Waste management: a study on generating organic fertilizer from oil and grease trap systems

The grease and oil trap systems (GOTS) of four university food service establishments (FSE) were assessed and treated to evaluate the potential use of the sludge collected to produce compost. The sludge collected from each FSE was kept in a drying bed for 30 days (SDB), during which time calcium oxide was frequently added for stabilization. The sludge deposited monthly was reduced to half after the drying process and was then deposited in a composter and mixed for a period of 22 days with constant agitation. The compost obtained was treated with degrading enzymes and was denominated enzymatic composting (EC), while the remaining compost was not treated with enzyme and was denominated non-enzymatic compost (NEC). The total composting cycle of the sludge lasted 83 days, during which time various physical and chemical analyzes were conducted in the three types of substrates (SDB, NEC, and EC). The total time of the research was 2.5 years. The percentages of phosphorus, potassium, magnesium, and calcium suggest the use of the three substrates as organic fertilizer. A recommendation resulting from this research is to evaluate the sludge quality by mixing it with other substrates such as fruit peels with high nitrogen content and the sludge from wastewater treatment systems.

Diesel-Like Biofuels Production Using Fatty Waste

According to the waste-to-energy (WTE) valorization and circular economy principles, the use of waste oil and grease (WOG) for obtaining biofuels shows the tendency towards sustainability, makes the interest in green chemistry, and the development of environmentally friendly processes grow. Three different fatty wastes (from the fat trap of a sewage station, lard waste, and frying oil) were analyzed and this work showed they have no potentially toxic metals. The frying oil sample and residual lard waste showed a higher percentage of triacylglycerides resulting in higher biodiesel conversion. The samples showed physical and chemical properties (density, viscosity, and ash) within the limits established by current regulations. Bio-oil samples formed a mixture of carboxylic acids, with high acidity. However, the parameters that deviated from the maximum permitted by the standard could be adjusted blending with petroleum diesel, replacing partially the fossil energy carriers with biomass-derived energy carriers which could bring positive impacts from multiple perspectives, i.e., economic, environmental, and health.

Characterization and Assessment of Stormwater Runoff Quality from Automobile Workshops in Nigeria Using Multivariate Linear Regression

An investigation into the pollution of stormwater runoff from automobile workshops in Nigeria was performed. Also, multivariate regression was used to predict the pH, oil, and grease (O&G) as well as the electrical conductivity (EC) in relation to the characteristics of the solids and metals pollutants of the untreated automobile workshop stormwater. The results indicated that automobile workshops contributed notable amounts of pollutants to stormwater runoff. Results were compared with Nigerian and USEPA standards. It was found that most of the parameters had mean value ranges far greater than standard limits. The multivariate regression showed variations in the results obtained from different automobile workshops. These variations could be due to the influence of factors such as the volume of automobile servicing activities and the waste generated from these activities that flow in the stormwater runoff. However, the bulk of the EC and pH of the stormwater were associated with the concentrations of the total dissolved solids and copper while the bulk of the O&G concentration was associated with the concentrations of lead and cadmium. It is recommended to treat automobile workshop stormwater to prevent detrimental effects in aquatic systems. Future research is aimed at modeling such treatment using multivariate regression techniques is warranted.

Water reuse in the post-tanning process: minimizing environmental impact of leather production

The post-tanning wastewater is very diversified, as the post-tanning stage should meet the desirable properties of the leather for the final product, with low standardization of the process (compared to beamhouse and tanning). This makes post-tanning effluent reuse less feasible, and reuse in the post-tanning stage still needs to be explored. This work aims to evaluate the reuse of liquid effluents in the post-tanning process. The work methodology consisted of (i) characterization of water streams (groundwater, liquid effluent after primary treatment, and liquid effluent after secondary treatment); (ii) pilot-scale post-tanning tests using groundwater, primary effluent, and secondary effluent; (iii) characterization of the residual baths from pilot-scale tests (pH, conductivity, total solids, chemical oxygen demand, biochemical oxygen demand, chloride, hardness and oil and grease); and (iv) testing the leather obtained for total sulfated ash and organoleptic properties. Results showed that the primary effluent and the secondary effluent could be reused in pilot-scale post-tanning tests. There was an increase in the conductivity of the residual baths when liquid effluents were reused, which confirms the accumulation of salts in the effluents after their reuse.

