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The hybrid aspen tree (Populus tremula L. × P. tremuloides Michx.) is a fast-growing tree species with the potential to produce biomass in an enhanced manner for industrial needs. Research has shown that by breeding hybrid aspen clones, tree properties (e.g., growth ability, resistance to disease, energy density and cellulosic pulp properties) can be influenced. However, there is a gap in the research on how clonal breeding affects the chemical composition of bark and whether this information can be used in the production of added value according to the cascading use principle. In this dissertation, chemical determinations were used to calculate variations in the chemical composition of the barks of different clonal trees and to evaluate the possibilities of clonal selection to produce added value to the bark. The results were also used to select the highest potential bark biomass for cascade use studies. Cascade use was investigated by linking the methods of extraction of bark and the torrefaction of extraction residue. The added value of the extract was evaluated experimentally by producing rigid foam and activated carbon. Applicability of pyroligneous acid was tested in herbicidal and fungicidal applications. This current study produced three key results: 1) clonal variation in the chemical composition of bark indicated that bark quality varies between clone types, and this has an impact on the added-value potential of bark-derived raw material, 2) by using hot water extraction, it is possible to separate an extract suitable as a precursor for producing rigid foam and activated carbon, and 3) hemicellulose of hybrid aspen bark can be converted into herbicidal and fungicidal active pyroligneous acid by torrefaction. In summary, clone selection can affect the bark quality of hybrid aspen in a situation in which bark pulp is collected from trees grown in certain growth areas. This information has value when the goal is to produce added value for hybrid aspe, Tiivistelmä Hybridihaapa (Populus tremula L. × P. tremuloides Michx.) on nopeasti kasvava puulaji, josta on mahdollista muodostaa tehostetusti biomassaa teollisuuden raaka-aineeksi. Hybridihaapakloonien jalostuksella tiedetään olevan vaikutusta puun ominaisuuksiin, kuten kasvukykyyn, taudinkestävyyteen, energiatiheyteen ja selluloosamassan latuun. Ei ole kuitenkaan tutkittu sitä, miten kloonijalostus vaikuttaa puun kuoren kemialliseen koostumukseen, ja voidaanko koostumuksellisia kloonivariaatioita hyödyntää kuoren käyttöarvon parannuksessa noudattaessa biojalostuksen kaskadikäyttöperiaatteita. Tässä väitöskirjassa määritetään erilaisten kloonipuiden kuorien koostumuksellisia vaihteluja ja arvioidaan kloonityyppien valinnan tuomia mahdollisuuksia tuottaa kuorelle uutta käyttöarvoa. Kloonivaihtelujen perusteella valitaan kiinnostavin kuorimassa biojalostustutkimuksiin, jonka jälkeen kuoren hyödyntämistä tarkastellaan ketjuttamalla kuoriuutteiden erotusmenetelmät sekä kuoren uuttojäännöksen termokemiallinen konversio, torrefiointi. Kuoriuutteen käyttöarvoa selvitetään valmistamalla uutteista hiilivaahtoa ja aktiivihiiltä, sekä tutkimalla torrefikaatiolla tuotettavan konversiotisleen käyttöä rikkakasvien ja sienitautien torjunta-ainekemikaalina. Tutkimuksen keskeisimmät tulokset ovat: 1) kuoren koostumuksellinen laatu vaihtelee kloonityypeittäin, ja tällä arvioidaan olevan merkitystä arvopotentiaaliin, 2) kuoriuute soveltuu hiilivaahdon ja aktiivihiilen valmistukseen, ja 3) kuoren uuttojäännöksen konversiotisleellä on herbisidi- ja fungisidiaktiivisuutta. Yhteenvetona todetaan, että kloonivalinnalla voidaan vaikuttaa hybridihaapapuun kuoren koostumukselliseen laatuun tilanteessa, jossa kuorimassa kerätään tietyllä kasvualueella kasvaneista kloonipuista. Tuloksilla nähdään olevan arvoa, kun tavoitteena on tuottaa kuoribiomassalle lisäarvoa kemianteollisuuden käyttöön ketjuttamalla menetelmiä kaskadikäyttöperiaatteen mukaisesti.

