ORIGINAL PAPER New concept of urban green management Josef Marous ˇek • Robert Zeman • Radka Vanı ´c ˇkova ´ • Simona Has ˇkova ´ Received: 30 January 2014 / Accepted: 24 February 2014 Ó Springer-Verlag Berlin Heidelberg 2014 Abstract Many cities face a long-term surplus of grass cuttings. Its management is usually financially demanding once many of the up to date technologies require high acqui- sition as well as variable costs. It was verified in a commercial scale if the newly proposed concept of anaerobic fermentation followed by continuous pyrolysis is technically and eco- nomically feasible to manage macerated cutting of urban green in a commercial scale. Design of the concept is thor- oughly described, documented in figures, and biochemically analyzed in detail. Assessment of the concept shows that subsequent pyrolysis of the anaerobically fermented residue allows among biogas to produce also high-quality charcoal. It was proved that the proposed solution improves the overall economy. In addition, it may be assumed that this applied research is consistent with previous theoretical assumptions stating that any kind of aerobic or anaerobic fermentation increases the heating value of the charcoal obtained. Keywords Management Á Grass Á Pyrolysis Á Charcoal Introduction Increasing the proportion of green areas in cities positively contributes to the improvement of the living conditions. However, this is associated with a surplus of the grass waste. The amount of the grass cuttings is continuously growing and it is hard to find any profitable or at least useful utilization. The traditional use for herding or forage production is almost impossible in the densely populated areas. Despite the pro- gress in accelerated composting (Nakasaki et al. 1994), which resulted in minimizing the costs, the composts are not selling. It is so because farmers are primarily interested in their fertilization value, which may be simplified into the nutrient concentration and the ion-exchange capacity. Admittedly, regarding the nutrients, any compost cannot compete with the prices of nutrients in conventional mineral fertilizers. To make matters worse, the accelerated composts have low ion-exchange capacity (20–80 mmol chem. eq. kg -1 ) and, therefore, it hardly provides any advantage (Kola ´r ˇ et al. 2008). It is also known to use the grass cuttings for biogas production (Seppala et al. 2009), but this is asso- ciated with odor and, therefore, such a solution will be dif- ficult to implement in large agglomerations. It is necessary to admit that there is an increasing criticism also on the fertil- ization value of the fermented residue (Kola ´r ˇ et al. 2008). Experiences with grass combustion were also reviewed (Grass and Jenkins 1994; Paulrud and Nilsson 2001); how- ever, it was shown that the flue gases are cleaner in higher temperatures (Bridgeman et al. 2008). Unfortunately, this is expensive in economic terms. Alvira et al. (2010) reviewed possibilities regarding the bioethanol production. In good agreement with Sun and Cheng (2002) and Himmel et al. (2007) they conclude that the biochemical nature makes the lignocellulose-based urban green resistant to hydrolysis without prior intensive disintegration. However, analysis on the perspective techniques of lignocellulose disintegration suggests that very notable investments are mandatory. First attempts to use the fermentation residue to produce biochar (Marous ˇek 2013) were already done. Unfortunately, it turned out that European farmers have so far no interest in this soil improver, because they are not familiar with it. It has been hypothesized that it is appropriate to find another economically viable alternative for the solid J. Marous ˇek (&) Á R. Zeman Á R. Vanı ´c ˇkova ´ Á S. Has ˇkova ´ The Institute of Technology and Businesses in C ˇ eske ´ Bude ˇjovice, Okruz ˇnı ´ 517/10, Ceske Budejovice 370 01, Czech Republic e-mail: josef.marousek@gmail.com 123 Clean Techn Environ Policy DOI 10.1007/s10098-014-0736-5