Posted at the German Newspaper gwf-Wasser|Abwasser 12|2020
There are many sewage treatment plants that were built in the 70s or 80s that now require overhauling and expansion due to poor structural conditions, increased population and outdated technologies. Often the required discharge values can no longer be adhered to and the pollution of the wastewater has changed resulting in the existing process no longer working properly. This means that further treatment stages and chemical requirements are necessary.
When a municipality decides to invest in the rehabilitation of their Sewage Treatment Plant, the first step is to collect cost comparisons for different process options. In the case for small sewage treatment plants <5000 PE, the process options are often compared to the alternative of connecting to a nearby larger sewage treatment plant by means of a pressure pipes. The process options examined are mostly limited to conventional aeration tanks with sludge stabilization and membrane aeration systems that are placed in the existing renovated tanks or in new tanks. All these process options will incur high costs for the construction works, new equipment and installation, which is why the municipalities usually decide in favor of the pressure pipelines.
Unfortunately, a “Package System” solution is often ignored in studies and cost comparisons. If one were to include Package Plants in the study, the connection line to a larger system would only be preferred under certain circumstances, for example the connection system is very close and the gradient in the pipeline does not require any further pumping manholes thus meaning the construction of the pressure pipeline does not involve high investment and additional land.
Sample: Upgrade of conventional Sewage Treatment Plant with flow of 400 m³/day to 2000 m³/day
using 2 x 40” MBR-Container, placed on buffer tank. Sludge Dewatering in Container behind.
An MBR (Membrane Biological Reactor) Package Plant is a cost-effective option. The complete membrane filtration unit including pumps, ventilation, control and sensor technology is pre-installed in a stainless steel container (see pictures). The MBR container can be placed as a “plug & play” unit next to the existing aeration tank (see example in picture) and fed by circulation pumps. The MBR system does not require any secondary clarifiers and no further treatment. Also since the entire control and equipment is arranged inside the compact stainless steel housing, it can be implemented quickly and has low operation and maintenance requirements. These factors result in reduced construction, installation and operating costs. As an option, it is also possible to facilitate operation by means of remote monitoring, minimizing maintenance costs and further reduce operating costs.
Since membrane filtration can be operated with a much higher concentration of activated sludge compared to the conventional process, the existing activated sludge tank can handle up to 4-times more wastewater. This means that if a conventional system is upgraded using an MBR Package Plant, it is possible to expand the plant by 4-times or possible more within the same space requirement and significantly improve drainage values (see Example in picture). Furthermore, the treated wastewater is bacteria-free and almost virus-free and has a very low phosphate content, so can safely be discharged into receiving waters and to sensitive catchment areas as it corresponds to the EU bathing water quality. The effluent can also be used for irrigation and other certain re-uses such as industrial purposes.
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Some of the many advantages of MBR Package Plants over conventional wastewater treatment are summarized below:
- Treatment of higher volumes of wastewater with small foot print
- Improved effluent values, which in conventional systems can only be achieved with more extensive treatment and additional chemicals
- Microplastics, bacteria and almost all viruses are removed. A key issue in the future
- Biological phosphate removal ≤0.1mg P / l without precipitants, which lowers the operating costs (precipitants)
- The purified water can be used directly as irrigation and other certain re-use purposes
- The purified water can be re-used in the area of the plant and not lost to another location, as in the case of a pressure pipe
- The Package Plant is fully automatic and can be monitored remotely improving process control and saving on operating personnel
- Easy installation, pre-installed “Plug & Play” system, which greatly reduces the on-site installation costs
- Closed system, no odor and noise emissions
- Clean looking solution which does not have an appearance of a sewage treatment plant
- Can be easily expanded as required in the future due to the modular design
Picture: Preinstalled Equipment (Pumps, Control- and Sensor-Technik) in a MBR-Package Plant from MENA-Water
MENA-Water produces complete MBR Package Plants in standard sizes and customized sizes if required. This enables us to guarantee easy handling and transport, rapid availability and smooth installation and commissioning process. The systems are not designed as a temporary solution, but made of stainless steel and equipped with quality equipment, which guarantees a long service life and functionality.
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The Package Plant includes all main components in a compact housing:
- Stainless steel tanks V2A / V4A
- Complete piping including scouring air system
- Blowers and ventilation elements for aeration and membrane cleaning
- Recirculation pumps, permeate pump, backwash and chlorine dosing system
- Process control with PLC, online measurement technology and modem for remote web monitoring
For further information and inquiries, please contact:
Mena Water FZC
info@mena-water.com