Municipal Wastewater Treatment Works Research Articles

Microplastics act as a carrier for wastewater-borne pathogenic bacteria in sewage.

Microplastic pollution, a pressing global environmental problem, has a severe impact on both aquatic ecosystems and public health worldwide. Due to the small size of microplastics, they are able to pass through the filtration systems of municipal wastewater treatment works (WWTWs). In recent years, studies have focused on the environmental abundance and ecotoxicological effects of microplastics, but there are limited studies investigating the colonization of microplastics by bacteria, especially those pathogenic ones. In this study, we examined the colonization and composition of the bacterial communities on polyethylene microbeads after incubation in raw sewage collected from three municipal WWTWs in Hong Kong (Sha Tin Sewage Treatment Works, Stonecutters Island Sewage Treatment Works, and Shek Wu Hui Sewage Treatment Works). Scanning electron microscopy (SEM) results indicate that bacterial cells were colonized on the surfaces of the microbeads and formed biofilms after sewage incubation. Metagenomic sequencing data demonstrated an increase in bacterial diversity after 21 days of sewage incubation when compared to shorter incubation periods of 6, 11 and 16 days. Importantly, human and fish pathogens such as Arcobacter cryaerophilus, Aeromonas salmonicida, Vibrio areninigrae and Vibrio navarrensis were found in the resident bacterial communities. Taken together, our results demonstrate that microplastics could act as a carrier for wastewater-borne pathogenic bacteria in municipal sewage.

Optimisation of energy usage and carbon emissions monitoring using MILP for an advanced anaerobic digester plant

This paper proposes a realistic model for energy and carbon management of an advanced municipal wastewater treatment works. Through minimisation of total cost of operations, it provides operators with a visual daily operational schedule based on varying tariffs. This site is the first in the UK with a mixed operational strategy for biomethane produced on site: to burn in CHP (Combined Heat and Power) engines to create electricity, burn in Steam Boilers for onsite steam use or inject the biomethane into the gas distribution network - Natural Gas can be imported to make up shortfalls in biomethane if required. Implemented using a novel mixed integer linear programming (MILP) approach, results indicate that biomethane injection should be maximised for the highest financial gain - the driving force for optimising the remaining operations being the site electricity imports and whether the electricity imported ‘generates’ carbon emissions. Based on the source of electricity and the new carbon emissions performance criteria, under the current operational strategy importing electricity from carbon-based sources has no tangible impact on site revenues (but does impact CO2 emissions), however carbon free (renewable) electricity sources could see shift in operations leading a revenue increase of 12%

The Removal of Selected Inorganics from Municipal Membrane Bioreactor Wastewater Using UF/NF/RO Membranes for Water Reuse Application: A Pilot-Scale Study.

Membrane technology has advanced substantially as a preferred choice for the exclusion of widespread pollutants for reclaiming water from various treatment effluent. Currently, little information is available about Ultrafiltration (UF)/Nanofiltration (NF)/Reverse Osmosis (RO) performance at a pilot scale as a practical engineering application. In this study, the effluent from a full-scale membrane bioreactor (MBR) municipal wastewater treatment works (MWWTWs) was treated with an RO pilot plant. The aim was to evaluate the effect of operating conditions in the removal of selected inorganics as a potential indirect water reuse application. The influent pH, flux, and membrane recovery were the operating conditions varied to measure its influence on the rejection rate. MBR/RO exhibited excellent removal rates (>90%) for all selected inorganics and met the standard requirements for reuse in cooling and irrigation system applications. The UF and NF reduction of inorganics was shown to be limited to meet water standards for some of the reuse applications due to the high Electron Conductivity (EC > 250 μS·cm−1) levels. The MBR/NF was irrigation and cooling system compliant, while for the MBR/UF, only the cooling system was compliant.

Development of a biogas distribution model for a wastewater treatment plant: a mixed integer linear programming approach.

