Air Pollution Projects As Part of
Overall Waste Management Schemes

1. Pig Farm—France (22,000 pigs)
Catalytic oxidation with ozone for odor control on process air in the waste treatment plant, and that extracted from the growing houses. Separately there was a system for cleaning and dehumidifying of the biogas. (See pictures)

2. Pig Farms—Portugal (three sites, 200–500 pigs)
Bio-scrubbers for odor control on extracted air from pig farm, with the scrubbing liquor, which was rich in nitrifying micro-organisms, being discharged into the slurry channels inside the pig farms to reduce the Ammonia.

3. Cork Dust—Portugal (six sites)
Bag filters (six sites) and cyclones (two sites) for dust recovery, as part of a total waste management package including effluent treatment. The recovered dust is either made into fuel bricks for use on their solid fuel boilers, or blended with the surplus biomass (sludge) from the effluent treatment, and marketed as an organic compost/fertilizer.

4. Cork Industry—Portugal (VOCs)
As part of the cork industry situated around Porto, one factory produces the foil seals for the wine and champagne bottles. The factory has a fume extraction system, and the VOCs, because of the relatively high levels of concentration, are destroyed in a thermal scrubber with natural gas as the fuel.

5. Tannery—Portugal
A full waste management plant was installed in an existing building on the site, and the air from within the building, together with VOCs from the shoe leather preparation shop, are cleaned through a bio-scrubber, utilizing specially selected bio-cultures. The scrubber water overflow is discharged into the wet effluent treatment plant.

6. Blood Dryer—Australia
At the abattoir in Brisbane, where we cleaned up the lagoons, they had another problem, associated with their rendering plant. The blood dryer exhaust discharged directly into atmosphere from the stack, and dried blood (powder) settled on the roofs of the factory and covered cars. We installed a contra-flow wet scrubber in between the exhaust and the stack, and fed the scrubber liquor (after concentration of solids) back into the dryer feed. The cleaned air exhaust continued to discharge through the stack.

7. Compost Bagging—Australia
The bagging unit within the compost building had an aquajet venturi extraction unit attached to it, and the dust was entrained in the water. The water discharge went into a solids flotation tank where the two phases were separated, and the water was recycled through the venturi, with the solids (sludge) being mixed with the compost.

8. Sludge Storage Odor Control—Australia
A building where activated sludge cake was stored prior to drying, was susceptible to very strong odors, such as skatole and mercapatans, from the degradation of the protein in the sludge. An extraction system was installed and the air was fed through a scrubber tower with a counter-current water wash containing alkaline sodium hypochlorite. The effluent chlorine was neutralized with sodium metabisulphite, and then discharged to sewer. (See pictures)

9. Grease Digestion Plant—Australia
A complete building and process tank fume extraction system, feeding extracted air through an activated carbon filter. (See pictures)

10. Refuse Incinerator—Oman
As part of a complete treatment complex for the Omani Army, all refuse had to be incinerated with nothing leaving site. A two-stage incinerator was installed, with all fume from the primary chamber being passed through a high temperature secondary combustion chamber to ensure full compliance with emission controls.

11. Abattoir—UK
As part of a total waste treatment plant, air from within the plant building was extracted and passed through a bio-scrubber (trickling filter) and fed back into the aeration process by compressor for the aerobic treatment phase of the wet effluent system. The scrubber liquid was fed into the inlet sump of the plant for treatment along with the rest of the effluent. (See pictures)

12. Plating Plant—UK
The cyanide cleaning tanks were hooded and the air extracted and passed through a chemical scrubber to destroy the cyanide before discharge to the stack.

13. Milk Processing—UK
A milk processing factory producing milk powder products had an existing dust extraction and scrubbing system, but the treatment plant associated with this was plagued with excess grease and consequent odors. A bio-augmentation program solved all problems. (See pictures)

14. Rendering Plant—Portugal
An animal waste rendering plant in a populated area of Porto, was threatened with closure because of odor emissions. A two-stage bio-scrubber was installed utilizing special bio-cultures in a bioaugmentation program, and all odor nuisance was eliminated.