Wastewater Flow Research Articles

Shrimp cracker industrial wastewater treatment with aerobic biological properties utilizing modified Contact-Stabilization method

The prawn cracker industry is one of the most common types of food industry in Indonesia. The existence of this industry has a positive impact in maintaining and improving the Indonesian economy, but it can also have a negative impact on the environment in particular, because this industry produces wastewater which can have a negative impact on the aquatic environment if the wastewater is directly discharged into the river. Based on the results of the analysis of the quality of wastewater from one of the shrimp cracker industries, it is known that wastewater contains Chemical Oxygen Demand (COD) which is 3446 mg/L, Biological Oxygen Demand (BOD) 1118.9 mg/L and acidity (pH) 5.88 – 6.13. Referring to the wastewater quality standards for the shrimp cracker industry, namely COD: 120 mg/L, BOD: 50 mg/L, and acidity pH: 6-9, the shrimp cracker industrial wastewater must be treated first before being channeled into the body. river receiving water. In this study, the treatment process used is an aerobic biological process with a modified contact-stabilization method. This method is the development of the contact-stabilization method, where in this modified method the wastewater from the treatment is recycled to the stabilization tank and together with the bacteria is transferred to the contact tank. Variations carried out in this study are the incoming wastewater flow rate (liters/hour): 4,5 ; 5.5; 6.5 ; 7.5 and 8.5 and flow rate of recycled water from treatment to stabilization tank (%) : 10 ; 20 ; 30 of the incoming wastewater flow rate. The best results were obtained at the wastewater flow rate of 5.5 liters/hour and the recycled water flow rate from the treatment to the stabilization tank 20% with a decrease in the COD value of 97.3% and BOD of 98.4% and the pH of the treated water 6.9.©2021 JNSMR UIN Walisongo. All rights reserved.

Experimental study on three simple tracers for the assessment of extraneous water into sewer systems.

In recent years, three simple tracers (conductivity, turbidity and temperature) have shown their advantages to many other tracers for tracing and assessment of extraneous water (or inflow and infiltration, I/I) into sewer systems due to low detection cost and high monitoring frequency. A better understanding of the error and uncertainty of the three simple tracers on the quantification of I/I will help to improve the reliability and reduce the cost of actual projects. A large-scale experimental model simulating a 36 m long sewer was constructed for conducting extraneous water flow tests including groundwater infiltration, wastewater inflow and hot water inflow under different I/I flow rates and concentrations. The accuracy and uncertainty of the three tracers were estimated, and their correlation with tracer concentration difference before and after extraneous inflow was also analyzed. Experimental results provide guidance for the practical applicability of the three tracers under different I/I conditions.

Assessing the effect of hydrothermal treatment (HT) severity on the fate of nitrates and phosphates in dairy wastewater

Dairy production facilities play a significant role in the local economy of Lesvos Island. The high production levels of dairy are also connected to high production levels of dairy wastewater, which has a notable pollution load and can exceed COD values of 70000 mg/L. Therefore, treatment of dairy wastewater before disposal is a necessary step. This study monitored the biggest commercial dairy production facility on Lesvos Island, implemented mass and energy balances for a whole calendar year, and applied hydrothermal treatment (HT) on the dairy wastewater in order to examine the effect of HT on the pollution load. The novelty of the study is highlighted on the sampling of different flows of dairy wastewater, on the examination of a wide range of conditions for HT treatment and on the assessment of the HT treatment effect specifically on the concentrations of phosphates and nitrates. HT experiments were performed in a HT reactor for a temperature range of 120 °C – 200 °C and for residence times of 30 – 120 min. The implementation of mass and energy balances showed that 30 t of input milk resulted to more than 50 t of produced dairy wastewater. The effect of the HT - according to its severity - was assessed in respect to the COD, the pH values, the volatile solids content, and primarily the phosphates and nitrates concentrations. HT reduced the COD from 75 g/L down to 62.2 g/ L but increased the nitrates from 25 to 427 mg/L and the phosphates from 260 to 410 mg/L. For the examined conditions, higher temperatures and residence times enhanced the dispersion of nitrogen and phosphorus in the aqueous phase.

