Biological Treatment Plant Research Articles

Anthropic impact assessment on surface water quality in the Bălţi urban ecosystem

Massive pollution of surface waters in the Balti urban ecosystem has been established with CODCr, BOD5 and suspended matter as a result of leaks from the city due to atmospheric precipitation prior to sampling corresponding to surface water quality class IV and V, and self-cleaning capacity(SCC); SCC= BOD5 / CODCr has very low values. According to the nutrient content, the surface waters of the researched ecosystem were marked by moderate signs of disturbed ecosystem functioning. The left tributary of the river Răut, Flămînda, was classified in quality class I for chlorides, nutrients, BOD5 and mineralization, II for CODCr and suspended solids. The functioning of the aquatic ecosystem is not affected. The highest values for most of the pollutants analyzed were found in the waters of the river, downstream of the confluence with the waters discharged by the Biological Treatment Plant.

The performance of a Multi-Stage Hybrid Reactor to treat real wastewater: Benzophenone and Diethyl Phthalate removal

One of the consequences of the increasing diversity of new chemical compounds used in industrialized products is the release of these compounds as micropollutants (MPs) in the environment around the world, particularly in aqueous matrices. Benzophenone (BP) and Diethyl Phthalate (DEP), two MPs of environmental concern due to their potential toxicity are widely used and found with considerable concentrations mostly in wastewaters. Information about the efficiency of biological treatment in removing DEP from the wastewater is scarce and until recently, there was no information on the removal of BP. Due to the risks these substances pose to the human and environmental health there is a worldwide demand for the improvement of biological treatment plants with focus on the removal of these and other MPs, since conventional Wastewater Treatment Plants (WWTP) have very limited capacity to remove them and advanced treatment steps (e.g.: ozonation, photocatalysis, ultrafiltration.) increases substantially the treatment costs. A promising biological treatment approach for the removal of MPs combines fixed and suspended biomasses in the same reactor (hybrid reactors) and includes multiple compartments with different redox conditions. The objective of this study was to assess the performance of a new Multi-Stage Hybrid Reactor, focusing on the removal of Benzophenone (BP) and Diethylphthalate (DEP). The pilot system has seven units (anaerobic, anoxic 1, aerobic, anoxic 2, re-aeration and 2 sedimentation tanks) and it was installed at a large Municipal WWTP in Rio to treat real domestic wastewater. The total volume was 400 L and 50% of the aerobic tank (120 L) was filled with carriers (support media). The reactor’s efficiency was evaluated during two periods: (a) one with predominantly suspended biomass and (b) another one with predominantly fixed biomass in the aerobic tank. The highly variable composition of the affluent, affecting the organic load, caused fluctuations in the treatment performance. Even though, multi-stage hybrid bioreactor was able to remove up to 69.6% of BP and up to 74.5% of DEP, being the highest removal efficiencies achieved during the period when the aerobic tank had predominantly fixed biomass.

Application of nanotechnology in anaerobic digestion for biohydrogen production improvement from natural coagulation/flocculation sludge using metallic oxide nanoparticles

ABSTRACT The production of second-generation biohydrogen from organic waste by the dark fermentation process is a solution to reduce the immense volume of waste generated by the food industry. In this study, a coagulation sludge was recovered from the settling tank after treating cheese whey wastewater by natural coagulation/flocculation process. The sludge was used as a substrate for dark fermentation. In the biodigestion study, mixed culture from a biological treatment plant was used as inoculum. The whole process was set under defined conditions to favor hydrogen production. A series of Inoculum/Substrate (I/S) ratios (1/2, 1/3, 1/4, 1/5 and 1/6, g VS inoculum/g VS substrate) were studied in order to determine the optimum ratio for better biohydrogen production. The optimum (I/S) ratio was found to be 1/2 resulting in the highest biohydrogen volume of 237 mL/gVS. The production of biohydrogen as a function of the concentration of different nanoparticles has been studied. Several nanoparticles have been synthetized and tested: CuO, Fe2O3, TiO2. The production of biohydrogen has varied widely depending on the concentration and type of nanoparticles used. All the studied nanoparticles showed an evolution of biogas production. The maximum biohydrogen volume increase was obtained by TiO2 NPs at 0.5 mg/L of concentration noting more than 337% of a biohydrogen volume improvement (total produced volume 800 mL/gVS).

