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

Marthe S De Graaff,Hardy Temmink,Grietje Zeeman,Cees J N Buisman

doi:10.3390/w2010101

Abstract

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 water.

Highlights

Separation of domestic waste(water) at the source results in black water from the toilet and less polluted grey water from showers, laundry and kitchen
This paper describes the feasibility of applying a compact UASB reactor for the treatment of concentrated black water from vacuum toilets at these conditions
The black water was more diluted in the second period of operation because more flushing water was used in the vacuum toilets due to installation of noise reducers (Table 3)

Summary

Introduction

Separation of domestic waste(water) at the source results in black water from the toilet (faeces and urine) and less polluted grey water from showers, laundry and kitchen. These source separated waste(water) streams differ in quantity and quality and should be treated separately according to their concentrations and composition. Black water contains half the load of organic material in domestic wastewater, the major fraction of the nutrients nitrogen and phosphorus [2,3] and can be collected with a small amount of water (one liter per flush) using, for example, vacuum toilets. The volume of black water depends on the type of toilet and amount of water needed to flush

Methods

Results

Discussion

Conclusion