Amit Gross | Ben Gurion University of the Negev (original) (raw)

Papers by Amit Gross

Science of The Total Environment, Mar 1, 2020

Potential bias associated with fish sampling in RAS was estimated. • Fish biomass sampling in RAS... more Potential bias associated with fish sampling in RAS was estimated. • Fish biomass sampling in RAS isn't standardized and deviates from the expected mean. • Biased fish biomass assessment has negative economic and environmental impacts. • Establishment of species-specific biomass correction tables may mitigate the bias.

Journal of Cleaner Production, Jul 1, 2019

Use of recirculating aquaculture systems (RAS) to grow fish is on the rise. Fish feed typically c... more Use of recirculating aquaculture systems (RAS) to grow fish is on the rise. Fish feed typically contains 25-60% protein and is the only significant input in RAS. Fish recover 20-30% of the applied feed as biomass, and the unassimilated nitrogen is released into the water, mainly as ammonia, which is toxic to fish. Nitrification is the most common treatment practice, converting ammonia to the less toxic nitrate, and nitrogen removal is achieved by either water exchange or denitrification. The aim of this study was to develop and test a novel approach to remove nitrogen based on a microaerophilic assimilation side-reactor. In the suggested system, fish solid waste and dissolved nitrogen are assimilated into protein-rich microbial biomass, which has the potential to partially offset fish feed input. Initially, a theoretical model based on the system's nitrogen mass balance was established. Then, an intensive pilot-scale RAS was constructed, growing ~50 kg fish/m 3. The system consisted of a fish tank, solids filter, and microaerophilic assimilation reactor based on activated sludge treatment. Intrinsic solid waste and wheat-flour waste were used as carbon source. After a trial run of about 2.5 months, the RAS was tested for 101 days. Average total ammonia nitrogen, nitrite, and nitrate removal were 89.1, 69.4 and 100%, respectively. Of the introduced solids, over 82% were lost as carbon dioxide by respiration, 11.7% were recovered as microbial biomass and 6.5% as fish biomass, and only 0.6% remained in the water. Biomass organic content was similar to aquafeed and nitrogen content was equivalent to 40% crude protein. Daily energy demand for the system's designed capacity of 80 kg/m 3 would result in a low energy consumption of 7.72 kW•h/kg fish. Overall, a novel concept for sustainable production in intensive aquaculture was developed and successfully demonstrated in a pilot-scale RAS.

Science of The Total Environment, Jun 1, 2020

Journal of Environmental Horticulture, 2003

Direct nursery runoff (runoff), wetland treated recycled nursery runoff (recycled), and a municip... more Direct nursery runoff (runoff), wetland treated recycled nursery runoff (recycled), and a municipal water source (tap) with and without elevated salt (NaCl targeted injection to 3.0 dS·m−1) levels were tested as potential drip irrigation sources for production of in-ground cut flower crops and landscape bedding plants. Two species of cut flowers, Helianthus annuus L. ‘Mammoth’ (sunflower) and Gladiolus hortulanus L. ‘Tout A Toi’ (gladiolus), and two bedding plants, Catharanthus roseus G. Don ‘Pacifica Red’ (vinca) and Zinnia elegans N.J. von Jacquin ‘Lilliput Mixed Colors’ (zinnia), were established in trial beds irrigated with the four water treatments during the summer of 2001 as a warm season experiment. A second experiment was conducted from November 2001 to May 2002 to investigate growth and flowering responses of two species of cut flower crops [Consolida ambigua (L.) P Ball & V Heywood (larkspur) and Narcissus tazetta L. ‘Galilea’ (paperwhite narcissus)] and two bedding plant...

We describe a novel solar hydrothermal reactor (SHR) under development by Ben Gurion University (... more We describe a novel solar hydrothermal reactor (SHR) under development by Ben Gurion University (BGU) and the European Organization for Nuclear Research CERN. We describe in broad terms the several novel aspects of the device and, by extension, of the niche it occupies: in particular, enabling direct off-grid conversion of a range of organic feedstocks to sterile useable (solid, liquid) fuels, nutrients, products using only solar energy and water. We then provide a brief description of the high temperature high efficiency panels that provide process heat to the hydrothermal reactor, and review the basics of hydrothermal processes and conversion taking place in this. We conclude with a description of a simulation of the pilot system that will begin operation later this year.