In this paper, we propose a realistic model for gas distribution of an advanced municipal wastewater treatment works and through minimisation of the total cost of gas distribution we perform retrospective optimisation (RO) using historical plant data. This site is the first in the UK with a mixed operational strategy for biomethane produced on site: to burn in combined heat and power (CHP) engines to create electricity, burn in steam boilers for onsite steam use or inject the biomethane into the National Grid. In addition, natural gas can be imported to make up shortfalls in biomethane if required. Implemented using a novel mixed integer linear programming (MILP) approach, to ensure a fast and robust solution, our results indicate the plant operated optimally within accepted tolerance 98% of the time. However, improving plant robustness (such as reducing unexpected breakdown incidents) could yield a significant increase in gas revenue of 7.8%.

Exclusion of Estrogenic and Androgenic Steroid Hormones from Municipal Membrane Bioreactor Wastewater Using UF/NF/RO Membranes for Water Reuse Application

In the context of water scarcity, domestic secondary effluent reuse may be an option as a reliable source for alleviating acute water shortage. The increasing risks linked with the presence of natural steroid hormones and many emerging anthropogenic micropollutants (MPs) passing through municipal wastewater treatment works (MWWTWs) are of concern for their endocrine-disrupting activities. In this study, domestic wastewater treated by a full-scale membrane bioreactor (MBR) at an MWWTW in the Western Cape Province, South Africa, was used directly as the influent to a reverse osmosis (RO) pilot plant for the removal of selected natural steroid hormones 17β-estradiol (E2) and testosterone (T) as a potential indirect water recycling application. Estrogenicity and androgenicity were assessed using the enzyme-linked immunosorbent assays (ELISA) and the recombinant yeast estrogen receptor binding assays (YES). The influent pH and flux did not influence the rejection of E2 and T, which was most likely due to adsorption, size exclusion, and diffusion simultaneously. RO and nanofiltration (NF) exhibited excellent removal rates (>95%) for E2 and T. All the E2 effluent samples with MBR/ultrafiltration (UF), MBR/NF, and MBR/RO were lower than the US EPA and WHO trigger value of 0.7 ng/L, as well as the predicted no-effect concentration (PNEC) values for fish (1 ng E2/L).

Industrial effluent treatment with immersed MBRs: treatability and cost.

A comprehensive OPEX analysis for both municipal and industrial wastewaters has been conducted encompassing energy, critical component (membrane) replacement, chemicals consumption, waste disposal and labour. The analysis was preceded by a review of recent data on industrial effluent treatability with reference to published chemical oxygen demand (COD) removal data for four effluent types: food and beverage, textile, petroleum and landfill leachate. Outcomes revealed labour costs to be the most significant of those considered, contributing 50% of the OPEX for a 10,000 m3/day capacity municipal wastewater treatment works. An analysis of the OPEX sensitivity to 12 individual parameters (labour cost, flux, electrical energy cost, membrane life, feed COD, membrane cost, membrane air-scour rate, chemicals cost, waste disposal cost, mixed liquor suspended solids (MLSS) concentration, recirculation ratio, and transmembrane pressure) revealed OPEX to be most sensitive to labour effort and/or costs for all scenarios considered other than a large (100,000 m3/day capacity) works, for which flux and electrical energy costs were found to be slightly more influential. It was concluded that for small- to medium-sized plants cost savings are best made through improving the robustness of plants to limit manual intervention necessitated by unforeseen events, such as electrical/mechanical failure, foaming or sludging.

