Treatment of domestic wastewater in an up-flow anaerobic sludge blanket reactor followed by moving bed biofilm reactor

The performance of a laboratory-scale sewage treatment system composed of an up-flow anaerobic sludge blanket (UASB) reactor and a moving bed biofilm reactor (MBBR) at a temperature of (22-35 A degrees C) was evaluated. The entire treatment system was operated at different hydraulic retention times (HRT's) of 13.3, 10 and 5.0 h. An overall reduction of 80-86% for CODtotal; 51-73% for CODcolloidal and 20-55% for CODsoluble was found at a total HRT of 5-10 h, respectively. By prolonging the HRT to 13.3 h, the removal efficiencies of CODtotal, CODcolloidal and CODsoluble increased up to 92, 89 and 80%, respectively. However, the removal efficiency of CODsuspended in the combined system remained unaffected when increasing the total HRT from 5 to 10 h and from 10 to 13.3 h. This indicates that, the removal of CODsuspended was independent on the imposed HRT. Ammonia-nitrogen removal in MBBR treating UASB reactor effluent was significantly influenced by organic loading rate (OLR). 62% of ammonia was eliminated at OLR of 4.6 g COD m(-2) day(-1). The removal efficiency was decreased by a value of 34 and 43% at a higher OLR's of 7.4 and 17.8 g COD m(-2) day(-1), respectively. The mean overall residual counts of faecal coliform in the final effluent were 8.9 x 10(4) MPN per 100 ml at a HRT of 13.3 h, 4.9 x 10(5) MPN per 100 ml at a HRT of 10 h and 9.4 x 10(5) MPN per 100 ml at a HRT of 5.0 h, corresponding to overall log(10) reduction of 2.3, 1.4 and 0.7, respectively. The discharged sludge from UASB-MBBR exerts an excellent settling property. Moreover, the mean value of the net sludge yield was only 6% in UASB reactor and 7% in the MBBR of the total influent COD at a total HRT of 13.3 h. Accordingly, the use of the combined UASB-MBBR system for sewage treatment is recommended at a total HRT of 13.3 h

Anaerobic Treatment of Concentrated Black Water in UASB Reactor at a Short HRT

This research describes the feasibility of applying a UASB reactor for the treatment of concentrated black (toilet) water at 25 °C. On average 78% of the influent load of COD at an HRT of 8.7 days was removed. Produced methane can be converted to 56 MJ/p/y as electricity and 84 MJ/p/y as heat by combined heat and power (CHP). Minimum reactor volume at full scale was calculated to be 63L per person (for black water containing 16 gCOD/L produced at 5 L/p/d) and this is more than two times smaller than other type of reactors for anaerobic treatment of concentrated black wate

MBR Technology: future research directions

Cutting down the operational costs of MBR technology will be the key driver for research. This article outlines some research areas and specific topics that potentially will contribute to lower costs. Special attention to these topics should be given the coming years. Long term research should focus on sustainable MBR concepts. A few innovative developments will be presente

Denitrificatie met opgelost methaan uit anaerobe vergisting: nieuwe mogelijkheid voor afvalwaterbehandeling

Huishoudelijk afvalwater bevat veel energie. Rioolwaterzuiveringsinstallaties hebben zodoende de potentie om energieproducerend te worden in plaats van energieconsumerend. Er zijn reeds initiatieven in gang gezet die zich richten op het terugwinnen van energie in de vorm van biogas door het vergisten van primair en secundair slib. Een meer directe route naar biogas is de anaerobe zuivering van het afvalwater. Het effluent van een anaerobe reactor bevat echter nog wel ammonium en opgelost methaan (een sterk broeikasgas). Beide kunnen omgezet worden met de recentelijk ontdekte DAMO-bacteriën: denitrificatie gekoppeld aan anaerobe methaanoxidatie. Dit biedt nieuwe mogelijkheden voor een energie-efficiënte afvalwaterbehandeling

Algemene aspecten van stikstofverwijdering uit afvalwater

De zuiveringsbeheerders hebben de afgelopen tien jaar omvangrijke investeringen gedaan om aan de effluenteisen voor stikstof te kunnen voldoen. Toch staat er alweer een nieuwe uitdaging op dit gebied te wachten en ontstaat er steeds meer belangstelling voor decentrale behandeling van gescheiden afvalwaterstromen

Method for releasing aquatic worms from a carrier and predation reactor

The invention relates to a method comprising providing a carrier, preferably a porous carrier, comprising a number of aquatic worms from the class of the Oligochaeta exhibiting a swimming motion. The method further comprises providing to the worms an escape reflex-inducing stimulus on at least one side of the carrier of, such that the worm biomass is at least partially released from the carrier. The method further comprises removing worm biomass released from the porous carrier for further processing. The invention further relates to a predation reactor suitable for applying the method according to the invention