Yoram Avnimelech

Yoram Avnimelech
Technion - Israel Institute of Technology | technion · Faculty of Civil and Environmental Engineering

Professor (Ameritus)

About

146
Publications
476,549
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Introduction
I worked for a few years on the development of the Biofloc Technology (BFT), wrote a manual on this system (3 editions, almost all sold out). I gave a number of courses on biofloc Technology (India, Mexico, Brazil, Thailand, Indonesia, Korea, China, Belgium, Colombia and more). Presently, due to the corona virus and stoppage of travel, I consult and guide using electronic media. As a vital part pf BFT, I developed new aeration systems, energy efficient and such that help sludge control.

Publications

Publications (146)
Article
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Global climate change threatens to lead to further sequences of drought in the already arid and semi-arid regions of the world and threatens the well-being and livelihoods of hundreds of millions of people living in these regions. We cannot heal global climate change within the near future but we can and should use all possible means to minimize th...
Article
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Municipal solid waste compost has been widely utilized in Israel in the production of field crops and reclamation of saline soils. This paper reviews laboratory and field studies defining the conditions under which an added compost improves the physical properties of soils and increases yields of crops. Specific attention is given to how applicatio...
Article
Inorganic nitrogen dynamics in a sequencing batch reactor (SBR) using biofloc technology (BFT) to treat suspended solids (SS) in a recirculating aquaculture system (RAS) stocking jade perch (Scortum barcoo) were explored in the current study. One group was dosed with glucose (SBR-glu) as an organic carbon source, and the other group had no added ca...
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Compost was prepared from the organic fraction of the municipal solid waste stream, using a windrow process. Stability was defined using rather simple tests. The pH was acidic at the beginning and stabilized near a neutral range. Electrical conductivity (EC) dropped and stabilized near a value of approximately 50 percent of the initial reading. The...
Article
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A stable compost is needed in plant growth media. However, when compost is land applied, its effect is through the initiation and acceleration of microbial process leading to the production of soil stabilizing agents. It was proposed that there is an optimum degree of maturity of compost used for land application, a degree characterized by the redu...
Article
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Temperature and oxygen profiles evolution in windrows were monitored in windrows located at a commercial composting plant. Controlled turning of the windrows was executed using a turning machine. Measurements were made from the onset of turning, when temperature and oxygen were uniform throughout, onward, to evaluate the development of the relevant...
Chapter
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Bioflocs Oxygen dynamics Resuspension, mixing, and sludge management Nitrogenous waste products Temperature Feeds and feeding Economics Sustainability Outlook and research needs Acknowledgment References
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The objective of the present work was to assess the potential of brackish water finfish to improve bottom soil conditions and thereby increase the growth and production of Penaeus monodon (tiger prawns). Experimental tanks with a bottom area of 6m2 were stocked with shrimp (6 shrimp/m2) and finfish (3fish/m2), and fed a commercial diet. Five tripli...
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A 50-day experiment was conducted to investigate the effectiveness of the bio-flocs technology for maintaining good water quality in over-wintering ponds for tilapia hybrid fingerlings (Oreochromis niloticus × Oreochromis aureus). To preserve adequate water temperatures in the ponds, they were covered with polyethylene sheets and the water exchange...
Article
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Uptake and excretion of 15N by tilapia was evaluated in simulated bio floc technology (BFT) tanks. Bio floc suspension (suspended solids in the range of 200 mg l−1) was enriched in respect to 15N by adding tagged ammonium salt and starch, to ensure a complete immobilization of ammonium in the bio flocs. Fish were held for 14 days in tanks, when the...
Article
This study analyses the combined effects of organic and inorganic fertilization and of feeding with pellets on fish performance and water quality in a polyculture of common carp. Cyprinus Carpio L., silver carp. Hypophthalmichthys molitrix (Val.), grass carp. Ctenopharyngodon idella (Val.) and hybrid tilapia, Oreochromis niloticus L. x O. aureus St...
Article
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Three types of circulated systems slocked with tilapia were studied: tanks: miniponds; and ponds. Water was continually circulated and aerated. Daily drainage of non-suspended material was applied in most systems. The continual circulation and resulting resuspension of the organic particular ma Her led to a very high rate of microbial activity. Org...
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One of the main obstacles toward the intensification of aquaculture systems is the accumulation of inorganic nitrogen in the water, A solution demonstrated in this work is to control inorganic nitrogen levels through the induction of microbial protein synthesis. This is achieved by adding a carbonaceous substrate, adjusted in a way so as to supply...
