Tolerable Risk for Hydrogen Sulfide in Sewage Treatment Plant- STP

Hydrogen sulphide is a toxic gas, it can cause a range of physiological responses from simple annoyance to permanent injury and death. There are a number of approaches to deal with the impacts of toxic gases. This study focused on minimizing the hazard exposure for hydrogen sulfide in the different operational zones for activated sludge process in sewage waterplant. Research tools/ approaches conducted were interviews, toxic gas testers, analysis report interpretation & quantitative risk assessment method. The study was conducted on Arabian Peninsula during the period (September 2019- September 2021). The (13) operational locations tested for toxic gas concentrations were inlet chamber, outlet channel, coarse /fine screens, primary sedimentation tank, activated sludge tanks, secondary sedimentation tanks, gas desulfurization unit, disc filters, chlorine dosing unit, sludge dewatering, sludge silos and digester tanks. The study found that the highest concentration for H₂S in the inlet chamber/ outlet channel. The severity hazards in the sewage treatment plant using activated sludge process are the asphyxiation by H₂S was extremely high can cause harm to public health, followed by the radiation hazard followed by electrical hazard, then (working at height, mechanical, traffic, health, chemical, physical, ergonomic, environmental, microbial and natural). The frequency of hazards occurrence is asphyxiation by H₂S was extremely high followed by the radiation hazard and health hazard including the infection with Covid 19 virus followed by mechanical hazard then (electrical, traffic, ergonomic, natural, chemical, physical and natural). Control measures were recommended to minimize the risk of asphyxiation by H₂S in the working environment at the STP.

Stability Analysis of Mechanical Sludge Dewatering Machine Frame Based on Numerical Simulation

Sludge is the inevitable product of sewage treatment plant and sewage treatment. Before sludge treatment, dewatering is generally required. Mechanical sludge dewatering machine is a common sludge dewatering equipment. Due to the complex operation conditions, the stability of sludge dewatering machine frame directly affects its reliability. In this paper, a mechanical sludge dewatering machine frame as the research object, based on ANSYS Workbench finite element analysis platform, static analysis and modal analysis. The analysis results show that: under normal working conditions, the maximum variable of the frame is 0.07mm, which can effectively ensure the normal operation of the sludge dewatering machine; the equivalent stress is 4.22Mpa, which is far less than the Xu Yong stress of the material; the vibration of the first two modes of the frame is relatively concentrated, and the corresponding motor speed under the interference frequency is 1241.4-1595.4r/min, which should be avoided in the use process.

