Super high-efficiency, solid-liquid separation technology (high rate filtration)

Outline

From Sedimentation to Filtration Improvement in treatment capacity by using an alternative to the primary sedimentation tank

In Japan, with the expansion in the coverage of sewage systems, there has been growing demand seen in recent years for the improvement and reinforcement of business management through expansion, public-private partnerships, and innovative technologies.
The high rate filtration system for all weather conditions is a technology for responding to the need for reducing the stock of aging facilities and equipment and for contributing to the efficiency of business management.

Benefits of sewage treatment facilities

• Stock reduction through capacity enhancement
• Response to increased water volume in rainy weather

Combined effects of implementation

• Energy creation
• Disaster response
• Response to increased water volume in rainy weather

Features

High filtration rates

• Filtration speed: 250-500 m/day (30-50 m/day for conventional primary sedimentation tank)
• Space saving is achieved with an area that is about half of that required for a conventional primary sedimentation tank
• Reduced construction costs

Existing tanks are usable

• Allows for the modification of an existing primary sedimentation tank to be made into a high-rate filtration tank

For all weather

• Filtration rates can be increased to a maximum of 1,200 m/day in rainy weather
• Reduction of chemicals for simplified disinfection in rainy weather

Efficient recovery of crude sludge

• Allows for the recovery of large amounts of crude sludge which generate large volumes of digestion gas

High performance when it comes to the removal of BOD and SS

• BOD removal of 40% or more (actual value for a filtration rate of 250-500 m/day)
  The BOD removal rate is calculated based on the relationship found among the percentages of the dissolved BOD, the SS removal rate and the suspended BOD.
• SS removal of 50-70% (actual example)
  SS removal rate is calculated based on the SS concentration in raw water
• 100% removal of debris (particle size of 1 mm or over; plastic pieces in wastewater may be removed)

This technology has been evaluated within the “Guidelines for the introduction of energy management system that is based on super high-efficiency solid-liquid separation technology” (by the National Institute for Land and Infrastructure Management, Ministry of Land, Infrastructure, Transport and Tourism) published in July 2013.

[Patent numbers]
3853738 High rate filtration method
3824583 Rainwater treatment equipment in a confluence type sewage system and a method of back washing thereof