LAWR

ENVIRONMENTAL NUISANCE release can occur if valves release gas for example but if the plant is managed properly these types of incident should be minimal. Sensible design normally includes some sort of reception building. For agricultural plants these buildings nor- mally hold products such as chicken manure which has a high odour poten- tial. Bulk feedstocks such as maize silage normally have a low odour impact and the odour is no worse than a normal working farmyard and is very localised. For plants accepting organic food waste type products, odour manage- ment is crucial. Strict protocols and odour management is required to eliminate odour risks and involve- ment in odour treatment technology is recommended. This normally involves a designated reception shed operated under negative pressure with an odour extraction system fitted. Again good management is impor- tant to reduce odour risks, therefore immediate cleaning of spills and the maintenance of an uncontaminated floor will help to minimise odour release. Deliveries of waste products should be dealt with as quickly as possible. If liquids are being pumped into the plant having sealed reception tanks will help to control odour and products can be released into the digester on a controlled basis. Handling digestate At the other end of the process is the management of digestate. Here again good practice needs to be followed with the spreading and handling of this product. One of the reasons that digestate is beneficial as a fertiliser is its high ammonia content, but ammonia is volatile, and if liquid digestate is spread on the land then ammonia can be released into the air and cause odour issues. This can be mitigated through fol- lowing good practice, for example ensuring that the material being received from the digester is fully digested, having a cover on the diges- tate store and by injecting liquid diges- tate into the soil, which will not only improve its effectiveness as a fertiliser, but also reduce any odour release. The timeliness of spreading is also crucial both to minimise issues of run-off and to apply at optimum times for crop uptake. Having reviewed some of the issues associated with odour and AD plants it is clear that careful planning and communication is key to minimis- ing odour issues and objections. Early identification of all those who might be affected by or have an interest in your proposals is important. You can then decide the best course of action in terms of communicating and educat- ing of the various parties. Information needs to be presented in a clear way and if necessary additional technical reports may need to be com- missioned to explain the science and the risks. If media such as public exhi- bitions and/or meetings are held it is important to listen to concerns and try and use them to improve your scheme. It should however be noted that AD can bring benefits in terms of odour reduction. The digestion of slurry and chicken manure, for example, is sig- nificantly less odorous than the com- mon practice of storing slurry in pits and the spreading of raw poultry litter to land. If managed properly anaerobic diges- tion should be the good news story for the waste industry: it takes the unpleasant, potentially odourous organic waste fraction and converts it into ultra-low carbon, baseload renew- able bio-gas, recycling the nutrients and organic matter back to land in the form of a natural and sustainable ferti- liser in the process, reducing the usage of inorganic fertilisers. The key to gaining public support is sensible siting and design, careful impact analysis, investment in odour treatment/reduction technology and measured communication. Stephen Locke is a chartered surveyor and town planner at Berrys. 34 Local Authority Waste & Recycling September 2014 • Listen to feedback and use it to help improve your plans. Don't forget to go back to people so they know what you've changed as a result of feedback. • Cast the net wide to uncover potential supporters: The silent majority are often the key to uncovering support. Don't ignore them! Source: Remarkable PR Other key tips for effectively communicating AD proposals The Environment Agency can refuse environmental permit applications if it is not satisfied with odour manage- ment plans from AD operators.

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