Deep ocean disposal of sewage sludge off Orange County, California: a research plan

Even though the discharge of sludge into the ocean via an outfall is not now permitted, this research plan has been prepared to show what could be learned with a full scale experimental sludge discharge of 150 dry tons/day by the County Sanitation Districts of Orange County into deep water (over 1000 feet). To provide a wide range of inputs and evaluation, a broad-based Research Planning Committee was established to advise the Environmental Quality Laboratory on the overall content and details of the research plan. Two meetings were held at EQL on: March 4-5, 1982: The entire Committee July 19-20, 1982: A working subgroup of the Committee The entire Committee is listed in Appendix B, with footnotes to indicate meeting attendance. Those unable to come to a meeting were asked to comment on the drafts by mail or telephone. We gratefully acknowledge the members of the Research Planning Committee for their generous help in formulating the research tasks and reviewing report drafts

An evaluation of metal removal during wastewater treatment: The potential to achieve more stringent final effluent standards

This is the author's accepted manuscript. The final published article is available from the link below. Copyright @ 2011 Taylor & Francis.Metals are of particular importance in relation to water quality, and concern regarding the impact of these contaminants on biodiversity is being encapsulated within the latest water-related legislation such as the Water Framework Directive in Europe and criteria revisions to the Clean Water Act in the United States. This review undertakes an evaluation of the potential of 2-stage wastewater treatment consisting of primary sedimentation and biological treatment in the form of activated sludge processes, to meet more stringent discharge consents that are likely to be introduced as a consequence. The legislation, sources of metals, and mechanisms responsible for their removal are discussed, to elucidate possible pathways by which the performance of conventional processes may be optimized or enhanced. Improvements in effluent quality, achievable by reducing concentrations of suspended solids or biochemical oxygen demand, may also reduce metal concentrations although meeting possible requirements for the removal of copper my be challenging

Application of NASA-developed technology to the automatic control of municipal sewage treatment plants

A search was made of NASA developed technology and commercial technology for process control sensors and instrumentation which would be applicable to the operation of municipal sewage treatment plants. Several notable items were found from which process control concepts were formulated that incorporated these items into systems to automatically operate municipal sewage treatment plants. A preliminary design of the most promising concept was developed into a process control scheme for an activated sludge treatment plant. This design included process control mechanisms for maintaining constant food to sludge mass (F/M) ratio, and for such unit processes as primary sedimentation, sludge wastage, and underflow control from the final clarifier

Effect of cytostatic drugs on microbial behaviour in membrane bioreactor system

The aim of this work is to evaluate the influence of cyclophosphamide and its principal metabolites (CPs) on microbial behaviour in a membrane bioreactor system. Two laboratory-scale membrane bioreactors (MBR) were run in parallel with a sludge retention time of 70 days (one with the cytostatic drugs, MBR-CPs, the second without, MBR-control). The microbial activity was measured by respirometric analysis. The endogenous and exogenous respirations of heterotrophic micro-organisms were evaluated. Micro-organisms exposed to CPs showed higher endogenous respiration rates and lower exogenous respiration rates than micro-organisms present in MBR-control. The effects were observed several days after adding the cocktail. Reduced sludge production was observed in MBR-CPs compared to MBR-control. This reduction of sludge production and the increase in the endogenous respiration rate in relation to MBR-control suggest that the chemical stress caused by CPs led to a diversion of carbon and/or energy from growth to adaptive responses and protection. In addition, the inhibitory effect on the assimilation of exogenous substrate (reduced exogenous respiration rate) suggests an inhibition of catabolism and anabolism despite the low CPs concentration studied (μg/L). However, this inhibitory effect can be offset by the biomass still active under low ratio (substrate/biomass) conditions in the bioreactor (due to complete retention of biomass and high sludge age), which helped to maintain high overall performance in the removal of conventional pollution

