Megablock™ Airlift™ Tubular Membrane Systems

The Megablock™ is a pre-engineered system that provides a quick and cost effective approach to large-scale MBR treatment systems and wastewater facility upgrades. The Megablock™ modules are equipped with the Airlift™ tubular membrane technology providing all the benefits of the bioPULSE™ Airlift™ systems on a larger scale.

bioPULSE™ Airlift™ Membrane Systems are designed to provide an external tubular Membrane Bioreactor "MBR" System that is both low in operating costs and easily maintained. The systems are installed external to the aeration basin without being immersed in MLSS to provide an operator friendly MBR treatment process.

How the Megablock™ UF Process Works

The Megablock™ system incorporates the bioPULSE™ Airlift™ Tubular UF system using the unique power saving airlift™ feature and a patented drain/flush procedure to reduce operating cost and increases productivity. The airlift™ feature directs air flow to the tubular channels providing an effective air scouring process. The result is a highly efficient air lift pump and scouring process which increases cross flow velocity and reduces the size of the membrane feed pump and blower. The controlled air scouring disrupts the fluid barrier on the membrane surface to increase and sustain the high system flux rates and minimize membrane fouling. The airlift™ feature directs air flow to the tubular channels providing air scouring exactly where it is needed. The result is a highly efficient air scouring and enhanced feed flow which reduces both blower and feed pump size.

The Polyethersulfone (PES) Ultrafiltration membrane acts as a positive barrier retaining all mixed liquor suspended solids "MLSS" and returning them to the aeration basin. The end result of the membrane process is a purified biologically treated wastewater stream with turbidity levels of less than 0.1 NTU for direct discharge or water reuse. Silt Density Index (SDI) levels of <3 can be achieved for provision of a suitable feed stream to nanofiltration and reverse osmosi systems.

Module Megablock™ systems provide simple installation, civil works and liabilities are reduced to a minimum. Operator exposure to MLSS/wastewater is eliminated. The combination of a fully automated external tubular membrane system with low operating expenses "OPEX" and low capital expenses "CAPEX" allows wastewater treatment facilities to install an MBR or upgrade a conventional activated sludge plant without the exorbitant costs typically associated with immersed membrane systems.

Process Description

The bioPULSE™ Airlift™ membrane separation process uses the Megablock™ 636 system modules. Each module consists of one (1) sections each having thirty-six (36) Norit Airlift™ tubular membrane elements. These pre-engineered modules can be arranged to match the required design flow. A system feed pump provides mixed liquor to each Megablock™ circulation pump which in turn provides feed material to each membrane element. Air is provided to specially designed air diffusers located on the bottom of each membrane module to provide enhanced cross-flow velocity, air scouring of the tubular membranes and airlifting of the mixed liquor. Concentrated mixed liquor is returned to the aeration tank and purified water is removed through the permeate manifold. Permeate extraction pumps dedicated to each train will be utilized to assist the withdrawal of permeate from the membrane modules and control the flow through the system.

In order to maintain a high flux rate the membrane bank will be backwashed based on permeate pump run time. The frequency and duration of backwash for the membrane bank can be set within certain parameters. Typical frequencies and durations range between 5 – 10 minutes frequency and 10 – 20 seconds duration. Backwash water will be supplied from a backwash tank that is replenished by the permeate pumps. Periodically (every ~25 days of operation) it will be necessary to chemically clean the membrane modules to enhance TMP and membrane flux. The Airlift™ bioPULSE membrane system will be provided with a complete chemical backwash system incorporating a permeate/backwash tank, backwash pumps and associated instruments and controls. Addition of chemicals directly into the backwash pipe manifold will be accomplished with chemical metering pumps for sodium hypochlorite (NaOCl), sodium hydroxide (NaOH) and hydrochloric acid (HCl).

Megablock™ and Airlift™ are trademarks of Norit X-Flow.