Short Rotation Coppice (SRC) is a farming method to cultivate fast growing trees. The main characteristic of SCR species is their ability to sprout again from their roots after harvesting. These plantations can be used to clean pre-treated domestic wastewater: the biologic activity in the soil purifies the wastewater and the plants can absorb nutrients. The wastewater can be spread on the fields using conventional irrigation systems. This can increase the yield of the trees up to 100%.
Design and Construction Principles
Short Rotation Coppice
For these plantations species like willows, poplars, eucalyptus or bamboo are used, since they are fast growing in their youth and can sprout again from their roots after harvesting. The plantations are arranged in a single or double row system. An average yield of 10 tons absolute dry wood per year and hectare can be expected. This has the energy content equivalent to 5,000 L heating oil. The harvesting is usually conducted in intervals between 3 to 5 years depending on the formation and the tree species. Since water is their main growth limitation factor, on nutrient poor and dry soil yield can be increased significantly by adding nutrient-rich wastewater. The chipped harvested wood is an excellent fuel, which can be used in regional power plants, district heating systems or households. While constructed wetlands focus mainly on wastewater treatment and are sealed at their base for groundwater protection, the advantage of SRCs over constructed wetlands lies in the combined wastewater treatment and the production of wooden biomass, which means an additional income for farmers. A SRC represents an open-bottom fixed-bed reactor of a construction height of between 1.0 and 1.5 m resulting in an effective reduction of pathogens. To avoid a nutrient overload it is important to control and document the amount and quality of the applied wastewater and sewage sludge.
Operation and Maintenance
For this treatment system the main requirement is land. In Europe, cost-effectiveness using fully mechanical planting and harvesting systems is reached starting at 5 ha. The plantation of a SRC and its harvest can be also done manually. Cuttings from tree nurseries are required as seedlings. In one hectare up to 12,000 trees like willows, popular or eucalyptus can be grown. For the distribution of the wastewater a drip irrigation system and slurry pump are needed. Before the wastewater enters the system, a mechanical pre-treatment would be needed to filter and avoid clogging. To maintain SRC, typical farmer skills like knowledge about plants, fertilizer, irrigation, and familiarity with agricultural machinery are needed.
The running cost of a SRC are minimal, mainly the rent of the land. After establishment the main cost factor is incurred in the harvesting process, cost largely compensated by the sales profit on the wood chips. As a reference, the total cost for establishing a plantation are around 2,500 €/ha in Germany. The material cost for a simple and cheap drip irrigation system are approximately 300€. External financing is usually not needed and since the most of the work needed is unskilled labour, it can be done by the entrepreneur himself. To avoid losses, it is very important to take care of the sprouts during the first year.
Experiences in Europe and other Cities of the World
The system SRC as water treatment system requires significant areas of land. The outskirts of urban areas are good locations due to the need of the produced fuel and availability of wastewater. Due to climatic conditions, in Europe the combination of SRC with wastewater treatment is only established in regions with less than 600 mm rainfall and nutrient poor soil. Different examples can be cited. For instance, a 5 ha SRC (willow, poplar, alder and robinia) was established in an old sewage sludge and wastewater dump nearby Berlin (Germany) (HECKER 2012). Other experiences can also be cited in the south of Europe (Granada-Spain, Ferrara-Italy)with poplars(EUBIA 2008), were it was possible to double the biomass production. As for other regions, reference projects in Bangladesh and China (INAWAB 2006; LADAS 2005) can be cited as well. With a pre-treated wastewater, the environmental risk is low, and contributes to the reduction of conventional wastewater treatment. The hygienic risk from SRC biomass is also low due to the fact that the biomass is not for the food sector. The use of wastewater and sludge saved natural drinking water sources for irrigation and fertiliser because it contains valuable plant nutrients (especially Nitrogen and Phosphorus).
Experiences in India
The experiences and established tree species in SRC made in Europe are not transferable one to one to India due to different climate conditions. Different climatic regions inside India make it even more difficult to transfer successfully used tree species into other regions. The potential use of timber in India has a broad spectra beginning with fire wood, raw material for industry or as building material (I.e. bamboo). A summary about the experiences made with SRC trees in India is presented: In Jodhpur (North West India) trials with SRC species Acacia nilotica and Eucalyptus camaldulensis irrigated with municipal wastewater where conducted. In this study, Eucalyptus showed the advantage of the highest uptake rate of nutrients, which is an important parameter towards avoiding negative long term effects by accumulation of nutrients (SINGH et al. 2010). In a study conducted in Palwal (70 km from New Delhi), different tree species were irrigated with secondary treated wastewater. The Tereticornis eucalyptus specie showed to have the highest biomass yield per tree. However, due to a higher survival rate the net biomass production per hectare was higher for Melia Azedarach (38 t/ha) followed by Ailanthus excels. The plants were grown for 2.5 years and showed a strong variation in survival rate. In this study different water/wastewater ratios where used with up to 100% wastewater. No effects were found concerning the ratio of wastewater used (TOKY 2011). The first species, which comes in mind for Indian climate, is probably bamboo. However studies on bamboo biomass production are scarce (NATH et al. 2009). A study conducted in subtropical warm and humid conditions in the Barak Valley Region found a biomass production of 37.7 t/ha /year. The productivity of acacia and bamboo was compared in a study in Kallipatty, India (SHANMUGHAVEL & FRANCIS 2001). The biomass production showed a strong increase with age and a high advantage of bamboo compared with acacia. The variation from 2.2 t/ha in year one to 298 t/ha in year 6 and back to 16 t/ha in year 10 after planting makes it clear that it is critical to consider rotation length when comparing studies. However, the biomass uptake was higher for bamboo during all periods. In a study carried out at the Haryana University of Agriculture, Leucaena leucocephala showed the highest net primary production of 33 t/ha /year closely followed by Eucalyptus teriticornis with 29 t/ha /year. Compared with these species, Acacia nilotica trees had just half the primary biomass production (SINGH & TOKY 1995). Altogether it has been seen that eucalyptus is the most experimented specie in India, not just as SRC plantation but also in combination with wastewater irrigation. Bamboo, which has a high potential due to its adaptation to Indian climate conditions as well as its broad spectrum for usage after harvesting, has been lest studied, and in particular not with irrigation of wastewater.