The pyroligneous acids (PAs) of woody biomass produced by torrefaction have pesticidal properties. Thus, PAs are potential alternatives to synthetic plant protection chemicals. Although woody biomass is a renewable feedstock, its use must be efficient. The efficiency of biomass utilization can be improved by applying a cascading use principle. This study is novel because we evaluate for the first time the pesticidal potential of PAs derived from the bark of hybrid aspen (Populus tremula L. × Populus tremuloides Michx.) and examine simultaneously how the production of the PAs can be interlinked with the cascade processing of hybrid aspen biomass. Hybrid aspen bark contains valuable extractives that can be separated before the hemicellulose is thermochemically converted into plant protection chemicals. We developed a cascade processing scheme, where these extractives were first extracted from the bark with hot water (HWE) or with hot water and alkaline alcohol (HWE+AAE) prior to their conversion into PAs by torrefaction. The herbicidal performance of PAs was tested using Brassica rapa as the test species, and the fungicidal performance was proven using Fusarium culmorum. The pesticidal activities were compared to those of the PAs of debarked wood and of commercial pesticides. According to the results, extractives can be separated from the bark without overtly diminishing the weed and fungal growth inhibitor performance of the produced PAs. The HWE of the bark before its conversion into PAs appeared to have an enhancing effect on the herbicidal activity. In contrast, HWE+AAE lowered the growth inhibition performance of PAs against both the weeds and fungi. This study shows that hybrid aspen is a viable feedstock for the production of herbicidal and fungicidal active chemicals, and it is possible to utilize biomass according to the cascading use principle.

The pyrolysis of biomass material results in pyroligneous acid (PA) and biochar, among other by-products. In agriculture, PA is recognized as an antimicrobial agent, bio-insecticide, and bio-herbicide due to antioxidant activity provided by a variety of constituent materials. Application of PA to crop plants and soil can result in growth promotion, improved soil health, and reduced reliance on polluting chemical crop inputs. More detailed information regarding chemical compound content within PA and identification of optimal chemical profiles for growth promotion in different crop species is essential for application to yield effective results. Additionally, biochar and PA are often applied in tandem for increased agricultural benefits, but little is known regarding the optimal proportion of each crop input. This work reports on the effect of combined applications of different proportions of PA (200-and 800-fold dilutions) and chemical fertilizer rates (100%, 75%, 50%, and 0%) in the presence or absence of biochar on Komatsuna (Brassica rapa var. perviridis, Japanese mustard spinach) plant growth. To elucidate the chemical composition of the applied PA, four different spectroscopic measurements of fluorescence excitation were utilized for analysis—excitation-emission matrix, ion chromatography, high-performance liquid chromatography, and gas chromatography-mass spectrometry. It was determined that PA originating from pyrolysis of Japanese pine wood contained different classes of biostimulants (e.g., tryptophan, humic acid, and fulvic acid), and application to Komatsuna plants resulted in increased growth when applied alone, and in different combinations with the other two inputs. Additionally, application of biochar and PA at the higher dilution rate increased leaf accumulation of nutrients, calcium, and phosphorus. These effects reveal that PA and biochar are promising materials for sustainable crop production.

Peat moss has historically been a key component of soil-free substrates in the greenhouse and nursery industries. However, the increasing expense of peat, negative impacts of peat mining on wetland ecosystems, and growing perception of peat as unsustainable have led to investigation for alternatives. Biochar (BC) is a promising substitute for peat, yet the majority of studies examine additions of BC to peat-based substrates rather than replacing the peat component or employ relatively low substitution rates. Furthermore, at high substitution rates the alkalinity common to many BCs may increase substrate pH and adversely impact plant production. We evaluated BC substitution for peat and pH adjustment of resulting substrates on marigold (Tagetes erecta L.) performance under standard greenhouse conditions. A high pH (10.9) softwood BC (800 °C) was substituted for peat in a standard 70:30 (v/v) peat:perlite mixture at 10% total volume increments. Substrate pH was either not adjusted or adjusted to pH 5.8 using a BC by-product, pyroligneous acid (PLA). Germination was inhibited in pH adjusted substrates with high BC substitution (50–70% total substrate volume) likely due to higher dosages of PLA needed to neutralize pH. At harvest (flowering stage, 9 weeks) the initial pH gradient (4.4–10.4) in substrates that were not pH adjusted had converged to pH 5.6–7.5, and BC substitution for peat did not negatively impact marigold biomass or flowering. At low substitution rates (10–30% total substrate volume), marigold biomass and leaf SPAD values were greater than the control peat-perlite mixture (0% BC). This study demonstrates that softwood BC can be considered as a full replacement for peat in soil-free substrates, and even at high rates (70% total substrate volume) does not require pH adjustment for marigold production. Crop- and BC-specific considerations and economic potential should be investigated for wider application.

