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The right amount of water at the right moment is vital in the composting process.
this kind of blend will also reach a higher tempera- ture than a blend made of straw that did not undergo a pre-wet treatment. Using an aerated floor right from the start of the process, and certainly after the chicken manure has been added, has an extremely positive effect on the uniformity of the compost and on homogenous moisture distribution. This effect has clearly been proven in practice, with higher production resulting from aeration being applied from the start of the process. Composting in windrows gives considerably lesser results than using an aerated floor. No, or too little, water slows down microlife activity, or can bring this activity almost to a halt. Too much water can easily create anaerobic patches during the pre-wet process, certainly in situations where aerated floors are not used. Every anaerobic patch, at no matter what stage of the process, will cause irrevocable damage on production. The extent of lost production depends on the number of anaerobic patches, and when they were formed. Overhead filling systems have been developed to ensure greater homogeneity. They are highly functio- nal, but due to the high investment costs involved not every composting plant can afford to implement such a system. For these companies a good recommen- dation is to pile up the compost first when a bunker is emptied before placing the compost back into the same, or another, bunker. This method will achieve the same uniform effect, it just takes more time and effort. An overhead filler is actually a very positive component of mixing, but not enough on its own to be considered a good mixing system. Spinners incorporated into a filling line not only positively con- tribute towards creating a more open structure and homogeneity in the compost, but also greatly benefit the effectiveness of mixing and blending water into the compost. If copious spraying is necessary while the bunker is being filled, a lot of unabsorbed water will be left in the compost after it has been filled in the tunnel. This water will gradually seep down and can easily cause anaerobic patches in the lower layers of compost. Production managers are advised to aerate the bunker while filling is taking place to help prevent a lack of oxygen in wetter patches of the compost. How much aeration, and in particular the velocity of the air being blown through the compost by the fan throughout the entire process, and definite- ly in the last few days of phase I, has a huge influence
Spinners are necessary to optimally mix and blend water through the compost after sprinkling or spraying.
on the evaporation of moisture and lowering the ammo- nia (NH3) concentration. Slightly more aeration already has a big impact – too much additional aeration will simply dry the compost out again. To correct compost that has become too dry after phase I , ‘too much’ water has to be given, which can subsequently jeopardise an optimal phase II process. The humidity of the outside air during phase I also has a great influence on the degree of evaporation, and any corrective measures possibly required. A good way of maintaining the right moisture content, without filling too warm compost into the tunnel, is a longer aeration time in the bunker using a lower air velocity (a lower fan RPM) during the final stage of the phase I process.
Moisture balance during phase II Soft compost contains far more internal moisture than harder compost (built-in moisture), so apply caution when adding water to already softer compost. The moisture content of soft compost that is dry to the touch is often underestimated at the end of phase I, when it is in fact often higher than assumed. Adding too much water while the tunnels are being filled will leave too much unabsorbed water in the compost when this process is finished. It is a better idea to hydrate the compost to the required level if this is necessary on the day before the tunnel is filled. This is also a good op- portunity to add a some compost with a rich microlife at the same time as the water is being mixed into the compost (2% spawnable compost is a reasonably good amount to add to fresh compost). An important detail in achieving optimal water ma- nagement is the duration of phase II. Each day longer spent in the tunnel will result in drier compost. The majority of commercial tunnel composters inoculate on day five. If an excess of ammonia means keeping the compost in the tunnel for longer, the compost will be drier at the end of phase II. Correcting the moisture content too much by adding water during inoculation is a bad idea, but with very dry compost it is a necessary evil. Too much compost per square metre demands more aeration, and involves a greater risk of dehydra- tion in the lower layer of compost. Opinions are divided on adding water during inoculation. It is evident that adding too much water to compost with a short struc- ture during inoculation is a recipe for disaster later on during the cultivation process. Compost that is too dry needs water. Provided that water is distributed evenly during inoculation, for instance via a pulling winch, and
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