Earth Today | ‘Wastewater too valuable to overlook’

FROM coping with water stress in an increasingly warmer climate to the promotion of agricultural sustainability, wastewater is too valuable a resource for the Caribbean to shy away from exploiting.

This is according to Chris Corbin, programme officer for assessment and management of environmental pollution/communication education, training and awareness with United Nations (UN) Environment.

“We need to consider wastewater as part of an integrated and holistic approach to water resources management and recognise that wastewater contains over 99% water. Initial focus should be on reuse of grey water (i.e. from kitchen, laundries) for reuse in irrigation, aquifer recharge, etc.,” he said.

“The reuse of sewage effluent requires much higher levels of treatment to be considered for reuse, and where such treatment is provided and from testing, we can ensure that there are no human health risk (and) it becomes a tremendous resource. Take, for example, Soapberry. Here the challenge is not whether or not it can be used but overcoming our own cultural resistance to reusing such treated wastewater,” he added.

A July 8 article from phys.org looks at the study titled ‘Resource recovery from sanitation to enhance ecosystem services’ by a team of researchers from the University of Illinois. That study, the artice said, “describes 17 potential ecosystem services made available from the nutrients, water and organic material recovered from sanitation systems serving human populations”.

“These include water purification, nutrient recycling, food provisioning, and climate regulation,” it added.

Another study by the research team developed a model “to clarify what parts of the world may benefit most from recirculation of human-waste-derived nitrogen, potassium and phosphorous from cities and back into farm fields”, according to a 2018 article, also published by phys.org.

NUTRIENT CYCLE

“We grow our crops in the field, apply nutrient-rich fertilisers, eat the crops, excrete all of the nitrogen, phosphorus and potassium, and then those nutrients end up at the wastewater treatment plant,” the article quotes study co-author Jeremy Guest as saying.

“It is a very linear, one-directional flow of resources. Engineering a more circular nutrient cycle would create opportunities that could benefit the environment, economy and agriculture,” he added.

These benefits are possible for Jamaica and the wider Caribbean. Corbin suggests a phased approach to accessing those benefits, in line with lessons learnt from the Caribbean Regional Fund for Wastewater Management (CReW) project that was funded by the Global Environment Facility.

That project was designed against the background of the degradation of the region’s marine environment through the discharge of untreated wastewater and in islands with a high dependence on natural marine resources. It looked, among other things, at investment and innovative financing and reforms for wastewater management, in addition to communication and outreach.

“Start with low-hanging fruit – grey water and fully treated sewage effluent. Support with public awareness and educational programmes to ensure no risk to human health. Present as integrated solution. All water is being recycled in nature so using treated wastewater is not such a novel idea,” advised Corbin.

Also critical, he said, is engaging various sectors, together with the general public.

“Tourism, agriculture, manufacturing have opportunities to reuse wastewater, including industrial water for cooling etc.,” the UN Environment officer noted.

At the same time, he recommends “less focus on large centralised and expensive treatment systems”.

“We need to consider more decentralised nature-based solutions that are less capital intensive but can offer similar levels of treatment,” Corbin maintained, adding that education is also vital since “we have to break some very old perceptions and thoughts about reusing wastewater. But we need to start small – greywater and then blackwater (raw sewage)”.

“Linking to other types of investments and projects (is also important). Provision of potable water and effective treatment of wastewater must be seen as an integral part of the national development agenda, achievement of Vision 2030 and the sustainable development goals,” Corbin said further.

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