Influence of composite particle formation on the performance and economics of grit removal

Grit is routinely removed at the headworks of municipal wastewater treatment works to limit its onerous impact on downstream processes. Grit separation technologies are normally based on sedimentation of a homogeneous material (usually sand). However, in practice inorganic grit particles are likely to be combined with organic matter, such as fats oils and grease (FOG), producing a composite particle whose settling properties vary with the inorganic/organic content.A study of the impact of particle composition on its sedimentation has been conducted encompassing theoretical description (for particle settling in transitional flow), practical measurement and economic analysis. Practical measurement included sedimentation tests of homogeneous and composite particles along with characterisation of accumulated granular material sampled from actual municipal wastewater treatment works. The economic assessment was based on data from full-scale installations in the UK and US pertaining to remedial measures undertaken as a result of grit impacts, primarily accumulation in vessels and channels and damage of mechanical equipment through abrasion.Practical tests revealed coating of the sand grains with a FOG analogue (candlewax) to generate composite particles containing 45% wax by weight. The coated particles were then 30% less dense, 22% larger and 14% less settleable, on average, than the uncoated particles. Samples of accumulated grit taken from anaerobic digesters and aeration lanes from a full-scale plant indicated a FOG content (43%) similar to that of the waxed particles in the bench-scale tests, thus leading to a similar grain retardation of 14% assuming the FOG to be entirely associated with the grit. An assessment of the impact of the consequential breakthrough of grit particles due to buoyancy generated by composite particle formation indicated a $1.1 increase in operating costs per megalitre (ML) wastewater.

Searching for indigenous anaerobic ammonium oxidizing (anammox) bacteria in South African habitats: Pretoria region

ABSTRACTIn South Africa, the information about the distribution and activity of anaerobic ammonium oxidizing (anammox) bacteria is very limited and anammox systems have not yet been tested and implemented. In this study, the existence and diversity of the anammox bacteria from various South African habitats are investigated. Batch systems were used to enrich anammox biomass from sludge collected from three Pretoria municipal wastewater treatment works. Anammox activity was tested and detected in two of the three wastewater treatment works after 90 days of primary enrichment. The activity was confirmed by consumption of both NH4 + and NO2 − in the system. The presence of anammox bacteria was also confirmed by polymerase chain reaction (PCR) amplification of the 16s rRNA of the anammox using anammox-specific primers. All clones retrieved were closely related to Brocadia species and were most abundant in all habitats tested. The maximum growth rate of anammox was also estimated on both experiments using a relatively new model.

Biogas production and feasibility of energy recovery systems for anaerobic treatment of wool-scouring effluent

The technical and economic feasibility of anaerobic digestion to produce biogas at a small wool-scouring facility in the United States was examined. The facility will process 90,800kg (200,000 pounds) of greasy wool per year at maximum capacity. Biochemical methane potential experiments showed that anaerobic biodegradation of organic constituents in wool-scouring effluent (WSE) ranged from 17 to 75% on a chemical oxygen demand (COD) basis and produced 0.10–0.39L methane per gram of WSE COD added. Microbial inhibition was observed when initial WSE concentrations exceeded 1000mg COD/L. A laboratory-scale continuous reactor operated at organic loading rates of 100–200mg COD/L/day produced biogas with an average methane content of 75% and provided 72–78% removal of total WSECOD. Life cycle costing predicted that the best alternative for energy recovery at a small wool-scouring facility was to offset natural gas used to heat water for wool-scouring with biogas. Economic feasibility should increase with increasing COD removal, increasing natural gas price, and increasing cost to discharge to the municipal wastewater treatment works. The key anaerobic treatment design challenge will be to maximize WSE organic loading rates while minimizing microbial inhibition.

The importance of assessment tools in promoting cleaner production in the metal finishing industry

Various cleaner production (CP) audits have been conducted in the South African metal finishing industry. These studies have been successful in effecting changes to the general status of the local metal finishing industry. In this paper, the initiatives undertaken by a Danish government sponsored project are detailed. The project included the conducting of in-plant assessments, using a tailor-made tool for CP benchmarking. Details on this tool's operations and typical results are presented. Typical assessments indicated potential water savings of 78%, with chemical savings of approximately 30%. The plant modifications undertaken in order to achieve the CP objectives, are described. The affects of these initiatives on local municipal wastewater treatment works are detailed with specific reference to significant reductions in incoming wastewater-borne heavy metals. The main challenge for companies has been data retrieval for the tool and overcoming social barriers for implementing the improvement options. Recommendations include redesigning the assessment tool.