PENGARUH WAKTU KONTAK AIR LINDI DAN UDARA TERHADAP LAJU KOROSI BAJA ST-41 DAN ST-60

The use of metals in the environment is especially important in environments such rubbish in heavy equipment or trucks, especially those of the tailgate is a tool to bring a variety of organic waste and inorganic bring the matter dissolved through a liquid called leachate and make contact or direct contact with the steel so that corrosion occurs due to leachate or wastewater flow contains many corrosive compounds that make part tailgate become quickly corroded. This study aims to determine the bias steel resist corrosion rate. The steel used is steel steel ST-41 and ST-60 is a low carbon steel and medium carbon steel. The methods used in research in the methods of losing weight and observe the types of corrosion that occurs by means of immersion with ASTM G31-72 which vary contact time for 3 weeks. Based on research conducted showed the corrosion rate of the fastest occur in steel ST-60 with a contact time of 1 week soaked the leachate and 2 weeks in contact with the air due to differences in the composition of the steel ST-60 and steel ST-41 which has a chromium content so high that steel ST-41 is superior in resisting corrosion rate while the type of corrosion that occurs is evenly corrosion and atmospheric corrosion.

Designing the sewerage network of the city in purpose to reduce impact to the environment and water bodies

Today, the study of the city’s sewerage network is an important part of the life of the city and the environment. Ensuring optimal living conditions not only for oneself, but also for other participants in the environment should be a priority for a person. Today we can face various problems that complicate the operation of the city sewer network and can cause detrimental effects on the environment. To prevent this impact on the environment, you first need to understand the cause of this impact, and then look for a solution. Wastewater is a pollutant of rivers, lakes and the water system in general. Wastewater is formed in connection with human activity, the appearance of rainwater, as well as under the influence of industrial enterprises. The purpose of the article is to develop the management of wastewater flows within the city sewer network to ensure the highest quality water clarification and minimize environmental harm.

Assessment of contamination of the estuarine area of the Northern Dvina River by calculating background concentrations (Fe, Mn, Zn, Cu, Cd, Pb, and Ni)

This publication is a continuation of research on the quantitation of the heavy metal contamination level (Fe, Mn, Zn, Cu, Cd, Pb, and Ni) in the ecosystem components of the estuarine area of the Northern Dvina River. To assess the contamination level with these metals in the ecosystem of the Northern Dvina estuarine area in the spot of the highest anthropogenic load (the area of Novodvinsk – Arkhangelsk – Severodvinsk urban agglomeration), we use the method of comparative analysis of the study object with the background plot – the river section above urban development. Using spatial mapping of the enrichment factor values for the aquatic ecosystem components, areas with abnormal excess of metal content in mollusc tissues, bottom sediments, and bottom water layer were determined. As established, the area adjacent to the city center and to an industrial zone on the left bank is subject to the highest anthropogenic load in the water area of the river delta top. The most likely sources of contamination with the considered heavy metals are the inflow of surface wastewater (meltwater and rain storm runoff), untreated municipal wastewater, and direct short-range atmospheric transport. The analysis of mollusc tissues proved to be a more informative and indicative approach to the assessment of the heavy metal contamination in water areas with complex hydrological and hydrochemical environmental gradients than the analysis of bottom water layer and bottom sediments.

A novel approach to baseline water quality assessment at local and catchment scale: a case study from Berambadi, India.

