| 1. |
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| 2. |
- Fidjeland, Jörgen, et al.
(författare)
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Ammonia sanitisation of sewage sludge using urea
- 2013
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Ingår i: Water Science and Technology. - : IWA Publishing. - 0273-1223 .- 1996-9732. ; 68, s. 1866-1872
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Tidskriftsartikel (refereegranskat)abstract
- The aim of the study was to develop a simple, low-cost treatment for sewage sludge using urea as a sanitising agent. Sewage sludge was spiked with Enterococcus faecalis and Salmonella typhimurium, treated with 0.5, 1, 1.5 and 2% w/w urea at laboratory scale, and the viability was monitored during 4 months of storage at 4, 10 and 22 degrees C (only 0.5%). A linear relationship was identified between Salmonella spp. inactivation rate and ammonia (NH3) concentration. Temperature had a positive impact on Salmonella spp. inactivation at higher temperatures, but in the range 4-10 degrees C temperature influenced this inactivation merely by its impact on the ammonia equilibrium. Enterococcus spp. was more persistent and a lag phase of up to 11 weeks was observed. Higher temperature and ammonia concentration reduced the lag phase duration significantly, and also had a clear effect on the inactivation rate for the treatments with 0.5% urea at 22 degrees C and 2% urea at 4 and 10 degrees C. Urea sanitisation of sewage sludge can give a 2 log(10) reduction of Enterococcus spp. and more than a 5 log(10) reduction of Salmonella spp. within 6 weeks with either 0.5% w/w urea at 22 degrees C or 2% urea at 10 degrees C.
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| 3. |
- Fidjeland, Jörgen, et al.
(författare)
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Ammonia sanitization of blackwater for safe use as fertilizer
- 2015
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Ingår i: Water Science and Technology. - : IWA Publishing. - 0273-1223 .- 1996-9732. ; 71, s. 795-800
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Tidskriftsartikel (refereegranskat)abstract
- Source-separated blackwater from low-flush toilets contains plant-available nutrients and can be used as a fertilizer. The aim of the study was to evaluate the impact on pathogen inactivation when treating blackwater with urea and/or lime. Blackwater was spiked with Salmonella typhimurium, Escherichia coli O157, Enterococcus faecalis, and Ascaris suum eggs, and treated with urea and/or lime in concentrations up to 0.1% w/w. The bottles were kept in a storage facility (manure slurry tank) for 102 days while monitoring the pathogen concentrations. The treatment time needed to meet the requirement for Salmonella and E. coli reduction could be reduced at least six-fold. The enterococci were more persistent, and only the highest treatment doses had a significantly higher inactivation than the controls. The Ascaris egg viability was only reduced by around 50%, so higher urea/lime doses and/or longer treatment times are required to fulfill the treatment requirements of 3 log(10) reductions of parasite eggs.
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| 4. |
- Fidjeland, Jörgen, et al.
(författare)
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Modeling the inactivation of ascaris eggs as a function of ammonia concentration and temperature
- 2015
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Ingår i: Water Research. - : Elsevier BV. - 0043-1354 .- 1879-2448. ; 83, s. 153-160
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Tidskriftsartikel (refereegranskat)abstract
- Ammonia sanitization is a promising technology for sanitizing human excreta intended for use as a fertilizer in agriculture. Ascaris eggs are the most persistent pathogens regarding ammonia inactivation and are commonly present in fecal sludge in low- and middle-income countries. In this study, a model for predicting ammonia inactivation of ascaris eggs was developed. Data from four previous studies were compiled and analyzed statistically, and a mathematical model for the treatment time required for inactivation was created. The inactivation rate increased with NH3 activity to the power of 0.7. The required treatment time was found to decrease 10-fold for each 16 degrees C temperature increase. Dry matter (DM) content and pH had no direct effect on inactivation, but had an indirect effect due to their impact on NH3 activity, which was estimated using the Pitzer approach. An additional model giving an approximation of Pitzer NH3 activity but based on the Emerson approach, DM content and total ammonia (NHTot) was also developed. The treatment time required for different log(10) reductions of ascaris egg viability can thus easily be estimated by the model as a function of NH3 activity and temperature. The impact on treatment time by different treatment options can then be theoretically evaluated, promoting improvements of the treatment e.g. by adding urea or alkaline agents, or increasing the temperature by solar heating. (C) 2015 Elsevier Ltd. All rights reserved.
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| 5. |
- Fidjeland, Jörgen, et al.
