Waste and recycling

Organic waste treatment

Biodegradable organic wastes can be collected or separated from miscellaneous wastes in order to provide a utility as a fuel for energy generation or as a raw material for compost or fertiliser manufacture. The main classifications of organic waste include manure, food waste, cutting waste and agricultural waste.

Anaerobic (without oxygen) decay processes are used to produce biogas, while compost is made through an aerobic (with oxygen) decomposition process. Either degradation process generates a complex gas mixture, which can generate unpleasant odours or, in the case of biogas, a risk of corrosion of combustion engines. With our molecular filtration we remove these unpleasant odours and gases from a valuable resource for renewable energies, compost and fertilisers.

The need for air treatment in biogas plants

Recycling organic waste is becoming increasingly important as a viable option to replace fossil fuels. The decomposition of this waste results in methane which is used to generate energy. However, it should be noted that the resulting methane may contain harmful contaminants that can cause corrosion or abrasion.

Some contaminants are: hydrogen sulphide (H2S), ammonia (NH3), siloxanes, aromatic hydrocarbons, halogens (chlorine, fluorine) and other particulates.

The aforementioned contaminants, such as hydrogen sulphide (H2S), can cause corrosion damage that leads to unexpected repairs and maintenance, thus decreasing production and increasing costs. Integrated molecular filtration is generally the most commonly used method to remove hydrogen sulphide from biogas prior to combustion.

Molecular filtration for odour treatment

During the biodegradation process in an aerobic process of organic waste, a large part of the volatile organic content of the waste is released. This creates a mixture of gases responsible for the intense and unpleasant odours. One of the main components are terpenes, such as alpha-pinene.

Our recommendation in these cases as a method of controlling strong odours is molecular filtration. Both in the air outlets of the production building and in the plant’s ventilation system.

Recycling and solid waste treatment

In solid waste recycling plants not only volatile organic compounds (VOCs) are emitted, but also a large amount of particulate matter is generated from the constant handling of a large amount of degraded materials.

Air treatment in these plants not only protects the environment, but also the plant workers and the plant machinery.

The materials mainly recovered in these facilities are solid waste such as cardboard, glass, plastic, among others.

Air filtration as an ally to minimise health risks

In solid waste recycling plants there are several risks that without proper filtration cannot be treated and are highly dangerous. For example, a common risk in these facilities is the large amounts of dust generated due to the recovered materials of industrial or domestic origin.

Another issue that needs to be addressed with adequate filtration systems is odour. In these installations, unpleasant odours are generated due to hydrogen sulphide, dimethyl sulphide and mercaptans, which even in low concentrations can be annoying and a hazard for human and industrial equipment.

Finally, another risk we highlight that is avoided by filtration in these plants is explosions and the possible danger of fire. These explosions are due to the fact that any solid waste converted into dust can explode, including metal.

Processes related to risks of generating problems

Incineration plants where mixed waste is burned for energy generation must also have odour control. During maintenance shutdown periods, molecular filtration will be the best solution.

Another process where molecular filtration will be key is in the transport of domestic waste from modern residential areas. These use underground pipes that go directly to the power station. In these cases, molecular and dust filtration will be needed at the outlets of the system to avoid problems in heavily populated areas.

Wastewater treatment

Wastewater treatment plants or WWTP’s are critical elements in the development of any civilisation. Water coming from industrial processes or from towns and cities must be treated before it is returned to nature.

These plants must not only treat the water, but also the foul or polluted air that comes from the emission of this water. Odours, gases and particles can be treated with Venfilter’s tailor-made solutions that will help you to prolong the life of your equipment, protect your staff and save energy.

Odours and their different origins

The most common challenge in most wastewater treatment plants is odour problems. Odours are generated in different treatment processes coming from different areas of the plant. For example, intake areas, pumping stations or sewage sludge areas.

They usually come from sewers, either industrial or residential. However, the pollutants generated in both are completely different. It can also come from the overflow of the same combined sewers.

Problems caused by odours

We often think that unpleasant odours are only a nuisance factor, but we overlook the fact that the process of odour generation affects the health of the plant personnel, but also the equipment. Furthermore, an added problem is that as time goes by, these plants are closer to densely populated areas due to the rapid growth of cities, affecting not only the plant personnel, but also a large collective of people.

Unlike the older plants, the more modern plants are enclosed and even started to be built underground. Although closing the plants eliminates the problems described above, it creates new ones. For example, the accumulation of methane, an odourless but explosive gas. Filtration therefore becomes a key element in keeping methane levels controlled and safe.

In addition, odour problems will persist because when ventilation air is discharged into the atmosphere, the gases responsible for the characteristic odour are also released. Therefore, odour control in the exhaust air system will be necessary.

Problems caused by corrosion

Another problem that wastewater treatment plants have to deal with is corrosion. Acid gases such as hydrogen sulphide mainly cause damage to the electrical systems of the plant. These attacks on computer controls and electrical devices will call into question the reliability of the plant.

In addition, if corrosion is not controlled with a good filtration system it can also lead to overheating, plate failure or clogged flows which will create plant downtime and costly repairs.

What are the most common contaminants?

• Hydrogen sulphide
• Mercaptans
• Organosulphurates
• Ammonia (NH3)
• Benzene
• Industrial chemical effluents

What can our molecular filtration offer you?

Reduce unpleasant odours

Molecular filtration is a method that will reduce that characteristic smell of plants. The sense of smell develops differently from person to person. Therefore, although they may seem to be of low perception, we must make sure to minimise the levels as much as possible to avoid generating complaints and discomfort.

Protect your staff

Exposure to the gases described above can be very dangerous. For example, exposure to hydrogen sulphide can cause unconsciousness or ammonia has corrosive effects on the skin, eyes and lungs.

Reducing costs

Some of the common contaminants in these plants cause corrosion damage. If not controlled with a good filtration system, this can lead to structural problems such as collapsed sewers or costly downtime.