Analysis of the Effect and Influencing Factors of Rural Domestic Sewage Treatment Based on A^(2)O-MBBR Integrated Process

[Objectives] This study was conducted to solve the prominent problems in the treatment of domestic sewage in southern rural areas of China. [Methods] An integrated process treatment mode of anaerobic/anoxic/aerobic moving bed biofilm reactor (A 2O-MBBR) was proposed to analyze and study its operating effect and influencing factors. [Results] The A^(2)O-MBBR mode had good COD removal efficiency and nitrogen and phosphorus removal performance, and the water quality index of the effluent met the Class A standard of GB181918-2002. This mode is suitable for treating rural domestic sewage, and has high treatment effects in different operating periods. In spring, the average removal rates of COD, NH_(4)^(+)-N, TN, TP and SS reached (83.53 ± 2.15)%, (89.44 ± 4.97)%, (67.36±18.53)%, (88.22±11.21)% and (91.73±2.25)%, respectively;In the autumn period, the average removal rates of COD, NH_(4)^(+)-N, TN, TP and SS were (83.49±2.64)%, (89.26±9.19)%, (66.05±17.00)%, (87.48±9.68)%, and (91.13±2.35)%. [Conclusions] This study provides theoretical reference and technical support for the popularization and application of A^(2)O-MBBR integrated process.

Rural Domestic Sewage Treatment Model: Case Study Based on Dongying Section of the Yellow River Basin

The 20th National Congress of the Communist Party of China proposed to promote the improvement of urban and rural living environment and build livable and workable villages and beautiful villages. The development and challenges of rural domestic sewage treatment coexist. Based on the field investigation of 15 administrative villages in 3 districts and counties of Dongying City, there is a big gap between the development status of rural domestic sewage treatment and expectations. Investigate rural domestic sewage treatment cases in-depth, and condense four modes of primitive, developmental, mature and advanced in a variety of different rural domestic sewage treatment models for discussion, among which, the village sewage treatment work under the mature mode has achieved remarkable results, and is at the forefront of the current rural domestic sewage treatment. Through the multi-case analysis method, the practical dilemma of sewage treatment in different models of villages is summarized, and the feasible improvement path is explored, which contributes to the ecological protection and high-quality development of Dongying and the Yellow River Basin.

Research Progress Related to Rural Domestic Sewage Treatment

Rural domestic sewage treatment is an important part of the rural revitalization strategy and a key action to build a livable, livable and beautiful countryside. This paper composes and summarizes the relevant studies on rural domestic sewage treatment from the governance techniques and modes of governance subjects and research perspectives, in order to provide reference for the implementation of rural revitalization strategy and rural domestic sewage treatment research and action implementation.

Application of subsurface wastewater infiltration system to on-site treatment of domestic sewage under high hydraulic loading rate

In order to enhance the hydraulic loading rate （HLR） of a subsurface wastewater infiltration system （SWIS） used in treating domestic sewage, the intermittent operation mode was employed in the SWIS. The results show that the intermittent operation mode contributes to the improvement of the HLR and the pollutant removal rate. When the wetting-drying ratio （RwD） was 1.0, the pollutant removal rate increased by （13.6 ± 0.3）% for NH3-N, （20.7 ± 1.1）% for TN, （18.6± 0.4）% for TP, （12.2 ± 0.5）% for BOD, （10.1 ± 0.3）% for COD, and （36.2 ± 1.2）% for SS, compared with pollutant removal rates under the continuous operation mode. The pollutant removal rate declined with the increase of the HLR. The effluent quality met The Reuse of Urban Recycling Water - Water Quality Standard for Scenic Environment Use （GB/T 18921-2002） even when the HLR was as high as 10 cm/d. Hydraulic conductivity, oxidation reduction potential （ORP）, the quantity of nitrifying bacteria, and the pollutant removal rate of NH3-N increased with the decrease of the RWD. For the pollutant removal rates of TP, BOD, and COD, there were no significant difference （p 〈 0.05） under different RwDS. The suggested RWD was 1.0. Relative contribution of the pretreatment and SWlS to the pollutant removal was examined, and more than 80% removal of NH3-N, TN, TP, COD, and BOD occurred in the SWIS.