(författare)
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The potential for self-sanitisation of faecal sludge by intrinsic ammonia
- 2013
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Ingår i: Water Research. - : Elsevier BV. - 0043-1354 .- 1879-2448. ; 47, s. 6014-6023
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Tidskriftsartikel (refereegranskat)abstract
- Faecal sludge has the potential to be used as a sustainable fertiliser in agriculture, but the sludge must be sanitised due to its content of pathogenic microorganisms. The intrinsic ammonia from the urine may be sufficient for sanitisation of the sludge if it is not too diluted by flush water or lost by ventilation. To evaluate the potential for this sanitisation method, inactivation of Enterococcus faecalis, Salmonella typhimurium and Ascaris suum eggs during treatment were assessed. The inactivation was studied at different storage temperatures (10-28 degrees C) and in several sludge mixes with different contents of urine, faeces and flush water, and with ammonia concentrations from 40 to 400 mM. All pathogens were inactivated by the ammonia, and ascaris eggs were the most persistent. Lower flush water volume and higher urine content favoured inactivation, mainly due to increased uncharged ammonia (NH3) concentration. The lag phase in ascaris inactivation was shortened by increasing temperature and NH3 concentration, while post-lag phase inactivation was not influenced by NH3 concentration. Faecal sludge can be sanitised by airtight storage without the use of additives when flush water volumes are sufficiently low. For temperatures of 23-28 degrees C, a 3 log reduction of ascaris egg viability can be achieved within 1-6 months depending on ammonia concentration and temperature. (C) 2013 Elsevier Ltd. All rights reserved.
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| 6. |
- Jönsson, Håkan, et al.
(författare)
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System för återföring av fosfor i källsorterade fraktion av urin, fekalier, matavfall och i liknande rötat samhälls- och lantbruksavfall
- 2013
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Rapporten behandlar system för återföring av fosfor från källsorterade fraktioner av urin, fekalier och matavfall, samt teknik för att omfördela fosfor från djurgårdar med fosforöverskott till gårdar med underskott. Arbetet har finansierats av Naturvårdsverket inom regeringsuppdraget M2012/317/Ke Uppdrag om hållbar återföring av fosfor. Rapporten belyser effekter på Giftfri miljö och God bebyggd miljö och i viss mån klimatpåverkan och energianvändning. Större delen av fosforn i gödsel och rötrest kan med befintlig teknik (centrifug eller skruvpress) separeras ut i en fast fraktion vars vikt endast är ca 10 % av det urspungliga materialets. Detta underlättar transport av fosfor från gårdar med överskott till gårdar med brist. Genom effektivt stöd till införandet av denna teknik bör fördelningen av fosfor i jordbruket snabbt kunna förbättras. Klosettvatten‐(KL‐)sortering, d.v.s. att toalettavlopp samlas separat, hygieniseras och återförs som gödsel, kan väsentligt förbättra återföringen av växtnäring från avlopp och ger samtidigt flera andra miljöfördelar. Kadmium‐fosforkvoten i källsorterat KL‐vatten är 11‐13 mg kadmium per kg fosfor, vilket är lägre än i naturgödsel. Införande av KL‐system ger en kraftig reduktion av spridningen av humanpatogener och antibiotikaresistenta bakterier till miljön. Systemet minskar också utsläpp av hormoner och läkemedelsrester liksom av övergödande ämnen till vatten, speciellt vid bräddning. Införandet av KL‐sortering skulle totalt sett minska utsläpp av växthusgaser och användningen av energi och dessutom ge god potential för sambehandling med matavfall. Systemet passar i storstad och i glesbygd. Det finns redan ca 122 000 anläggningar med slutna tankar i Sverige och det källsorterade KL‐vattnet från dessa kan snabbt återföras till kretsloppet. Källsorterad urin har låga tungmetallhalter, kadmium‐fosforkvoten är endast 0,3‐2 mg kadmium per kg fosfor. Urinsortering ger synergier i form av stor reduktion av hormoner och läkemedelsrester och minskade utsläpp av övergödande ämnen till vatten, speciellt vid bräddning. Utsläppen av växthusgaser och energianvändningen minskar, men synergierna är mindre än för KL‐sortering, då spridningen av humanpatogener knappt påverkas och sambehandling med matavfall inte är trolig. Källsorterat matavfall från hushåll har en högre kadmium‐fosforkvot (ca 37 mg kadmium per kg fosfor) än källsorterad urin eller KL‐vatten, men matavfall från andra källor, t.ex. livsmedelshandel, är troligen renare. Mängden fosfor som återförs med rötat matavfall är redan idag lika stor som den skulle bli om KL‐vattnet från alla befintliga tankar återfördes till lantbruk och utbyggnadstakten är hög. Det finns stora möjligheter till synergi med KL‐system genom samhantering och –behandling. Gödsel från källsorterade produkter bedöms ha god acceptans. För att öka återföringen av källsorterad avloppsnäring behövs organisatoriska förbättringar, information, utbildning om kretsloppssystem och ett miljömål som inkluderar kväve.
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| 7. |
- Kinobe, Joel, et al.
(författare)
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Optimization of waste collection and disposal in Kampala city
- 2015
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Ingår i: Habitat International. - : Elsevier BV. - 0197-3975. ; 49, s. 126-137
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Tidskriftsartikel (refereegranskat)abstract
- Waste collection and transportation is an important municipal service that involves high expenditures if not handled efficiently. This has hindered waste management in many Sub-Saharan African countries. In this study, Geographic Information System (GIS) tools were used to optimize travel distances, trips and collection time, which leads to maximizing total waste collection, yielding large savings and keeping the environment clean. The study suggested the best waste collection routes, and determined a suitable vehicle fleet and capacity to be used by Kampala Capital City Authority (KCCA), which is the body responsible for waste management in Kampala. The use of the GIS tools led to the reduction in the total number of trips and travel distances, which decreased fuel consumption and vehicle emissions. In addition, the model can be used by the various outsourced private operators, collecting and disposing of solid wastes. Since the current municipal landfill for Kampala city is almost full, the GIS tool was used to identify the optimum location of a new proposed landfill site, based on optimized travel distances. The results of this study can help KCCA to decrease costs of managing wastes and environmental as well as social impacts. (C) 2015 Elsevier Ltd. All rights reserved.