Peat moss has historically been a key component of soil-free substrates in the greenhouse and nursery industries. However, the increasing expense of peat, negative impacts of peat mining on wetland ecosystems, and growing perception of peat as unsustainable have led to investigation for alternatives. Biochar (BC) is a promising substitute for peat, yet the majority of studies examine additions of BC to peat-based substrates rather than replacing the peat component or employ relatively low substitution rates. Furthermore, at high substitution rates the alkalinity common to many BCs may increase substrate pH and adversely impact plant production. We evaluated BC substitution for peat and pH adjustment of resulting substrates on marigold (Tagetes erecta L.) performance under standard greenhouse conditions. A high pH (10.9) softwood BC (800 °C) was substituted for peat in a standard 70:30 (v/v) peat:perlite mixture at 10% total volume increments. Substrate pH was either not adjusted or adjusted to pH 5.8 using a BC by-product, pyroligneous acid (PLA). Germination was inhibited in pH adjusted substrates with high BC substitution (50–70% total substrate volume) likely due to higher dosages of PLA needed to neutralize pH. At harvest (flowering stage, 9 weeks) the initial pH gradient (4.4–10.4) in substrates that were not pH adjusted had converged to pH 5.6–7.5, and BC substitution for peat did not negatively impact marigold biomass or flowering. At low substitution rates (10–30% total substrate volume), marigold biomass and leaf SPAD values were greater than the control peat-perlite mixture (0% BC). This study demonstrates that softwood BC can be considered as a full replacement for peat in soil-free substrates, and even at high rates (70% total substrate volume) does not require pH adjustment for marigold production. Crop- and BC-specific considerations and economic potential should be investigated for wider application.

In many tropical developing countries, economic incentives are small for soil remediation to take place. Such locations demand special strategies that are energy-efficient, locally adapted and economic. In situ technologies are appealing where energy and material costs are more limiting than the time factor. One potentially sustainable and economic way to enhance the self-organizing capacity of soil ecosystems is by applications of locally available organic by-products to stimulate the polluted ecosystem´s inherent capacity to heal by utilising the embodied energy of the organic pollutant itself, as an energy source for the necessary biochemical transformations. Tropical climate is favourable for biodegradation but many tropical soils are rich in clay which can inhibit the bioavailability of the pollutant and reduce biodegradation kinetics. A pilot scale experiment was performed in order to assess the capability of three amendments based on by-products; whey, pyroligneous acid and compost tea, to enhance degradation of diesel in ultisol. Biweekly applications of 6 mL whey kg-1 soilsignificantly increased the degradation rate but no positive effect on degradation was found of any of the other amendments., Hållbara utvecklingsprocesser (HUP)

In many tropical developing countries, economic incentives are small for soil remediation to take place. Such locations demand special strategies that are energy-efficient, locally adapted and economic. In situ technologies are appealing where energy and material costs are more limiting than the time factor. One potentially sustainable and economic way to enhance the self-organizing capacity of soil ecosystems is by applications of locally available organic by-products to stimulate the polluted ecosystem´s inherent capacity to heal by utilising the embodied energy of the organic pollutant itself, as an energy source for the necessary biochemical transformations. Tropical climate is favourable for biodegradation but many tropical soils are rich in clay which can inhibit the bioavailability of the pollutant and reduce biodegradation kinetics. A pilot scale experiment was performed in order to assess the capability of three amendments based on by-products; whey, pyroligneous acid and compost tea, to enhance degradation of diesel in ultisol. Biweekly applications of 6 mL whey kg-1 soilsignificantly increased the degradation rate but no positive effect on degradation was found of any of the other amendments., Hållbara utvecklingsprocesser (HUP)

In many tropical developing countries, economic incentives are small for soil remediation to take place. Such locations demand special strategies that are energy-efficient, locally adapted and economic. In situ technologies are appealing where energy and material costs are more limiting than the time factor. One potentially sustainable and economic way to enhance the self-organizing capacity of soil ecosystems is by applications of locally available organic by-products to stimulate the polluted ecosystem´s inherent capacity to heal by utilising the embodied energy of the organic pollutant itself, as an energy source for the necessary biochemical transformations. Tropical climate is favourable for biodegradation but many tropical soils are rich in clay which can inhibit the bioavailability of the pollutant and reduce biodegradation kinetics. A pilot scale experiment was performed in order to assess the capability of three amendments based on by-products; whey, pyroligneous acid and compost tea, to enhance degradation of diesel in ultisol. Biweekly applications of 6 mL whey kg-1 soilsignificantly increased the degradation rate but no positive effect on degradation was found of any of the other amendments., Hållbara utvecklingsprocesser (HUP)

