Improved Wastewater Recycling Technologies — Feasible Solutions to Future Scarcity

Published on 27 Jun, 2017

Over 663 million people across the world don’t have access to clean drinking water.  We’ll have 40% less potable water than what we’ll need in 2030. With growing populations relying on shrinking freshwater sources, it’s imperative that we, as a species, get serious about sustainability and prudent use of our dwindling water reserves.

While we’ll need to do whatever we can to stretch existing sources, recycling the copious amounts of wastewater we’re producing right now could go a long way toward addressing our growing demand for clean water. 

The emergence of viable and scalable technologies that can do just that has made it a serious possibility, perhaps even within our lifetime.

Several countries across the world are doing more than just dabbling in wastewater recycling right now. Singapore, Israel, Spain, a few Scandinavian countries, as well as the United States recycle a significant portion of the wastewater they generate. Recycled wastewater is generally disposed of in larger bodies of water (seas, rivers, ponds, etc.) or used for gardening, cleaning, as well as for industrial applications.

Israel is a world leader in wastewater treatment; around 85% of their wastewater is treated and recycled for reuse in sectors like agriculture.

Singapore, Australia and the US (especially California) generate significant amounts of portable water through wastewater recycling.

Still, very little (probably less than 2%) of recycled wastewater is used as potable water.


Is Recycled Water Safe to Drink?

While a scarcity of potable water sources across the globe is certainly spurring efforts, recycling initiatives in play right now aren’t able to treat wastewater to an extent that’s fit for direct human consumption.

Low-cost water treatment technologies have several inefficiencies that need to be addressed, while advanced (more successful) technologies aren’t viable right now due to the high upfront investment and operational costs associated with them.

Current research is trying to address these issues by modifying existing wastewater technologies to make them more efficient. Tweaks to existing wastewater treatment technologies include advanced anaerobic digesters, biofilm sheets and dry cycle biofilms, multistage aerated biofilms, as well as Membrane Aerated Biofilm Reactors (MABR).

While they’ve been reasonably successful, the hunt is on for new and improved technologies that could supersede existing processes that are still somewhat inefficient.


Future Technologies for Wastewater Recycling

Besides modifications to existing technologies, a series of new wastewater technologies have been developed as viable alternatives to older, less feasible options.

These new wastewater recycling technologies aren’t just improving the quality of recycled water significantly; they’re also doing it at lower costs.

New Technologies  
       Description
        Benefit
Bio-electrochemical Systems (BES)       
Organic matter in water is broken down into electrochemical cells through electrically active bacteria.

This system is still in trial phase.
Electrochemical cells produced in the process can be used to produce electricity, hydrogen and other high-value chemicals.

Forward Osmosis (FO)
In the FO process, water molecules from wastewater pass through FO membrane to the other side with a more concentrated solution. The process does not require energy input.
Concentrated waste can be processed to yield useful byproducts.

Nanoparticle Water Filtration System
Employing low-cost nanoparticle technology, a nano-silica-silver composite material is used for passive filtration, serving as an effective antifouling, antimicrobial, and chemical adsorptive material.
A passive process that does not need any chemicals, high temperature, pressure, or electricity, it’s one of the most cost-effective treatment processes available.

N-E-W Tech
The technology integrates hydrous ferric oxide reactive filtration in a moving bed sand filter, with added ozone and between 1 to 10 grams per gallon of functionalized biochar.

The technology is still in a pilot trial phase.
Efficiently recovers nutrients from wastewater and removes antibiotic-resistant bacteria and antibiotic resistance genes.

Nanofiltration (NF) Hollow Fiber Membrane
Hollow fiber membranes are used for water filtration, with the pressure required for effective filtration much lower than other systems.

The technology is still in an initial commercialization phase.
Does not require additional processes such as ultrafiltration and reverse osmosis for complete treatment, resulting in overall treatment costs far lower than similar processes.


Nereda
The Nereda process purifies water through the unique features of an aerobic granular biomass.
Needs significantly lower initial investments, and saves around 25 to 35% in total energy costs.

Besides reducing initial setup costs, upcoming wastewater technologies are focusing on lowering their operational costs by lowering their energy consumption.

There’s also growing interest in generating electricity from sludge (waste materials generated during the treatment process) in order to reduce operational cost further, besides reducing the amount of leftover (unusable) sludge byproducts.

Most new and advanced wastewater treatment and recycling technologies are still in their trial phase, and could take another four to five years before they’re anywhere close to being commercialized.


Adoption of New Wastewater Treatment Technologies in the Future

The adoption of advanced wastewater treatment and recycling technologies is limited to a few countries, principally due to limited government initiatives supporting wastewater treatment and recycling.

While plenty of countries across the world have policies in place that focus on the quality of discharged effluents (wastewater) in order to protect the environment, few, if any,  have one in place governing the reuse of recycled wastewater.

Adoption of more holistic wastewater treatment policies and technologies is expected to increase significantly in the future, driven by growing environmental awareness, improvement in technologies, as well as policies and regulations focused on wastewater reuse.

An inevitable rise in the demand for potable water as well as dwindling fresh water resources will also spur aggressive adoption of such technologies in the long run. Developing countries are likely to record double-digit growth in the adoption of wastewater treatment technologies over the next five years, driven predominantly by a growing scarcity of fresh water.

With operational costs sufficiently minimized, the commercialization and mass adoption of advanced wastewater treatment technologies such as Bio-electrochemical Systems (BES), nanoparticle water filtration systems, and Nanofiltration (NF) Hollow Fiber Membrane technology are likely to pick up in the future. 



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