Optimal design and maintenance are necessary for the sustainability of wastewater treatment systems. In this study, we present the outcome of a novel approach to baseline assessment conducted prior to the design and deployment of a decentralized wastewater treatment system at a school in rural India. The baseline water quality monitoring protocol was deployed to assess (a) the quality and quantity of wastewater (greywater and blackwater) flows from the school and (b) the status of surface water and groundwater quality in the catchment. Hourly greywater flows and water quality trends were monitored across four seasons at the school. Average freshwater consumption at the school was 518 ± 322 L/day for hand washing and 287 ± 97 L/day for cooking meals. Greywater generation showed high hourly variations in COD levels. Greywater generated from hand wash and kitchen sources contributed to 110g/day and 96g/day of BOD5 respectively and 214g/day and 141g/day of COD respectively. Based on additional data from a self-reporting sanitation survey, the organic contaminant load generated from the toilet was estimated to be 1.5 ± 0.1kg COD/day. At the catchment scale, both groundwater and surface water quality were monitored seasonally to assess the impact of raw sewage and stormwater inputs. Compared with borewells, high nitrate-N levels (> 10mg/L) were observed in the village hand pump samples throughout the year. Maximum nitrate-N (16mg/L) and fecal coliforms (3.9 log MPN/100mL) levels were observed in surface waters during monsoons, indicating the impact of sewage and surface runoff on water quality. The proposed approach is useful to estimate data on freshwater use and wastewater generation at the school and hence to make the case for, and design of, a sustainable water management intervention.

Quali-quantitative characterization of biogas with the temporal behavior of organic load on wastewater treatment plant with upflow anaerobic sludge blanket reactors through measurement in full‑scale systems

This study aims to present the time behavior of wastewater flow parameters, organic matter, biogas flow, biogas composition, and its relations, measured through online sensors, in a municipal wastewater treatment plant (WWTP) operating full-scale upflow anaerobic sludge blanket (UASB) reactors, installed in the south of Brazil. WWTP has online measurement devices to evaluate some physicochemical variables of the sewage and the biogas. The COD analyzer (UV– Vis probe), ultrasonic flow meter, biogas flow meter, and biogas composition analyzer were the equipment used. The monitoring occurred for two time periods each of 72 h and one time period for 48 h in the year 2018. Data were checked with descriptive statistics, data independence was checked through the autocorrelation Box– Ljung test, normality behavior was checked with several tests (Shapiro– Wilk, Kolmogorov–Smirnov, Lilliefors, Anderson–Darling, D’Agostino K2, and Chen–Shapiro), and Spearman’s correlation coefficient was used to evaluate the correlations among the parameters. The mean sewage flow was 345 ± 120 L.s-1; removed organic load was, in average, 48%; biogas quality values were 82.32% ± 3.62% v/v (CH4), 2.66% ± 1.19% v/v (CO2), and 3453 ± 1268 ppm (H2S); and the production per capita obtained was 4.51 ± 1.65 NL.hab-1.d-1. It was estimated an electric power generation of 3118.6 kWh.d-1, which is equivalent to an installed power of 130 KW. The behavior of removed organic load and biogas flow (Nm3.h-1), produced in the treatment plant, showed variable, periodic, and nonstationary time behavior.

Temporal variations of antibiotic resistance genes in influents and effluents of a WWTP in cold regions

Diurnal variation in wastewater flows is a common phenomenon associated to peak water use periods. However, short-term variations of ARGs in WWTPs are not clear due to relatively long sampling intervals or inadequate sampling modes. Therefore, a one-year experimental study was conducted to reveal the time-scale changes in ARG abundance in a WWTP. In particular, sample surveys were carried out to determine the inter-day and intra-day fluctuations in the absolute abundance of several ARGs. Hourly measurements of the ARG absolute abundances revealed three peak concentrations at 9:00–11:00, 17:00–19:00 and 23:00–1:00 due to peak use of toilet in morning and evening. The relative standard deviations (RSDs) in effluent were about three times lower than that in influent due to the mixing and treatment of wastewater treatment process. And the peak effluent discharge was related to the influent fluxes and hydraulic retention time. Seasonality in ARG absolute abundance was found for all target ARGs, with the highest in spring and the lowest in summer. The absolute abundance in spring was one order of magnitude higher than that in summer. In general, the fluctuation of ARG absolute abundance was mainly evident at the intra-day scale, while the variation of the inter-day scale was relatively small. The relative abundance of ARGs showed less temporal variations than that of absolute abundance, indicating that normalization ARGs to 16S rRNA may correct for minor variations in sample processing. Based on the removal rate of ARGs, hydraulic retention time (HRT) was recommended as a guiding principle for sampling strategies. Data from this study are needed for future sampling activities focusing on ARGs and estimating peak concentrations discharged from wastewater sources.

