Loughborough University
Thesis-2001-Surendran.pdf (158.16 MB)

The development of an in house greywater and roof water reclamation system for large institutions during 1994 to 1998

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posted on 2010-10-29, 10:22 authored by Sundaralingam S. Surendran
For sustainable water management, here is a necessity to consider alternatives, in addition to conventional systems. The aim of this research is to develop and demonstrate a sustainables, from and greywater reclamation system for WC flushing and it was started in 1994. In the UK there are no water quality standards for WC flushing water use. There were no design guidelines for greywater water reclamation and no published study on the supply-dernandb alance, in detail, for water recycling in institutions such as universities. The research has shown the feasibility of planned direct grey and storm water reclamation and recycling system to manage growing water and wastewater problems. This thesis is based on the information gathered from 4 universities, 3 hotels and 3 recreational centres, and experiences gained at Loughborough University during the development and demonstration of the full scale "in-house grey and roof water" reclamation and recycling systems. The water use, greywater quality and roof water characteristics were studied in detail and this information was used for the development of the reclamation and recycling system. The studies showed that the water usage at the university halls were not similar to usage in households. Unlike large water supply schemes, small in-house systems generate a large peak factor for water use. To avoid deficit, in addition to personal washing waters, a top-up of laundry wastewater or roof water, and a well-designed balancing tank is necessary. The demonstration study shows that there was no standby mains' water used, which means that the water reclaimed was sufficient for reuse. The quality characterisation study shows that the greywater and first flush storm water roof runoff were polluted. The characteristics of combined grey and roof water are suitable for biological treatment. Based on the infomation, a lab-scale unit was developed; the reactor characteristics and performance such as head losses and removal efficiency were monitored; and the unit was refined. Two novel multi-barrier reclamation systems were developed to achieve sufficient quantity and near potable quality of water with minimum maintenance and cost. During 1997 the grey and roof water recycling system with laboratory tested physical and biological reclamation processes without the use of coagulants and disinfection were installed. The performance of the treatment system was closely monitored until 1998. This provided benefits in near potable quality of reclaimed water, low head loss, reliability, failure free operation and simple maintenance. The reclaimed effluent from Project I and 2 met the UK/EU bathing water standards and was also able to meet the US EPA standards for WC flushing. The microbial (using coliform as an indicators) quality of reclaimed water without disinfection is acceptable for controlled recycling systems (carefully monitored and fully informed). There were no odour problems in the treated water or sludge blockages. Comparatively, Project I was more efficient at removing coliform, turbidity, solids (suspended, dissolved, volatile), and Project 2 better at removing carbon (organic and inorganic). A simple cost benefit analysis done for the recycling system at Royce Hall of Residence showed 10 years pay back. More detailed cost-benefit analysis including comparisons of new built and retrofit recycling system and fife cycle analysis are recommended. This study shows that most of the people questioned were accepted and were willing to consider using the recycling system for toilet flushing, if the water was clear, colourless, odour free, carried no risk and gave cost-benefits. During the demonstration stage the users willingly accepted non-potable grey water reuse.



  • Architecture, Building and Civil Engineering


© S. Surendran

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A Doctoral Thesis. Submitted in partial fulfillment of the requirements for the award of Doctor of Philosophy of Loughborough University.

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  • en

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    Architecture, Building and Civil Engineering Theses


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