Decentralised or centralised wastewater treatment in Asia’s megacities – understanding regulatory and social barriers
Effective decentralised wastewater treatment may begin with innovative technology, but it doesn’t end there. Successful implementation means overcoming other hurdles, as well. In an INNOQUA-hosted workshop at the 2019 IWA Water and Development Congress & Exhibition in Colombo, Sri Lanka, more than 50 international experts engaged in a lively discussion on regulatory and social barriers in Asia’s megacities.
A key barrier to decentralised systems is previous experience and the on-going perception that such systems do not work ‘as well as’ centralised systems. Poor experiences in the past may be due to a combination of inappropriate solutions and inadequate training or ‘ownership’ of the implemented solution. Since smaller systems are normally managed by individuals, community groups or small companies, our workshop participants agreed that robust solutions need to be combined with appropriate training. Examples from Europe show that training is compulsory where householders or communities adopt decentralised systems – local or central government / regulators can oversee this training, providing assurance that risks to human or environmental health are properly managed.
The need for adequate treatment was also highlighted in discussion around the lack of standards for decentralised systems. Although construction standards and performance declarations are in place for these systems in Europe (such as standard EN12566), they do not set limits on discharge quality for treated wastewater. Elsewhere, the recently published ISO30500 may become the default for non-sewered sanitation systems, since it combines construction standards and discharge quality limits.
The language around non-sewered or decentralised systems was also highlighted as a potential barrier, as different terms are used to mean different things by different people. Several participants suggested ‘on site sanitation’ as most applicable in our case.
Social acceptance was also identified as a barrier. There is still a prevailing NIMBY mentality (Not In My Back Yard) when it comes to selecting locations for decentralised systems in communities, said Ganapathy Ganeshan, Director of Bangalore-based CDD Society, in reference to his long experience.
At the IWA workshop, there was overall good support for decentralised solutions, and even questions on how centralised systems could be de-centralised! Interest in nature-based approaches was also high, with some intriguing examples of vertical wetlands that could (in future) integrate urban landscaping and wastewater treatment on very small footprints. The discussions begun during the workshop continued at our booth, where we registered an overwhelming interest in our innovative technology, especially from local experts in Sri Lanka.
