# VOC Removal from Manure Gaseous Emissions with UV Photolysis and UV-TiO\({}_{2}\) Photocatalysis
## 3. Materials and Methods
### UV/TiO\({}_{2}\) Photocatalysis of Real Poultry Atmosphere  
A larger photoreactor was designed as a flow-through reaction chamber and used for the treatment of a real poultry manure atmosphere [35]. An air-purged liquid manure suspension served to prepare the desired flow-through atmosphere. Fresh manure suspensions were prepared as follows: 4 L of air-dried poultry manure (broiler farms; Ramat David and Alonim, northern Israel) were mixed with 40 L of tap water and stirred manually in a bucket. Large particles were then removed by using a 1 mm plastic mesh, and the rest of the suspension was transferred into a 200 L tank of the flow-through setup (Figure 7A). A new suspension was prepared every several weeks such that the source VOCs atmosphere varied from one experiment to another. A 60 cm long (2.5 L) photoreactor was assembled from a 5 cm diameter quartz tube surrounded by a ring of individually controlled 24 \"black\" UV lamps (18 W Philips TLD 18W/08; output range between 340 and 400 nm, with a peak at 365 nm; Figure 7B). An aqueous 2% TiO\({}_{2}\) suspension (Anatase form; <10 nm particle size; HOMBIKAT UV 100; Sachtleben Chemie, Germany) was used as the catalyst. A round brush was selected to serve the large surface area for coating. The aqueous 2% TiO\({}_{2}\) suspension was sprayed on the brush and dried using a hairdryer. This configuration was selected to enable light penetration through the hairs and to provide an extensive reacting surface for the flow-through air (Figure 7C). Energy used for this reactor is evidently less attractive because of the geometry of the lamp layout. Thus, energy dosage was calculated from the actual irradiation received by the reactor per lamp, as follows: Each lamp distributes its light equally in all directions in cylinder shapes of increasing diameter. Of interest will be the power intensity at the distance of the reactor to the nearest light. This power intensity will be distributed over a cylinder of 0.1375 m radius (distance from lamp to the reactor) and 0.6 m (length of the lamp). Irradiated area would then be \(2\pi\times 0.1375\times 0.6=0.52\) m\({}^{2}\) = 5200 cm\({}^{2}\). The input radiation intensity will be 18 W/(5200 cm\({}^{2}\)) = 0.0035 W cm\({}^{-2}\). The radiation received will be over the projected area of the reactor = 0.6 \(\times\) 0.05 m = 0.03 m\({}^{2}\) = 300 cm\({}^{2}\). Irradiation received by the reactor per lamp = 300 \(\times\) 0.0035 W = 1.05 W. Considering output lamp efficiency of ca. 35%, the irradiation received by the reactor per lamp is 0.36 W. The much larger catalyst area obtained with the brushes (inside the reactor) is not easily determined, and this would increase the effective values of the energy input per volume of air treated. The results for this reactor have been used mainly  
Figure 7: UV/TiO\({}_{2}\) photocatalysis of real poultry atmosphere. **(A)** Pilot-scale setup: 1. A 200 L tank containing 40 L of poultry manure suspension; 2. Lamp cover; 3. UV lamp control board; 4. Compressed air inlet; 5. Manure bypass; 6 and 7. Gas sampling ports (before and after treatment); 8. Exit of treated air. **(B)** A 2.5 L (2” diameter) quartz tube reactor surrounded by individually controlled 24 UV lamps. **(C)** TiO\({}_{2}\)-coated brush inside the quartz reactor, shown in **(B)**. to consider some practical aspects and how well real manure odors could potentially be removed rather than determine energy requirements. Oil-free compressed air was used to purge the manure and flow through the system. Air sampling ports were installed before and after the reactor and included ports for SPME (VOCs), Kitagawa colorimetric tubes (NH\({}_{3}\) and O\({}_{3}\)), and Tedlar bags (odor). The effects of energy dose were tested by manipulating either treatment time (controlled by flow rate) or light intensity (controlled by the number of lamps operated). The system was operated outside at ambient summer day temperatures (33 to 35 \({}^{\circ}\)C).