Municipal wastewater treatment and fouling in microalgal-activated sludge membrane bioreactor: Cultivation in raw and treated wastewater

Since the advent of conventional activated sludge biological treatment plants, their low efficiency in nitrogen and phosphorus removal has become a significant concern. Therefore, in this study, the performance of microalgal-activated sludge membrane bioreactor (MAS-MBR) as a self-biological treatment or as a post-treatment for conventional biological treatments was investigated. A continuous MAS-MBR with two ratios of algae/sludge (only microalgae and 5:1) was used to treat raw and treated wastewater. The optimum case was achieved with the cultivation of mixed algae/sludge in raw wastewater (R2 case). In this case, the ammonium and phosphorus removal efficiencies were 94.36 ± 3.5 and 88.37 ± 3 %, respectively. Furthermore, the highest oxygen production rate (OPR) and oxygen uptake rate (OUR) values were obtained in this case (145.58 ± 3 and 68.43 ± 1.5 mgO2/lit.d, respectively). In addition, membrane fouling was adversely increased in R2 compared with other cases, indicating the necessity of membrane cleaning for high-performance bioreactors in nutrient removal. Transmembrane pressure (TMP) jump in R2 was captured after 14 days, while the results supported that the membrane fouling was influenced by raised production of carbohydrate fraction of soluble microbial products (SMPc) and protein fraction of extracellular polymeric substances (EPSp) at first and last stages, respectively. Therefore, although the MAS-MBR is a potential candidate as a self-biological treatment, the membrane fouling is high in this case.

Hydrothermal carbonization of the wet fraction from mixed municipal solid waste: Hydrochar characteristics and energy balance

Mixed municipal solid waste (MSW) may be pre-treated in a mechanical–biological treatment (MBT) plant to produce an exiting stream with improved combustible characteristics. The process also produces a second waste stream, which is generally separated on a size basis by industrial sieving equipment. It contains fractions with a high moisture content such as residual food waste, soiled paper and cardboard, and small fragments of other materials. Samples of this stream, collected at an existing plant, were characterized and processed by hydrothermal carbonization (HTC) at laboratory scale, at various temperatures (180, 200 and 220 °C), reaction times (1, 4 and 8 h) and solid to water ratios (0.15 and 0.07). The primary energy balance, on a hypothetical industrial scale, was performed. In brief, the results confirmed that the produced hydrochar was a brittle, hydrophobic, solid carbonaceous product which gave a better combustion performance as the residence time of the HTC process was increased. Moreover, the dewaterability of the carbonized waste was greatly improved when compared to raw, wet samples. The results of the primary energy balance confirmed that the energy contained in the produced hydrochar was higher than the energy consumption for the process itself, under all the HTC working conditions. The energy consumed in the process was in the range of 40–70 % of the energy content of the produced hydrochar.

A new environment-friendly polyferric sulfate-catalyzed ozonation process for sludge conditioning to achieve deep dewatering and simultaneous detoxification

