# The Quantity and Composition of Leachate from Hop Plant Biomass during Composting Process
## 3 Results and Discussion
### The Impact of Composting Procedure on the Leachate Quantity and Composition during Composting  
There was no significant difference in leachate quantity between compost piles LES and ZUP, or between ZUP and ROZ piles in terms of the whole composting season. In comparison with Time stamps 1 and 2, each lasting one month, the leachate quantity was significantly higher in Time stamp 3, which also had the longest observed period (approximately 5 months). Figure 4 shows the amount of leachate in relation to the pile and time stamp. Compost pile LES had the highest quantity of leachate (17 L/m\({}^{2}\)) in the first month of composting (Time stamp 1), whereas the other two piles had significantly lower leachate quantity (pile ZUP 1.9-times lower and pile ROZ 2.6-times lower) in this period. In the second month of composting (Time stamp 2), pile LES leached the highest amount of leachate again, while pile ZUP was 3-times less (11.3 L/m\({}^{2}\)) and pile ROZ was 3.6-times less (9.9 L/m\({}^{2}\)). In the fourth week of composting, compost pile LES produced the most leachate in a short period of time, averaging 3.2 L/m\({}^{2}\) daily in 7 days. This can be attributed to a great deal of rain (more than 95 mm) in the week before the samples were taken. However, during the winter (Time stamp 3), from 19 November to 1 April, a daily average of 0.28 L/m\({}^{2}\) of leachate  
was recorded in pile LES, with 320 mm of rain and snow reported during that time. On the other hand, pile ZUP had the highest leachate generation in Time stamp 3 with a daily average of 0.38 L/m\({}^{2}\). It is indicated that perhaps in the maturation phase, biochar as an amendment in the pile helped to prevent leachate (if we compare LES and ZUP piles). These first data obtained already suggested that more caution is required when composting small particles and turning the pile frequently; one of the solutions would be to cover the compost pile in the event of increased rain forecasts, which would occur during the first two months of composting (in the thermophilic phase). It has been found that the leachate quantity can vary greatly. According to [PERSON] [21], a compost pile containing 6000 kg of fruit and vegetable waste produced more than 400 L of leachate per day. Leachate quantity in our experiment varied between piles in all three Time stamps. In the first two time stamps, the highest leachate quantity was observed in the LES pile, while the highest leachate quantity in pile ZUP was recorded in the stabilization phase (Time stamp 3). This indicates that when using the composting procedure employed in pile ZUP, considering leachate quantity, the pile should be covered immediately after the thermophilic phase, which is roughly 2 months after the start. It is shown that it would be recommended to keep the pile covered all the time for all composting procedures, throughout the stabilization/maturation period when the pile is not turned anymore (Time stamp 3). In further research, we will focus on the emissions in the first two months of composting in order to determine whether covering during this period would be necessary. When we compare the anaerobic pile ROZ to the other two piles, we notice that approximately half the quantity of leachate in Time stamp 3 was collected in this pile compared to other aerobic piles. According to [PERSON] et al. [22], water consumption through an anaerobic reaction in a landfill cell reduced the discharged leachate by more than 10%. That suggests that anaerobic degradation is likely to consume more water than composting, resulting in less leachate production.