Environmental Science & Engineering - www.esemag.com - May 2004
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Clean Harbours achieves odour reduction at Ontario landfill operation

By Irene Hassas,
Filter Innovations Inc.

BioStreme rejuvenates the system by incorporating the growth and gradual strengthening of facultative bacteria in the lagoon.

Clean Harbours, one of the largest Ontario landfill operators, had problems with strong odours emitted from the leachate collected in their lagoons, symptomatic of the incomplete and improper decomposition of solids.

There are two interconnected lagoons on the landfill site. The existing volume of each is five million litres. The wastewater (rain run-off from the landfill) is pumped into the lagoons as needed and this process is controlled by a pumping system.

More solids are accumulated in the first lagoon because wastewater is pumped by two inlets from landfill to Lagoon 1 and then it flows to Lagoon 2. There are four propeller type surface aerators - two in each lagoon. Each lagoon is aerated and mixed by the aerators. The wastewater is pumped 24 hours a day into the incinerator where the water is evaporated. The incinerator burns 100,000 litres per week of the lagoon’s water. Each week, 45 buckets of ash from the incinerator are spread on the landfill and the landfill is then covered by a layer of mixed cement, water and newspaper. The run-off in the landfill only fills up substantially when the incinerator cannot keep up with rain run-off and the lagoons are full.

Challenge Hydrogen sulphide, ammonia and volatile fatty acids are common odours associated with the treatment of industrial wastewater. Odours become a serious problem in the summer because of increasing temperatures. Odour issues not only cause concern with local neighbours and residents of the area but are also a potential cost issue for the facility.

Treatment Clean Harbours had originally applied hydrogen peroxide to treat the leachate for odour. It showed a limited odour removal ability both in the lab analysis and in the lagoons. In addition to its limited effect, hydrogen peroxide is also a hazardous product to work with. It is corrosive to mucous membranes, eyes and skin and causes nose and throat irritation.

Left: Each lagoon was aerated and mixed by two propeller-type surface aerators. Right: 250 litres of BioStreme were used to shock each pond.

The existing biological population in a leachate consists of both aerobes and anaerobes. They have specific nutrient and micronutrient requirements for optimal growth and reproduction, many of which may not be present in the leachate environment. This can often become a rate-limiting variable in the processing of wastes, resulting in decreased operating efficiencies, loading rates and/or undesirable by-products, such as excessive odours, scum formation, and solids.

BioStreme is a custom engineered micronutrient formulation that is used for the enhancement and acceleration of existing biological treatment systems. Its proprietary formula is derived from 100% all-natural sources of amino acids, plant extracts and foodgrade nutrients, which have been blended to encourage the growth and metabolism of existing and/or introduced bacteria for dramatically improved treatment results and odour control.

The long-standing leachate environment is very similar to a septic system’s environment, emitting various types of off gases venting from the lagoon (odours). BioStreme rejuvenates the system (as a source of nutrient) by incorporating the growth and gradual strengthening of facultative bacteria in the lagoon. As this excess population devours the overload, the lagoon’s functional operation improves until treatment can be diminished and maintained minimally as a preventative measure. Based on the dimensions and depths of the ponds (5,000,000 litres of leachate) a 60% reduction of odour was expected.

Each lagoon was shocked to achieve 50 ppm concentration in the pond. To shock each pond, 250 litres of BioStreme concentrate were used. The concentrate was initially diluted 100:1 with water (this was later revised to approximately 20:1) and spread over the surface of each lagoon. The batch mixer mixed the micronutrient and water to provide the appropriate dilution.

Application was done using a mobile water cannon with a 1,000 gallons holding tank and spraying the mixed solution on the surface. The surface aerators provided accurate mixing. According to the operator, within approximately four to five days, odours were noticeably reduced.

Since the level of leachate changed due to the addition of rain run-off to the lagoons, BioStreme was added to encourage growth. An additional 100 to 150 litres per week (with the dilution of approximately 20:1) were required to treat 1,000,000 litres per week of new, incoming leachate and the remaining liquid in the lagoons to maintain odour control.

Although the nature of incoming materials to the lagoons was not completely known, Filter Innovations was able to determine the required concentration and necessary dilution rate of BioStreme to control the odour of the lagoons.

The process has been extremely effective in achieving odour reduction With the Accu-Tab chlorination system, there are no bulky drums or cylinders to handle. in the leachate environment at Clean Harbours landfill. According to the landfill manager, odours were completely removed from the first lagoon and noticeably reduced in the second one. Downstream of the lagoons, the odours are virtually non-existent.

Irene (Aranak) Hassas, M.E.S., B.Sc., is the Environmental Manager at Filter Innovations Inc.
Contact, e-mail: irene@filterinnovations.com.

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