Decentralised urban water reuse: The implications of system scale for cost and pathogen risk

2002 ◽  
Vol 46 (6-7) ◽  
pp. 281-288 ◽  
Author(s):  
S.A. Fane ◽  
N.J. Ashbolt ◽  
S.B. White

The non-potable reuse of treated sewage in urban areas provides significant conservation of potable supplies beyond that available through water use efficiency. Effluent reuse is also an inevitable requirement in novel decentralised wastewater systems. At present, urban water reuse, where pursued, usually involves large-scale schemes based on new or existing centralised sewage treatment plants. This is despite the diseconomy of scale inherent in pipe networks that balances economies of scale in sewage treatment and negates any cost advantage for wastewater systems with more than around 1,000 connections. In light of this, the theoretical relationship between effluent reuse system scale and pathogen risks was examined at various effluent qualities. Waterborne disease was seen to be a significant factor when reusing effluent in urban areas and smaller systems were found to pose a lower risk of waterborne infection, all other things being equal. Pathogen risks were then included within an economic analysis of system scale. It was concluded that with the inclusion of pathogen risks as a costed externality, taking a decentralised approach to urban water reuse would be economically advantageous in most cases. This conclusion holds despite an exact evaluation of increased waterborne disease due to effluent reuse remaining problematic.

2014 ◽  
Vol 70 (11) ◽  
pp. 1774-1781 ◽  
Author(s):  
Yifan Ding ◽  
Deshan Tang ◽  
Yuhang Wei ◽  
Sun Yin

Water resources in many urban areas are under enormous stress due to large-scale urban expansion and population explosion. The decision-makers are often faced with the dilemma of either maintaining high economic growth or protecting water resources and the environment. Simple criteria of water supply and drainage do not reflect the requirement of integrated urban water management. The Urban-Water Harmony (UWH) model is based on the concept of harmony and offers a more integrated approach to urban water management. This model calculates four dimensions, namely urban development, urban water services, water–society coordination, and water environment coordination. And the Analytic Hierarchy Process has been used to determine the indices weights. We applied the UWH model to Beijing, China for an 11-year assessment. Our findings show that, despite the severe stress inherent in rapid development and water shortage, the urban water relationship of Beijing is generally evolving in a positive way. The social–economic factors such as the water recycling technologies contribute a lot to this change. The UWH evaluation can provide a reasonable analysis approach to combine various urban and water indices to produce an integrated and comparable evaluation index. This, in turn, enables more effective water management in decision-making processes.


2017 ◽  
Vol 12 (3) ◽  
pp. 737-744 ◽  
Author(s):  
T. McAlister ◽  
M. Stephens ◽  
A. Allen

Aura, the ‘City of Colour’, is a 48,000 person masterplanned community on Queensland's Sunshine Coast. Aura commenced construction in 2015 and will be developed over the next 25 years. Aura sets a benchmark in Australia regarding large scale urban water sustainability through the application of techniques such as rainwater capture and reuse, construction and operational stormwater treatment, water conservation, advanced sewer system designs and potentially a major stormwater harvesting and indirect potable reuse scheme. This paper outlines the journey taken in seeing Aura advance from ‘concept’ to ‘reality’, describes data collection undertaken and modelling tools applied and outlines activities being implemented at Aura to protect sensitive downstream environments and simultaneously deliver water cycle and project sustainability benefits.


2011 ◽  
Vol 1 (1) ◽  
pp. 2-10 ◽  
Author(s):  
Harold L. Leverenz ◽  
George Tchobanoglous ◽  
Takashi Asano

As a result of population growth, urbanization, and climate change, public water supplies are becoming stressed, and the chances of tapping new water supplies for metropolitan areas are getting more difficult, if not impossible. As a consequence, existing water supplies must go further. One way to achieve this objective is by increased water reuse, particularly in supplementing municipal water supplies. Although water reuse offers many opportunities it also involves a number of problems. A significant cost for nonpotable water reuse in urban areas is associated with the need to provide separate piping and storage systems for reclaimed water. In most situations, the cost of a dual distribution system has been prohibitive and thus, has limited implementation for water reuse programs. The solution to the problem of distribution is to implement direct potable reuse (DPR) of purified water in the existing water distribution system. The purpose of this paper is to consider (a) a future in which DPR will be the norm and (b) the steps that will need to be taken to make this a reality. Following an overview, the rationale for DPR, some examples of DPR projects, technological and implementation issues, and future expectations are examined.


