DOI: 10.5061/dryad.f7m0cfz18
title: Harnessing waterfleas for water reclamation: A nature-based tertiary wastewater treatment technology

description: Urbanisation, population growth, and climate change have put unprecedented
 pressure on water resources, leading to a global water crisis and the need
 for water reuse. However, water reuse is unsafe unless persistent chemical
 pollutants are removed from reclaimed water.. State-of-the-art
 technologies for the reduction of persistent chemical pollutants in
 wastewater typically involves high operational and energy costs and
 potentially generates toxic by-products (e.g., bromate from ozonation).
 Nature-base solutions are preferred to these technologies for their lower
 environmental impact. However, so far, bio-based tertiary wastewater
 treatments have been inefficient for industrial-scale applications.
 Moreover, they often demand significant financial investment and large
 infrastructure, undermining sustainability objectives. Here, we present a
 scalable, low-cost, low-carbon, and retrofittable nature-inspired solution
 that could be retrofitted into current wastewater treatment systems to
 remove persistent chemical pollutants. The technology uses the water flea
 Daphnia to non-selectively uptake and retain persistent chemical
 pollutants (pharmaceutical, pesticides and industrial chemicals). We
 showed Daphnia’s removal efficiency at laboratory scale ranging between
 50% for PFOS and 90% for diclofenac. We validate the removal efficiency of
 diclofenac at prototype scale showing sustained performance over four
 weeks in outdoor seminatural conditions. A techno-commercial analysis on
 the Daphnia-based technology suggests several technical, commercial and
 sustainability advantages over established and emerging treatments at
 comparable removal efficiency, benchmarked on available data on individual
 chemicals. Further testing of the technology is underway in open flow
 environments holding real wastewater. The technology has the potential to
 improve the quality of wastewater effluent  meeting requirements
 to produce water appropriate for reuse in irrigation, industrial
 application, and household use. By preventing persistent chemicals from
 entering waterways, this technology has the potential to maximise the
 shift to clean growth, enabling water reuse, reducing resource depletion
 and preventing environmental pollution.
description: A total of 216 exposures were completed to quantify the removal
 efficiency of four classes of chemicals-an industrial chemical (PFOS:
 70ng/L; CAS:2795-39-3), a biocide (atrazine:0.2 mg/L; CAS:1912-24-9), a
 pharmaceutical (diclofenac: 2 mg/L; (CAS:15307-79-6) and a heavy metal
 (arsenic 1 mg/L; CAS: 7784-46-5), by four genotypes of <em>Daphnia
 </em>manga: DM1900; DM1960; DM1980; and DM2015. Following an
 acclimation phase, the removal efficiency of the four genotypes was
 quantified following exposure to individual chemicals and chemical
 mixtures from wastewater. the removal efficiency was quantified for PFOS,
 diclofenac and atrazine over three days with ultraperformance liquid
 chromatography (UPLC) coupled with high-resolution mass spectrometry.
 Arsenic samples were quantified using a Nexion 300X inductively coupled
 plasma mass spectrometer (ICP-MS) (PerkinElmer, Seer Green, U.K) fitted
 with a cyclonic spray chamber. The removal efficiency of the chemicals was
 calculated as [starting concentration - final concentration / starting
 concentration] x 100. Removal efficiency variation by genotype and day was
 assessed through an ANOVA analysis using the Satterthwaite's method
 (lmerTest package in R). We assessed removal efficiency
 of other inorganics from secondary treated wastewater by
 <em>Daphnia </em>in laboratory conditions over a period of 3
 weeks. Using the HACH colorimeter, we tested removal efficiency of
 ammonia, total phosphorus and nitrogen, chemical oxygen demand (COD),
 suspended solids and pH. This quantitation was done on wastewater sourced
 from the Finham treatment plant from both aeration tanks and the secondary
 clarifiers. After collection, the wastewater was equally split in
 triplicate 20L aquaria and inoculated with <em>Daphnia </em>at
 a density of 100 individuals/L. The inorganics were quantitated twice a
 week over 3 weeks. Having identified the strains with
 the highest removal efficiency in the laboratory exposures, we tested
 removal efficiency of a population of these strains in a prototype of the
 technology in outdoor conditions for four weeks to test whether the
 removal efficiency at scale was comparable to the one measured in the
 laboratory experiments and to measure performance over time. The prototype
 was filled with borehole water spiked with diclofenac, a common
 anti-inflammatory present in wastewater. Removal efficiency was tested
 daily over a period of 4 weeks using the same approach described for
 laboratory-based experiments.
