Slaughterhouse Wastewater Treatment: A Review on Recycling and Reuse Possibilities

Slaughterhouses produce a large amount of wastewater, therefore, with respect to the increasing water scarcity, slaughterhouse wastewater (SWW) recycling seems to be a desirable goal. The emerging challenges and opportunities for recycling and reuse have been examined here. The selection of a suitable process for SWW recycling is dependent on the characteristics of the wastewater, the available technology, and the legal requirements. SWW recycling is not operated at a large scale up to date, due to local legal sanitary requirements as well as challenges in technical implementation. Since SWW recycling with single-stage technologies is unlikely, combined processes are examined and evaluated within the scope of this publication. The process combination of dissolved air flotation (DAF) followed by membrane bioreactor (MBR) and, finally, reverse osmosis (RO) as a polishing step seems to be particularly promising. In this way, wastewater treatment for process water reuse could be achieved in theory, as well as in comparable laboratory experiments. Furthermore, it was calculated via the methane production potential that the entire energy demand of wastewater treatment could be covered if the organic fraction of the wastewater was used for biogas production.

Physiology of milk production and modelling of the lactation curve.

Lactation is defined as the combined processes of synthesis, secretion, and excretion of milk, starting at calving and continuing until natural or induced drying off in the lactating female. Milk production follows a common pattern in several mammalian species known as a lactation curve. A typical lactation curve starts at day four after calving, reaching peak yield in early lactation, followed by a daily decrease in milk yield (persistency) until the lactating female is artificially dried off, or the lactation comes to a natural end. Mathematical models have been applied to lactation curves to provide information in relation to lactation curve parameters, providing valuable information for herd management and breeding decisions. Therefore, the aim of this study was to review the most used mathematical models for the prediction of dairy production curves. The importance of modelling lactation curves is to predict the yield for each day with the minimum possible error, to be able to elucidate the underlying pattern of milk production in the presence of local variation associated with the effect of the environment. The usefulness of any model of adjustment to the lactation curve depends on its capacity to mimic the biological process of developing milk production and to adjust the factors that affect it. Furthermore, these models can only be used to adjust productive records adequately, or to provide a biological understanding of the lactation process.

Development of Hydrolysis and Defatting Processes for Production of Lowered Fishy Odor Hydrolyzed Collagen from Fatty Skin of Sockeye Salmon (Oncorhynchus nerka)

Lipid oxidation has a negative impact on application and stability of hydrolyzed collagen (HC) powder from fatty fish skin. This study aimed to produce fat-free HC powder from salmon skin via optimization of one-step hydrolysis using mixed proteases (papain and Alcalase) at different levels. Fat removal processes using disk stack centrifugal separator (DSCS) for various cycles and subsequent defatting of HC powder using isopropanol for different cycles were also investigated. One-step hydrolysis by mixed proteases (3% papain and 4% Alcalase) at pH 8 and 60 °C for 240 min provided HC with highest degree of hydrolysis. HC powder having fat removal with DSCS for 9 cycles showed the decreased fat content. HC powder subsequently defatted with isopropanol for 2 cycles (HC-C9/ISP2) had no fat content with lowest fishy odor intensity, peroxide value, and thiobarbituric acid reactive substances than those without defatting and with 1-cycle defatting. HC-C9/ISP2 had high L*-value (84.52) and high protein (94.72%). It contained peptides having molecular weight less than 3 kDa. Glycine and imino acids were dominant amino acid. HC-C9/ISP2 had Na, Ca, P, and lowered odorous constituents. Combined processes including hydrolysis and defatting could therefore render HC powder free of fat and negligible fishy odor.

Intensification of heat and mass transfer and dewatering of thermolabile organic materials

Ukraine has a high level of industry, agriculture and consumption. As a result of underutilization of recovered materials and their products into the environment returns significant amount of waste that contaminate soil, water, air. Dumps occupy large areas, long ground beneath them put out of production, they pollute the environment. The main causes of waste, lack of effective processes and capacities of processing residues, spatial and chronological dissociation processes of waste and their use, lack of sufficient market. Of all the organic waste in Ukraine is one of the main places belong chicken droppings. Fresh droppings quickly oxidizes the soil, humus and inhibits microorganisms, disrupting its natural ecosystem biological community. With some preparation and processing of chicken manure is a high quality fertilizer that contains chemical elements (N, P, K), macro- and micronutrients, humic acid and other components that are essential for growth and fertility of different plants. For decontamination litter widely used thermal drying at t = 600 – 800 °C. This product is well kept dry, easily transported, but using traditional drying facilities for its handling used large amount of heat. Today continually created and offered new modern technologies for processing chicken manure. At the Institute of Engineering Thermophysics NAS of Ukraine many years conducted investigations on the creation of modern technologies and equipment for processing organic waste. Analysis of the traditional intensification methods and processes of heat and mass transfer during drying of materials was presented in the paper. The author has proved the promising nature of the method of the combined processes of drying and dispersion using a mechanical rotor to intensify the process of drying of high–moisture thermolabile materials.