Effects of temperature on the degradation pathway of domestic sewage in upflow anaerobic sludge blanked reactor

To understand the anaerobic degradation pathway of domestic sewage,three lab-scale upflow anaerobic sludge blanked reactors (UASB) were employed to study the degradation pathway of different particle size and the effect of temperature on this process.Under the operation conditions of the hydraulic retention time of 24 h,the MLVSS of approximate 11200 mg·L-1 and the water temperature at 10,15 and 20℃,the overall degradation pathway of soluble fraction was characterized according to zero-order kinetics.As for the colloidal fraction (between 0.45 and 4.5 μm),the degradation processes followed a first-order kinetic,and should firstly disintegrated into soluble fraction before finally degrading.In contrast,suspended solids (bigger than 4.5 μm) degraded to soluble and colloidal fractions according to first-order kinetics,and the colloidal fraction originating from suspended solids further degraded into soluble fraction which had the same degradation kinetics as the original soluble fraction.There existed the difference of temperature effect on different fraction degradation.Under the temperature at 20,15 and 10 ℃,the first-order rate constant of suspended solids depredating into collide was 4.97,3.01 and 1.01 d-1 respectively.Whereas the degradation of collide to soluble fraction was slightly affected by the temperature change.On the other hand,the zero-order degradation rate constant of soluble fraction was 0.26,0.18 g and 0.12 gCOD·gVSS-1d-1,respectively.

Performance Characteristics of Pollutants along the Longitudinal Profile of a Subsurface Flow Constructed Wetland Domestic Sewage Treatment Plant in the University of Lagos, Nigeria

The paper reports the findings of a research work carried out to examine the performance and efficiency of a subsurface constructed wetland (SSFCW) for the treatment of domestic sewage in the University of Lagos (Unilag), Nigeria. The removal patterns and efficiencies of the physical, chemical and biological sewage pollutants parameters of domestic waste water generated within Unilag community by the SSFCW were studied. The wastewater was sampled and analysed along the SSFCW from influent (point1) to effluent (point 11). Total Dissolved Solids (TDS) reduced from 471 mg/l to 11.85 mg/l (97.48%), Turbidity reduced from 108.75 HTU to 0.05HTU (99.95%), Manganese reduced from 6.05 mg/l to 0.61 mg/ (89.92%), Nitrate reduced from 27.5 mg/l to 2.0 mg/l (92.73%), Sulphate reduced from 48.5 mg/l to 28 mg/l (42.27%), Iron reduced from 1.13 mg/l to 0.03 mg/l (97.35%), BOD reduced from 73.14 mg/l to 12.8 mg/l (82.5%), and E-coli reduced from 874 MPN/100 ml to 0.15 MPN/100 ml (99.98%). On the other hand, Dissolved Oxygen content increased along the SSFCW from 3.14 mg/l to 7.49 mg/l (138.54%) while the pH improved from slightly acid level of 6.49 to slightly above neutral level of 7.05 (9.3%). All the parameters at effluent point are within the Nigerian Federal Environmental Protection Agency (FEPA) acceptable standard. The study concludes that the SSFCW is a cheap, efficient and appropriate technology for the treatment of domestic sewage under tropical conditions.

Study on the Innovative Rural Domestic Sewage Processing Technique

On the basis of analyzing domestic sewage features in rural China and also previous experience in sewage processing, a high-efficiency and low-cost technique for the rural domestic sewage processing was proposed, that is, "new bio-trickling filter + ecological concrete tank". Such an innovative technique is fit for national conditions of China, and worth to be popularized in rural China. The study also provides a referential support for other researches.

Comparison of Catalysts Used to Determine COD_(Cr) of Severe Domestic Sewage

[Objective] The study aimed to find the best catalyst for the determination of CODc, of severe domestic sewage. [ Method] Adopting po- tassium dichromate reflux method, respectively using MnSO4, Ag2 SO4 ·MgSO4, CuSO4, KAI （ SO4 ） 2, CuSO4 ·KAI （ SO4 ） 2 · （ NH4 ） 2 MoO4 and Ag2 SO4 .Al2 （SO4）3· MgSO4 as catalysts, we determined CODo of severe domestic sewage, and compared their results with that of Ag2 SO4. [ Result] Used as catalysts in the determination of CODc, of severe domestic sewage, MnSO4, Ag2SO4. MgSO4, CuSO4, KAI （SO4）2, CuSO4· KAI （ SO4 ） 2 · （ NH4 ） 2 MoO4 and Ag· SO4- AI2 （ SO4 ） 3· MgSO4 had good catalytic effects, especially Ag2 SO4- AI2 （ SO4 ） 3·MgSO4. Average CODcr of Ag2 SO4·Al2 （SO4）3·MgSO4 and Ag2 SO4 was 229.32 and 254.28 mg/L separately, that is, the former accounted for 90.18% of the latter, so the result of Ag2SO4 could reflect the actual CODc, of severe domestic sewage better. [ Conclusion] Ag2SO4 is the optimal catalyst for the determination of CODc, of severe domestic sewage.