The dewaterability of sludge from biological sewage treatment plants is extremely poor since the highly hydrophilic biomacromolecules. This work developed a new polyferric sulfate-catalyzed ozonation (PFS/O 3 ) process to disintegrate sludge flocks and extracellular hydrophilic substrates for liberating bound water. With 40 mg/gTS PFS catalyzing 60 mg/gTS O 3 , bound water content declined to 1.42 g/gTS, and water content of dewatered sludge dropped to 59.79%. Meanwhile, microbial cells were inactivated by 47.3%, and extracellular protein-like components were degraded substantially, rendering the neutral potential and low apparent viscosity. PFS/O 3 treatment significant facilitated CHO-compound decomposition, reactions of nitrogenous groups, and P-containing biomolecule release. And more hydrophobic groups were exposed on the bio-matrix surface. Besides, polyhydroxy Fe as skeleton builder reconstructed sludge drainage passages for more water permeation. The predominant mechanism for enhancing sludge dewaterability in PFS/O 3 process was the oxidation role of improved • OH, and the chemical reaction chains were proposed tentatively. Moreover, this process simultaneously removed 26.95%–60.05% heavy metals and 31.18%–80.91% polycyclic aromatic hydrocarbons in dewatered sludge, and its chemical cost was preliminarily estimated as 88.80 USD$/tonTS. Therefore, the PFS/O 3 process was of great prospect and practical value in sludge treatment for dewatering and detoxification. • A new PFS-catalyzed O 3 process assisted sludge deep dewatering and detoxification. • EPS conformation turned to be loosened with more hydrophobic groups exposed. • Molecular composition and transformation of DOM were shown by ESI FT-ICR MS. • Chemical reaction mechanism of PFS-catalyzed O 3 was put forward for the first time. • Polyhydroxy Fe serving as supporting skeleton rebuilt multihole drainage passages.

Can the biological stage of a mechanical–biological treatment plant that is designed for mixed municipal solid waste be successfully utilized for effective composting of selectively collected biowaste?

Although the requirements for overall recycling rates can only be met when organic recycling is not overlooked, information is scarce regarding adaption to biowaste composting of existing mechanical–biological treatment (MBT) plants originally designed for stabilization of organic municipal solid waste (OFMSW). Thus, this study aimed to assess the suitability of the operational conditions in the biological part of a full-scale MBT plant now used for stabilization of OFMSW (working line: closed-module–covered-pile–open-pile) with a view to producing compost from biowaste. Temperatures above 75 °C were maintained in the closed module and reached again in the covered pile, indicating that intensive organic-matter mineralization occurred in both stages. In the covered pile, the temperature sharply decreased, indicating depletion of easily biodegradable organic matter. An aerobic 4-day respiration test (AT4) value below 10 mg O2/g dry matter, the cut-off for assessing compost stability, was obtained after 8 weeks. However, a high content of humic substances (HS), reflecting compost maturity, was obtained only after 120 days. The increase in HS content proceeded in two phases. In the first phase (45–84 day), the rate constant and the rate of HS formation were lower than in the second phase (84–120 day) (0.072 vs. 0.087 day−1, 1.97 vs. 3.06 mg C/(g organic matter·d)). All the above-mentioned indicators and the nutrient content (N, P, K, Mg, Ca) in the compost indicates that the biological stage of an MBT plant can successfully treat biowaste. This is in accordance with a circular economy and will contribute to increasing recycling rates.

Optimization of the Biostabilization Process of an Italian Mechanical–Biological Treatment Plant to Account for Changes in Waste Composition

In this paper, we present a case study on the optimization of the biostabilization process of an Italian mechanical–biological treatment (MBT) plant to account for changes in feed waste composition related to a progressive increase in separate collection of MSW fractions, biowaste in particular. After ten years of operation (2009–2019), a decrease of the stabilization degree of the output material of the plant was detected, with Dynamic Respiration Index (DRI) values above the established limit of 1,000 mgO2/kgVS/h (average values of 4,000 mgO2/kgVS/h determined weekly for eight weeks). The investigations carried out in 2019 on the waste samples feeding the MBT plant showed that paper and plastic materials constitute around 75% of the input waste to the two aerobic bioreactors of the MBT plant, against 55% at the start-up (2009). Furthermore, the airflow rates and the moisture content analyzed weekly for eight weeks in the bioreactors resulted below the optimal values suggested in the literature. To improve the performances of the biostabilization process, a series of modifications were implemented in the plant. The main modification involved the primary mechanical treatment by varying the mesh size of the screens to 50 mm circular holes mesh. Furthermore, the configuration of the aerobic bioreactors was changed by placing the two bioreactors in series (instead of the previous configuration in parallel) and using a screening unit (25 mm) between the two bioreactors instead of at the end of the process. In this way, the residence time of the materials in the aerobic treatment was enhanced from 16 days with the previous configuration to 27 days. Together with an increase of the airflow rates of around 40% and a water supply of approximately 10% in the bioreactors, these modifications allowed to achieve the desired stability of the output waste, with DRI values below 1000 mgO2/kgVS/h.Graphical

