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| 2. |
- Ciuk Karlsson, Susanna, et al.
(författare)
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Hydraulic Properties and Reduction of COD, Phosphorus and Nitrogen in a Sand Filter used for Greywater Treatment – Simulation and Verification
- 2013
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- A vertical flow sand filter is a simple, effective and inexpensive system for treating greywater. The performance of sand filters treating artificial greywater was tested in the laboratory over a time period of 113 days. The filters consisted of columns (0.2 m diameter) filled with sand to a height of 0.6 m. The hydraulic properties of the filters were measured as well as the inflow and outflow concentrations of COD, BOD5, total and phosphate phosphorus and total-, ammonia- and nitrate nitrogen. To get a better quantitative understanding of the treatment processes inside the filters, the HYDRUS-CW2D computer software was used to simulate the filters. The simulation of water flow through the filter could be well fitted to the measured flow by adjusting three model parameters: the air entry value, the pore size distribution index, and the pore connectivity parameter. For the COD reduction the simulated results agreed well with experimental data after an adjustment of the microbial lysis parameters of HYDRUS-CW2D. The simulated reduction of COD was 65 %, while a 72 % reduction was measured for the filters in the lab. Simulated reduction of phosphorus in the sand filter effluent corresponded well to the measured reduction: the simulated reduction of phosphorus was 72 % while the experimental filters achieved a 79 % reduction. Also, the simulated effluent concentrations of nitrate compared quite well to the measured values. Almost no reduction (4 %) in total nitrogen took place in the experimental filters, which agreed with the simulated reduction (0 %). For the phosphorus and nitrate components in HYDRUS-CW2D, so far no changes have been made to the default parameters.
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| 3. |
- Dalahmeh, Sahar, et al.
(författare)
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Effects of changing hydraulic and organic loading rates on pollutant reduction in bark, charcoal and sand filters treating greywater
- 2014
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Ingår i: Journal of Environmental Management. - : Elsevier BV. - 0301-4797 .- 1095-8630. ; 132, s. 338-345
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Tidskriftsartikel (refereegranskat)abstract
- Greywater flows and concentrations vary greatly, so evaluation and prediction of the response of on-site treatment filters to variable loading regimes is challenging. The performance of 0.6 m x 0.2 m (height x diameter) filters of bark, activated charcoal and sand in reduction of biochemical oxygen demand (BOD5), chemical oxygen demand (COD), total nitrogen (Tot-N) and total phosphorus (Tot-P) under variable loading regimes was investigated and modelled. During seven runs, the filters were fed with synthetic greywater at hydraulic loading rates (HLR) of 32-128 L m-2 day-1 and organic loading rates (OLR) of 13-76 g BOD5 m-2 day-1. Based on the changes in HLR and OLR, the reduction in pollutants was modelled using multiple linear regression. The models showed that increasing the HLR from 32 to 128 L m-2 day-1 decreased COD reduction in the bark filters from 74 to 40%, but increased COD reduction in the charcoal and sand filters from 76 to 90% and 65 to 83%, respectively. Moreover, the models showed that increasing the OLR from 13 to 76 g BOD5 m-2 day -1 enhanced the pollutant reduction in all filters except for Tot-P in the bark filters, which decreased slightly from 81 to 73%. Decreasing the HLR from 128 to 32 L m-2 day-1 enhanced the pollutant reduction in all filters, but decreasing the OLR from 76 to 14 g BOD5 m-2 day-1 detached biofilm and decreased the Tot-N and Tot-P reduction in the bark and sand filters. Overall, the bark filters had the capacity to treat high OLR, while the charcoal filters had the capacity to treat high HLR and high OLR. Both bark and charcoal filters had higher capacity than sand filters in dealing with high and variable loads. Bark seems to be an attractive substitute for sand filters in settings short in water and its effluent would be valuable for irrigation, while charcoal filters should be an attractive alternative for settings both rich and short in water supply and when environmental eutrophication has to be considered.
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| 4. |
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| 5. |
- 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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| 6. |
- Lalander, Cecilia, et al.
(författare)
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Faecal sludge management with the larvae of the black soldier fly (Hermetia illucens) - From a hygiene aspect
- 2013
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Ingår i: Science of the Total Environment. - : Elsevier BV. - 0048-9697 .- 1879-1026. ; 458-460, s. 312-318
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Tidskriftsartikel (refereegranskat)abstract
- Inadequate and lacking sanitation and wastewater treatment systems can lead to the spreading of diarrhoeal diseases. One contributing factor in the lack of such treatment systems is the lack of economic incentives for stakeholders throughout the service chain. However, the organic fraction of the waste is high in valuable plant nutrients and could be reused in agriculture and as animal feed. For example, grown larvae of the black soldier fly, Hermetia illucens L (Diptera: Stratiomyidae), make an excellent protein source in animal feed, while the feeding activity of the larvae substantially reduces the dry mass of the treated material. This study examined the effect of black soldier fly larvae on the concentration of pathogenic microorganisms in human faeces and found a 6 logic, reduction in Salmonella spp. in human faeces in eight days, compared with a <2 log(10) reduction in the control. No increased reduction was observed for Entero coccus spp., bacteriophage phi X174 or Ascaris suum ova. (C) 2013 Elsevier B.V. All rights reserved.
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| 7. |
- Lalander, Cecilia, et al.