In many tropical developing countries, economic incentives are small for soil remediation to take place. Such locations demand special strategies that are energy-efficient, locally adapted and economic. In situ technologies are appealing where energy and material costs are more limiting than the time factor. One potentially sustainable and economic way to enhance the self-organizing capacity of soil ecosystems is by applications of locally available organic by-products to stimulate the polluted ecosystem´s inherent capacity to heal by utilising the embodied energy of the organic pollutant itself, as an energy source for the necessary biochemical transformations. Tropical climate is favourable for biodegradation but many tropical soils are rich in clay which can inhibit the bioavailability of the pollutant and reduce biodegradation kinetics. A pilot scale experiment was performed in order to assess the capability of three amendments based on by-products; whey, pyroligneous acid and compost tea, to enhance degradation of diesel in ultisol. Biweekly applications of 6 mL whey kg-1 soilsignificantly increased the degradation rate but no positive effect on degradation was found of any of the other amendments., Hållbara utvecklingsprocesser (HUP)

In many tropical developing countries, economic incentives are small for soil remediation to take place. Such locations demand special strategies that are energy-efficient, locally adapted and economic. In situ technologies are appealing where energy and material costs are more limiting than the time factor. One potentially sustainable and economic way to enhance the self-organizing capacity of soil ecosystems is by applications of locally available organic by-products to stimulate the polluted ecosystem´s inherent capacity to heal by utilising the embodied energy of the organic pollutant itself, as an energy source for the necessary biochemical transformations. Tropical climate is favourable for biodegradation but many tropical soils are rich in clay which can inhibit the bioavailability of the pollutant and reduce biodegradation kinetics. A pilot scale experiment was performed in order to assess the capability of three amendments based on by-products; whey, pyroligneous acid and compost tea, to enhance degradation of diesel in ultisol. Biweekly applications of 6 mL whey kg-1 soilsignificantly increased the degradation rate but no positive effect on degradation was found of any of the other amendments., Hållbara utvecklingsprocesser (HUP)

The production of vegetable charcoal generates atmospheric emissions, which can be controlled by the instalation of collectors for the condensation of such emissions, forming the pyroligneous acid. The development of collectors for the condensations and characterization of the acid for commerce can contribute with the local sustainable development. This study intends to investigate the technological, economical and legal aspects of the production and commerce of the pyroligneous acid. The chosen method was case study in Presidente Lucena/RS, Brazil, with use of surveys, interviews with producers and responsible government sectors’ representatives. The results indicate that the pyroligneous acid extraction technique is little-known and little used by the producers, that the current market does not absorb the pyroligneous acid offering and the ruling is not relevant.

Catalytic upgrading of pyroligneous acid, by-product from slow pyrolysis of woody biomass for char production, was carried out using zirconia-supported iron-oxide catalysts under a steam atmosphere at temperatures ranging from 623 to 723 K, and the effect of ZrO2 content in the ZrO2-FeOX catalysts on catalytic activity and ketone yields was investigated. It was demonstrated that hydroxyacetone and carboxylic acids (acetic and propionic acids) in the pyroligneous acid were converted into aliphatic ketones (acetone and 2-butanone) via a ketonization reaction over the ZrO2-FeOX catalyst. However, reaction inhibition by metal impurities in the pyroligneous acid such as potassium (K) and magnesium (Mg) was also observed. These metal impurities could be removed from the pyroligneous acid without changing the organic composition by using an ion-exchange resin. The removal of the metal impurities was effective in increasing the ketone yields. Moreover, as the W/F value (W: Amount of catalyst, and F: Flow rate of the pyroligneous acid in the feed) increased, the ketone yield increased up to approximately 30 C mol%, and the ketone fraction in the liquid product reached 55 C mol%.