Methods of trichlorosilane synthesis for polycrystalline silicon production. Part 2: Hydrochlorination and redistribution

Novel technical solutions and ideas for increasing the yield of solar and semiconductor grade polycrystalline silicon processes have been analyzed. The predominant polycrystalline silicon technology is currently still the Siemens process including the conversion of technical grade silicon (synthesized by carbon-thermal reduction of quartzites) to trichlorosilane followed by rectification and hydrogen reduction. The cost of product silicon can be cut down by reducing the trichlorosilane synthesis costs through process and equipment improvement. Advantages, drawbacks and production cost reduction methods have been considered with respect to four common trichlorosilane synthesis processes: hydrogen chloride exposure of technical grade silicon (direct chlorination, DC), homogeneous hydration of tetrachlorosilane (conversion), tetrachlorosilane and hydrogen exposure of silicon (hydro chlorination silicon, HC), and catalyzed tetrachlorosilane and dichlorosilane reaction (redistribution of anti-disproportioning reaction). These processes remain in use and are permanently improved. Catalytic processes play an important role on silicon surface, and understanding their mechanisms can help find novel applications and obtain new results. It has been noted that indispensable components of various equipment and process designs are recycling steps and combined processes including active distillation. They provide for the most complete utilization of raw trichlorosilane, increase the process yield and cut down silicon cost.

TRANSFORMATIVE LEADERSHIP IN MULTICULTURAL SCHOOLING CONTEXTS: A CRITICAL REFLECTION OF IN-SERVICE TEACHERS’ PRACTICES AND SCHOOL MANAGERS’ ROLES

In exercising their power and authority, School Management Teams (SMTs) should engage in transformative leadership which commences with interrogations regarding social justice, democracy and social responsibility. According to Freire’s philosophy of education it is further expected of SMT members to support and shape the belief that autonomy is a condition arising from the responsible engagement with decision-making; that we are ‘unfinished’ in our development as human beings; and that we are responsible for the development of a critical consciousness as a necessary condition of freedom and the creation of democratic and equitable learning spaces. In a transformative leadership context, authority must inform all critical practices of pedagogical intervention and goal setting should support in-service teacher’s autonomy, self-worth and develop their potential and the level of intrinsic motivation to flourish in inclusive school settings. This paper reports on a qualitative pilot study conducted with SMT members and teachers in the Northern Cape Province of South Africa to gain their insights regarding their roles as leaders in devising mechanisms to invest in radical democratic principles and the promotion of inclusive school practices. The key findings indicate that the SMT’s role require that they interrogate their frame of reference and transform their thinking in terms of social justice in multicultural school settings and create opportunities for in-service teachers to develop professionally and use digital technology creatively to enhance teaching and learning. As a force for transformation, we conclude that transformative leadership may be a catalyst to engage school leaders and teachers in individual and combined processes of awareness of inclusive practices and action.

Combined Granular Activated Carbon And UV/H₂O₂Processes For The Treatment Of Pharmaceutical Wastewater

The treatment of pharmaceutical wastewater was performed at the lab scale using UV/H₂O₂, process granular activated carbon (GAC) adsorption and their combination to investigate the total organic carbon (TOC) removal efficiency for different inlet TOC loadings and treatment times. Experimental study revealed that GAC adsorption alone had 81% efficiency in TOC removal in 10 min breakthrough time for flow rate of 0.6 L/min with granular activated carbon dosage of 333.33 mgActivated Carbon/L whereas UV/H₂O₂ process alone showed 26 and 29% TOC reduction at with 21.7 g/LH₂O₂ concentration with 254 and 185 nm wavelength lamps a 6 h hydraulic retention time, respectively, with average feed concentration (TOC) of 1,7555.75 mgC/L and COD of 5,214.6 mg/L at 25 ± 5°C. Experimental results showed that the optimum H₂O₂ dosage for the UV/H₂O₂ process was 1:2 stoichiometric COD: H₂O₂ molar ratio to achieve up to 26 and 29% TOC reduction efficiency than that at pH 12.01 which resulted 15-20% TOC reduction efficiency. The Bohart-Adams rate constants (K) and maximum adsorption capacity of carbon (N) from column breakthrough studies for synthetic pharmaceutical wastewater at 81% were found to be 7.10 x 10⁻³ L/(min.mgC) and 1.06 x 10³ mgC/L, respectively. In combined processes, it was found that GAC adsorption followed by desorption of contaminants from GAC by steam and UV₂₅₄/H₂O₂ treatment of the condensed steam let to 81% of TOC removal from the wastewater. Out of 358.73 mgC/L of TOC desorbed 88.1% of TOC was degraded in the UV₂₅₄/H₂O₂ treatment was degradation. Total operating cost of GAC adsortpion followed by desorption of contaminants from GAC by steam and UV₂₅₄/H₂O₂ treatment of condensed steam were found to be $11/L. While the pre-treated wastewater by UV₂₅₄H₂O₂ treatment followed by GAC adsorption, along the desorption of contaminants from GAC using steam and UV₂₅₄/H₂O₂ treatment of the condensed steam, let to an overall 81% TOC removal and 75.1% of TOC degradation using UV₂₅₄/H₂O₂ process. The cost of this combined treatment was found to be $6/L of wastewater treated which led to an economical saving of $5/L with respect to the combined TOC removal and degradation efficiency achieved. The savings predictions were achieved due to the less carbon dosage requirement and ability of UV/H₂O₂ process to degrade the TOC present in the wastewater. Based on single and combined treatments, the minimum total cost and time for 81% TOC removal were determined for the combination of UV₂₅₄/H₂O₂ treatment followed by GAC adsorption, along with desorption of contaminants from GAC using steam and UV₂₅₄/H₂O₂ treatment of the condensed steam. The overall minimum cost and minimum time were found to be $6/L of wastewater treated and 114.5 h, respectively. The treatment parameters and conditions for treating 30 L of the synthetic pharmaceutical wastewater were at an average feed concentration of TOC = 1,755.75 mgC/L and COD = 5,214.6 mg/L leading to TOC = 333.5 mgC/L of the effluent concentration which was near to the industrial effluent disposal level in Canada.

