Treated Greywater Reuse for Hydroponic Lettuce Production in a Green Wall System: Quantitative Health Risk Assessment

Eregno, Fasil Ejigu; Moges, Melesse Eshetu; Heistad, Arve

doi:10.3390/w9070454

Cited by 40 publications

(26 citation statements)

References 37 publications

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“…Therefore we suggest that digested brewery wastewater has the potential to provide plants with the required nutrients to obtain high yields, at least with certain crops. This is consistent with a similar study that grew tomato, Solanum lycopersicum, using digested brewery wastewater [12] and other research that successfully used nutrient solutions partially or totally made with wastewater or organic waste for soilless production [10,[39][40][41][42].…”

Section: Discussionsupporting

confidence: 91%

Anaerobically-Digested Brewery Wastewater as a Nutrient Solution for Substrate-Based Food Production

et al. 2019

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Urban agriculture, due to its location, can play a key role in recycling urban waste streams, promoting nutrient recycling, and increasing sustainability of food systems. This research investigated the integration of brewery wastewater treatment through anaerobic digestion with substrate-based soilless agriculture. An experiment was conducted to study the performance of three different crops (mustard greens (Brassica juncea), basil (Ocimum basilicum), and lettuce (Lactuca sativa) grown with digested and raw brewery wastewater as fertilizer treatments. Mustard greens and lettuce grown in digested wastewater produced similar yields as the inorganic fertilizer control treatment, while basil had slightly lower yields. In all cases, crops in the digested wastewater treatments produced higher yields than raw wastewater or the no fertilizer control, indicating that nutrients in the brewery wastewater can be recovered for food production and diverted from typical urban waste treatment facilities.

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Section: Discussionsupporting

confidence: 91%

Anaerobically-Digested Brewery Wastewater as a Nutrient Solution for Substrate-Based Food Production

et al. 2019

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“…The concentration of arsenic in lettuce from Source Waters 2, 3 and 4, however, were above the maximum allowable level. A study by Eregno et al [12] involved growing lettuce hydroponically with treated greywater with added human urine and found that lettuce leaves across all treatments were below estimated Health Risk Index and Target Hazard Quotient values and therefore implied to have low health risk for consumption. However, Eregno et al [12] did report that the HRI for As and THQ for As and Cr were relatively higher than the other metal(loid)s tested, which is similar to our findings for arsenic.…”

Section: Resultsmentioning

confidence: 99%

“…Treatment of wastewater has been shown to be possible over 7 days with a Pistia stratiotes phytofiltration lagoon, with an average biomass production of 5.8 g of dry weight per square meter per day [11]. Lettuce (Lactuca sativa) can successfully be produced with treated greywater without posing a substantial health risk for pathogens or metal(loid)s, while also providing a 5.1 log10 reduction of E. coli in the final effluent [12]. Hydroponic barley (Hordeum vulgare) production using wastewater has been investigated [13] and found a decrease in yields of 47% and 17% for conventional activated sludge and lagoon system water compared to half-strength Hoagland Solution, concluding that further fertilization with wastewater would be necessary and that metal(loid) concentrations in plant tissue increased, but did not exceed, toxic levels.…”

Section: Introductionmentioning

confidence: 99%

Hydroponic Lettuce Production Using Treated Post-Hydrothermal Liquefaction Wastewater (PHW)

et al. 2019

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Post-hydrothermal liquefaction wastewater (PHW) is a byproduct of the hydrothermal liquefaction (HTL) process. Previous research indicates that PHW is free of pathogens and contains nutrients needed for crop growth, but may contain metal(loid)s. This study evaluated the ability of differentially treated PHW for effective and safe hydroponic lettuce production. Water containing only hydroponic fertilizer (Source Water 1) had the highest total dry yield of all five treatments; 3.1 times higher than Source Water 2 (diluted PHW with sand filtration), 3.5 times higher than Source Water 3 (diluted PHW with sand + carbon filtration), 2.6 times higher than Source Water 4 (diluted and nitrified PHW with sand filtration), and 1.3 times higher than Source Water 5 (diluted PHW supplemented with hydroponic fertilizer). Findings also indicated that while PHW was below the US Department of Agriculture Foreign Agriculture Service maximum levels for cadmium, lead, and mercury in food, the concentration of arsenic was 1.6, 2.4, and 2.0 times higher than the maximum level for Source Waters 2, 3, and 4, respectively. There was no detectable E. coli or fecal coliforms in any of the treated PHW. While nitrogen was present in the raw PHW, only 0.03% was NO3-N and NO2-N. Diluted PHW supplemented with hydroponic fertilizer had lower lettuce yield than hydroponic fertilizer alone, indicating a potential non-nutrient inhibition of plant growth by PHW. Therefore, this research demonstrates that treated PHW does not pose a biological contamination risk for lettuce, but may entail levels of arsenic in edible leaf tissues that are in excess of safe levels. Additional treatment of PHW can benefit crop production by allowing crop utilization of a greater fraction of total nitrogen in the raw PHW.

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“…In order to counteract this, disequilibrium atmospheric CO 2 dissolves in water through the liquid-air interface until equilibrium is reached, Eq. (7). Carbonic acid, Eq.…”

Section: Lime Chemical Precipitation (Lcp)mentioning

confidence: 99%

Manual Treatment of Urban Wastewater by Chemical Precipitation for Production of Hydroponic Nutrient Solutions

Correia¹,

Regato²,

Almeida³

et al. 2020

J. Ecol. Eng.

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An urban wastewater treatment system was developed in Portugal for posterior in situ feasibility testing at the Bulgarian Antarctic Base, using its domestic wastewater. The aim of this system was to develop a low cost, integrated approach for wastewater treatment and production of nutrient solutions (NS) for hydroponic cultivation of lettuce (Lactuca sativa var. crispa) in Antarctic stations, or any other place where the lack of resources and logistical hardships make the wastewater treatment and reuse impractical. The wastewater treatment system consisted in manual agitation lime chemical precipitation (LCPm) and effluent natural neutralization (NN) by atmospheric CO 2 carbonation reactions (with and without air injection). The resulting effluent/NS had macronutrient values (nitrogen and phosphorous) for the hydroponic cultivation of lettuce below the values of commercial NS and a high pH (pH ≈ 8).The treatment achieved a total coliform removal rate of 100%. Before the LCPm treatment system development, several lime-based reagents were tested under different reaction pH and using mechanical agitation, to access their organic matter removal efficiency, as chemical oxygen demand (COD). The best COD removal results obtained were: commercial Ca(OH) 2 (pH 11.5 -89%), reagent grade Ca(OH) 2 (pH 11.5 -79%) and CaO (pH 12.0 -64%).

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Treated Greywater Reuse for Hydroponic Lettuce Production in a Green Wall System: Quantitative Health Risk Assessment

Cited by 40 publications

References 37 publications

Anaerobically-Digested Brewery Wastewater as a Nutrient Solution for Substrate-Based Food Production

Anaerobically-Digested Brewery Wastewater as a Nutrient Solution for Substrate-Based Food Production

Hydroponic Lettuce Production Using Treated Post-Hydrothermal Liquefaction Wastewater (PHW)

Manual Treatment of Urban Wastewater by Chemical Precipitation for Production of Hydroponic Nutrient Solutions

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