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During the past ten years, anaerobic process has become a popular technology for treating concentrated effluents. Research and development programmes led by both engineers and microbiologists have resulted in a better understanding of the microbiology of anaerobic reactions and reactor design for anaerobic processes. Considerable progress has been achieved in the development of high rate anaerobic reactors with several configurations for treating concentrated industrial effluents. In this review, attention is paid to highlighting the conceptual and full scale developments of anaerobic fluidized bed reactors, in respect of process performance, design concepts, start‐up of the reactor, stability of the system with respect to various operating parameters, reactor configurations, comparison with competing reactor designs for concentrated industrial effluents and kinetics and modelling of reactor systems.

The main purpose of this study is to provide a simple, efficient and economic system for saline wastewater treatment.

Industrial auditing was conducted to determine the water usage and wastewater characteristics during the manufacturing processes of pickling vegetables. In‐plant control measures were carried out prior to the end‐off‐pipe treatment. The treatment process was a simple pilot scale using two compartments alternated anaerobic fixed bed reactors (AAFBR).

The study indicated that applying the in‐plant control measures prior to final treatment of wastewater reduced the organic load and total suspended solids by almost 50 per cent. Post treatment of the end‐off‐pipe reduced the chemical oxygen demand, total suspended solids and dissolved salts by 84.2 per cent, 71 per cent and 52.4 per cent, respectively.

The proposed scheme was already implemented. The treated effluent from the factory was complying with the National regulatory standards for wastewater discharge into the public sewage network.

In this study tannery industrial wastewater was supplied from a leather industry plant in the south of Germany. An anaerobic pilot plant was erected for the treatment of this wastewater. Discusses the effect of such an anaerobic process with special reference to the fate of chronium and the other associated heavy metals throughout the process. The studied metals were Cr, Cd, Pb, Ni, Cu, Fe and Zn. The elimination rate of these metals throughout the anaerobic processes from the wastewater and the increasing rate of metal correlations in the sludge were studied extensively. Levels of Cr, Cu, Fe, Cd, Ni, Pb and Zn in the raw wastewater after acidification were 33.72, 0.13, 1.82, 0.06, 0.19, 0.21 and 1.07 mg/l respectively. In the sludge the levels were 6,296, 16, 141, 31, 12.4, 23 and 94 mg/kg dry weight respectively. The levels of these metals were decreased by stabilization. The overall results revealed that a remarkable decrease has been achieved in the reduction level of metals in the final wastewater. The elimination of such metals reached 98 per cent for Cr, 53.8 per cent for Cu, 81.3 per cent for Fe, 16.7 per cent for Cd, 21.1 per cent for Ni, 72.9 per cent for Zn. On the other hand, such metals were concentrated in the sludge, on the dry weight basis, up to the levels of 13,193 mg Cr/kg, 27.7 mg Cu/kg, 348 mg Fe/kg, 3.2 mg Cd/kg, 13.7 mg Ni/kg, 28 mg Pb/kg and 110 mg Zn/kg. Meanwhile, the studied anaerobic process exhibited significant improvement in the quality of the tannery wastewater to meet the guideline characteristics. However, the partial high level of Cr (III) and the other associated metals in the produced sludge strongly militate against the use of such tannery sludges as manure in agriculture.

In Turkey, treatment sludge that obtained from domestic wastewater and water treatment plants causes storage and disposal problems. In the current situation, there are 69 domestic wastewater treatment plants in Turkey and this corresponds to approximately 13% of the population. Total 500 thousand tons of treatment sludge is released from these treatment plants, annually. In the case of all municipalities establish a wastewater treatment plant in Turkey, approximately, 4 million tons of treatment sludge is projected to release in a year. Additionally, 3.6 million tons of treatment sludge will be obtained from the manufacturing industry. In other words, approximately 7.6 ↔ 10⁶ tons of treatment sludge potential exists in Turkey and in the same amount of the storage area (7.6 ↔10⁶m³) is needed for the storage of this treatment sludge, perennially.

In this study, energy production from wastewater treatment sludge through the anaerobic method has been investigated and compared to the aerobic treatment method. Also, advantages and disadvantages of both methods have been introduced. In order to determine biogas production capacity from treatment sludge, some amount of sample sludge has been taken from the final sedimentation tank before belt press in a wastewater treatment plant and it has been experimentally analyzed.

Examines the treatability of highly polluted wastewater from a dairy factory prior to its final disposal into the public sewerage system. Physical treatment of the dairy waste via aeration, followed by settling, resulted in a 25 per cent chemical oxygen demand (COD) reduction and elimination of odours. Chemical treatment achieved almost 50 per cent removal of COD. The chemical‐biological process using activated sludge/trickling filter resulted in 64 per cent and 90 per cent removal of the volatile organic matter value respectively. However, the quality of the waste produced does not meet with the National Regulatory Standards for wastewater disposal into the sewerage system. Chemical‐biological treatment using an upflow anaerobic reactor succeeded in reducing the pollutional parameters to coincide with the limits of the Egyptian Law 93/1962 and produces biogas as a source of energy at a rate of 0.39m³/kg COD removed.

