abstract The article presents research results of the introduction of powdery activated carbon to the existing technological system of the groundwater treatment stations in a laboratory, pilot plant and technical scale. The aim of the research was to reduce the content of organic compounds found in the treated water, which create toxic organic chlorine compounds (THM) after disinfection with chlorine. Nine types of powdery active carbons were tested in laboratory scale. The top two were selected for further study. Pilot plant scale research was carried out for the filter model using CWZ-30 and Norit Sa Super carbon. Reduction of the organic matter in relation to the existing content in the treated water reached about 30%. Research in technical scale using CWZ-30 carbon showed a lesser efficiency with respect to laboratory and pilot-plant scale studies. The organic matter decreased by 15%. Since filtration is the last process before the individual disinfection, an alternative solution is proposed, i.e. the second stage of filtration with a granular activated carbon bed, operating in combined sorption and biodegradation processes. The results of tests carried out in pilot scale were fully satisfactory with the effectiveness of 70–100%.

Risk in Water Supply System Crisis Management

Risk in Water Supply System Crisis Management Water supply system belongs to the so called critical infrastructure of cities, and it should be a priority task for waterworks and even for the local authorities to ensure the suitable level of its safety. This system is characterised by its continuous work and requires high reliability level for its operating as well as for its safety, it is unique and its particular elements have different functions and simultaneously they interact forming an integral whole. The main aim of this paper is to present problems associated with water supply system safety management in a crisis situation. Ryzyko W Zarządzaniu Kryzysowym Systemem Zaopatrzenia W Wodę System zaopatrzenia w wodę należy do tzw. infrastruktury krytycznej miast a jego bezpieczeństwo powinno mieć priorytetem dla przedsiębiorstw wodociągowych a nawet władz lokalnych. System ten charakteryzuje się praca ciągłą o wysokim wymaganym poziomie niezawodności i bezpieczeństwa, składa się z podsystemów, pełniących różne funkcje i stanowiących integralna całość. Głównym celem pracy jest przedstawienie problemu zarządzania bezpieczeństwem systemu zaopatrzenia w wodę w sytuacji kryzysowej.

Water Producers Risk Analysis Connected with Collective Water Supply System Functioning

The paper presents threats to water producers related to the collective water supply systems (CWSS) functioning which is the background for safety assessment based on risk analysis. Risk is commonly used as a measure of systems safety. Risk analysis takes into account probability of adverse events occurrence, effects of these events and vulnerability to dangerous situations. The developed method is based on calculating an expected value of losses incurred by water company as a result of adverse events and calculating an expected value of water company financial profit. Its innovative character is to use incomplete or uncertain database. Water company profitability is one of the basic conditions for CWSS continued functioning. The developed methodology is presented on the application example for the county town in south-eastern Poland.

THE USE OF BIOFILTRATION PROCESS TO REMOVE ORGANIC MATTER FROM GROUNDWATER

The article describes the research on the removal of organic matter from natural underground water using biofiltration process. The study was carried out in semi-technical scale on a model filter composed of activated carbon WD-extra. The development of biological activity in a biosorption bed, as well as observations on the relationship between the processes of sorption and biodegradation was evaluated based on the Eberhardt, Madsen, Sontheimer (EMS) test. Leading operation control parameters of biologically active carbon filter BAF included: change of TOC content, dissolved oxygen and permanganate index. To evaluate the colonization of granular carbon determination of ATP value was used. The presence of the biofilm was found by observation using light and scanning microscopes. The organic compounds in the water taken were adsorbed 100% and 70% biodegradable. The combination of sorption process with biodegradation until depletion of activated carbon adsorption capacity allowed in the initial phase of coalbed work for the removal of organic matter in approx. 100%. Formation of biofilm at the right time allowed to extend the filtration cycle and helped lower the TOC by 70%, i.e. from 10 mg C/l to 3–4 mg C/l.

The Use Of Fuzzy Set Theory In Exploitation Management Process On The Water Supply Network

Abstract Daily exploitation of the network, collected data base concerning the pipes failures and knowledge of employees forming the base of data using in effective failure removal process. The paper presents a methodology of assessment of technical condition of water pipes, based on ranking the failures and danger degree they present resulting the lack of water supply to the water consumers. Often decision making process take place under uncertainty conditions, therefore presented method is based on assessment of degree of danger pipe failure making by experts using fuzzy theory and fuzzy sets. In the paper a fuzzy graph including various types of failures causing lack of water supply was presented.

Analysis and assessment of water treatment plant reliability

Abstract The subject of the publication is the analysis and assessment of the reliability of the surface water treatment plant (WTP). In the study the one parameter method of reliability assessment was used. Based on the flow sheet derived from the water company the reliability scheme of the analysed WTP was prepared. On the basis of the daily WTP work report the availability index Kg for the individual elements included in the WTP, was determined. Then, based on the developed reliability scheme showing the interrelationships between elements, the availability index Kg for the whole WTP was determined. The obtained value of the availability index Kg was compared with the criteria values.

Security management of water supply

Abstract The main aim of this work is to present operational problems concerning the safety of the water supply and the procedures for risk management systems functioning public water supply (CWSS) and including methods of hazard identification and risk assessment. Developed a problem analysis and risk assessment, including procedures called. WSP, which is recommended by the World Health Organization (WHO) as a tool for comprehensive security management of water supply from source to consumer. Water safety plan is a key element of the strategy for prevention of adverse events in CWSS.

Analysis of chemical stability of tap water in terms of required level of technological safety

Abstract The main goal of this work is to show the new approach to determining safety technological levels (SLs) in terms of water quality and its chemical stability, as well as issues of water corrosion properties in water distribution systems (WDSs), due to the fact that water supply pipes are prone to corrosion. In the paper the methodology of determining the risk associated with threat to technical infrastructure was considered. The concept was studied on the basis of real operational data from the water treatment plant. The probability of exceeding the individual parameters for WTPI is slightly larger than for WTPII, which means that this water treatment process may cause lack of chemical stability in the water supply network. Operators should anticipate in the process of designing water distribution system, using proper materials, as to ensure an adequate level of safety from the water source to the water recipient. It should be noted that it is necessary to adjust the material of internal installation of water supply networks to the parameters of the water. At present, there are no correlations between the designing step and water parameters. It was concluded that to protect the water supply infrastructure, which belongs to critical infrastructure, water company should put more emphasis on distribution of stable water that has not potentially corrosion properties. Some suggestions were made for the protection of WDS and to ensure safety of system functioning and long-term usability of water pipes.

Safety Problems of Small Water Supply Systems

Abstract The paper presents issues related to risks associated with the operation of small water supply systems on the background of water consumer safety assessment made on the basis of risk analysis. Definition of water consumer safety loss as a risk associated with the water consumption of poor quality or water lack was proposed. For this purpose, a three-parameter matrix is implemented with the parameters of the probability of a representative accident scenario, the losses of the water consumers and their protection. Risk management, together with the implementation of protective barriers of small water supply system against threats is a fundamental condition for the continued operation of the system.

The Method of Identification the Failure Risk on Water Supply Networks

Abstract Daily exploitation of the water network, collecting of data concerning the failure of water pipes and knowledge of the repair team are the basis of the data used in the process of effectively removing and identifying failures. The paper proposes a methodology to identify the risk of failure of the water supply system that uses risk indexes according to the proposed three-stage scale of risk levels. An example of application methods for the actual operational data broken down by analysis and risk assessment for bus cables and a separate analysis for the distribution network.