Applied Energy, Mar 1, 2018

• 250°C hydrochar has combustion behavior similar to sub-bituminous coal. • HTC results in 24% mo... more • 250°C hydrochar has combustion behavior similar to sub-bituminous coal. • HTC results in 24% more net energy generated than slow pyrolysis. • Pollutant emissions decreased as HTC production temperature increased. • Hydrochar from poultry litter can replace 10% of electricity generated by coal.

Global Food Security, Sep 1, 2023

Bioresource Technology Reports, Dec 1, 2022

Science of The Total Environment, Aug 1, 2022

Aquaponics is gaining renewed interest to enhance food security. This study aimed to investigate ... more Aquaponics is gaining renewed interest to enhance food security. This study aimed to investigate the performance of a novel off-grid aquaponics system with near-zero water and waste discharge, focusing on the carbon cycle and energy recovery that was achieved by the addition of onsite anaerobic treatment of the solid waste streams. Following a stabilization stage, the system was closely monitored for four months. Fish tank water was recirculated via solid and nitrification reactors, from which 66% was recycled to the fish tank directly and 34% indirectly through the hydroponically grown plants. Fish solid waste was anaerobically treated, energy was recovered, and the nutrient-rich supernatant was recycled to the plants to enhance production. Plant waste was also digested anaerobically for further recovery of energy and nutrients. Fish stocking density was 15.3 and over time reached approximately 40 kg/m3 where it was maintained. Feed (45% protein content) was applied daily at 2% of body weight. Typical fish performance was observed with a survival rate >97% and feed conversion ratio of 1.33. Lettuce production was up to 5.65 kg/m2, significantly higher than previous reports, largely because of high nutrients reuse efficiency from the anaerobic supernatant that contained 130 and 34 mg/L N and P, respectively. Of the feed carbon, 24.5% was taken up by fish biomass. Fish solid wastes contained 38.2% carbon, of which 91.9% was recovered as biogas (74.5% CH4). Biogas production was 0.84 m3/kg for fish sludge and 0.67 m3/kg for dry plant material. CO2 sequestration was 1.4 higher than the feed carbon, which reduced the system's carbon footprint by 64%. This study is the first to demonstrate highly efficient fish and plant production with near-zero water and waste discharge and with energy recovery that can potentially supply the system's energy demand.

Water Research, May 1, 2022

Waters contaminated with micropollutants are of environmental and public health concern globally.... more Waters contaminated with micropollutants are of environmental and public health concern globally. Stormwater is a significant source of anthropogenic micropollutants to receiving waters. Hence, sustainable stormwater remediation is needed to reduce contamination of waterways. Yet designing sustainable bioremediation solutions, including those targeted to remove micropollutants, is a major scientific challenge. This study aimed to adapt the design of stormwater biofiltration systems, to improve the removal of micropollutants and understand the role of the micropollutant-degrading bacteria in this bioremediation process. We investigated the atrazine removal performance of a prototype biofiltration system, in which the filter media was supplemented with Granulated Activated Carbon (GAC). The prototype biofiltration system completely removed atrazine to below detectable limits, significantly exceeding the GAC's adsorption capacity alone, suggesting other biological processes were present. We showed that atrazine degradation capacity, measured by the kinetics of the trzN gene abundance, was accelerated in the prototype system compared to the standard system (which had no added GAC; 0.8 vs. 0.37 week-1, respectively). Notably, this high level of atrazine removal did not come at the expense of the removal performance of other typical stormwater macropollutants (e.g., nutrients, suspended solids). The prototype biofiltration system showed a proof-of-concept of sustaining microbial remediation of a model micropollutant alongside stormwater macropollutants, which could be used to reduce impacts on receiving waterways and protect our ecosystems and human health.

Aquaculture International, Oct 1, 2020

Aquaponics plant waste, such as the non-edible parts of many vegetable crops, can be a source of ... more Aquaponics plant waste, such as the non-edible parts of many vegetable crops, can be a source of environmental pollution, while its treatment might cause an economic burden. Therefore, efficient use of this waste would be advantageous. This study aimed at investigating anaerobic digestion of aquqponic lettuce waste to recover nutrients and energy through biogas production. A 700 L commercial anaerobic system was used to treat lettuce wastes from an aquaponic farming system that operated under desert climate and steady-state conditions. Digestion efficiency of the lettuce waste was 90.1% by weight, producing a maximum biogas volume of 0.65 m 3 /kg dry weight per day. Biogas composition contained on average 59.2% methane and 38.9% CO 2 with only negligible hydrogen sulfide content. Moreover, the supernatant from the anaerobic digester contained elevated nutrient concentrations (N, P, K, Ca, and Fe), which can potentially be used onsite as a fertilizer. Onsite anaerobic digestion of lettuce plant waste from the aquaponic system under summer desert conditions is demonstrated for the first time to efficiently reduce pollution burden, produce high-quality biogas, and recover nutrients.