Rough estimations of water gain through greywater reuse and rainwater harvesting together with energy recovery from wastewater generated from a fictitious eco-city of population 100,000 located in Istanbul, Turkey form the main framework of the study. As such, the highly important concept of water–energy nexus will be emphasised and domestic wastewater will be partly considered for water recycling and the rest for energy recovery. The paper aims to discuss these issues.

Distribution of daily domestic water consumption among different household uses and the population in the residential area are the two governing parameters in the practical calculation of daily wastewater generated. Therefore, domestic wastewater will be initially estimated based on population, and in turn, the amount of greywater will be found from the per cent distribution of water use. After segregation of greywater, the energy equivalency of the rest of the wastewater, known as blackwater, will further be calculated. Besides, the long-term average precipitation data of the geographical location (Istanbul) are used in determining safe and sound rainwater harvesting. Harvesting is considered to be only from the roofs of the houses; therefore, surface area of the roofs is directly taken from an actual residential site in Turkey, housing the same population which is constructed in four stages. Similarly, the fictitious eco-city in Istanbul is assumed to be constructed in a stage-wise manner to resemble real conditions.

The water consumption of the fictitious eco-city ABC is considered as 15,000 m³/day by taking the unit water consumption 150 L/capita.day. Therefore, total water savings through on-site reuse and reuse as irrigation water (9,963 m³/day) will reduce water consumption by 64 per cent. Minimum 40 per cent water saving is shown to be possible by means of only greywater recycling and rainwater harvesting with a long-term average annual precipitation of 800 mm. The energy recovery from the rest of the wastewater after segregation of greywater is calculated as 15 MWh/day as electricity and heat that roughly correspond to electricity demand of 1,300 households each bearing four people.

A fictitious eco-city rather than an actual one located in Istanbul is considered as the pilot area in the study. So far, an eco-city with population around 100,000 in Turkey does not exist. An important implication relates to rainwater harvesting. The amount of safe water to be gained through precipitation is subject to fluctuations within years and, thus, the amount of collected rainwater will highly depend on the geographical location of such an eco-city.

The study covering rough calculations on water savings and energy recovery from domestic wastewater will act as a guide to practitioners working on efficient water management in the eco-cities, especially in those that are planned in a developing country.

Practising water–energy nexus in an eco-city of population 100,000 regarding water savings and energy recovery from wastewater forms the originality of the study. Sustainable water use and energy recovery from wastewater are among the emerging topics in environmental science and technology. However, safe and sound applications are lacking especially in the developing countries. Guiding these countries with practical calculations on both water gain and energy recovery from wastewater (blackwater) is the value of the work done. Moreover, Istanbul is deliberately selected as a case study area for various reasons: its annual rainfall represents the worlds’ average, it is one of the most crowded megacities of the world that supply water demand from the surface water reservoirs and the megacity has not yet significantly increased wastewater reuse and recycling practices.

Chemical treatability of dairy wastewater originating from a dairy and dairy products plant at Istanbul was investigated on the basis of chemical oxygen demand (COD) parameter as a pre‐treatment alternative. FeCl₃, FeSO₄ and alum were used as coagulants in the jar‐test experiments of four sets of daily composite wastewater samples taken once every month. The effect of acid cracking has also been searched through acid addition and pH adjustment. Characterisation studies demonstrated that wastewater characteristics varied within a wide range in spite of no significant production changes at the plant during the experimentation period. Optimum coagulant dosage has been determined as 200mg l^–1 for all the coagulants with the optimum pH values between 4 and 4.5 for FeCl₃ and FeSO₄, and 5‐6 for alum. Maximum overall COD removal efficiencies were obtained as 72 per cent, 59 per cent and 54 per cent for FeCl₃, FeSO₄ and alum, respectively. Nevertheless, COD removal efficiencies were found to be inadequate to meet the current discharge standards of Greater Metropolitan Istanbul to sewer systems indicating that chemical treatment is insufficient for discharging chemically pre‐treated dairy wastewater to a sewage system, which was actually the main objective of the study. The results showed that the wastewater composition greatly influences the maximum removal efficiencies and also the conditions for optimum coagulation. However, attention to such chemical treatment studies on dairy wastewater has started to accelerate within the last decade in various countries of the world, such as United Arabic Emirates and Scandinavian countries where the targets of applying chemical treatment varied. In Scandinavian countries, biodegradable coagulants have been applied to use the sludge arising from the system for livestock feeding, leading to reuse of sludge. In Arabic Emirates, chemically treated dairy effluents are utilised for irrigation purposes. These recent studies point out that application of chemical treatment to dairy wastewater with various coagulants lead to a variety of utilities apart from being a pre‐treatment alternative.