Environmental Comparison of Different Mechanical–Biological Treatment Plants by Combining Life Cycle Assessment and Material Flow Analysis

The role of Mechanical–Biological Treatment (MBT) is still of the utmost importance in the management of residual Municipal Solid Waste (MSW). These plants can cover a wide range of objectives, combining several types of processes and elements. The aim of this work is to assess and compare, from an environmental point of view, the performance of seven selected MBT plants currently operating in different countries, which represent the main MBT layout and processes. For the scope, a combined Life Cycle Assessment (LCA) and Material Flow Analysis (MFA) approach has been adopted to assess plant-specific efficiencies in materials and energy recovery. Metals recovery was a common and high-efficiency practice in MBT; further recovery of other types of waste was often performed. Each assessed MBT plant achieved environmental benefits: among them, the highest environmental benefit was achieved when the highest amount of waste was recovered (not only with material recycling). Environmental results were strongly affected by the recycling processes and the energy production, with a little contribution from the energy requirement. The impacts achieved by the MBT process were, on average, 14% of the total one. The main condition for a suitable MBT process is a combination of materials recovery for the production of new raw materials, avoiding disposal in landfill, and refuse-derived fuel production for energy recovery. This work can be of help to operators and planners when they are asked to define MBT schemes.

Anaerobic co-digestion of paper sludge: Feasibility of additional methane generation in mechanical–biological treatment plants

In this work, the feasibility of the anaerobic digestion of paper sludge as a co-substrate in anaerobic digestion mechanical–biological treatment (MBT) plants is investigated. In the first phase, the biochemical properties, biomethane potential (BMP), and pollutant contents of 20 different industrial paper sludges are determined. Following the general evaluation in the BMP tests, the second phase of the project involves the semi-continuous co-digestion of six paper sludges in continuous stirred reactors (CSTR). Paper sludges are categorized according to their origin within the pulp and paper mills: Deinking Sludge (DS), Primary Sludge (PS) and Biological Sludge (BS). The analysis of potentially inhibiting elements shows that the concentrations of chlororganic compounds, mineral oil and some heavy metals are highest in DS, while the mean heavy metal loads in all paper sludges are relatively low compared to other industrial sludges. Large differences in total solids (TS) and volatile solids (VS) contents are observed among the different paper sludges investigated, with DS having the highest TS due to the high inorganic contents. The BMP of the investigated sludges ranges from 90 to 355 NL CH4 kg−1 VS. In subsequent semi-continuous co-digestion experiments simulating MBT conditions, three DS and two fiber sludges (a mixture of PS and BS) show good methane generation rates, while one fiber sludge causes inhibition and indicates an increase in viscosity. In general, co-digestion of paper sludge in anaerobic digestion MBT plants can be a viable option for energy production and also facilitates a safe disposal of the paper sludge digestates.

Sludge pits of biological treatment plants and their reclamation

The paper describes different methods of sludge pits reclamation and biological methods of their purification. It shows that sludge pits purification becomes possible due to sludge dewatering and its membrane composting. Membrane composting at the moment helps solve different problems. The main danger lies in the fact that sludge pits pose a potential threat to water bodies pollution and are also a source of pathogenic microbiological pollution, as well as a source of unpleasant smells and harmful gases (methane, hydrogen sulfide, mercaptan, carbon dioxide, etc.). Excessive pressure, semi-permeable membrane shells and optimization of oxygen content are able to minimize this harmful effect. As a result of these procedures, silt and sludge turn into technical soil with a humidity of 40-50%, which can be used as a backfill. It is often used to restore recreational areas and to set out various plants as well. Due to its high content of phosphorus and nitrogen sludge is a very good fertilizer.

