Badania właściwości odcieku ze składowiska IBB za pomocą analiz biologicznych oraz fizykochemicznych

Yemen is one of the developing countries suffering from water pollution. Landfill is one of the sources of water pollution. A study of composition of landfill leachate was conducted at Ibb landfill, located at Al-Sahool area, north of Ibb City, Yemen. The leachate was sampled at five different landfill locations during dry season, due to the excessive generation of leachate during this season. The physicochemical characteristic of leachate, such as pH, temperature, EC, TDS, DO were measured in-situ. Also, biological parameters such as COD and BOD5, major anions and nitrogenous compound such as Cl, SO4, NO2, NO3, NH3-N, major cations (Na, Mg, Ca, K, Fe) and heavy metals (Pb, Zn, Ni, Cr, Cd, Cu) were analysed in the laboratory. The results showed that, the leachate from Ibb landfill is in methanogenic phase. The first leachate site at Al-Sahool area was characterized by the highest values of most physico-chemical parameters. However, the quantitative results of most studied parameters were generally decreased towards downstream sites (1-5). The BOD5/COD value of 0.1 to 0.7 obtained for leachate suggested the partially stabilization. The concentrations of heavy metals were found in relatively high levels (except Cu). Therefore, a leachate collection pond should be built to collect and treat the leachate to prevent further contamination as well as build more sanitary landfill facilities in Al-Sahool area to prevent further ecological contamination and keep public health safer.Jemen jest jednym z krajów, które borykają się z zanieczyszczeniem wód. Składowiska odpadów są jednym ze źródeł zanieczyszczeń wód. Celem pracy jest badanie właściwości oraz charakterystyka odcieku ze składowiska zlokalizowanego w mieście Al-sahool, w północnej części województwa IBB w Republice Jemenu. Próbki przeznaczone do badań pobrano z pięciu różnych lokalizacji na ww. składowisku. Próbki odcieku zebrano podczas pory suchej, ze względu na nadmierną ilość wytwarzania odcieków w tym sezonie. Właściwości fizykochemiczne takie jak pH, temperatura, przewodnictwo elektryczne właściwe (PE), suma substancji rozpuszczonych (SSR), rozpuszczony tlen (RT) zbadano na miejscu. Parametry biologiczne takie jak chemiczne zapotrzebowanie tlenu (ChZT), biologiczne zapotrzebowanie na tlen (BZT), główne aniony takie jak chlorek (Cl), siarczan (SO4) oraz azotowe związki takie jak azotyny (NO2), azotany (NO3), amoniak (NH3-N), główne kationy (Na, Mg, Ca, K, Fe) oraz metale ciężkie (Pb, Zn, Ni, Cr, Cd, Cu) analizowano w wojewódzkim laboratorium Wody i Służby Sanitarnej, IBB. Wyniki przeprowadzonych badań wykazały, iż badane odcieki są w metagonicznej fazie. Odcieki z pierwszej lokalizacji charakteryzują się najwyższymi wartościami głównych parametrów fizykochemicznych. Natomiast wyniki ilościowe większości badanych parametrów na ogół miały tendencję spadkową w kierunku lokalizacji (1-5). Wartości (BZT)/ (ChZT) od 0,1 do 0,7 otrzymano dla odcieku częściowo stabilizowanego. Koncentracja metali ciężkich była na wysokim poziomie (oprócz Cu). Wyniki badań rekomendują, że budowa basenu do gromadzenia ścieków, budowa sanitarnego składowiska jest bardzo potrzebna aby ochronić przed zanieczyszczeniami ekologicznymi

Monitoring nonrevenue water performance in intermittent supply

Water utilities should monitor their nonrevenue water (NRW) levels properly to manage water losses and sustain water services. However, monitoring NRW is problematic in an intermittent water supply regime. This is because more supplied water to users imposes higher volumes of NRW, and supplying significantly less water results in an unmet water demand but interestingly less NRW. This study investigates the influence of the amount of water supplied to a distribution system on the reported level of NRW. The volume and indicators of NRW all vary with variations in the system input volume (SIV). This is even more critical for monitoring NRW for systems shifting from intermittent to continuous supply. To enable meaningful monitoring, the NRW volume should be normalised. Addressing that, this research proposes two normalisation approaches: regression analysis and average supply time adjustment. Analysis of the NRW performance indicators showed that regression analysis enables the monitoring of NRW and tracking its progression in an individual system only, but not for a comparison with other systems. For comparing (or benchmarking) a water system to other systems with different supply patterns, the average supply time adjustment should be used. However, this approach presents significant uncertainties when the average supply time is less than eight hours per day

Assessment of water losses in distribution networks: Methods, applications, uncertainties, and implications in intermittent supply

Reducing all water loss components to zero is neither technically possible nor economically viable. The water loss components should be accurately assessed and prioritised for a reduction. This paper investigates all methods that break down the water losses in distribution networks into apparent and real losses. Their accuracies and uncertainties are discussed and applications to three case studies in developing countries are presented. The results show that different methods estimate the water loss components differently. Consequently, different reduction measures are planned and prioritised. Interestingly, the least accurate methods have a low level of uncertainty, but more realistic assumptions yield higher uncertainties. This suggests that the uncertainty analysis only assists in improving the outputs of each of the methods but does not demonstrate their accuracy. The cost of water loss varies depending on the used assessment method and the economic feasibility of the reduction measures is significantly influenced. The water loss components should therefore be assessed for the whole network using at least two methods to reasonably model and monitor the loss reduction in water distribution networks