The project site is a farm located in Sydingösby. The Gunnarsson family is living here. Carina and Stefan have two children. Stefan works at the farm while Carina works at SLU. This site has already a system for waste treatment, but it is not satisfying and not sustainable. Actually it does not permit a good reduction of BOD, nitrogen or phosphorus coming from the waste, and does not offer good recycling of the nutrients. Moreover the family has planned to build a guest apartment, and need to install toilets in the honey room. Thus maybe some of the existing parts of the current one-site system need to be re-dimensioned. And a new system has to be installed to fulfill the aims of BOD, N and P removal. In the first part we are going to describe the site, the current one-site system and the problems which occur. Then we are going to analyze in three other parts three possibilities to improve the waste treatment: the urine diversion, the composting, and the sand filter. We will after that conclude with the system seems to be, according to us, the best choice.
[...] Which means that the installation of the WME-DS toilet reduces the blackwater by 5 times (currently equal to 136865 So we have in average 75 L of black water produced each day. When the guest house will be rent the maximal consumption will be 5*10+5*10= 100 L/day. Concerning the greywater, as we have calculated previously, it is about 273.8 m3 per year. So in average 0.75 m3 are produced each day with a maximum reach during the rent of the guest room equal to 1 m3 per day if 100 L are used per person per day. [...]
[...] The water economy will be more than 50% Finally two WME-DS will be installed in the first and second flour of the house. The guest room will be also equipped with the same toilet model. Concerning the Honey annexe a conventional toilet should be used, we think to reuse the current toilet of the residential house. Figure The Wost Man Ecology toilet The pipe system Some considerations have to be taken in account. First of all metal pipe are prohibited for such installation because of the high corrosive potential of the urine. [...]
[...] Ed Stewart, Master of science in environmental engineering michigan technological university, Evaluation of septic tank and subsurface flow wetland for Jamaican public school wastewater treatment Jönsson, H., Baky, A., Jeppsson, U., Hellström, D., & Kärrman, E Composition of urine, faeces, greywater and bio-waste for utilisation in the URWARE model. Report 2005:6, Urban Water, Chalmers. Sweden. Download: www.urbanwater.org Jönsson, H., Baky, A., Jeppsson, U., Hellström, D., & Kärrman, E. 2006.Urine diversion one step towards sustainable sanitation. Report 2006:1, Urban Water, Chalmers. [...]
[...] Microorganisms are very important in this kind of treatment system. Enough air must be applied and too high loading of the sand filter can stop aerobic reaction and the BOD reduction as well . A dosing chamber can be installed before the sand filter to regulate the loading. To ensure good aeration we may need a pump. No liner will be used at the bottom of the sand filter, the clay soil can easily reduce the infiltration and the water will be readily collected. [...]
[...] Blackwater and greywater treatment The septic tank As we said before all the faecal material and the flush water will be discharged into the septic tank using the same piping system as before the installation. The other fraction of the wastewater, the greywater, will be discharged in the septic tank as well. The capacity of the septic tank is 2 times 2 m3 thus 4 m3. The hydraulic retention time is at least 24 hours. In average the reduction of the BOD in a septic tank is 30 and 50%. [...]
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