About 50 epidemiological reports about possible associations between cancer morbidity and exposure to electromagnetic fields (EMFs) were published between 1979 and 1994. The majority of them (60‐75 per cent) documented a slight (1.5 to twofold) but significant increase in the incidence of certain rare forms of neoplasms (leukaemia, lymphoma, brain tumours). A limited support for carcinogenic potencies of EMFs is provided from cellular studies, but the effects appear to be generally weak, transient and difficult to replicate. Concludes that the available evidence associating cancer and EMF exposure is too tenuous to be convincing but too consistent to be ignored. Further progress needs better quantification of exposure levels and conditions, evaluation of dose‐effect relationships and liability to confounding carcinogenic factors that may influence morbidity rates in the investigated populations.

Micropollutants in the aquatic environment pose threats to both ecosystems and human health. Traditional wastewater treatment plants (WWTP) reduce some micropollutants, especially those who adhere to sludge or suspended matter. The hydrophilic micropollutants, on the other side, which may be non-biodegradable and resistant to UV-treatment etc. are typically transported untreated into the water recipients. This paper contains a literature study on the state of the art of advanced wastewater treatment technologies for reducing micropollutants such as pharmaceutical degradation products, personal care products, surfactants and industrial chemicals including heavy metals.

This literature study is completed using the most extensive and expansive literature database in the World to date, Google Scholar (GS). Published papers in recognized scientific journals are sought out in GS, and for relevance for this literature study, papers published here from 2016 and onwards (the last 5 years) have been chosen to eliminate irrelevant studies.

The result of the study is that there are many promising technologies on the market or emerging; however, no one solution treats every micropollutant equally well. Since advanced technologies often require expensive investments for municipalities and companies, it is important to identify which micropollutants pose the highest risk towards human health and the environment, because choosing systems to eliminate them all is not economically wise, and even choosing a system combining the existing technologies can be more expensive than states, municipalities and private companies are capable of investing in.

The research is limited to published papers on GS, which may omit certain papers published in closed databases not sharing their work on GS.

The practical implications are that practitioners cannot find go-to solutions based on the conclusions of the research and thus need to use the results to investigate their own needs further in order to make the wisest decision accordingly. However, the paper outlines the state of the art in advanced wastewater treatment and explains the benefits and downsides of the technologies mentioned; however, more research in the field is required before practitioners may find a proper solution to their specific issues.

The social implications are that the consequences of introducing a removal of micropollutants from the water environment can ultimately effect the citizens/consumers/end-users through added costs to the tariffs or taxes on advanced wastewater treatment, added costs on everyday goods, wares and products and added costs on services that uses goods, wares and products that ultimately produces micropollutants affecting the water environment.

This paper presents a much needed state of the art regarding the current advanced technologies to mitigate micropollutants in wastewater. The overview the paper provides supports politics on national as well as international levels, where larger unions such as the EU has stated that advanced wastewater treatment will be the next step in regulating pollutants for aquatic outlet.

This paper seeks to focus on energy recovery from municipal solid waste (MSW) in Croatia. The state strategy is based on the mechanical and biological treatment of waste in the future waste management centers (WMC). Left over after the treatment is waste that can be used as fuel (e.g. RDF).

Starting from the geographical distribution of waste generation (quantities and transport distances), taking into account the costs of collection, transfer and thermal treatment, recommendations on optimal number and size of the dedicated waste‐to‐energy (WtE) plants in Croatia as well as their potential locations are given. The opportunity of the cement industry to utilize ash from thermal treatment of waste in the process of the cement production and the RDF as a substitute fuel is also examined.

By varying the number of WMCs, the minimal specific cost of waste collection of €33 is obtained, for maximal number of WMCs, which is 21. The optimal capacity of WtE facility is approximately 300,000 t/year, for expected quantity of 600,000 t/year of waste available for energy recovery. However, the geographical shape of Croatia and traffic connections suggest that its area could be better covered by four WtE facilities, each with the capacity of 150,000 t/year. The alternative solution could include the existing cement industry. In this case one bigger WtE plant (preferably near the city of Zagreb) could be built, with the capacity of 400,000 t/year, while the rest of the waste would be used in the cement industry, which capacity amounts to 167,000 tons of RDF annually.

This analysis gives another view of a possible system for energy recovery from MSW in Croatia. MSW has never been used in Croatia for the purpose of energy generation on a wider scale.