Applying novel methods in conventional activated sludge plants to treat low-strength wastewater

Conventional activated sludge system is confidently widely used for biological treatment plants of municipal wastewater but suffering from operation problems that affect their efficiencies and effluent qualities, especially when treating low-strength wastewater with increasing incoming flow. The objective of this study is to evaluate and compare the novel methods used in upgrading conventional activated sludge treatment systems receiving low-strength wastewater to generate good effluent quality. GPS-X Simulator V 8.0 was used for model calibration and plant performance prediction. The calibrated GPS-X model proved that eliminating primary settling from the treatment process does not affect BOD5 and COD removal, while TSS removal is decreased, and NH4-N removal is increased. Increasing the return activated sludge flow from 50 to 150% of influent flow does not affect conventional activated sludge process, while the change of waste activated flow had a vital effect on process performance. The presence of an anoxic zone in conventional activated sludge processes treating low-strength wastewater has no significant impact on plant performance. Also, the model outputs proved that adding filling media to the aeration tank was able to handle an increase of influent flow and a stable performance of BOD5, and NH4-N removal was observed.

Assessment of Pretreatments for Highly Concentrated Leachate Waters to Enhance the Performance of Catalytic Wet Peroxide Oxidation with Sustainable Low-Cost Catalysts

Matured compost, derived from a mechanical and biological treatment (MBT) plant, was used as a precursor to produce catalysts through hydrothermal and thermal carbonization, HC and PC, respectively. HC and PC displayed suitable properties to act as catalysts in the catalytic wet peroxide oxidation (CWPO) treatment of the highly polluted leachate waters generated in the same MBT plant (TOC0 = 27 g L−1; COD0 = 60 g L−1; BOD5,0 = 23 g L−1). The influence of catalyst loading and pH were studied, considering multiple additions of H2O2. The best experimental conditions found were T = 80 °C, pH0 = 3.0, 7.2 g L−1 of HC catalyst, 85.7 g L−1 of H2O2, added in five batches in one-hour intervals between each addition. Under these experimental conditions, removals of 43%, 52%, 93%, 82%, 35%, 95% and 93% for the COD, TOC, BOD5, aromaticity, chlorides, turbidity and color number (CN) were, respectively, observed. Ion exchange resins and coagulation–flocculation were studied as pretreatment options to reduce the complexity of the leachate waters and enhance the CWPO results. Both strategies resulted in higher mineralization and enhanced the consumption efficiency of H2O2 (ηH2O2). The sequential treatment using coagulation–flocculation and CWPO with PC catalyst showed the best results, achieving abatement of 94%, 70%, 98%, 93%, 31%, 96% and 95% for COD, TOC, BOD5, aromaticity, chlorides, turbidity and CN, respectively.

Оптимізована технологія отримання біодобрив на основі осадів стічних вод

Goal. To develop an optimized technology for the production of biofertilizers based on sewage sludge (SS) of biological treatment plants (BTP) “Pivdenna” and “Pivnichna” (Odessa) with the participation of microorganisms with phosphate-mobilizing properties. Methods. Generalization and analysis of research materials on biofertilizer production technologies, the calculation method of carbon/nitrogen ratio in composted substrates, agrochemical methods of biofertilizer research. Results. Optimized technology of producing biofertilizers involves composting SS with plant fillers with the inclusion in the technological process of a new biotechnological element — the introduction of a new strain of Microbacterium barkeri LP-1, which was isolated from SS of BTP Odessa with high phosphate-mobilizing properties. Conclusions. According to the results of research, the optimized technology of composting of municipal solid waste with carbonaceous plant fillers in the form of solid waste from agricultural production (winter wheat straw, sunflower seed husk) with the inclusion of a new biotechnological element – the introduction of a new strain of Microbacterium barkeri LP-1 with phosphate-mobilizing properties in the technological process, which allows managing the processes of composting waste (accelerate them) and ensures the improvement of the quality of the finished compost.

