Phosphorus Removal and Recovery from Wastewater

Transcription

1 Phosphorus Removal and Recovery from Wastewater Darragh Hobbs, Dr. John McGrath and Dr. John Quinn ATWARM and the QUESTOR Centre, The Queen s University of Belfast, 97 Lisburn Road, Belfast, BT9 7BL, Co. Antrim, Northern Ireland.

2 roject Overview P removal and recovery from wastewater Tackling the issue of nutrient pollution as a result of inadequate wastewater treatment Exploiting environmental stress for biological P removal Using PAOs and their ability to accumulate phosphorus in the form of polyphosphate Ubiquitous biopolymer made up of tens or hundreds of orthophosphates linked by high energy phosphoanhydride bonds

3 Project Plan Timeline of the project and three chapter thesis outline: Initial Studies -Year 1: Batch culture studies using A. calcoaceticus, P. putida and POLYTOX Confirmation that environmental stress can be exploited for biological P removal Isolation of microorganisms from wastewater to investigate the occurrence of the phenomenon over a wide spectrum of bacteria Scale-up Year 2/3: Chemostat culture analysis Logical progression form batch culture Using a system that can best simulate the conditions of a wastewater treatment plant Biochemical Analysis Year 2/3: PPK and PPX (p)ppgpp The biochemical triggers of the observed enhanced Pi uptake

4 Recent Findings Previously investigations were carried into the possibility that environmental stress might trigger large accumulation of P in bacteria Observed in isolates of A. calcoaceticus and P. putida in batch culture Stored as intracellular polyp In recent months efforts have been focused on confirming the initial findings that environmental stress can be exploited for biological P removal in a WWT system Manipulation of growth conditions Variations in control methods Alternating the way in which the stress is relieved Changes in cell harvesting Each test served to further solidify the idea that PAOs can be readily encouraged to perform enhanced biological P uptake without the need for complex anaerobic/aerobic cycles (EBPR)

5 Recent Findings

6 Current Point We have established that there is indeed a novel biotechnological process worth investigating. Replicable time and time again at shake flask scale Works with a range of PAOs and with mixed culture The bioreactor unit has been installed and is fully operational Initial runs have been carried out to establish the most effective and thorough way to demonstrate the process at this scale An inoculum of A. calcoaceticus was used to seed the reactor. The aim being to achieve steady state before the culture is manipulated in an effort to stimulate the characteristic enhanced biological P removal Bioreactor Units Turn-key System

7 Proposed Process A In order for the process to be demonstrated at this scale a number of potential paths will be examined B The culture will run in continuous fashion with intermittent shock periods after which either of 2 options can be explored 1. A direct C injection (Pulsed) 2. A switch from one media configuration to the other

8 Impact on Other Projects Rather than having a direct impact on one project or another?? Clues in the operation of some processes that might be worth exploring in others U.V. light Carlo The forum and ATWARM/QUESTOR networks play pivotal roles in nurturing potential collaborations The secondments are perfect examples of how one project can benefit from another A wide knowledge of each project and how if effects the water industry can lead on to innovative research Communication

9 Relevance to Industry The process involves a stand alone trigger with no need for a major revamp of the current WWT infrastructure Offset the costs of current wastewater treatment technologies Increase recovered P yields High value product ~50% of P in WW is recovered as struvite Room for improvement Water is another natural resource that is under threat Similar attitude towards water as P Water charges Contribute enormously to solving the global problem of eutrophication Stopping excess P discharge into the surrounding waterways The findings offer hope in the fight to stem the global loss of phosphorus from unnecessary over-production

10 Further research Further scaling up if bioreactor work proves to be successful 20/000 Litre and Pilot scale plant operation Part II The recovery of P from the PAOs and its commercial exploitation as a high value product Investigating suitable methods for the recovery of P Incineration Struvite/calcium phosphate deposits Other novel methods Acid induced One stress in another stress out?

11 Thank You