Minimizing greenhouse gas emissions of an industrial wastewater treatment plant in terms of water\u2013energy nexus

In this paper, (CO2) and methane (CH4) emissions of an industrial wastewater treatment plant were monitored. GHG emissions originated from treatment processes were considered as the direct emissions and determined using closed chamber method. GHG emission due to energy consumption was regarded as the indirect emissions. In the second stage of the study, it was aimed to reduce GHG emissions in terms of water–energy nexus. If the plant is operated under design conditions, energy consumption would be lower according to water–energy nexus. Also, the effect of design conditions on GHG emissions was investigated. Firstly, the correlation was defined between GHG emissions and operational parameters in terms of chemical oxygen demand (COD) and wastewater flow rate using Monte Carlo simulation. Then, design COD and wastewater flow rate were simulated to determine the possible GHG emission for each month. The simulation results show that minimization of GHG emissions might be possible if wastewater plant is operated under design conditions. The minimum greenhouse gas emission in the result of the simulation study is 8.25 kg CO2-eq/d if the plant is operated under design COD and flow rate. Total reduction in GHG emissions is approximately 30% if the plant is operated under design conditions.

Effect of small-scale illegal mining on surface water and sediment quality in Ghana

ABSTRACT In Ghana, small-scale mining (SSM) has been carried out for many years, generating employment and income. Currently, illegal artisanal mining (‘galamsey’) has impacted the environment negatively, resulting in land degradation and water pollution. The government of Ghana, responding to public outcry against the negative effects of ‘galamsey’, placed a ban on illegal small-scale mining activities in March 2017. This ban stopped both ‘legal’ small-scale and the illegal artisanal miners from carrying out any such activity. In July 2018, this study was carried out to examine the status of water and sediment quality in eight endemic regions of illegal mining to ascertain the outcome of the ban on the water quality of the rivers. Methodologies in the Standard Methods for the Examination of Water and Wastewater were followed. Results of the study indicated that the rivers were high in total suspended solids (TSS), turbidity and colour, suggesting inflow of wastewater from the illegal mining activities and some run-off. Colour had a strong correlation with turbidity (r = 0.95) and TSS (r = 0.94), suggesting that the pollution originates from the same sources. Low levels of metals were found in both water and sediment. However, very high concentrations of Fe were detected in both water and sediment. Mercury concentrations were low in the water column but relatively higher in the sediment. A comparison of the general water quality status of the water bodies in the Pra Basin in 2013 and 2018 using the Water Quality Index (WQI) showed a marginal improvement in quality in 2018 over 2013 in the Pra Basin. The improvement of water quality in 2018 is attributable to the ban.

