91福利

This system was tested as part of a demonstration study commissioned by the National Institute for Land and Infrastructure Management. The technology for improving the treatment capacities of final sedimentation tanks evaluated during the study (FY2017 B-DASH Project) was commercialized as the product called the Final Filter.
The results of the above-mentioned study have been publicized by the NILIM as the Guideline for introducing demonstration of filter-aided secondary clarifier for improving wastewater treatment capacity (December 2019).

Outline

Sedimentation combined with filtration to improve the waste water treatment capacities of final sedimentation tanks

In Japan, the aging of sewage facilities is ongoing. We are now reaching the time for full-scale renovation and refurbishment. Local governments, who are managing such facilities, are required to formulate and review optimum planning for sewage lines while taking into account future flow volumes and other factors.
METAWATER’s Final Filter can improve treatment capacities of the final sedimentation tanks both quantitatively and qualitatively, while using the existing civil engineering frameworks, and thus, can contribute to the solving of problems faced by local governments.

Features

- Enhances the waste water treatment capacities of final sedimentation tanks (quantitative improvement)

This product features combination of the sedimentation and separation of the existing final sedimentation tank together with the removal of solid matter by filtration. Therefore, even if water quantity exceeding the existing treatment capacity flows into the final sedimentation tank, which would make sedimentation and separation insufficient, the capacity to remove solid matter is enhanced by the downstream filter units, thereby keeping the water quality at a normal level. During the demonstration study, it was confirmed that the existing treatment capacity can be enhanced up to twice as much.

- Alternative to high-speed filtration (quantitative improvement)

When water quantity falling within the existing treatment capacity flows into the final sedimentation tank, sedimentation and separation sufficiently functions, so solid matter is further removed by filtration. This means that a water quality equivalent to that produced by high-speed filtration can be achieved. The Guideline (Draft) mentioned above approves the Final Filter to be used as technologies deployed for high-speed filtration.

- Utilization of existing civil engineering frameworks

Final Filter features low pressure loss at filtration units, allowing for filtration involving the utilization of water level differences between the reaction tank and the final sedimentation tank. Also, no major modification to civil engineering frameworks is required for implementation.

- Reduced downtime of water supply during implementation

The cassettes of the filtration unit are made at factories and delivered to the site, saving man-hours at the site. If installation can be done by hanging, for example, using a crane, the downtime of water supply can be drastically reduced; The downtime per tank was shortened to about 1 week during the demonstration study.

- Stable, continuous operation by means of automatic cleaning

Final Filter features a built-in automatic cleaning mechanism. The cleaning is done by introducing air into the filtration unit to separate solid matter inside the filtration unit, which enables stable, continuous operation without the need for human intervention. Waste water produced during cleaning is returned upstream from the final sedimentation tank by a pump, for example, to a shared water channel provided between the reaction tank and the final sedimentation tank. The cleaning is performed roughly once a day, with each instance of cleaning taking about 40 minutes.

Examples of implementation and advantages

- Reduces stock in the final sedimentation tank
- Spares the need to construct additional lines during the refurbishment of final sedimentation tank equipment

It is expected that water flow volumes will decrease at many water treatment facilities in the future. With this background in mind, additional care must be taken when it comes to designing and planning in order to maximize the cost-effectiveness when refurbishing machines and equipment such as sludge collecting machines, or when adding earthquake-resistant structures to civil engineering frameworks..
Final Filter can quantitatively enhance the existing treatment capacity and contributes to reducing existing facility stock since the treatment capacity is kept at the present level, even if the tanks requiring refurbishment or earthquake-resistance are discontinued or put out of service. It also saves an operator trouble of increasing the number of lines that are only used during facility refurbishment.

Example of implementation during facility refurbishment

- Spares an operator of the need to construct additional lines when expanding service areas or extending the shared-use of facilities

Many local governments plan to consolidate multiple water treatment plants, including those used for rural sewage, based on reviews on sewage planning which reflect the situation in terms of depopulation, etc. In this case, the sewage volume at the consolidated waste water treatment plant will accommodate the sewage volume of the discontinued waste water treatment plants, which is expected to exceed the existing treatment capacity of the consolidated plant immediately after consolidation. Given these circumstances, Final Filter, in combination with METAWATER’s all-weather high-speed filtration technology, carrier methods, and so on, allows the existing plant to process the sewage volume after consolidation without having to construct additional lines.

Example of implementation upon the consolidation and discontinuation of plants

- Spares operators of the need to construct new high-speed filtration equipment

Some local governments plan to introduce costly high-speed filtration equipment (including civil engineering frameworks) due to the implementation of advanced treatment.
Introducing Final Filter within the final sedimentation tank qualitatively improves its treatment capacity, with the resulting water quality being equivalent to that produced by high-speed filtration. This saves operators the need for a construction site for high-speed filtration system, meaning that the product provides a great advantage in that it means a drastic reduction in construction costs.

Example of implementation as an alternative for high-speed filtration

Outline of the FY2017 B?DASH Project

The objective of the project was to demonstrate a technology for improving the water treatment capacity of the final sedimentation tank by adding low-cost modification to existing facilities without constructing additional civil engineering frameworks.
Matsumoto City, which shared the demonstration site, states in its general city planning the following: “We aim to achieve clean and comfortable living environments while preserving the water quality of rivers through the appropriate maintenance and management of sewage.” The city is working proactively to extend the service lives of its sewage facilities. In addition, METAWATER is a company offering total solutions related to water environments, seeking to create circulation cycles for water, resources, and energy based on cutting-edge, core technologies. In the future, through mutual collaboration with Matsumoto City and JS, METAWATER will further establish innovative technologies that contribute to the advancement and sustainability of the sewage industry.

Project name: Demonstration study for improving the waste water treatment capacities of final sedimentation tanks
Project members: Joint research team of METAWATER Co., Ltd., Japan Sewage Works Agency, and Matsumoto City
Demonstration period: FY2017 to 2018