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Two major players are active in determining the development of environmental policies: the government and “the public.” These diverse players have intrinsic limitations and are often driven by different agenda, different aims, and different means. Therefore, inconsistent actions and lack of a clear agenda and action plan characterize the environmen...
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The uptake of microbial flocs by tilapia was evaluated. Fish (tilapia Mozambique, 107 g) were stocked in 1 m3 tanks filled with water from a limited exchange intensive tilapia producing pond (bio-floc technology, BFT system). Tagged ammonium nitrogen (15NH4(SO4)2) and starch to ensure incorporation of the 15N into the bio-flocs, were added. Fish we...
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The aquaculture industry struggles to profit in light of low product prices, increasing costs of inputs and constrains due to environmental, water and land limitations.Intensive aquaculture systems are relevant to efficiently produce fish and shrimp. The two important limiting factors of intensive aquaculture systems are water quality and economy....
Chapter
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Sewage sludge (biosolids) application on land as a fertilizer and soil improver, and high-volume sulfidic mining waste disposal and use as a common fill are anthropogenic activities that increasingly contribute to heavy metal enrichment of soil and ground water.
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Intensive aquaculture systems are being used to efficiently produce fish and shrimp. However, an intrinsic problem of these systems is the rapid accumulation of feed residues, organic matter, and toxic inorganic nitrogen species. This cannot be avoided, since fish assimilate only 20-30% of feed nutrients. The rest is excreted and typically accumula...
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As the aquaculture industry intensively develops, its environmental impact increases. Discharges from aquaculture deteriorate the receiving environment and the need for fishmeal and fish oil for fish feed production increases. Rotating biological contactors, trickling filters, bead filters and fluidized sand biofilters are conventionally used in in...
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Bioturbation activity generated by fish has the potential to improve bottom soil quality by increasing oxygen supply to a greater depth in aquaculture ponds bottoms. This study was designed to assess the common carp (Cyprinus carpio L) potential to improve conditions in pond bottom soils.Enclosures (3×2 m) constructed within a tilapia production po...
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This study quantified the accumulation of nitrogen (N) in the water column, sediments, fish and seepage water during a production cycle of Colossoma macropomum. By combining estimates of the deposition rates of uneaten feed, faeces and dead phytoplankton with measurements of N accumulation in the sediment, the rate of decomposition of organic matte...
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Compost extracts or intact compost suspensions, with or without CaCO3, were equilibrated with Na+-saturated cation exchange resin used as a model of sodic soil. A release of cations from the solid phases (compost or CaCO3) and subsequent exchange with Na+ was evaluated through the apparent deviation from electro-neutrality in the solution. (Electro...
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Pond bottom conditions change with time, affected, to a large extent, by the accumulation of organic matter residues leading to high oxygen consumption and the development of reducing conditions. Presently, the common method to evaluate this accumulation is through the determination of soil organic matter, using a vigorous oxidation of dried bottom...
Article
Soil pH is a key factor in several chemical processes occurring in the pond bottom environment. Conventionally, pH determinations are made on 1:1 dry soil:distilled water paste (pH1:1). However, such pH data might not be relevant for flooded soil conditions, conditions under which several pH modifying processes take place. A better estimate for the...
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Intensive shrimp ponds are commonly aerated by placing paddlewheel aerators parallel to the pond dikes. This placement creates a relatively rapid water current along the pond banks, while leaving a center region with much slower flow. Implications of this flow mode were studied in three 0.25-ha ponds. Measurements of water flow, sludge depth, disso...
Article
A new approach for a simple and rapid fractionation of compost-derived dissolved organic matter (DOM) has been tested. Aqueous extracts of municipal solid waste composts were fractionated by flocculation with alum (Al2(SO4)3·18H2O), similar to the flocculation process used in water treatment. Flocculation curves of diluted compost extracts (100 mg/...
Article
Commercial intensive aquaculture systems werebuilt and are managed in a somewhat differentway in each farm. To evaluate the effects ofseveral management procedures on water qualityin intensive fish ponds, data from severallocations, times and culture conditions indifferent farms were collected and are hereinanalyzed through multivariate statistics....