Science of The Total Environment

Bioresource Technology Reports

On-site in-vessel composting of sewage sludge is considered to be applied in Israel for periphera... more On-site in-vessel composting of sewage sludge is considered to be applied in Israel for peripheral wastewater treatment plants (WWTPs). Based on lab-scale simulations using municipal sewage sludge and green waste, this study identifies a prospective range of values related to biomass stabilization during short-term processing. Within two weeks, 26-30% of the initial organic carbon was released as CO 2 , potential heat formation was decreased by 73-82%, and odor emissions by 87-99.5%. This reduction was mainly associated with co-decrease of NH 3 , dimethyl disulfide, and dimethyl trisulfide. Phytotoxicity was reduced by 28-52% whereas some residual toxicity might be attributed to non-biodegradable inorganic compounds. Stabilization rates observed in flexibly controlled lab-scale simulations can represent closed and efficiently aerated large-scale industrial systems. These prospective ranges of stabilization parameters are critical for deciding on the necessity of a curing stage for on-site enclosed installations in WWTPs.

Water Research, 2022

Science of The Total Environment, 2021

A near-zero waste treatment system for food processing wastewater was developed and studied. The ... more A near-zero waste treatment system for food processing wastewater was developed and studied. The wastewater was treated using an anaerobic membrane bioreactor (AnMBR), polished using an outdoor photobioreactor for microalgae cultivation (three species were studied), and excess sludge was treated using hydrothermal carbonization. The study was conducted under arid climate conditions for one year (four seasons). The AnMBR reduced the total organic carbon by 97%, which was mostly recovered as methane (~57%) and hydrochar (~4%). Microalgal biomass productivity in the AnMBR effluent ranged from 0.25 to 0.8 g·L-1·day-1. Nitrogen (N) and phosphorous (P) uptake varied seasonally, from 18 to 45 mg·L-1·day-1 and up to 5 mg·L-1·day-1, respectively. N and P mass balance analysis demonstrated that the process was highly efficient in the recovery of nitrogen (~77%), and phosphorus (~91%). The performance of the microalgal culture changed among seasons because of climatic variation, as a result of variation in the wastewater chemistry, and possibly due to differences among the microalgal species. Effluent standards for irrigation use were met throughout the year and were achieved within two days in summer and 4.5 days in winter. Overall, the study demonstrated a near-zero waste discharge system capable of producing high-quality effluent, achieving nutrient and carbon recovery into microalgae biomass, and energy production as biogas and hydrochar.

Journal of Environmental Management, 2020

The conversion of poultry litter to hydrochar has been proposed for stabilization of the soils an... more The conversion of poultry litter to hydrochar has been proposed for stabilization of the soils and to eliminate pathogens. Still, research on the hydrochar's effect on soil properties as a function of production temperature, and its direct use with plants is limited in general and even less so on poultry litter. We characterized poultry litter hydrochar as an amendment for sandy soils in terms of changes to the soil's bulk density, porosity, waterretention capacity, and fertility. Soil bulk density, porosity and water-retention capacity were determined in a pneumatic tension plate system for sand with hydrochar-amendment rates of 0.5, 1 and 2%, and hydrocharproduction temperature of 180, 220, and 250 � C. Soil fertility was assessed by growing lettuce seedlings in a randomized block design planter experiment, consisting of 16 blocks that were sampled every 10 days. The addition of poultry litter hydrochar resulted in decreased soil bulk density. Soil porosity increased with hydrochar generated at a temperature of up to 220 � C, and decreased with hydrochar generated at 250 � C. Soil water content increased as compared to unamended sand, but decreased with increasing hydrochar-production temperature, probably due to increasing hydrophobicity of the poultry litter hydrochar. The addition of hydrochar at concentrations of 0.5 and 1% resulted in improved plant growth despite an initial delay. While increased soil moisture due to increased soil water-retention capacity was confirmed, it did not seem to be responsible for the improved plant growth. It was also demonstrated for the first time that hydrochar decreases nitrate leaching from soils. Therefore, poultry litter-derived hydrochar seems to be an adequate amendment for sandy soils.

Aquaculture International, 2020

Applied Energy, 2018