Combined Granular Activated Carbon And UV/H₂O₂Processes For The Treatment Of Pharmaceutical Wastewater

The treatment of pharmaceutical wastewater was performed at the lab scale using UV/H₂O₂, process granular activated carbon (GAC) adsorption and their combination to investigate the total organic carbon (TOC) removal efficiency for different inlet TOC loadings and treatment times. Experimental study revealed that GAC adsorption alone had 81% efficiency in TOC removal in 10 min breakthrough time for flow rate of 0.6 L/min with granular activated carbon dosage of 333.33 mgActivated Carbon/L whereas UV/H₂O₂ process alone showed 26 and 29% TOC reduction at with 21.7 g/LH₂O₂ concentration with 254 and 185 nm wavelength lamps a 6 h hydraulic retention time, respectively, with average feed concentration (TOC) of 1,7555.75 mgC/L and COD of 5,214.6 mg/L at 25 ± 5°C. Experimental results showed that the optimum H₂O₂ dosage for the UV/H₂O₂ process was 1:2 stoichiometric COD: H₂O₂ molar ratio to achieve up to 26 and 29% TOC reduction efficiency than that at pH 12.01 which resulted 15-20% TOC reduction efficiency. The Bohart-Adams rate constants (K) and maximum adsorption capacity of carbon (N) from column breakthrough studies for synthetic pharmaceutical wastewater at 81% were found to be 7.10 x 10⁻³ L/(min.mgC) and 1.06 x 10³ mgC/L, respectively. In combined processes, it was found that GAC adsorption followed by desorption of contaminants from GAC by steam and UV₂₅₄/H₂O₂ treatment of the condensed steam let to 81% of TOC removal from the wastewater. Out of 358.73 mgC/L of TOC desorbed 88.1% of TOC was degraded in the UV₂₅₄/H₂O₂ treatment was degradation. Total operating cost of GAC adsortpion followed by desorption of contaminants from GAC by steam and UV₂₅₄/H₂O₂ treatment of condensed steam were found to be $11/L. While the pre-treated wastewater by UV₂₅₄H₂O₂ treatment followed by GAC adsorption, along the desorption of contaminants from GAC using steam and UV₂₅₄/H₂O₂ treatment of the condensed steam, let to an overall 81% TOC removal and 75.1% of TOC degradation using UV₂₅₄/H₂O₂ process. The cost of this combined treatment was found to be $6/L of wastewater treated which led to an economical saving of $5/L with respect to the combined TOC removal and degradation efficiency achieved. The savings predictions were achieved due to the less carbon dosage requirement and ability of UV/H₂O₂ process to degrade the TOC present in the wastewater. Based on single and combined treatments, the minimum total cost and time for 81% TOC removal were determined for the combination of UV₂₅₄/H₂O₂ treatment followed by GAC adsorption, along with desorption of contaminants from GAC using steam and UV₂₅₄/H₂O₂ treatment of the condensed steam. The overall minimum cost and minimum time were found to be $6/L of wastewater treated and 114.5 h, respectively. The treatment parameters and conditions for treating 30 L of the synthetic pharmaceutical wastewater were at an average feed concentration of TOC = 1,755.75 mgC/L and COD = 5,214.6 mg/L leading to TOC = 333.5 mgC/L of the effluent concentration which was near to the industrial effluent disposal level in Canada.