(författare)
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Hygienic quality of artificial greywater subjected to aerobic treatment: a comparison of three filter media at increasing organic loading rates
- 2013
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Ingår i: Environmental Technology. - : Informa UK Limited. - 0959-3330 .- 1479-487X. ; 34, s. 2657-2662
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Tidskriftsartikel (refereegranskat)abstract
- With a growing world population, the lack of reliable water sources is becoming an increasing problem. Reusing greywater could alleviate this problem. When reusing greywater for crop irrigation it is paramount to ensure the removal of pathogenic organisms. This study compared the pathogen removal efficiency of pine bark and activated charcoal filters with that of conventional sand filters at three organic loading rates. The removal efficiency of Escherichia coli O157:H7 decreased drastically when the organic loading rate increased fivefold in the charcoal and sand filters, but increased by 2log (10) in the bark filters. The reduction in the virus model organism coliphage phi X174 remained unchanged with increasing organic loading in the charcoal and sand filters, but increased by 2log (10) in the bark filters. Thus, bark was demonstrated to be the most promising material for greywater treatment in terms of pathogen removal.
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| 8. |
- Lalander, Cecilia, et al.
(författare)
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Hygienic quality of faeces treated in urine diverting vermicomposting toilets
- 2013
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Ingår i: Waste Management. - : Elsevier BV. - 0956-053X .- 1879-2456. ; 33, s. 2204-2210
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Tidskriftsartikel (refereegranskat)abstract
- On-site sanitation solutions have gained much interest in recent years. One such solution is the urine diverting vermicomposting toilet (UDVT). This study evaluated the hygienic quality of the composted material in six UDVTs in operation in France. Samples were taken from three sampling positions in each toilet, with increasing distance from the fresh material. The concentration of Salmonella spp., Enterococcus spp., thermotolarent coliforms and coliphages were analysed and plotted against a number of variables. The variables found to have the greatest impact was the pH (for Enterococcus spp. and thermotolarent coliforms (TTC)) and time since last maintenance (coliphages). The pH was found to correlate with the material maturity. The current practise of maintenance can cause recontamination of the stabilised material and increase the risk of regrowth of pathogenic microorganisms. A modification in the maintenance procedure, in which a fourth maturation point is introduced, would eliminate this risk. UDVTs were found to be a good on-site sanitation option as the maintenance requirement is small and the system effectively reduced odour and concentration of pathogen and indicator organisms in human waste while keeping the accumulation of material down to a minimum. If the vermicompost is to be used for crops consumed raw, an additional sanitisation step is recommended. (C) 2013 Elsevier Ltd. All rights reserved.
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| 9. |
- Lalander, Cecilia
(författare)
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The Effectiveness and Safety of Vermi- Versus Conventional Composting of Human Feces with Ascaris suum Ova as Model Helminthic Parasites
- 2013
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Ingår i: Journal of Sustainable Development. - : Canadian Center of Science and Education. - 1913-9063 .- 1913-9071. ; 6, s. 1-10
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Tidskriftsartikel (refereegranskat)abstract
- Composting toilets have been promoted for management of human waste at remote sites in parks and alpine areas of recreation, but they may not be effective for producing a stable and safe end product. Vermicomposting has been shown to result in a more degraded final product but its effectiveness for pathogen destruction was unclear due to conflicting information in the literature. This study sought to resolve the debate on whether or not vermicomposting could produce a hygenic end product that would be safe for disposal locally. Vermicomposting was tested for destruction of the model pathogens, helminthic parasites, in an experiment with highly concentrated and viable Ascaris suum (2626±1306 ova/g, 61.6±8.7% viable) inoculated into fecal matter and coir (30:70 ratio) with and without Eisenia fetida worms. After 90 days at 19±3 ºC six, eight, and 12 worms were found alive with no significant difference between treatments or through time found in TS% (12-15%), ova concentration and ova viability. A 100 times reduction in the concentration of Escherichia coli resulted from the worm treatment versus the control. Significantly higher nitrate (22 735±4 741 mg/kg NO3-) and lower pH (pH 4.60±0.01) were found in the treatment as compared to the control (5 078±2 167 mg/kg NO3-) (pH 6.56±0.30). Despite these improvements in fecal matter processing, vermicomposting was found ineffective at reducing Ascaris suum ova concentration and viability. Decentralized vermicomposting can efficiently stabilize and mature fecal matter; however prior to unrestricted end product use, an additional sanitation step is necessary.
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| 10. |
- Niwagaba, Charles, et al.
(författare)
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Experiences on the implementation of a pilot grey water treatment and reuse based system at a household in the slum of Kyebando-Kisalosalo, Kampala
- 2014
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Ingår i: Journal of Water Reuse and Desalination. - : IWA Publishing. - 2220-1319 .- 2408-9370. ; 4, s. 294-307
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Tidskriftsartikel (refereegranskat)abstract
- Grey water constitutes the largest fraction of domestic wastewater. It causes environmental sanitation and pollution problems if it is not managed well. If treated, grey water can be a resource for a variety of uses. A pilot system was constructed in February 2013 to treat grey water from a four-member household for sub-surface irrigation of local vegetables. A hydraulic loading rate (HLR) of 60 L m(-2)d(-1) and an organic loading rate (OLR) of 519-1,580 g BOD(5)m(-2)d(-1) were implemented on a multi-media filter of gravel, charcoal, geotextile and mulch (charcoal being the predominant layer) operated as a batched type-system, with a 36-hour retention time. The system was operated for 3 months, during which it showed remarkable removal efficiencies of 90.8 +/- 5.4 and 96.1 +/- 3.0% after 36 hours for chemical oxygen demand (COD) and biochemical oxygen demand (BOD), respectively, and 95 +/- 3.1% for faecal coliforms (FC). The removal efficiencies at 36 hours, of total nitrogen (TN), total phosphorus (Tot-P), total suspended solids (TSS) and total dissolved solids (TDS) were 39.0, 30.1, 85.2 and 78.6%, respectively. Plant response to sub-surface irrigation with treated grey water was largely masked by rainy season and the effluent had a limited effect on the soil.
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