description: Excel, & RStudio.
description: # Harnessing waterfleas for water reclamation: a nature-based tertiary
 wastewater treatment technology ## Description of the data and file
 structure Abdullahi_Recovery_individual-Recovery of individual chemicals.
 Recovery of PFOS, diclofenac, atrazine and arsenic in the exposures of the
 four genotypes of Daphnia magna used in this study (Genotype ID) to
 individual chemicals. The two technical replicates (replicate) and the day
 of the experiment (Day; the experiments were conducted over 3 days) are
 shown. Control refers to the chemical control run alongside the exposures.
 Abdullahi_Removal Efficiency- Removal efficiency of individual chemicals.
 Removal efficiency of four individual chemicals (PFOS, diclofenac,
 atrazine and arsenic) quantified in spiked borehole water in
 laboratory-controlled conditions. Genotype ID (DM1900; DM1960; DM1980; and
 DM2015); replicate (rep); day of exposure (day); concentration of the
 chemical without Daphnia (Initial Concentration; IC this is the chemical
 control in Table S2); concentration of the chemical after exposure to
 Daphnia after three days (Final Concentration; FC); and removal efficiency
 (RE) calculated as [initial concentration final concentration /starting
 concentration] 100 are shown. Abdullahi_Recovery_wastewater-Recovery of
 chemicals from wastewater. Recovery of PFOS and diclofenac in the exposure
 of the four genotypes of Daphnia magna used in this study (Genotype ID) to
 wastewater. The two technical replicates (replicate) and the day of the
 experiment (Day; the experiments were conducted over 3 days) are shown.
 Control refers to the chemical control run alongside the exposures
 Abdullahi_Removal_efficiecny-Removal efficiency from wastewater. Removal
 efficiency of two chemicals (PFOS and diclofenac) from wastewater by the
 four genotypes (genotype ID) used in the study. Replicate (rep); day of
 exposure (day); concentration of the chemical without Daphnia (Initial
 Concentration; IC this is the chemical control in Table S4); concentration
 of the chemical after exposure to Daphnia after three days (Final
 Concentration; FC); and removal efficiency (RE) calculated as [initial
 concentration final concentration /starting concentration] 100 are shown.
 Abdullahi_Removal_efficiecy_prototype-Removal efficiency of diclofenac in
 the outdoor prototype. Removal efficiency of diclofenac in the outdoor
 prototype quantified in spiked borehole water with 2mg/L of diclofenac.
 Sample ID, the week and day of sampling; concentration of the chemical on
 the day of spiking (Initial Concentration; IC); concentration of the
 chemical after daily exposure to Daphnia (Final Concentration; FC); and
 removal efficiency (RE) calculated as [initial concentration final
 concentration /starting concentration] 100 are shown. Missing FC and RE
 are on the days in which the prototype was spiked with 2mg/L of
 diclofenac. Abdullahi_other_Inorganics: removal of organics and inorganics
 by Daphnia from aeration tanks and secondary clarifiers. Every 3 days and
 up to 4 weeks the following parameters were measured: Suspended Solids
 (SS), chemical oxygen demand (COD), total nitrogen (TN), total phosphorus
 (TP), ammonia and pH. Abdullahi_Arsenic - Daphnia tissue: Arsenic
 quantified in the four genotypes of Daphnia across three days. Genotype ID
 (DM1900; DM1960; DM1980; and DM2015); replicate; day of exposure;
 treatment (Arsenic versus control) and concentration of Arsenic retrieved
 in the Daphnia tissue (ng/L) are shown. Replicate ("1, 2, 3")-
 Technical replicates for both chemical controls run along side the
 exposures across