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Recently developed, active suspension intensive ponds are based on the idea that fish ponds (aerated and mixed as required for the well-being of the fish) can also serve as water purification units. The present paper compares water quality and fish growth in conventional intensive ponds (daily water exchange 500%), with active suspension intensive...
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Several basic properties of pond bottom soil are shown to be related, a relation that enable to evaluate pond bottom soil characteristics through the determination of one parameter (e.g. soil moisture). In addition, these relationships give some insight into the properties of flooded sediments. Unlike terrestrial soils, made of gas, liquid and soli...
Article
Reclaimed landfills can be used after closure, yet environmental and physical problems impose restrictions on their after-use. Due to these restrictions, there is an advantage in using landfills as open spaces. A procedure for selecting a suitable open space for a closed landfill site is presented. The procedure includes two main parts: criteria fo...
Article
This study focuses on the processes influencing hydrocarbon residue persistence in soil, following land treatment of refinery oily sludge. Treating sludge applied to soil resulted in 70% to 90% degradation of total petroleum hydrocarbon (TPH) during 2 months, regardless of their initial concentrations (9 to 60 g/kg soil). Kinetic analyses performed...
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The increased concern about environmental problems caused by inadequate waste management, as well as the concern about global warming, promotes actions toward a sustainable management of the organic fraction of the waste. Landfills, the most common means to dispose of municipal solid waste (MSW), lead to the conversion of the organic waste to bioga...
Article
In order to comply with the Kyoto Protocol agreements, Israel has to assess all the sources contributing to greenhouse gases (GHG) and analyze the alternative options to reduce these emissions. The waste sector in Israel contributes 13% of total GHG emissions for a time horizon of 100 years (for a time horizon of 20 years, the waste sector contribu...
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Pile composting is the most commonly used method in composting today. Heat and water balances quantification was conducted in three different windrows in a commercial Municipal Solid Waste composting plant in Israel. The windrows differ in the turning frequencies and in the supplied water amounts. The measured data included temperature, water conte...
Article
The paper describes the application of a multidimensional life cycle analysis (LCA) for packaging soft drinks in Israel. The suggested approach combines the conventional product LCA, vertical summation of all environmental burdens along the chain of production, use and disposal activities, and horizontal comparison of different products and disposa...
Article
The surface layer of fish pond sediments is characterized by very high microbial activity. Oxygen uptake by the microbes at the sediment surface leaves little oxygen to penetrate the sediment. In marine and freshwater lake sediments, oxygen only penetrated a few millimeters. In this study, oxygen penetration into the sediment layer in fish ponds an...
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Resuspension of particles from pond sediment into the water column may be an important nutrient transfer mechanism in aquaculture ponds. However, the magnitude of sediment resuspension cannot be determined directly because sediment traps collect particles settling from the water column as web as those resuspended from the pond bottom. We developed...
Article
Peat, defined as young Quaternary, mainly Holocene, organogenic sedimentary rock in the first stage of coalification, has received increasing attention due to its potential to act as an ubiquitous effective agent for the recovery of valuable metals, for the removal of metal ions from dumping site leachate and wastewater, or for retrospective monito...
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Controlling the inorganic nitrogen by manipulating the carbon/nitrogen ratios is a potential control method for aquaculture systems. This approach seems to be a practical and inexpensive means of reducing the accumulation of inorganic nitrogen in the pond. Nitrogen control is induced by feeding bacteria with carbohydrates, and through the subsequen...
Article
A program based on a lumped parameter model was developed to estimate three parameters of a composting process in windrows. The first two parameters represent two types of heat loss from the compost pile. The third parameter represents the effective composting rate. Most of the heat is dissipated at a rate proportional to the total biodegradable ma...
Chapter
The bottom soil of water bodies such as reservoirs, ponds, and shallow lakes acts as the storage, regulation and buffer organ of the system. As an illustration, the quantities of several components in the bottom soil can be compared to the equivalent terms in the water. The range of concentrations in the water of organic carbon, nitrogen and phosph...
Article
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Measurement of the COD of an aqueous solution involves firstly digestion of a test sample with dichromate solutions and secondly measurement of the dichromate remaining either by titration by terrous ammonium sulfate (FAS) to a color indicator endpoint, or via colorimetric determination using a spectrophotometer. In this paper, a potentiometric end...
Article
In Israel, the design and execution of wastewater recycling as a national policy started at about 1970. The basic approach was to collect, treat and reuse as much water was possible. The emphasis was on the quantity of the recycled water and not on the quality. Within about 10 years, Israel recycled and used for irrigation about 70% of its wastewat...