POTENCIAL DE REÚSO DE EFLUENTES TRATADOS PARA IRRIGAÇÃO PERIURBANA NO MUNICÍPIO DE GUARABIRA/PB

POTENCIAL DE REÚSO DE EFLUENTES TRATADOS PARA IRRIGAÇÃO PERIURBANA NO MUNICÍPIO DE GUARABIRA/PB LIBIANE MARINHO BERNARDINO1; PATRÍCIA DA SILVA COSTA2; VERA LÚCIA ANTUNES DE LIMA3 E RENER LUCIANO DE SOUZA FERRAZ4. 1 Mestranda em Gestão e Regulação em Recursos Hídricos, Unidade Acadêmica de Tecnologia do Desenvolvimento, UFCG, Rua Luiz Grande, s/n, Frei Damião, CEP 58540-000, Sumé, PB, Brasil, [email protected] 2 Doutoranda em Engenharia Agrícola, Unidade Acadêmica de Engenharia Agrícola, UFCG, Rua Aprigio Veloso, 882, Universitário, CEP 58429-900, Campina Grande, PB, Brasil, [email protected] 3 Profa. Doutora em Engenharia Agrícola, Unidade Acadêmica de Engenharia Agrícola, UFCG, Rua Aprigio Veloso, 882, Universitário, CEP 58429-900, Campina Grande, PB, Brasil, [email protected] 4 Prof. Doutor em Engenharia Agrícola, Unidade Acadêmica de Desenvolvimento Sustentável do Semiárido, UFCG, Rua Luiz Grande, s/n, Frei Damião, CEP 58540-000, Sumé, PB, Brasil, [email protected] 1 RESUMO A água é um recurso finito que se encontra escasso, o que justifica a busca por gestão e inovação de práticas que a preserve. O objetivo da pesquisa é avaliar o potencial de reúso dos efluentes tratados para irrigação periurbana. Foram levantados dados de uma Estação de Tratamento de Esgotos (ETE), localizada no município de Guarabira, PB, e operada pela Companhia de Água e Esgotos do Estado da Paraíba (CAGEPA), durante o período de janeiro a dezembro de 2019. Analisou-se os seguintes parâmetros físico-químicos e bacteriológicos: Potencial Hidrogeniônico (pH), Condutividade Elétrica (CE), Demanda Bioquímica de Oxigênio (DBO), Demanda Química de Oxigênio (DQO), Sólidos Totais (ST), Oxigênio Dissolvido (OD), Fósforo Total, e Coliformes Termotolerantes. Os dados foram submetidos à análise descritiva e expresso em valores mínimos, máximos e médios. Os indicadores foram satisfatórios para irrigação restrita, porém com a necessidade de tratamento complementar para determinados cultivos. O potencial de reúso dos efluentes tratados na ETE pode beneficiar uma área de 118,7 ha considerando uma demanda de irrigação de 18.000 m³ ha-1 ano-1, o que demonstra ser um recurso sustentável e que precisa ser regulamentado no Brasil. Palavras-chave: recursos hídricos, resíduos líquidos, tratamento de água, fertirrigação. BERNARDINO, L. M.; COSTA, P. S.; LIMA, V. L. A.; FERRAZ, L. R. S. REUSE POTENTIAL OF TREATED EFFLUENTS FOR PERIURBAN IRRIGATION IN THE MUNICIPALITY OF GUARABIRA/PB 2 ABSTRACT Water is at the center of sustainable development and a finite resource that is in short supply, which justifies the search for management and innovation of practices that preserve it. This research aims to evaluate the potential for reuse of treated effluent for periurban irrigation. Data were collected from a Sewage Treatment Plant (STP), located in the municipality of Guarabira, PB, and operated by the Water and Sewage Company of the State of Paraíba (CAGEPA), during the period from January to December 2019, with the analysis of the following physicochemical and bacteriological parameters: Hipogenic Potential (pH), Electrical Conductivity (CE), Biochemical Oxygen Demand (DBO), Chemical Oxygen Demand (DQO), Total Solids (ST), Dissolved Oxygen (OD), Total Phosphorus, and Thermotolerant Coliforms. The data were submitted to the descriptive analysis and expressed as minimum, maximum and average values. The indicators were satisfactory for restricted irrigation, but with the need for complementary treatment for certain crops. The potential for reuse of the effluents treated in the ETE can benefit an area of 118.7 ha considering an irrigation demand of 18,000 m³ ha-1 year-1, which demonstrates to be a sustainable resource that needs to be regulated in Brazil. Keywords: Water resources, liquid waste, water treatment, fertigation.

A New Imagination for Waste and Water in India’s Peri-Urban Interface

Cities are often seen as incubators for enterprise and innovation. However, in this urbanisation era, we seem to suffer from a lack of imagination on how to handle the many environmental problems associated with expanding cities. This is especially true in the case of the peri-urban interface (PUI), a geographical and conceptual landscape with which the city core often has a contentious relationship. In this chapter we look at the complex linkages between water and waste in the PUIs of two metropolitan cities: Bengaluru and Kolkata. We look at two water systems: Kannuru lake in Bengaluru and Kolkata’s wetlands. Kannuru is a freshwater lake that supported traditional livelihoods and subsistence use by local communities, while Kolkata’s peri-urban wetlands not only served as the city’s natural sewage treatment plant but also enabled agriculture and aquaculture. Urbanization has adversely impacted both these water systems. Kannuru lake is threatened by a landfill on its periphery, while sewage-based farming and fisheries in Kolkata’s wetlands have been impacted by changes in land use and composition of sewage. We unravel the complexity in the waste-water relationship, where waste is seen as a pollutant in one and as a nutrient in the other. We attempt to understand how we can re-envision waste and water linkages in the PUIs of expanding cities if India needs to move towards a sustainable future.

