Sustainability Report 2016 . 2017 53 Moreover, any amendments to Fertiliser Ordinance regulations are automatically incorporated into Delos, making the farmer's administrative work far easier. Delos has been distributed exclusively through cooperatives and AGRAVIS agricultural centres since 2016 and already has 3,000 active users.Innovative solutions for biogas plants Biogas production has become a significant branch of industry in agriculture. Plant management is the key finan-cial control factor since generating energy from biomass is a complicated process. There is a need to constantly scrutinise and optimise the individual processes to ensure that biogas systems are operated efficiently. Against this backdrop, the cross-segment biogas unit Terravis brings together AGRAVIS's specialist knowledge and provides help to customers, partners and colleagues in the form of innovative product solutions and other means. Products and services are offered in the Field, Silos, Fermenters and Energy Generation segments. In the Field seg-ment, location-specific consultation is provided on energy crop cultivations with product recommendations such as maize, grain or permanent crops. The Silos segment comprises products for practical, low-loss substrate storage such as barrier foils, silage additives or fasteners. Gela Energie GmbH helps with power generation and marketing in the Energy segment. Gas engine oils and anti-freeze are also offered. Personalised consultation is provided for optimum substrate efficiency in the largest segment, Fermenters. The product portfolio comprises trace elements, enzymes, incident resources and desulphurisation agents.The desulphurisation agent iron hydroxide Iron hydroxide-based reactants play a key role in chemical desulphurisation of biogas plants. These are mainly derived as a by-product from drinking water treatment. Until now, there had been few utilisation options for such residues. TerraVis has developed a method to treat iron hydroxide derived from water purification to produce high-grade process additives. The procedure can be summarised as follows: • Iron is removed from untreated water by regular (gravel) filter flushing during drinking water treatment.• The iron sludge temporarily stored in special sludge tanks is released, cleaned of impurities such as stones and plant roots, dried and then processed into a product.• The end product – iron hydroxide in this case – is used together with the substrate to bind harmful sulphur com-pounds in the biogas plant.• Regular quality control checks are performed during the entire production process to verify the active ingredient and ensure compliance with Fertiliser Ordinance requirements.• Iron hydroxide may also possibly be used to bind phosphate and arsenic during water treatment in the future. Suitable processes are already being developed.