Effect of metal content from sewage sludge on the growth of Orthosiphon stamineus

Municipal sewage sludge can be used as fertilizer as it contains a lot of nutrients. By focusing on copper (Cu), iron (Fe), manganese (Mn), and zinc (Zn) contents in municipal sewage sludge from primary oxidation ponds and in plant tissue sections, this study attempts to explain the relationship between plant yield and metal concentrations. Raw sludge samples were collected, air-dried, and ground to powder form at the beginning of fieldwork. The metal concentrations of sewage sludge were copper 6.9 mg/kg; iron 330.2 mg/kg manganese 6.7 mg/kg and zinc 9.1 mg/kg. Orthosiphon stamineus (cat’s whiskers) was selected and the plant received a different quantity of sludge application ranging from 1 g to 4 g per plant weekly for six consecutive weeks while observations were done for eleven weeks. Physical parameters such as shrub width and height were monitored to determine plant growth. Through this study, the determined optimum sewage sludge dosage for cats’ whiskers was between 2 to 3 g per plant.

Wastewater Treatment Process: A Modified Mathematical Model for Oxidation Ponds

Wastewater treatment aims to eliminate as many suspended solids as possible from the remaining water, known as effluent, before it is released into the environment. Pond oxidation methods have been practically proven successful for the wastewater treatment process because of their low construction and maintenance costs. This study aimed to investigate the degradation of wastewater pollutants through an oxidation pond treatment system. The purpose was to observe the relationship between the concentration of bacteria which are phototrophic and coliform, chemical oxygen demand (COD), and dissolved oxygen (DO). In this paper, a modified model consist of a set of an ordinary differential equation (ODE) has been developed by incorporating the Monod Equation. The model was solved numerically using the 4th order Runge Kutta method embedded in the MATLAB software. The sum of squared estimate of errors (SSE) for the modified model was compared with the SSE of the existing model. The results revealed that the modified model demonstrated a lower SSE compared to the existing model. Thus, the modified mathematical model gives better result than the existing model. The model provides an excellent approximation for concentration needed for an oxidized pond to produce good water quality.

Genome Sequences of Microviruses Identified in a Sample from a Sewage Treatment Oxidation Pond

Oxidation ponds are often used in the treatment of sewage as an aeration step prior to discharge. We identified 99 microvirus genomes from a sample from a sewage oxidation pond. This diverse group of microviruses expands our knowledge of bacteriophages associated with sewage oxidation pond ecosystems.

Stakeholders’ perceptions of environmental injustices and of community-based environmental education : a case study of the Stortplaats community in KwaZulu Natal

The purpose of this study was to investigate stakeholders’ perceptions of environmental injustices and of community-based environmental education at Stortplaats, in order to address the injustices through community-based environmental education. Environmental injustice is a phenomenon that entails the unfair distribution of environmental burdens, disproportionately exposing human life to environmental hazards. Communities in poor socio-economic circumstances are excessively exposed to negative environmental burdens such as sewage oxidation ponds, pollution, unprecedented land degradation due to sand poaching and inadequate infrastructure. Stortplaats faces such an oppressive environment. It was historically created by apartheid, but the current system seems to be paying minimum attention to corrective services. The stakeholder theory, environmental perception framework, place attachment theory and community-based environmental education model were used as frames of reference for this study. This study was informed by the interpretivist paradigm and the case study research design was adopted. A qualitative research approach was used. Convenience and purposive sampling were used to sample 25 participants who included five learners above 18 years, five educators, 10 community members, the chief, the community head, the councillor, a business person and the environmental health officer. Semi-structured individual interview schedules were utilised to gather data. These were complemented by photovoice narrations and indirect observation. A thematic data-analysis approach was used to analyse generated data. The key findings of the study indicate that apartheid contours are still visible at Stortplaats and postapartheid promises have not been kept. The findings also show that some community members lack knowledge about environmental policies and this results in irresponsible environmental behaviour. There is also lack of effective communication between leaders and community members, leading to struggles for power and recognition and causing poor service delivery. Finally, the findings show a need for community-based environmental education to address environmental injustices in Stortplaats.

Enhancing High-concentrated Wastewater Quality on Evaporation Rate from Five-Consecutive Oxidation Ponds as Located in Phetchaburi, Southerly Thailand

This research aimed to examine the environmental factors determining the rates of evaporation, a natural phenomenon contributing to the treatment of wastewater of 5-consecutive oxidation ponds of the King’s Royally Initiated Laem Phak Bia Environmental Research and Development Project. Data collected from the 17th of April to 30th of May 2019 by US Class A Evaporation Pan revealed that the sedimentation pond (Pond 1) has the highest rate, 7.22 mm d-1, the oxidation pond 1 (Pond 2), 5.70 mm d-1, the oxidation pond 3 (Pond 4), 5.56 mm d-1, the stabilization pond (Pond 5), mm d-1, the reference pond at 5.07 mm d-1 and the oxidation pond 2 (Pond 3), 3.59 mm d-1. Concluding the evaporation in domestic wastewater treatment plants is characterized by 1) heat generated from short and long wave radiation emitted by earth and the sun, 2) local wind profiles of the area affected the height differences of the roughness length, and 3) heat generated by the respiration and digestion process of microbial activities and other grey body contaminants. Presenting the day and night variations made for the analysis, the day evaporation was significantly higher resulted by the net radiation were accountable. Wind profile generated from the measurement of speeds and directions at two different sites at 3 and 10 m has explained for the roughness length heights over each pond as lower roughness height have cause the increased in the rates of evaporation in Pond 4 and 5 however, these process were also suppressed by high ionic bonding molecules effected suggested by the high TDS and EC values. The vertical temperature profile has conveyed the movement in the heat flux that dominated an upward flux movement in Pond 1. This is the exothermic reaction from the digestion process have suggested that extra heat has been added.