Catalytic upgrading of pyroligneous acid, by-product from slow pyrolysis of woody biomass for char production, was carried out using zirconia-supported iron-oxide catalysts under a steam atmosphere at temperatures ranging from 623 to 723 K, and the effect of ZrO2 content in the ZrO2-FeOX catalysts on catalytic activity and ketone yields was investigated. It was demonstrated that hydroxyacetone and carboxylic acids (acetic and propionic acids) in the pyroligneous acid were converted into aliphatic ketones (acetone and 2-butanone) via a ketonization reaction over the ZrO2-FeOX catalyst. However, reaction inhibition by metal impurities in the pyroligneous acid such as potassium (K) and magnesium (Mg) was also observed. These metal impurities could be removed from the pyroligneous acid without changing the organic composition by using an ion-exchange resin. The removal of the metal impurities was effective in increasing the ketone yields. Moreover, as the W/F value (W: Amount of catalyst, and F: Flow rate of the pyroligneous acid in the feed) increased, the ketone yield increased up to approximately 30 C mol%, and the ketone fraction in the liquid product reached 55 C mol%.

The production of vegetable charcoal generates atmospheric emissions, which can be controlled by the instalation of collectors for the condensation of such emissions, forming the pyroligneous acid. The development of collectors for the condensations and characterization of the acid for commerce can contribute with the local sustainable development. This study intends to investigate the technological, economical and legal aspects of the production and commerce of the pyroligneous acid. The chosen method was case study in Presidente Lucena/RS, Brazil, with use of surveys, interviews with producers and responsible government sectors’ representatives. The results indicate that the pyroligneous acid extraction technique is little-known and little used by the producers, that the current market does not absorb the pyroligneous acid offering and the ruling is not relevant.

Contaminated soil from industrial or agricultural activities poses a health threat to animals and humans and can also have a detrimental effect on economic systems by making land unsuitable for agriculture and other economic purposes. This problem is of particular concern in tropical developing countries where agriculture is the economic base. Traditional methods for soil remediation are often expensive and energy consuming. In-situ bioremediation has been proposed as a cheaper alternative to conventional methods in areas where remediation would otherwise not be implemented. Despite encouraging results in the laboratory, the practice of in-situ bioremediation is limited, partially due to its inefficiency at low temperatures. The objective of this study is to provide an inventory of some waste products that potentially can be used as amendments for in-situ bioremediation in developing countries in tropical climate. Emphasis has been given to map efficient methods that are appropriate to economically marginalised people in such countries. Waste from livestock operations, crop residues and processing waste constitute the major waste flows in many developing countries. A number of organic by-products can potentially be used to stimulate microbial activity for bioremediation purposes. Three amendments; whey, pyroligneous acid and compost teas were selected to be studied in detail due to their liquid nature and documented capacity to stimulate microorganisms with capacity to degrade pollutants. Experiments are needed to determine their potential for in-situ bioremediation in developing countries in tropical climate., Bioremediation

Contaminated soil from industrial or agricultural activities poses a health threat to animals and humans and can also have a detrimental effect on economic systems by making land unsuitable for agriculture and other economic purposes. This problem is of particular concern in tropical developing countries where agriculture is the economic base. Traditional methods for soil remediation are often expensive and energy consuming. In-situ bioremediation has been proposed as a cheaper alternative to conventional methods in areas where remediation would otherwise not be implemented. Despite encouraging results in the laboratory, the practice of in-situ bioremediation is limited, partially due to its inefficiency at low temperatures. The objective of this study is to provide an inventory of some waste products that potentially can be used as amendments for in-situ bioremediation in developing countries in tropical climate. Emphasis has been given to map efficient methods that are appropriate to economically marginalised people in such countries. Waste from livestock operations, crop residues and processing waste constitute the major waste flows in many developing countries. A number of organic by-products can potentially be used to stimulate microbial activity for bioremediation purposes. Three amendments; whey, pyroligneous acid and compost teas were selected to be studied in detail due to their liquid nature and documented capacity to stimulate microorganisms with capacity to degrade pollutants. Experiments are needed to determine their potential for in-situ bioremediation in developing countries in tropical climate., Bioremediation

