Handling contaminated rainwater from heavily-used operating areas creates increasing problems for operators of biogas plants. Sealed surfaces of a few thousand square metres can easily lead to several tens of thousands of euros of storage and output costs each year. In the past, a part of the rain water also led to negative headlines. In this way, the disposal of water from biogas plants is coming more and more into the focus of the authorities and legislators.
revis bioenergy GmbH offers plant operators a flexible and affordable system for purifying the contaminated water where authority requirements can be fulfilled with certainty and costs reduced.
The typical drifts of biomass as well as contamination of the operating surfaces ensure that rainwater becomes contaminated. Due to the undefined fibres as well as the fluctuating rainfall distribution, classic purification procedures do not lead to an optimal separation of solids. The downstream purification stages are endangered by this.
With the physical-biological waste water treatment plant, PB-Clean, the operator has a user-friendly, reliable and long-term proven technology available. Occurring waste water and contaminated surface water is processed efficiently and safely. PB-Clean combines proven waste water technology and supplements this with its own modifications to harmonise with the requirements of a biogas plant.
Thanks to the upstream active physical separation, predominantly solid-free water is filtered off. The filtered solid substances (mainly organic material) are conveyed against the gravitational force to be discharged and can be led back into the fermentation process for use as energy.
After the solids are separated, the water is led into the PB-Clean reactor. Depending on the purification quality desired, the plant runs through sequential biological process phases. Setting the duration, frequency and arrangement of these phases ensures an operation which can be adapted for robust and seasonally-varied rainfall quantities. With the filling phase, the first breakdown processes take place under anaerobic or anoxic conditions. In the actual breakdown or reaction phase, the reactor is ventilated. The change between oxic and anoxic phases is adjusted to the waste water load and the prescribed purification aim. The sedimentation phase follows where the activated sludge settles. The clear water can be removed and discharged.
As usual, revis bioenergy also focuses on high-value industry quality with the PB-Clean system. All PB-Clean system elements in contact with the media are produced from stainless steel to achieve durability and operational safety. In the container there are no moving parts, which means that maintenance work can be carried out quickly and without difficulty. The specially-developed controls ensure a flawless and automated operation. Low energy requirements as well as low maintenance costs round the whole package off.
Operators of a PB-Clean system can also stay relaxed in the face of possible stricter limit values. This gives plant operators the security of also being well-equipped for future requirements. If new requirements, such as the reduction of the CSB limit value, require it, the basic version can be modified at any time. PB-Clean makes it possible to fulfil stricter, legal requirements quickly and affordably.
- Saving output costs and storage space
- Short payback period
- High industry quality
- Compliance with limit values
- Low operational and maintenance costs
- Future-proof thanks to adaptability
- Quick to implement
- High availability
- Proven technology
- Meaningful and environmentally-conscious use of resources
In practice, it is normal to store contaminated surface water in the fermentation residue container and then to remove this with the fermentation residue. Already removing and transporting this only a few kilometres and removal and discharge causes costs of € 5 to 12/m³, depending on the region.
In addition, biogas plants are faced with the challenge of creating additional new storage spaces due to shortened discharge periods and increased storage obligations (9 months).
Introducing contaminated surface water saves the plant operator from setting up storage space for water and makes it possible to use the storage space used today for fermentation residue again in the future. PB-Clean thus reduces investments (€ 50 to 60/m³) or rent for storage space.
With PB-Clean the profit of the plant operation improves thanks to saving costs today and in the future. In addition, the investment in PB-Clean has often paid itself off after a few years thanks to the low operational costs.
With PB-Clean, biogas plant operators can significantly improve the profitability of their plant
|CSB * mg/l
|BSB * mg/l
|NH4N * mg/l
|gesamt N * mg/l
|Pges. * mg/l
|…with additional denitrification
|…with additional phosphorus elimination
*assuming the Ø standard load of contaminated surface water of a biogas plant at the beginning.