Moving Bed Biofilm Bioreactor (MBBR) -Design and Construction Principles of FMR

Moving Bed Biofilm Bioreactor (MBBR) process uses the whole tank volume for biomass growth. It uses simple floating media, which are carriers for attached growth of biofilms. Biofilm carrier movement is caused by the agitation of air bubbles. This compact treatment system is effective in removal of BOD as well as nitrogen and phosphorus while facilitating effective solids separation.

Design and Construction Principles

MBBR units are placed in series based on the load entering each reactor. Neutralised and settled wastewater passes through MBBR for reduction in BOD/COD. Most of the MBBR plants are provided with vertically or horizontally mounted rectangular mesh sieves or cylindrical bar sieves. Biofilm carriers are made up of high density (0.95 g/cm³) polyethelene. These are normally shaped as small cylinders with a cross inside and fins outside. The standard filling of carrier is below 70% with a maximum specific area not more than 465 m²/m³. Generally, design load for COD-BOD removal is 20 g COD / m²d. Smaller carriers need smaller reactor volume at a given loading rate (as g/m²d) when the carrier filling is same. 

It is advisable to use MBBR in combination with a septic tank, DEWATS or a pre-coagulation step as a pre-treatment unit, depending on the local conditions and input characteristics. It is a very robust and compact alternative for secondary treatment of municipal wastewater, having removal efficiency for BOD 90 – 95% (low rate) and that of 75 – 80% for high rate. Average nitrogen removal is about 85%. There is no need for sludge recirculation. Phosphorus and faecal coliform reduction is feasible with additional passive (non-mechanical) or active (mechanical) system components.

A constantly operating MBBR does not require backwashing or return sludge flows. It has minimal head-loss. Coarse-bubble aeration in the aeration zone in the wastewater treatment tank provides ease of operation at low-cost. Agitation continuously moves the carrier elements over the surface of the screen thus preventing clogging. Maintenance of MBBR system includes screening, influent equalisation, clarifier system, sludge handling and integrated control system. There is no need to maintain f/M ratio as there is self-maintenance of an optimum level of productive biofilm. Skilled labour is required for routine monitoring and operations of pumps and blowers.

You always need expert advise to design a efficient and cost effective system.

	ITEMS OF ENVO COMPACT MODULE
Sr No	Item	Specification	Qty	Cost
1	Raw Sewage Pump	Submersible,auto running,kirlosker	1 No
2	Compact module consisting of following units,. 1.Aeration-I with aeration grid 2.Aeration-II with aeration grid 3.Tube settler with baffle and weir 4.Treated water tank 5.Sludge holding tank with aeration	MS with support frame, inside FRP, outside painted	LOT
3	Diffuser in Aeration Tank-I & II	Dome type,Make:ENVO	LOT
4	Floating Media in aeration tank-I & II		LOT
5	Tube Deck Media in Tube Settler		LOT
6	Air Blower,	Twin lobe Rotary type, Make: SGN	1 No
7	Filter Feed Pump	Kirlosker	1 No
8	Pressure sand  filter	MS module with media and frontal pipes and valves,Make:ENVO	1No
9	Activated carbon filter	MS module with media and frontal pipes and valves,Make::ENVO	1No
10	Electric starters,wires	Panel,starter  and wires to pump and blowers	LOT
11	Pipe & Fittings, PVC	PVC pipe and fittings	LOT
12	Sludge Pump	kirlosker pump	1 No
13	Filter Press	PP plates with filter cloth, Make:Saraswati	1 No
14	Erection commissioning of the system		LOT