Action Plan for Urban Waste Water Recycling in Lucknow

Abstract: Urban waste water generation per day in Lucknow city is 84 MLD and the treatment capacity of this urban waste water is 446 MLD and 445 MLD urban waste water flows in Gomti River and 339 MLD urban waste water partially treated. Some waste water is recycled by Water treatment plant which are treating 560 MLD urban waste water and remaining are polluted to ground and as well as gomti river.to achieve 100% recycling and treatment we need a action plan for it. The formation of Lucknow municipal board took place in 1882, while as the water supply demand is fulfilled by tube wells, river Gomti, Sharda Sahayak feeder canal, aquifers, and so on, the maximum source of intake is Gomti which is geographically distinguished as Cis and Trans Gomti. The Cis Gomti side is comparatively lower than the area on Trans Gomti side. Since the city is located on alluvial aquifers of Indo-Gangetic plain, where due to easy accessibility, private tube well construction activity is going on unchecked, especially in residential colonies and multi-storeyed buildings, and this is the reason why the private tube wells/borings have almost mushroomed in this capital city. This has led to heavy pumpage/continuous abstraction of groundwater resources, widespread depletion of aquifers and as a result, going down of groundwater levels drastically to almost unsustainable levels, from where it seems very difficult that the depleted conditions of ground water could ever improve (6). The water supply network depends on sources like tube wells, river Gomti and the Sharda Sahayak feeder canal. The distribution of water supply has a very vast network and it is reported to be 2884 km. The rate of water supply is assumed to be 150 LPCD and water demand is calculated accordingly, The availability of water, as reported by Jawaharlal Nehru national urban and rural mission (JNNURM) on November 2016, was 619 MLD from various sources, however, it keeps fluctuating as the city is more vulnerable to migration from other parts of state. Keywords: urban waste water, waste water recycling, reuse of waste water, sewage treatment plant

Unravelling capability of municipal wastewater treatment plant in Thailand for microplastics: Effects of seasonality on detection, fate and transport

Many factors can affect microplastics (MPs) behaviors in aquatic environments. The effects of seasonal and meteorological conditions on MPs are not well understood. This study demonstrates the impacts of seasonality on the fate and transport, and the efficacy of MPs removal by a wastewater treatment plant. The fate and transport of MPs at a WWTP in Nonthaburi, Thailand were tracked during the dry and wet seasons of 2019–2020. Polypropylene (PP), polyethylene (PE), and toothpaste formulations were the most abundant MP types observed. Total detected MP quantities ranged between 76 and 192 particles L−1 during the dry season, and only 36–68 particles L−1 during the wet season, indicating runoff dilution effects. T-test analysis found a statistically significant difference between MP concentrations between the dry and wet seasons of 2019–2020. Spearman's correlation showed statistically strong negative relationships between MP concentrations versus wastewater flow, and MP concentrations versus precipitation; a positive correlation between MP abundance versus temperature in the treatment system was observed. During the dry seasons, MPs were mostly found in the aeration process, and were mostly rayon or polyester particles in the shape of fibers. Contrarily, in the wet seasons, MPs were detected in both the raw influent and aeration process, with PE, polyacrylate, and polyethylene terephthalate fragments dominating the make-up. MPs were also detected in the return activated sludge, thus calling for proper sludge age and drainage management. No MPs were detected in the plant's effluent during the wet season, suggesting that the plant had sufficient MPs removal capability during normal wet-season conditions. Overall, this study suggests that municipalities should focus on increasing MPs removal efficiency of wastewater treatment plants for dry seasons, while properly managing the water flows of combined sewage systems to prevent overflows that may inevitably become point-sources of MPs release into water bodies during wet seasons.

Impact of Hospital Wastewater on the Occurrence and Diversity of Beta-Lactamase Genes During Wastewater Treatment with an Emphasis on Carbapenemase Genes: A Metagenomic Approach

The diversity of beta-lactam antibiotic resistance genes, with particular emphasis on carbapenemase genes, during the treatment process at two wastewater treatment plants (WWTPs) with different levels of hospital wastewater inflow was investigated using high-throughput sequencing. An additional aspect of the study was to determine the taxonomic diversity of microorganisms in the studied samples. The obtained results suggest that bacteria of the Fusobacteriaceae family, not associated to date with this phenomenon, may be involved in the spread of antibiotic resistance in the environment. In samples from both wastewater treatment plants, the dominant beta-lactamase genes included blaOXA, blaGES, blaBEL, blaCfxA, and blaTEM. It is worth noting that the blaKPC and blaNDM genes were only found in untreated municipal wastewater with a higher hospital wastewater content. Moreover, an increase in the abundance of the blaIMP gene after the biological treatment stage in the studied treatment plants was found. In wastewater characterized by a higher proportion of hospital wastewater, 94 correlations were observed, while in wastewater with its lower proportion, 41 correlations were noted. Considering the above, the current research indicates that the inflow of hospital wastewater contributes to the spread of antibiotic resistance in the aquatic environment.