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| 8. |
- Kinobe, Joel, et al.
(författare)
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Reverse logistics system and recycling potential at a landfill: A case study from Kampala City
- 2015
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Ingår i: Waste Management. - : Elsevier BV. - 0956-053X .- 1879-2456. ; 42, s. 82-92
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Tidskriftsartikel (refereegranskat)abstract
- The rapid growing population and high urbanisation rates in Sub-Saharan Africa has caused enormous pressure on collection services of the generated waste in the urban areas. This has put a burden on landfilling, which is the major waste disposal method. Waste reduction, re-use and recycling opportunities exist but are not fully utilized. The common items that are re-used and re-cycled are plastics, paper, aluminum, glass, steel, cardboard, and yard waste. This paper develops an overview of reverse logistics at Kiteezi landfill, the only officially recognised waste disposal facility for Kampala City. The paper analyses, in details the collection, re-processing, re-distribution and final markets of these products into a reversed supply chain network. Only 14% of the products at Kiteezi landfill are channeled into the reverse chain while 63% could be included in the distribution chain but are left out and disposed of while the remaining 23% is buried. This is because of the low processing power available, lack of market value, lack of knowledge and limited value addition activities to the products. This paper proposes possible strategies of efficient and effective reverse logistics development, applicable to Kampala City and other similar cities. (C) 2015 Elsevier Ltd. All rights reserved.
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| 9. |
- Komakech, Allan, et al.
(författare)
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Characterization of municipal waste in Kampala, Uganda
- 2014
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Ingår i: Journal of the Air and Waste Management Association. - : Taylor & Francis. - 1096-2247 .- 2162-2906. ; 64:3, s. 340-348
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Tidskriftsartikel (refereegranskat)abstract
- In Kampala, Uganda, about 28,000 tons of waste is collected and delivered to a landfill every month. Kampala Capital City Authority (KCCA) records show that this represents approximately 40% of the waste generated in the city. The remaining uncollected waste is normally dumped in unauthorized sites, causing health and environmental problems. However, the organic fraction of domestic waste can provide an opportunity to improve livelihoods and incomes through fertilizer and energy production. This study characterized the municipal waste generated in Kampala and delivered to Kiteezi landfill between July 2011 and June 2012, that is, covering the dry and wet months. On each sampling day, waste was randomly selected from five trucks, sorted and weighed into different physical fractions. Samples of the organic waste from each truck were analyzed for total solids, major nutrients, and energy content. During the wet months, the waste consisted of 88.5% organics, 3.8% soft plastics, 2.8% hard plastics, 2.2% paper, 0.9% glass, 0.7% textiles and leather, 0.2% metals, and 1.0% others. During the dry months, the waste consisted of 94.8% organics, 2.4% soft plastics, 1.0% hard plastics, 0.7% papers, 0.3% glass, 0.3% textile and leather, 0.1% metals, and 0.3% others. The organic waste on average had a moisture content of 71.1% and contained 1.89% nitrogen, 0.27% phosphorus, and 1.95% potassium. The waste had an average gross energy content of 17.3 MJ/kg. It was concluded that the organic waste generated can be a suitable source of some plant nutrients that are useful especially in urban agriculture. Implications: The result of the waste characterization in Kampala was found to be significantly different from that obtained for other Sub-Saharan African (SSA) cities, showing that studies assuming average values for the waste fractions are likely to result in erroneous results. Furthermore, no reduction in organic fraction of the waste was noticed when compared with a study done two decades ago in spite of greatly improved economic status of Kampala city, a finding that is not in agreement with several other similar studies done for other SSA cities.
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| 10. |
- Komakech, Allan, et al.
(författare)
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Life cycle assessment of biodegradable waste treatment systems for sub-Saharan African cities
- 2015
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Ingår i: Resources, Conservation and Recycling. - : Elsevier BV. - 0921-3449 .- 1879-0658. ; 99, s. 100-110
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Tidskriftsartikel (refereegranskat)abstract
- Most of the waste collected in sub-Saharan African cities is biodegradable but it is usually dumped in landfills, creating environmental and health challenges for residents. However, there are biodegradable waste treatment methods that could mitigate these challenges. This study analysed anaerobic digestion, composting, vermicomposting and fly larvae waste treatments using life cycle assessment (LCA). The impact categories assessed were energy use, global warming and eutrophication potential. The results showed that anaerobic digestion performed best in all impact categories assessed. However, management of the anaerobic digestion process is critical and methane losses must be kept very small, as otherwise they will cause global warming.
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