Evaluation of a hydrocyclone system and ceramic membrane for oily water treatment purposes

The management of produced water is a huge challenge for oil companies, as environmental agencies use increasingly strict laws and require a primary treatment for the disposal of waste. The conventional methods used in the treatment of oily water, cannot satisfactorily remove the environmental laws. A system is presented, with a hydrocyclone built within LABDES/UFCG, tested and characterized with oily waters with different levels of oil concentrations, in order to study its efficiency. It was observed that for different oil concentrations in the hydrocyclone feed stream of (100 to 2000) mg L-1, total oil and grease, reached an efficiency above 85%. The set of ceramic membranes, MR01-10 and MR02-20, with porosities of 43% and 52%, were used in the assembly of two types of systems, SMC-DE and SMC-FC. SMC-FC showed a removal rate above 80% for an average production of 165 L h-1 m-2. However, SMC-DE proved to be more efficient in relation to TOG, above 98%, but less efficient in relation to the permeate production flow, 63.3 L h-1.m-2. The hydrocyclone system with cross-flow ceramic membrane (SH-MC/FC) was chosen to study the reduction of oil in oily water, for a concentration range of (200 to 2000) mg L-1, which presented a removal rate above 95%.

Treatment of wastewater from separators for rainfall runoff using electrochemical oxidation processes

In recent years, industry has increased and with it the amount of oily wastewater, which are considered hazardous waste because they contain various types of heavy metals and oils that endanger the environment and human health. In the last twenty years, there has been increased research on new technologies to treat wastewater as efficiently and environmentally friendly as possible. A recent approach to wastewater treatment is the application of electrochemical processes such as the electro-Fenton process, which belongs to the group of electrochemical advanced oxidation processes and electrocoagulation. The aim of this work was to remove organic contaminants and heavy metals from wastewater originating from oil and grease separators that clean stormwater runoff from traffic areas. The use of stainless steel, iron and aluminum electrodes results in electrooxidation, electroreduction and electrocoagulation. At a current of 15 A the treatment efficiency was 50% for COD and 73% for mineral oil. At a current of 110 A the treatment efficiency was 96% for COD and 90% for mineral oil.

Distribution of oil, grease and polycyclic aromatic hydrocarbons in coastal water and sediments of Suez Bay

The permanganate index (PI), oil and grease (O&G), and 17 polycyclic aromatic hydrocarbons (PAHs) were analyzed in surface sediment and water samples collected at 13 sites along the western coast of Suez Bay (SB). PI and O&G in the SB coastal seawater ranged from 9.6 mg O2 l−1 and 17.0 mg l−1 to 16.0 mg O2 l−1 and 37.0 mg l−1, respectively. The level of polycyclic aromatic hydrocarbons (PAH) in water and sediment in the SB offshore area was determined by gas chromatography/flame ionization detection. The concentration ranged from 0.574 to 16873.2 ng g−1 in the sediment and 0.502 to 43.540 ng l−1 in water. The collected data were compared with values reported in the literature. The possible source and origin of pollution was also assessed based on the determined relative PAH levels at the study sites, the ratio of low molecular mass PAHs (LPAHs) to high molecular mass PAHs (HPAHs), and molecular indices of samples.

The Treatment of Wastewater Produced from Al-Doura Refinery to Increase Production and Minimize Pollutant Materials

The undertaken study includes investigating the performance and effluent characteristics of the treatment plant of Al-Doura refinery. Influent concentrations for some important contaminants, which are TDS, oil and grease, TSS, COD, BOD, and turbidity were 2595 mg/L, 13934 mg/L, 466.45 mg/L, 2538.9 mg/L, 1739.2 mg/L, and 89.18 NTU, respectively, while the effluent concentrations were 1337.8 mg/L, 0.53mg/L, 21.7mg/L, 25.45 mg/L, 17.81 mg/L, and 7.08 NTU, respectively, giving removal efficiencies of 44.47%, 99.99%, 94.4%, 98.96%, 98.96% and 92.05%, respectively. All these results indicate that Al-Doura wastewater treatment plant was efficient in removing contaminants according to Iraqi and EPA specifications. Hence, the second part of this study concentrated on finding a simple and efficient treatment method to treat the effluent so that it can be reused in the boiler system. A pilot plant was designed and dedicated for this purpose, including three units of granular activated carbon filter, ultra filtration filter, and reverse osmosis filter. Average removal efficiencies of oil and grease, turbidity, COD, and BOD were 85.25%, 100%, 34.92%, and 31.11%, respectively at the granular activated carbon filter, with very low efficiencies for the removal of TDs and conductivity. Ultra filtration showed average removal efficiencies for COD and BOD of 30.81% and 32.31%, respectively. While the average removal efficiencies for TDs and conductivity was very low. The reverse osmosis filter removed TDs and conductivity very efficiently, giving average removal efficiencies of 97.63% and 95.43%, respectively. In addition, it provided good removal percentages for COD and BOD, with values of 61.73% and 64.1%, respectively. A recycling procedure was created and the results were eventually comparable to those conferred by some of the traditional approaches.