Performance of UK wastewater treatment works with respect to trace contaminants

This is the post-print version of the final paper published in Science of Total Environment. The published article is available from the link below. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. Copyright @ 2013 Elsevier B.V.This study examined the performance of 16 wastewater treatment works to provide an overview of trace substance removal in relation to meeting the objectives of the Water Framework Directive (WFD). Collection and analysis of over 2400 samples including sewage influent, process samples at different stages in the treatment process and final effluent has provided data on the performance of current wastewater treatment processes and made it possible to evaluate the need for improved effluent quality. Results for 55 substances, including metals, industrial chemicals and pharmaceuticals are reported. Data for sanitary parameters are also provided. A wide range of removal efficiencies was observed. Removal was not clearly related to the generic process type, indicating that other operational factors tend to be important. Nonetheless, removals for many substances of current concern were high. Despite this, current proposals for stringent water quality standards mean that further improvements in effluent quality are likely to be required

Forecasting wind speed data by using a combination of ARIMA model with single exponential smoothing

Wind serves as natural resources as the solution to minimize global warming and has been commonly used to produce electricity. Because of their uncontrollable wind characteristics, wind speed forecasting is considered one of the best challenges in developing power generation. The Autoregressive Integrated Moving Average (ARIMA), Simple Exponential Smoothing (SES) and a hybrid model combination of ARIMA and SES will be used in this study to predict the wind speed. The mean absolute percentage error (MAPE) and the root mean square error (RMSE) are used as measurement of efficiency. The hybrid model provides a positive outcome for predicting wind speed compare to the single model of ARIMA and SES

Model based study of autothermal thermophilic aerobic digestion (ATAD) processes : a thesis presented in partial fulfilment of the requirements for the degree of Master of Technology in Engineering and Automation of Massey University

An Autothermal Thermophilic Aerobic Digestion process, or ATAD process, is a relatively new sewage sludge treatment process. The ATAD process has been developed for the disinfection and stabilisation of sewage sludge, which is a by-product of wastewater treatment. The end product can be applied to the land as a soil additive or fertiliser with no restrictions, as the process dramatically reduces public health and environmental risks. The process is comparable to the composting process used for municipal solid waste and garden wastes. The process requires oxygen, usually in the form of air, to be applied to the sludge by an aeration system. The oxygen stimulates an exothermic biochemical reaction, which in turn heats the sludge up to thermophilic temperatures (between 50 and 65°C). At these temperatures the pathogenic bacteria, viruses and parasites in the sludge that are harmful to human health are effectively destroyed. The biochemical reaction also degrades a large portion of the organic sludge, which means that unstable, volatile odour generating substances are removed; this reduces the likelihood of smells and the attraction of flies and rodents (vector attraction) to the sludge.[FROM INTRODUCTION

Interpretation of the characteristics of ocean-dumped sewage sludge related to remote sensing

Wastewater sludge characteristics in general, and characteristics of wastewater sludges generated by the City of Philadelphia in particular, were addressed. The types and sources of wastewater sludges, a description of sludge treatment and disposal processes, examination of sludge generation and management for the City of Philadelphia, and definition of characteristics for typical east coast sludges undergoing ocean disposal were discussed. Specific differences exist between the characteristics of primary and secondary wastewater sludges, especially with the nature and size distribution of the solids particles. The sludges from the City of Philadelphia monitored during remote sensing experiments were mixtures of various sludge types and lacked distinguishing characteristics. In particular, the anaerobic digestion process exerted the most significant influence on sludge characteristics for the City of Philadelphia. The sludges generated by the City of Philadelphia were found to be typical and harbor no unique features

A framework for modelling, simulation and control of integrated urban wastewater system

This paper is concerned with the integrated modelling, and control of urban wastewater systems (UWS) comprising the wastewater treatment plants (WTP), receiving waters (river) and the sewer networks. A unified framework is developed and simple models are used and implemented in Matlab/Simulink to produce a toolbox. Novel linear and nonlinear control structures are then proposed to design integrated control systems to improve the river water quality. A case study is simulated and simulation results are presented to demonstrate the possible improvement that can be achieved using a holistic integrated control system approac