Browsing by Author "Heinonen-Tanski, Helvi"
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- Fecal Sludge Derived Products as Fertilizer for Lettuce Cultivation in Urban Agriculture
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä(2019-12-02) Pradhan, Surendra K.; Cofie, Olufunke; Nikiema, Josiane; Heinonen-Tanski, HelviFecal sludge (FS) contains a significant amount of plant nutrients. FS (treated/untreated) has been used as soil ameliorant in several countries. Use of FS-based compost on lettuce may meet reservations due to possible microbiological contamination. The objectives of this research are: (1) To determine the fertilizer value of different formulations of sawdust and fecal sludge compost (SDFS) pellets, and (2) to compare the effect of these SDFS formulations with poultry manure, commercial compost, mineral fertilizer, and non-fertilization on lettuce cultivation. The SDFS products were made by enriching, and pelletized with ammonium sulphate, mineral-NPK, or ammonium sulphate + muriate of potash + triple superphosphate. Lettuce was cultivated in a greenhouse and an open field. The result showed that the saleable fresh weight lettuce yield obtained from all SDFS pellets with/without enrichments were higher than those obtained from commercial compost, poultry manure, mineral fertilizer, or no fertilizer. Cultivation in the open field gave higher yields than those in the greenhouse. No helminth eggs were detected in composts or lettuces. Some fecal coliforms were detected in lettuces fertilized with almost all fertilizers tested, including NPK and non-fertilized control. A properly treated fecal sludge-based fertilizer can be a sustainable solution for lettuce production, which helps urban and peri-urban agriculture. - Recovery of nitrogen and phosphorus from human urine using membrane and precipitation process
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä(2019-10-01) Pradhan, Surendra K.; Mikola, Anna; Heinonen-Tanski, Helvi; Vahala, RikuThe nitrogen (N) and phosphorus (P) contents in human urine have been recovered using struvite precipitation and N-stripping techniques. Struvite precipitation technique recovers mainly phosphorus whereas N-stripping technique only recovers nitrogen. In this study, we developed an NPharvest technique which recovered both nitrogen and phosphorus separately in the same process, enabling their use independently. The technique used Ca(OH)2 to increase the pH of urine converting ammonium into NH3 gas and simultaneously precipitating P with Ca. The NH3 gas is passed through a gas permeable hydrophobic membrane (GPHM) and reacts with H2SO4 forming ammonium sulfate. Our result showed that more than 98% (w/w) of N and P can be harvested from urine in 8 h at 30 °C. The harvested ammonium sulfate contained 19% (w/w) N, and the sediment contained 1–2% (w/w) P. The extraction of N and P from 1 m3 of urine could give a profit of 1.5 €.