Membrane operations

The success of any industrial pretreatment program is dependent on correct choice of technology and management. The rapid growth in the industrial sector has increased the mass of toxic and hazardous pollutants to the municipal wastewater treatment works. This may again inhibit the conventional biological treatment processes. Membrane separation is in this context a physical pretreatment process which splits the flow of water in two; a less toxic permeate and a more concentrated retentate. Typically, the volume reduction is one order of magnitude from the feedflow to the retentate. Engineering contractors in general do not possess proper knowledge of membrane technology to convincingly include membranes as a viable process option in design of pre-treatment systems. Attractive features of membranes are low weight and space requirements without use of chemicals. Moreover, the equipment is modular and can be scaled up or operated at partial capacity. The paper documents examples of accumulated field experiences with the intention to prove that membrane separation is a mature technology for the industry to utilize and for the engineering contractor to master. Also, the paper conveys information pertinent to advances in membrane separation to better enable academia to adjust curricula to meet industrial demands for separation engineers. The challenge is to pick the right membrane for a specific wastewater and couple the membrane to compatable auxiliary equipment such as pumps, pipes, valves and meters.

Aspects of the phosphorus cycle in Hartbeespoort Dam (South Africa) Phosphorus loading and seasonal distribution of phosphorus in the reservoir

Hartbeespoort Dam, a hypertrophic, warm monomictic impoundment in South Africa, receives extremely high phosphorus loads (14.6–25.9 g m−2 a−1) that are dominated by point source discharges from municipal wastewater treatment works. The reduced state of the phosphorus discharged from the works has led to the dominance of the dissolved phosphorus pool by low molecular weight orthophosphates which are analytically detectable as soluble reactive phosphorus (SRP; 60% of total phosphorus pool). Seasonality in the in-lake total phosphorus pool is regulated by a combination of abiotic and hydrological processes; biotic processes appear to play a minor role. Mass balance calculations indicate that between 62 and 77% of the annual total phosphorus inflow load is retained within the impoundment each year.

Investigations on the concentration of radionuclides in sewage sludges of Ruhrverband wastewater treatment plants 1960 through to 1986

The Ruhrverband operates a total of 118 municipal wastewater treatment works. Predominantly, biological treatment is applied. Annually, some 1.9 million m 3 of raw sludge is produced and mainly anaerobically digested. Supplementary to common analyses the digested sludges are investigated concerning radioactivity since 1960. Thus, the additional loading resulting from fall out and wash out after the reactor accident on 26 April 1986 in Chernobyl could be precisely recorded. p ]Prior to the description of the effects of the Chernobyl accident on river water, potable water and on wastewater sludges, a short background information on the occurrence of the accident and its consequences for the F.R.G. is given.