Contaminated soil from industrial or agricultural activities poses a health threat to animals and humans and can also have a detrimental effect on economic systems by making land unsuitable for agriculture and other economic purposes. This problem is of particular concern in tropical developing countries where agriculture is the economic base. Traditional methods for soil remediation are often expensive and energy consuming. In-situ bioremediation has been proposed as a cheaper alternative to conventional methods in areas where remediation would otherwise not be implemented. Despite encouraging results in the laboratory, the practice of in-situ bioremediation is limited, partially due to its inefficiency at low temperatures. The objective of this study is to provide an inventory of some waste products that potentially can be used as amendments for in-situ bioremediation in developing countries in tropical climate. Emphasis has been given to map efficient methods that are appropriate to economically marginalised people in such countries. Waste from livestock operations, crop residues and processing waste constitute the major waste flows in many developing countries. A number of organic by-products can potentially be used to stimulate microbial activity for bioremediation purposes. Three amendments; whey, pyroligneous acid and compost teas were selected to be studied in detail due to their liquid nature and documented capacity to stimulate microorganisms with capacity to degrade pollutants. Experiments are needed to determine their potential for in-situ bioremediation in developing countries in tropical climate., Bioremediation

Contaminated soil from industrial or agricultural activities poses a health threat to animals and humans and can also have a detrimental effect on economic systems by making land unsuitable for agriculture and other economic purposes. This problem is of particular concern in tropical developing countries where agriculture is the economic base. Traditional methods for soil remediation are often expensive and energy consuming. In-situ bioremediation has been proposed as a cheaper alternative to conventional methods in areas where remediation would otherwise not be implemented. Despite encouraging results in the laboratory, the practice of in-situ bioremediation is limited, partially due to its inefficiency at low temperatures. The objective of this study is to provide an inventory of some waste products that potentially can be used as amendments for in-situ bioremediation in developing countries in tropical climate. Emphasis has been given to map efficient methods that are appropriate to economically marginalised people in such countries. Waste from livestock operations, crop residues and processing waste constitute the major waste flows in many developing countries. A number of organic by-products can potentially be used to stimulate microbial activity for bioremediation purposes. Three amendments; whey, pyroligneous acid and compost teas were selected to be studied in detail due to their liquid nature and documented capacity to stimulate microorganisms with capacity to degrade pollutants. Experiments are needed to determine their potential for in-situ bioremediation in developing countries in tropical climate., Bioremediation

Contaminated soil from industrial or agricultural activities poses a health threat to animals and humans and can also have a detrimental effect on economic systems by making land unsuitable for agriculture and other economic purposes. This problem is of particular concern in tropical developing countries where agriculture is the economic base. Traditional methods for soil remediation are often expensive and energy consuming. In-situ bioremediation has been proposed as a cheaper alternative to conventional methods in areas where remediation would otherwise not be implemented. Despite encouraging results in the laboratory, the practice of in-situ bioremediation is limited, partially due to its inefficiency at low temperatures. The objective of this study is to provide an inventory of some waste products that potentially can be used as amendments for in-situ bioremediation in developing countries in tropical climate. Emphasis has been given to map efficient methods that are appropriate to economically marginalised people in such countries. Waste from livestock operations, crop residues and processing waste constitute the major waste flows in many developing countries. A number of organic by-products can potentially be used to stimulate microbial activity for bioremediation purposes. Three amendments; whey, pyroligneous acid and compost teas were selected to be studied in detail due to their liquid nature and documented capacity to stimulate microorganisms with capacity to degrade pollutants. Experiments are needed to determine their potential for in-situ bioremediation in developing countries in tropical climate., Bioremediation

Contaminated soil from industrial or agricultural activities poses a health threat to animals and humans and can also have a detrimental effect on economic systems by making land unsuitable for agriculture and other economic purposes. This problem is of particular concern in tropical developing countries where agriculture is the economic base. Traditional methods for soil remediation are often expensive and energy consuming. In-situ bioremediation has been proposed as a cheaper alternative to conventional methods in areas where remediation would otherwise not be implemented. Despite encouraging results in the laboratory, the practice of in-situ bioremediation is limited, partially due to its inefficiency at low temperatures. The objective of this study is to provide an inventory of some waste products that potentially can be used as amendments for in-situ bioremediation in developing countries in tropical climate. Emphasis has been given to map efficient methods that are appropriate to economically marginalised people in such countries. Waste from livestock operations, crop residues and processing waste constitute the major waste flows in many developing countries. A number of organic by-products can potentially be used to stimulate microbial activity for bioremediation purposes. Three amendments; whey, pyroligneous acid and compost teas were selected to be studied in detail due to their liquid nature and documented capacity to stimulate microorganisms with capacity to degrade pollutants. Experiments are needed to determine their potential for in-situ bioremediation in developing countries in tropical climate., Bioremediation