Rethinking water management: From centralised to decentralised water supplyand sanitation models

Abstract

Since the second half of the 19 th Century, centralised water and sanitation systems have been expanding all over the world. However, the limitations of this model are becoming increasingly obvious and, in recent times, a renewed interest for decentralised approaches is emerging owing to the capacity of decentralised systems to enhance water security and minimise environmental degradation. The decentralised alternatives explored in this paper include the use of rainwater harvesting and greywater reuse at the household level. This paper analyses the main distinctive features of decentralised water supply and sanitation systems and the main requirements to achieve a successful transition to decentralised water management. Key words: decentralised water management; rainwater harvesting; greywater reuse; urban model. Resum. Repensant la gestió de l'aigua: D'un model centralitzat a un model descentralitzat de subministrament d'aigua i sanejamentDes de la segona meitat del segle xix, els sistemes centralitzats d'aigua i sanejament s'han anat expandint arreu del món. No obstant això, les limitacions d'aquest model són cada vegada més evidents i per això, en els últims anys, ha començat a créixer un interès renovat pel model descentralitzat de subministrament d'aigua i sanejament, ja que aquests darrers sistemes permeten augmentar la seguretat hídrica i minimitzar la degradació ambiental. Aquest article analitza principalment dos sistemes descentralitzats que poden ser instal·lats a nivell domèstic: els sistemes de captació d'aigües pluvials i els sistemes de reutilització d'aigües grises. L'objectiu principal d'aquest article és analitzar les característiques distintives més importants dels sistemes descentralitzats i els requeriments necessaris per assolir una transició amb èxit cap a un model descentralitzat de gestió de l'aigua. Paraules clau: gestió de l'aigua; models alternatius; captació d'aigües pluvials; reutilització d'aigües grises; model urbà. Resumen. Repensando la gestión del agua: De un modelo centralizado a un modelo descentralizado de suministro de agua y saneamientoDesde la segunda mitad del siglo xix, los sistemas centralizados de agua y saneamiento se han ido expandiendo por todo el mundo. No obstante, las limitaciones de estos sis-

Comparison of Trihalomethane Formation Using Chlorine-Based Disinfectants Within a Model System; Applications Within Point-of-Use Drinking Water Treatment

“…Chlorine is the most widely used disinfectant in drinking water treatment due to its availability, low cost, and broad spectrum antimicrobial efficacy (Rodriguez and Serodes, 2001;Farghaly et al, 2013;Kumari and Gupta, 2015). Decentralized point-of-use (POU) drinking water treatment systems typically utilize alternative disinfectant solutions (Mbilinyi et al, 2005;Peter-Varbanets et al, 2009;Domènech, 2011;Attisani, 2016;Carratalà et al, 2016;Pooi and Ng, 2018) or chlorine release tablets (Jain et al, 2010;Werner et al, 2016), rather than conventional chlorination solutions (i.e., NaOCl) for the production of biologically safe water. Alternatives to conventional chlorination are adopted due to quicker disinfection times, ease of transport and storage (Clasen and Edmondson, 2006;Jain et al, 2010).…”

Performance assessment of water reuse strategies using integrated framework of urban water metabolism and water-energy-pollution nexus

“…On the other hand, decentralised water reuse is gaining more attention in cities for its modular design that is implementable near the source of generation such as households, high-rise buildings, or parts of a city in response to demand (Novotny 2013;Bieker et al 2010). Wastewater in decentralised reuse strategies can generally be divided into greywater (effluent from the shower, washing machine, hand basin, dishwasher and kitchen) and black water (urine and faeces; Larse et al 2016;Friedler et al 2013;Domènech 2011). Existing reuse guidelines recommend effluent concentrations of biochemical oxygen demand (BOD) < 30 mg/L for use in urban irrigation or toilet flushing, which require treatments up to tertiary level (EPA 2012).…”

Making Rainwater Harvesting a Key Solution for Water Management: The Universality of the Kilimanjaro Concept

“…Drinking water supply has two main challenging aspects: water quantity and water quality. These two aspects have shaped the current paradigm of water management, including drinking water supply since the 1850s [2,14,15]. For any considered population (e.g., rural or urban communities), there are three predominant scenarios pertaining to drinking water provision: (i) clean water sources are locally available to quantitatively cover the needs, (ii) available water is polluted and should be treated (including blended) before supply, and (iii) drinking water is introduced from distant locations (e.g.…”

“…In non-inhabited areas, rainwater management (e.g., harvesting, infiltration, and storage) can also be universally adopted as a counter-measure against climate change. In the developed world, there are highly integrated water management systems encompassing millions of kilometers of pipes to achieve the following: (i) deliver drinking water to users at homes or in the industry, and (ii) transport wastewater away from human settlements to wastewater treatment plants [2,14,15,24,25,[34][35][36]. The present communication presents a modification of this infrastructure to cope with changing anthropogenic pollution inputs and impacts of climate change on global water supply.…”