Delftia acidovorans: A Rare Pathogen Isolated from Pleural Fluid in an Immunocompromised Host

Delftia acidovorans is an aerobic, non fermentative gram negative rod that belongs to the Pseudomonas ribosomal Ribonucleic Acid (rRNA) homology Group III. The sources of isolation are sludge, biological waste water treatment plants. Patients in hospitals or with compromised immune systems are more likely to be affected. Delftia acidovorans can result in infectious endocarditis, ocular infections, otitis media, peritonitis, urinary tract infections, empyema, cavitary and interstitial pneumoniae, and nosocomial bacteraemia, including bacteraemia linked to central venous catheters in people with compromised immune systems. This case report is about a 57-year-old male with complaints of loss of appetite for six days and vomiting, as well as loss of weight. He was diagnosed with HIV two years ago and was on HAART (Highly Active Antiretroviral Therapy). This atypical bacterium was isolated from pleural fluid of the patient; and he was managed with albumin infusion, anticoagulants, beta blockers, fluid and salt restriction and intravenous antibiotics. It is an emerging source of Gram negative bacilli which is normally a non pathogen causing serious infections among immunocompromised patients.

Evaluation of the anaerobic degradation of food waste collection bags made of paper or bioplastic

The amount of compostable bioplastics collected with the food waste is constantly growing, particularly due to the bags used for collection. According to the Italian legislation, compostable bioplastics must be accepted by all biological treatment plants, including aerobic and anaerobic facilities. Anyway, the compostability standard requires only the assessment of the aerobic degradability, while it is generally not required to test the behaviour under anaerobic conditions. This aspect is evaluated in the paper, where the anaerobic degradability of bioplastic bags used for the food waste collection is assessed. First, Biochemical Methane Potential (BMP) tests were performed on four commercial types of bioplastic bags, including those designed only for the collection of food waste and the shoppers, that can be reused for the same purpose. Subsequently, an innovative approach for this kind of substrate was applied, subjecting two bags to semi-continuous co-digestion tests together with the food waste. Both tests were performed by comparing the behaviour of bioplastic bags with that of an alternative collection paper bag. Finally, tests to evaluate the influence of physical phenomena on the degradation of bioplastics were performed to better understand the results of biological tests. BMP tests indicated a good degradability (>71%) of bioplastic bags, while semi-continuous tests showed a much lower degradability (<27%), confirmed by the observation of the undigested bag pieces. On the contrary, the paper bag presents interesting characteristics, because its degradability in the semi-continuous tests (82%) resulted even higher than that observed in the BMP tests (74%). These results highlight an important difference between the bags mono-digestion by means of BMP tests and the semi-continuous co-digestion tests with food waste, which better simulate the full-scale operational conditions.

Occurrence, removal, and mass balance of contaminants of emerging concern in biological nutrient removal-based sewage treatment plants: Role of redox conditions in biotransformation and sorption

The study investigates the fate of 20 contaminants of emerging concern (CECs) in two full-scale wastewater treatment plants (WWTPs) based on the Biodenipho™ (WWTP 1) and anaerobic-anoxic-oxic (WWTP 2) processes. Samples of both the dissolved and solid phases (particulate and sludge) from all the wastewater and sludge processing-related units were studied using the mass balance approach to understand the distribution of CECs. The total mass load removal efficiency for anti-inflammatory (4), antibiotics (4), and hormones (5) was 76, 46, 93%, and 72, 38, 90% from WWTP 1 and 2, respectively. The mass load analysis showed that 8.3 kg and 6.5 kg of targeted contaminants enter the treatment plants per day while 0.35 kg and 0.32 kg are discharged along with effluent, and 1.5 g and 7.7 g (dry weight) are released through sludge in WWTP 1 and 2, respectively. Both biodegradation and sorption mechanisms depended on the redox conditions. Ammonia oxidizing conditions favoured the most for the biotransformation, followed by anaerobic and nitrate-reducing conditions. The study stresses the need for separate redox conditions for optimum removal of CECs and advanced tertiary treatment to remove recalcitrant compounds. The results help better understand the removal mechanisms of the CECs in BNR treatment.

