Optimisation of Existing Wastewater Treatment Plants
From Wastewater Treatment
There are many reasons to optimise a existing wastewater treatment plant. For instance, the volume and concentration of inflow might have changed over time or it might have become necessary to minimise energy consumption or operating resources. DAS Environmental Expert assists you in optimising your wastewater treatment plant and develops individual wastewater concepts.
Basis for Optimisation
Examining the hierarchy of objectives is an important step when optimising wastewater treatment. This is because this serves as the basis for developing the right concept for changing the parameters of the entire treatment plant. The results of optimisation are always tailored to your exact individual needs.
Process of a Plant Optimisation
- Objective analysis and inventory
- Understanding substance dynamics
- Prepare draft concepts for optimisation
- Generate optimisation concept
- Planning and engineering
- Verification of results and final report
There is no 'one-size-fits-all' concept for optimising a wastewater treatment plant. A solution always needs to be project oriented and developed on-site. There are, however, typical key characteristics, which usually render a complete new construction unnecessary.
Even though the cost for ventilation in a biological wastewater treatment plant with activated sludge process is usually only a small fraction of its entire investment expense, it often provides significant potential for optimisation. Is your plant still operating on classic turbo compressors? If so, you could be passing on the opportunity to save up to 25% in energy costs! Using magnetic bearing turbo compressors or speed-controlled rotary compressors will significantly increase the energy efficiency of your biological wastewater treatment plant.
If the inflow to your plant is subject to heavily fluctuating pollution levels or volume streams then adjusting the oxygen supply is a reasonable step. This is because an oversupply of oxygen is not only not economical but will also negatively affect the treatment process.
Relying on out-dated wastewater technology often causes unfavourable flow conditions. For multi-stage wastewater treatment plants in particular, irregular feedings are an oftentimes underestimated effect; specifically if it affects an upstream de-nitrification stage, then high operation costs are a homemade problem. On the one hand, flow conditions of 60:40 will lead to a short retention period allowing sufficient de-nitrification. However, on the other hand, this will cause an over- and undersupply of oxygen in the activated sludge stage that follows.
Modifying the dividing mechanism often cures the problem. If the wastewater evenly distributes into all stages and is switched to intermittent de-nitrification much higher capacities of de-nitrification will be achieved. This is how wastewaters with a certain C-defect can reach effective nitrogen decomposition levels.
Implementing measuring probes to control oxygen levels completes the optimisation phase by allowing demand-oriented aeration.