Assessment of Human Stability in Sewer Systems during Dry Weather Conditions

Inspection and maintenance tasks are essential to guarantee the correct operation of sewer drainage networks. In combined sewers, these tasks are generally carried out during dry periods when only wastewater flow circulates in the system. When the sewer is big enough to allow the access of people, this inspection is done in person with consequent potential exposure to several hazards such as the presence of toxic gases, the possibility to fall or the loss of stability due to the presence of a continuous wastewater flow. In this context, this paper presents a methodology to assess hazard conditions related to human stability in sewer systems during dry weather periods. Hazard assessment has been performed by applying several hazard criteria to the results of a 1D sewer model simulations regarding a real network in Spain. Results show that the influence of the selection of hazard criteria is relevant, although only a small part of the whole system can be classified as high hazard. Regardless, the proposed method is highly effective to detect these kinds of pipes and we consider them as critical point to improve health and safety procedures during maintenance and inspection tasks.

Analysis of the Water Quality Characteristics of Urban Streams Using the Flow–Pollutant Loading Relationship and a Load Duration Curve (LDC)

For urban streams, wastewater inflow makes water quality management difficult. This study attempted to analyze the water quality characteristics and pollution sources for the efficient management of water quality in the upper, middle, and lower Gul-po stream reaches. The water quality and flow characteristics for each point were analyzed using five-year water quality and flow discharge data at Gul-po stream from 2016 to 2020. The results showed that the flow increased and the water quality improved in the upper part of the stream, under the influence of a treated water discharge. The flow–pollutant loading equation revealed that the flow coefficient (slope of the regression equation) values of the water quality characteristics, except T-N, were lower than 1 in the upper part, indicating that the water quality decreased as the flow increased. In the middle and lower parts, the flow index values of the water quality characteristics, except T-N, were greater than 1, indicating that the water quality increased with the flow. For the middle and lower parts, the overage rate of target water quality by the Ministry of Environment was high for high-flow discharge sections, indicating the significant influence of nonpoint pollution sources. These results show that it is necessary to consider different pollution sources at each point for urban stream quality management.

Continuous two phase partitioning bioreactor (C-TPPB) for removal of xenobiotics: Design criteria

This paper proposes a new continuous two phase bioreactor (C-TPPB) configuration for the removal and degradation of xenobiotic compounds from wastewaters. The reactor is made of three principal parts: a tube side in which the wastewater flows; a polymeric membrane which constitutes the tube walls; a shell side, set as a continuous stirred tank reactor (CSTR), in which the xenobiotics are degraded by means of a bacterial population. A mathematical model for the system description was developed and validated by means of fitting using literature experimental data obtained from a similar configuration. Since the nature of the fitting parameters did not depend upon the particular set-up, such validation procedure was possible. A dimensionless analysis was also carried out by defining a modified Stenton (St’) and Damköhler (Da’) number in order to detect the C-TTPB design criteria. The removal of 4-NtiroPhenol was reported as a case study and an algorithm for a preliminary design procedure was developed.

Experimental development of the plate shower heat exchanger to reduce the domestic hot water energy demand

The article describes an experimental development of a new prototype of the horizontal plate shower exchanger for wastewater heat recovery. The prototype is designed so that while achieving the highest possible value of efficiency, it also respects the requirements of the spatial arrangement of the heat exchanger casing and, thus, allows an appropriate flow of wastewater on both sides of the heat transfer surface. At the same time, emphasis is placed on the smallest possible height of the heat exchanger casing with regard to the minimisation of the built-up space and the expected wastewater flow during the shower cycle. Experimental testing was performed according to the conditions meeting the certification criteria of the Passive House Institute, while for a given heat exchanger, the investigated flows and water temperatures, as well as the heat transfer efficiency of the new prototype was determined, reaching peak values ​​of up to 62%. An energy analysis and derivation of the equation was also performed, according to which it is possible to determine the achieved heat savings in the preparation of domestic hot water from the heat transfer efficiency of the exchanger, including all heat losses of the system. With new prototype, heat savings more than 21% are achieved.