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Short Rotation Plantations: Opportunities for Efficient Biomass Production with the Safe Application of Wastewater and Sewage Sludge
This two-page factsheet by the European Biomass Industry Association gives a brief and concise overview on the topic of Short Rotation Plantations. Especially the benefits of this technology are highlighted.EUBIA (2008): Short Rotation Plantations: Opportunities for Efficient Biomass Production with the Safe Application of Wastewater and Sewage Sludge. Brussels: European Biomass Industry Association (EUBIA) URL [Accessed: 26.05.2019]
Article on a short rotation plantation trial in Berlin, Germany.HECKER, S. (2012): Forschung zu Kurzumtriebsplantagen und Abwassernutzung in Praxis umgesetzt. Leibniz: Zentrum fuer Agrarlandschaftsforschung (ZALF) e.V. URL [Accessed: 20.04.2012]
Article on the project INAWAB (Integrated Approach for Sustainable Wastewater Management and Biomass Production in Bangladesh) which aims to determine the possible applications of short rotation plantations in Bangladesh.INAWAB (2006): Einsatzmoeglichkeiten von Kurzumtriebsplantagen in Bangladesch. Bremerhaven: ttz Bremerhaven URL [Accessed: 20.04.2015]
Article about LADAS, a project, which aims to investigate possibilities for land amelioration, and for combating desertification and migration into cities in the Gansu province in China, by testing the salt resistance and growth behaviour of the Short-Rotation-Plant Salix.LADAS (2005): Erforschung von Moeglichkeiten der Landverbesserung (China). Bremerhaven: ttz Bremerhaven URL [Accessed: 20.04.2012]
A study which offers insights into the opportunity of village bamboos in the rural landscape for carbon storage through carbon sequestration. Management and utilization of village bamboos as a potential source of carbon sink by smallholder farmers are discussed in the context of their livelihood security and the Millennium Development Goals of the United Nations.NATH, J. ; DAS, G. ; DAS, A.K. (2009): Above Ground Standing Biomass and Carbon Storage in Village Bamboos in North East India. In: Biomass and Bioenergy: Volume 33 , 1188-1196. URL [Accessed: 20.04.2015]
This study mainly aimed to investigate the bioproductivity and nutrient cycling processes in plantation forests of bamboo and acacia. In India, multipurpose tree (MPT) species are extensively planted to meet the increasing demand for fuel and industrial wood.SHANMUGHAVEL, P. ; FRANCIS, K. (2001): Bioproductivity and Nutrient Cycling in Bamboo and Acacia Plantation Forests. In: Bioresource Technology: Volume 80 , 45-48. URL [Accessed: 20.04.2012]
Use of Tree Seedlings for the Phytoremediation of a Municipal Effluent Used in Dry Areas of North-Western India
This study deals with the impacts of municipal effluent (ME) irrigation on soil physicochemical properties and its remediation by tree species with a view on utilizing this resource in growing woodlot, controlling land degradation and improving environmental quality in suburban areas.SINGH, G. ; BHATI, M. ; RATHOD, T. (2010): Use of Tree Seedlings for the Phytoremediation of a Municipal Effluent Used in Dry Areas of North-Western India. Plant Growth and Nutrient Uptake. In: Ecological Engineering : Volume 36 , 1299-1306. URL [Accessed: 20.04.2012]
Biomass and Net Primary Productivity in Leucaena, Acacia and Eucalyptus, Short Rotation, High Density (Energy) Plantations in Arid India
The present study estimates above-ground biomass and net primary productivity in high density (‘energy’) plantations of three important species raised at Hisar (29 °10′N, 75 °46′E, 215 m.a.s.l.) in arid India.SINGH, V. ; TOKY, O.P. (1995): Biomass and Net Primary Productivity in Leucaena, Acacia and Eucalyptus, Short Rotation, High Density (Energy) Plantations in Arid India. In: Journal of Arid Environments: Volume 31 , 301-309. URL [Accessed: 20.04.2012]
This study estimates above-ground biomass in high density plantations of six important semi-arid tree species at Palwal (70 km from Delhi) irrigated with secondary treated sewage water at the rate of 0, 25, 50 and 100% of daily net evaporation potential (EP).TOKY, O.P. ; RIDDELL-BLACK, D. ; HARRIS, P.J.C. ; VASUDEVAN, P. ; DAVIES, P.A. (2011): Biomass Production in Short Rotation Effluent-irrigated Plantations in North-West India. In: Journal of Scientific and Industrial Research: Volume 70 , 601-609. URL [Accessed: 20.04.2015]
Compendium of Natural Water Systems and Treatment Technologies to cope with Water Shortages in Urbanised Areas in India
The Compendium of NaWaTech Technologies presents appropriate water and wastewater technologies that could enable the sustainable water management in Indian cities. It is intended as a reference for water professionals in charge of planning, designing and implementing sustainable water systems in the Indian urban scenario, based on a decentralised approach.BARRETO DILLON, L. ; DOYLE, L. ; LANGERGRABER, G. ; SATISH, S. ; POPHALI, G. (2013): Compendium of Natural Water Systems and Treatment Technologies to cope with Water Shortages in Urbanised Areas in India. Berlin: EPUBLI GMBH URL [Accessed: 11.12.2015]