Phosphitispora fastidiosa gen. nov. sp. nov., a new dissimilatory phosphite-oxidizing anaerobic bacterium isolated from anaerobic sewage sludge

A new strictly anaerobic bacterium, strain DYL19T, was enriched and isolated with phosphite as the sole electron donor and CO2 as a single carbon source and electron acceptor from anaerobic sewage sludge sampled at a sewage treatment plant in Constance, Germany. It is a Gram-positive, spore-forming, slightly curved, rod-shaped bacterium which oxidizes phosphite to phosphate while reducing CO2 to biomass and small amounts of acetate. Optimal growth is observed at 30 °C, pH 7.2, with a doubling time of 3 days. Beyond phosphite, no further inorganic or organic electron donor can be used, and no other electron acceptor than CO2 is reduced. Sulphate inhibits growth with phosphite and CO2. The G+C content is 45.95 mol%, and dimethylmenaquinone-7 is the only quinone detectable in the cells. On the basis of 16S rRNA gene sequence analysis and other chemotaxonomic properties, strain DYL19T is described as the type strain of a new genus and species, Phosphitispora fastidiosa gen. nov., sp. nov.

Nitrogen Removal by an Anaerobic Iron-Dependent Ammonium Oxidation (Feammox) Enrichment: Potential for Wastewater Treatment

Nitrogen pollution in water is a growing concern. Anthropogenic activities have increased the amount of nitrogen released into watercourses, which harms human health and the environment, and causes serious problems, such as eutrophication. Feammox is a recently discovered biological pathway associated with the nitrogen cycle that has gained scientific interest. This process couples anaerobic ammonium oxidation with iron reduction. This work presents a study on the Feammox mechanism from the enrichment of an activated sludge obtained from a sewage treatment plant. The enrichment was carried out at neutral pH to study the N2 pathway, that is, the Feammox process with the oxidation of ammonium (NH4+) directly to N2. In addition, different sources of iron were studied: iron chloride (FeCl3); ferrihydrite; and goethite. The characterization of the sludge showed the genes associated with ammonia monooxygenase, nitrate and nitrite reductases processes, along with relevant microbial species. The enrichment, carried out for 42 days and monitored every 14 days, showed that FeCl3 as a source of Fe was more effective for the coupled process of oxidation of NH4+ and the reduction of Fe(III) to Fe(II). At the end of the enrichment period, a removal of 31% and 32.2% of NH4+, and an increase in Fe(II) concentration by 52.4 and 63.9 times regarding the initial value were achieved in aerobic and anaerobic sludge, respectively. This study provides information on the potential of Feammox in the removal of N from wastewater, and the oxidation/reduction yields in the initial enrichment phase.

Pine Wood and Sewage Sludge Torrefaction Process for Production Renewable Solid Biofuels and Biochar as Carbon Carrier for Fertilizers

This work presents the results of research on the thermo-chemical conversion of woody biomass–pine wood coming from lodzkie voivodship forests and sewage sludge from the Group Sewage Treatment Plant of the Łódź Urban Agglomeration. Laboratory scale analyses of the carbonization process were carried out, initially using the TGA technique (to assess activation energy (EA)), followed by a flow reactor operating at temperature levels of 280–525 °C. Both the parameters of carbonized solid biofuel and biochar as a carrier for fertilizer (proximate and ultimate analysis) and the quality of the torgas (VOC) were analyzed. Analysis of the pine wood and sewage sludge torrefaction process shows clearly that the optimum process temperature would be around 325–350 °C from a mass loss ratio and economical perspective. This paper shows clearly that woody biomass, such as pine wood and sewage sludge, is a very interesting material both for biofuel production and in further processing for biochar production, used not only as an energy carrier but also as a new type of carbon source in fertilizer mixtures.