A new approach of the constrained groove pressing process on Al5083-O alloy using PMMA polymer, without die non-friction coefficient: nanostructure, mechanical Properties and hardness

The Constrained Groove Pressing (CGP) on annealed Al5083 (Al5083-O) alloy sheets by means of Polymethyl Methacrylate (PMMA) polymer is investigated in this research. Input parameters include Traverse Speed (1, 2, and 3 mm/min), Pass Number (1, 2, 3, and 4), and Lubricants (Grease, Oil, and without lubricants). Reciprocally, output parameters consist of Nanostructure (SEM and EBSD images), Hardness (HV), and Mechanical Properties – Impact Strength (kJ/m2), Tensile Strength (MPa), Young's Modulus (MPa), and Elongation (%). Revealed by the results, the impact strength is gradually improved in the 1st, 2nd, 3rd, and 4th passes by respectively adding oil and grease, compared to the state of using no lubricant. The impact strength results demonstrated that the addition of grease has a significant effect on the impact strength of composite samples. In order to build a high-quality product through the CGP process, it is very important for the mechanical properties to be based on the input parameters. In CGP processes, the Continuous Dynamic Recrystallization (CDRX) is considered as the ultrafine-grained mechanism. To predict the grain size evolution and the plastic deformation rate, the combination of Finite Element (FE) method and the ETMB model is utilized. Indicating the high generalizability and reliability as compared to other modeling methods, both the experimental test results and the ETMB model data, which have a higher degree of accuracy, are presented.

Bioaccumulation of auto-mechanic wastes in the tissues of Pellonula Afzeliusi (Johnels, 1954) collected from Agba stream Ilorin, Kwara State, Nigeria

Hydrocarbons and heavy metals (HM) present in automobile wastes get into water bodies close to automobile mechanic villages. They deteriorate the physico-chemical qualities of such water bodies and exert toxic effects on fish and other aquatic fauna. They also pose risks to humans that consume fish from streams near such automechanic villages. There is paucity of information on the HM contents of Agba stream, Ilorin and no information on the bioaccumulation of HM in the tissues of Pellonula afzeliusi is currently available. The purpose of this study was to assess the physico-chemical qualities of water and bioaccumulation of HM in the tissues of Pellonula afzeliusi fish collected from Agba stream, Ilorin, Kwara State, Nigeria. Water and samples of Pellonula afzeliusi were collected from the upstream (station A), midstream (station B) of Agba stream located close to an auto-mechanic village and Oyun dam (control site, station C) located within the University of Ilorin. Standard methods were used to analyse oil and grease (OG), total petroleum hydrocarbon (TPH) and HM in water samples. The concentrations of TPH and HM were analysed in the skin, bone, muscle, gills, gastrointestinal tract, liver and kidney of the fish. The order of water HM concentrations indicated Zn > Cd > Ba> Fe > Pb at station A; Cd > Zn > Fe > Ba > Pb at station B, and Zn > Ba > Pb > Fe >Cd at station C. TPH and HM bioaccumulated in the tissues of fish while lead was not detected in all tissues from station C. Bioaccumulation factor varied with the highest values t station C. The result of this study indicated heavy pollution burden in station B with lower pollution burden in station C (the control site). These call for attention of government in ensuring ecological restoration and prevention of further discharge of automobile wastes into the stream. Keywords: Automobile wastes, Heavy metals, Hydrocarbons, Bioaccumulation, Pellonula afzeliusi