1992 ◽  
Vol 26 (7-8) ◽  
pp. 1565-1571 ◽  
Author(s):  
K. K. Chin ◽  
S. L. Ong

Land area in the City State of Singapore is highly urbanized. Although 48% of the total land area of 620 square kilometres is reserved for water catchment and parks, water collected is insufficient to meet its needs. It derives its water mainly from Johor, Malaysia. To conserve water, reuse and recycling of wastewaters is encouraged in both the residential and industrial sectors. The Jurong Industrial Water Work was designed to reclaim treated sewage from the Ulu Pandan Sewage Treatment Plant. It has a capacity of 45,000 cubic metres per day. Pilot scheme to use this water for toilet flushing in housing estate was tried out. The scheme although highly successful is being suspended. The demand for reclaimed water from sewage for industrial water, however, increases steadily. This paper summarises the experience gained on reclaiming sewage for industrial uses.


2013 ◽  
Vol 3 (2) ◽  
pp. 222-229 ◽  
Author(s):  
Clarissa Brocklehurst ◽  
Murtaza Malik ◽  
Kiwe Sebunya ◽  
Peter Salama

A devastating cholera epidemic swept Zimbabwe in 2008, causing over 90,000 cases, and leaving more than 4,000 dead. The epidemic raged predominantly in urban areas, and the cause could be traced to the slow deterioration of Zimbabwe's water and sewerage utilities during the economic and political crisis that had gripped the country since the late 1990s. Rapid improvement was needed if the country was to avoid another cholera outbreak. In this context, donors, development agencies and government departments joined forces to work in a unique partnership, and to implement a programme of swift improvements that went beyond emergency humanitarian aid but did not require the time or massive investment associated with full-scale urban rehabilitation. The interventions ranged from supply of water treatment chemicals and sewer rods to advocacy and policy advice. The authors analyse the factors that made the programme effective and the challenges that partners faced. The case of Zimbabwe offers valuable lessons for other countries transitioning from emergency to development, and particularly those that need to take rapid action to upgrade failing urban systems. It illustrates that there is a ‘middle path’ between short-term humanitarian aid delivered in urban areas and large-scale urban rehabilitation, which can provide timely and highly effective results.


1992 ◽  
Vol 27 (2) ◽  
pp. 221-238 ◽  
Author(s):  
W. Ripl

Abstract Densely populated urban areas, which have developed over the last century, depend heavily on centralized water supply, sewage treatment plants, and hydroelectric or thermal power generation with vast demand of cooling water. Considerable areas have been drained or sealed, and the short-circuited water cycle has been distorted. Large rivers have been converted to shipping canals with the permanent risk of accidental pollution. Technical means such as sewage treatment, air filters, emission control and lake and soil restoration measures have contributed to correct the environmental damage. However, a balance sheet for irreversible matter losses (mainly base cation charges) from the urbanized areas and the surrounding landscape into the sea shows ever-increasing trends. These losses are destabilizing the ecosystems. In this paper, management of the water cycle in urban areas, together with the coupled matter cycles, is discussed. Particular reference is given to Metropolitan Berlin, with a network of shipping canals, which move biologically treated waste, containing base cations and nutrients to the surrounding rural areas. This could create manageable productive wetlands and re-establish soil fertility. At the same time, the natural cooling system close to the urban areas will be improved by providing more areas with permanent vegetation. In addition, reduction of the present large oscillations of the groundwater table, resulting from groundwater pumping and its recharge with less polluted surface water, is contemplated. The widely used shoreline infiltration of the Havel River should then be eliminated and the severe damage of the littoral vegetation in large sections of the Havel River system be avoided.


1994 ◽  
Vol 29 (12) ◽  
pp. 279-282 ◽  
Author(s):  
C. Güldner ◽  
W. Hegemann ◽  
N. Peschen ◽  
K. Sölter

The integration of the chemical precipitation unit which would inject a lime solution into a series of mechanical-biological processes, including nitrification/denitrification, and the sludge treatment are the subject of this project. The essential target is the large-scale reconstruction of a mechanical-biological sewage treatment plant with insufficient cleaning performance in the new German states and the adjustment of the precipitation stage to the unsteady inflow of sewage. First results indicate that the pre-treatment performance could be improved by ≅ 20% and the discharge of concentrations of COD, BOD, N and P could be reduced and homogenized. In addition, experiments on hydrolysis and acidifiability of the pre-treatment sludge have been carried out on a laboratory level with the object of making sources of carbon readily available for denitrification. In the course of the experiment, inhibition of fatty acid production by calcareous primary sludge could not be detected. The characteristics of the sludge, such as draining and thickening were considerably improved by the adding of lime.


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