Chapter
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The use of composts or bio-solids is widely advocated, both as an environmentally sound solution to recycle the increasing amounts of these materials (or wastes) as well as an economic means to raise soil productivity. Soil compaction, soil structure deterioration and an accompanying decrease of soil fertility are worldwide problems (Barnes et al.,...
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Wastewater irrigation is an environmentally sound wastewater disposal practice, but sewage is more saline than the supplied fresh water and the salts are recycled together with the water. Salts have negative environmental effects on crops, soils, and groundwater. There are no inexpensive ways to remove the salts once they enter sewage, and the prev...
Article
Water quality in intensive aquaculture systems is to a large extent controlled by the microbial biodegradation of organic residues. The ability to simulate processes in such systems depends on the availability of data on the rates of these processes. The first order kinetic rate constants for both organic carbon and organic nitrogen degradation in...
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Since the inception of the Middle East Peace Process in 1991, arms control and regional security issues have been one of the most difficult areas to address. The establishment and functioning of the official multilateral Arms Control and Regional Security (ACRS) Working Group in the multilateral process has had to overcome at best lack of knowledge...
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The results of a two year field experiment verified hypotheses concerning use of compost to improve saline and alkaline soils. The addition of compost to such soils was expected to release acids which would ultimately lead to the replacement of exchangeable sodium by calcium. The addition of compost would also stabilize soil structure and enhance p...
Article
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A model describing the nitrogen sub-system in a completely mixed and aerated pond is proposed. Inputs of nitrogen include feed and influent water; outputs of nitrogen include uptake by fish, removal of sediment from the pond and discharge water. Internal transformations between the inorganic and organic pools are also computed. The organic nitrogen...
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Individual granules within a given granule population of a slow-release fertilizer (SRF) have a different release pattern. The populations studied differed both in relation to the time delay before the start of the release process and to the duration of the release. An association between a short delay period and a rapid release was found. The rand...
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Intensive fish culture is possible if the pond is properly aerated and mixed to avoid the creation of anaerobic sites. However, ammonium and nitrite may accumulate under such conditions up to toxic levels. The efficiency of water exchange as a means to flush out those toxic components was computed. A mathematical model relating the concentration of...
Article
A biofilter made out of chopped wheat straw was shown to be an effective system to remove nitrogen from waste-water, both due to nitrogen immobilization as well as to a nitrification-denitrification sequence (Lowengart, A., Diab, S., Kochba, M. & Avinmelech, Y. 1993. Development of a biofilter for turbid and nitrogen-rich irrigation water. A: Organ...
Article
A major problem associated with the recycling of some wastewaters is the high level of nitrogen in the water. The conventional methods for nitrogen removal are rather expensive. The system presented here was based upon the use of a carbonaceous residue, wheat straw, as a substrate for microbial activity. Microorganisms degrading such a substrate we...
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Nitrification does not occur in conventional fish ponds or in oxidation ponds. Yet, intensive nitrification occurs in continually aerated and mixed fish ponds and in activated sludge systems. In a combined fish pond system, water from a conventional pond is pumped through a continually aerated and mixed pond, with a 5 h average hydraulic residence...
Article
As a country in a semi-arid region, Israel depends on irrigation for virtually any intensive farming. The Israelis recycle wastewater for agricultural irrigation as a way to conserve water resources. This paper summarizes the Israeli experience and suggests the necessary research and system upgrading. In Israel wastewater reuse in irrigation is abo...
Article
The biofilter system proposed and tested here, for upgrading irrigation water, is based upon the use of a carbonaceous material, such as wheat straw, as a substrate for microbial activity. Microorganisms degrading a carbon-rich and nitrogen-poor substrate are expected to take up nitrogen from the water. When wastewater flows along a column of the c...
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Both aeration and mixing are important design parameters in intensive aquaculture systems. The present study deals with the examination of the effect of each of these variables and their combined effect on the microbial transformations of organic carbon and of nitrogen. The most efficient organic carbon metabolism was found when both aeration and m...
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Combined intensive-extensive (CIE) pond system composed of four 500-m3 intensive ponds and a 1.4-ha lagoon was studied. Water was circulated between the intensive and extensive components. The average hydraulic residence time in the intensive ponds was 5 h. The role of nitrification was studied in the CIE system. It was shown that the nitrifying ba...