The Governance of the Metropolis as a Problem in Diplomacy

Previous articleNext article No AccessThe Governance of the Metropolis as a Problem in DiplomacyMatthew Holden, Jr.Matthew Holden, Jr. Search for more articles by this author PDFPDF PLUS Add to favoritesDownload CitationTrack CitationsPermissionsReprints Share onFacebookTwitterLinkedInRedditEmail SectionsMoreDetailsFiguresReferencesCited by The Journal of Politics Volume 26, Number 3Aug., 1964 Sponsored by the Southern Political Science Association Article DOIhttps://doi.org/10.2307/2127511 Views: 3Total views on this site Citations: 20Citations are reported from Crossref PDF download Crossref reports the following articles citing this article:Jay Rickabaugh Regional Public Sector Organizations: A broader taxonomic classification to cross‐pollinate empirical research, Public Administration 81 (Aug 2021).https://doi.org/10.1111/padm.12779David K. Hamilton Assessing the Future of Regional Governance in North America, (Jul 2012): 167–180.https://doi.org/10.1007/978-1-4614-1626-5_10David K. Hamilton The Government Centralization-Decentralization Debate in Metropolitan Areas, Review of Policy Research 21, no.55 (Sep 2004): 663–680.https://doi.org/10.1111/j.1541-1338.2004.00100.xVolker Schneider Organizational Governance — Governance in Organisationen, (Jan 2004): 173–192.https://doi.org/10.1007/978-3-531-90171-8_9James A. Visser Understanding Local Government Cooperation in Urban Regions, The American Review of Public Administration 32, no.11 (Jul 2016): 40–65.https://doi.org/10.1177/0275074002032001003H. George Frederickson The Repositioning of American Public Administration, PS: Political Science & Politics 32, no.0404 (Sep 2013): 701–712.https://doi.org/10.1017/S1049096500056547Joseph McCormick, Steven M. Teles Matthew Holden Jr.: Between Theory and Practice, PS: Political Science & Politics 31, no.0303 (Sep 2013): 653–657.https://doi.org/10.1017/S1049096500055074Kathryn A. Foster Regional Impulses, Journal of Urban Affairs 19, no.44 (Dec 2016): 375–403.https://doi.org/10.1111/j.1467-9906.1997.tb00503.xMichael N. Danielson, Paul G. Lewis City Bound: Political Science and the American Metropolis, Political Research Quarterly 49, no.11 (Jul 2016): 203–220.https://doi.org/10.1177/106591299604900113BRUNO DENTE Metropolitan Governance Reconsidered, or How to Avoid Errors of the Third Type, Governance 3, no.11 (Jan 1990): 55–74.https://doi.org/10.1111/j.1468-0491.1990.tb00107.xR L Morrill Regional Governance in the United States: For Whom?, Environment and Planning C: Government and Policy 7, no.11 (Mar 1989): 13–26.https://doi.org/10.1068/c070013John G. Heilman, Gerald W. Johnson SYSTEM AND PROCESS IN CAPITAL-INTENSIVE PRIVATIZATION: A COMPARATIVE CASE STUDY OF MUNICIPAL WASTEWATER TREATMENT WORKS, Review of Policy Research 8, no.33 (Mar 1989): 549–572.https://doi.org/10.1111/j.1541-1338.1989.tb00979.x John R. Logan Growth, Politics, and the Stratification of Places, American Journal of Sociology 84, no.22 (Oct 2015): 404–416.https://doi.org/10.1086/226790Max Neiman Analogues and Policy Analysis, American Politics Quarterly 5, no.11 (Nov 2016): 3–26.https://doi.org/10.1177/1532673X7700500101E. Torgovnik Urban Political Integration in Israel: A Comparative Perspective, Urban Affairs Review 11, no.44 (Jun 1976): 469–488.https://doi.org/10.1177/107808747601100403W. Bruceshepard Metropolitan Political Decentralization, Urban Affairs Quarterly 10, no.33 (Aug 2016): 297–313.https://doi.org/10.1177/107808747501000303Richard Child Hill Separate and Unequal: Governmental Inequality in the Metropolis, American Political Science Review 68, no.44 (Sep 2013): 1557–1568.https://doi.org/10.2307/1959941John Rehfuss Comparative Politics and the Study of American Local Government, Journal of Comparative Administration 3, no.44 (Sep 2016): 491–510.https://doi.org/10.1177/009539977200300405Timothy Schiltz, William Moffitt Inner-City/Outer-City Relationships in Metropolitan Areas, Urban Affairs Quarterly 7, no.11 (Aug 2016): 75–108.https://doi.org/10.1177/107808747100700105John J. Hebal APPROACHES TO REGIONAL AND METROPOLITAN GOVERNMENTS IN THE UNITED STATES AND CANADA, Canadian Public Administration/Administration publique du Canada 10, no.22 (Jun 1967): 197–208.https://doi.org/10.1111/j.1754-7121.1967.tb00975.x