Bioaerosol Emission from Biofilters: Impact of Bed Material Type and Waste Gas Origin

Three semi-technical scale biofilters were applied to treat waste gases at different industrial sites in Poland: a mechanical–biological treatment plant of municipal solid waste, a wastewater treatment plant and a food industry plant. Two types of materials were used as beds in the biofilters: stumpwood chips and pine bark, and stumpwood chips, pine bark and compost from green waste. Both bed materials supported the microbial growth and high numbers (106–108 cfu/g dry mass (DM)) of culturable bacteria, and fungi in beds were observed. There was no correlation between the number of microorganisms (cfu/g DM) and the respiratory activity in the biofilter beds. However, microbial respiration activity corresponded with microbial abundance expressed as microbial equivalents (ME), which was calculated based on adenosine triphosphate (ATP) determination. The biofilters either reduced or increased bioaerosol emissions from industrial plants, depending on the microbial content in the waste gases. A high microbial content in the waste gases made the effect of microbial emission from the biofilter bed negligible. The type of biofilter bed and number of microorganisms in the bed also influenced the final bioaerosol emission, but these factors were relevant for biofilters that treated waste gases with low microbial concentrations.

Застосування добрив на основі осадів стічних вод для додаткового фосфорного живлення рослин

Goal. To substantiate the use of fertilizers based on sewage sludge (SS) to increase soil fertility and crop yields through additional phosphorus nutrition. Methods. Field experiment — to determine the effectiveness of new types of bio-fertilizers based on SS, mathematical — to analyze and evaluate the reliability of the results. Results. In recent decades, there has been a decline in the livestock industry, which in turn has affected the decline in the production of organic fertilizers and, as a consequence, the deterioration of soil fertility and reduced agricultural productivity. This situation has led to the search for new types of fertilizer resources and the development of effective measures to increase the composition of phosphorus compounds available to plants. These are sewage sludge. One of the promising areas for solving the problem of soil enrichment with available phosphorus compounds for plants may be the composting of SS in urban treatment plants. The result of composting is an available organic product with the participation of phosphate-mobilizing microorganisms, which can be used in agricultural production. Conclusions. The prospects of using non-traditional organic fertilizers — SS and composts based on them — in increasing crop yields are shown. Thus, the main application of the studied types of non-traditional organic fertilizers based on SS of biological treatment plants (BTP) “Pivdenna” and “Pivnichna” (Odessa) with vegetable fillers (winter wheat straw, sunflower seed husk) under corn for grain yield provided an increase of yield ability of crop by 31.6–50.0%.

Identification and removal of sulfhydryl groups from wastewaters

Thiols represent a source of environmental pollution especially wastewater. This work proposed to study the elaboration of cellulose acetate polymer-based membranes for their application in the removal of a sulfhydryl groups of real biological treated wastewaters. The addition of nanoparticles to membranes improves the water purification capacity by promoting a good separation of sulfur, more particularly by ZnO-NPs. We used ultrafiltration membrane-assisted ZnO and TiO2 NPs application on real effluents from different biological treatment plants. We identified the hydrosulfite (thiol) group in wastewater and we used membrane processes ultrafiltration technique for sulfur removal. We evaluated the degradation of sulfur in biological treatment plants in Tunisia: The urban wastewater treatment plant or the conventional plant of Rades Malienne is a secondary biological wastewater treatment plant noted STEP1. The rural wastewater treatment plant based vertical flow planted with Phragmites australis from the Grombalia region noted STEP2 and rural wastewater treatment plant based horizontal flow planted with Phragmites australis from the Grombalia region noted STEP3. STEP1 is found to be more loaded with sulfur. Application of AC-ZnO membrane gives 99.07% and 99.55% of sulfur removal from wastewater of STEP1 and STEP3. STEP3 is 50 times less charged on sulfur than STEP1. We suggested that when the sulfur content is high, this leads to an increase in mineral elements. This could be explained by the interactions between thiols and the major elements that cause mineral pollution.