Combined sewer overflow treatment: Assessing chemical pre-treatment and microsieve-based filtration in enhancing the performance of UV disinfection

Disinfection of combined sewer overflow (CSO) is necessary to reduce the amount of microorganisms discharged into surface waters. In this study, an efficient and cost-competitive treatment for CSO, employing UV disinfection, was developed. High suspended solids content in CSO poses a significant challenge for UV disinfection so laboratory experiments were carried out to asses the effect of chemical pre-treatment followed by micro-sieve filtration on the reduction of total suspended solids (TSS) and the increase of UV transmittance (UVT). The efficiency of UV, with and without pre-treatment, was investigated and a microbial inactivation model was developed to describe the fecal coliforms (FC) inactivation kinetics. Finally, the environmental impacts of the proposed treatment were simulated at the large-scale by stormwater management model (SWMM), and the cost of the proposed treatment train was evaluated and compared with current CSO treatment strategies.Experimental results showed that UV alone achieved 3.6-log reduction of FC at a UV fluence of 80 mJ/cm2, while a 4-log reduction of FC was achieved at a much lower UV fluence of 10 mJ/cm2, when the UV disinfection was preceded by chemical pre-treatment and microsieving filtration using a 32 μm mesh. Under these conditions, the TSS removal achieved was 73%, and the UVT increased from 14% to 32%.The SWMM showed that the proposed CSO treatment achieved a reduction in TSS by one order of magnitude and a decrease in number of FC from 1.05 × 1014 to 1.24 × 1010 CFU. The cost analysis performed herein suggests that the proposed treatment train is competitive to current CSO treatment strategies in terms of cost-effectiveness.The study demonstrates the potential of the innovative CSO treatment scheme to quickly and effectively treat a large amount of wastewater flow thus providing municipalities with a low footprint treatment unit for CSO.

АНАЛИЗ ТЕХНИЧЕСКИХ РЕШЕНИЙ КОМПАКТНЫХ УСТАНОВОК ДЛЯ ОЧИСТКИ СТОЧНОЙ ЖИДКОСТИ

Introduction. In this paper, we consider the operation principle, features, advantages, and disadvantages of compact domestic wastewater treatment plants designed by domestic manufacturers. The compact plants used until 2000 were designed to reduce such two indicators in the waste liquid as BOD and suspended solids. Since 2000, modern compact plants capable of reducing four indicators (BOD, suspended solids, nitrogen, and phosphorus) have been developed and installed in Russia. Methods. Biological methods of removing organic substances and nitrogen from the waste liquid are used at modern compact plants. Phosphorus is removed by using both biological and physical-and-chemical methods. The main issue in the operation of compact domestic wastewater treatment plants is the extremely nonuniform flow of wastewater; the coefficient of hourly nonuniformity can be 3.5 or higher. Another serious issue is the reduction in the waste liquid temperature in the cold period to critical values that hinder the biochemical oxidation of organic substances in aeration tanks. In permafrost areas (Yakutia), the influence of this factor can be observed even in the warm period. Results. Based on theoretical research and many years of experience in commissioning, we identified the consequences of design flaws and violations during operation for the stability and performance efficiency of compact plants of various modifications. Conclusion. The performed study made it possible to develop and recommend the optimal option for wastewater treatment, which allowed us to ensure that the indicators were brought to the maximum permissible concentrations of pollutants (suspended solids — 2–3 mg/l, BODult — 3–5 mg/l, ammonium nitrogen — 0.4 mg/l, nitrate nitrogen — 9 mg/l, phosphorus — 0.2 mg/l), established for discharge into fishing reservoirs.