Application of CASS in Treating Domestic Sewage at Low Temperatures

The feasibility of using CASS technique for treating domestic sewage at low temperatures was investigated. The results indicate that for domestic sewage (averagely, ρ(BOD5)=295.7 mg/L; ρ(CODCr )= 811.7 mg/L; ρ(SS)= 119.6 mg/L), the removal rates are 95.3%, 85.7%, 91%, respectively. The CASS technique is operable in a wide range of temperature (about -5～20 ℃), but φ(S) and ρ(S) values are higher at low temperature than those at normal temperature. A low temperature is good for oxygen transmission and the cyclic fluctuation of DO (dissolved oxygen) is benefit for the removal of P and N, preventing the sludge from bulking.

Effect of domestic sewage on growth of phytoplankton-mathematical model

A mathematical model relating to the change in phytoplankton biomass in the period of growth and nutrient concentration in the media was proposed on the basis of the Monod equation and was testified by simulation experiments. Analysis of the experiment data showed that: the half-saturation constants for growth Kp (μmol/L) for Skeletonema, Chaetoceros and Prorocentrum were 5.52, 1.90 and 0.46, respectively; the balance between stimulation of nutrients and the inhibition of some other materials was found in the effect of domestic sewage on algal growth and the stimulation played a leading role; domestic sewage was more stimulative on dinoflag-ellate than on diatom and chlorophyte when the assemblage of the algae was cultured. The experiment suggested that mathematical model reasonably explained the characteristics of phytoplankton growth in different nutrient conditions and was worthy to be further improved for eutrophication prediction in off-shore water.

SFRC Subjected to Domestic Sewage and Sustained Load

The article aimed to study the durability of steel fiber reinforced concrete under the coupled sewage-loading according to compressive strength,flexural strength,compressive strength corrosion coefficient,flexural strength corrosion coefficient,compressive strength balance coefficient,flexural strength balance coefficient.Through the homemade load frame applied to design specimens,the pre-loading level are equivalent the damage intensity of 0%,10%,30% and 50% four different ways.The experimental results show that the performance of concrete down gradually and sustaining load aggravated the degree of domestic sewage attacking concrete after six month;under different stress states,the more loading levels,the more serious domestic sewage attacked the steel fiber reinforced concrete.It is proved that the concrete damage can be inhibited by adding the steel fiber,when steel fiber volume fraction is 1.0%,the corrosion resistance of concrete is best.

Estimation of the Optimal Tax Rate of Domestic Sewage in Binzhou City

The optimal tax rate of COD and ammonia nitrogen was estimated based on the estimated economic loss caused by domestic sewage and the determined tax base in Binzhou City.The results show that due to the pollution of COD and ammonia nitrogen,the average economic loss of domestic sewage in Binzhou City from 2010 to 2017 was 167.292 million and 178.040 million yuan respectively.The average pollution equivalent amount of COD and ammonia nitrogen in domestic sewage in Binzhou City was 43435 and 3900 t respectively,and the average optimal tax rate of COD and ammonia nitrogen was 3.85 and 45.65 yuan/kg respectively.That is,residents should pay a pollution tax of 3.85 yuan for every 1 kg of COD discharged and a pollution tax of 45.65 yuan for every 1 kg of ammonia nitrogen discharged.

Application of Constructed Wetland in Treating Rural Domestic Sewage in Guangxi

We provide a brief overview of the constructed wetland treatment technology and list two demonstration cases of its application in treating rural domestic sewage in Guangxi and its effect. Meanwhile, existing problems of the treatment technology are summarized.

Study on Treatment Technologies of Decentralized Domestic Sewage

The significance and necessity of decentralized domestic sewage treatment were introduced firstly, and then three main decentralized technologies of domestic sewage such as constructed wetlands, subsurface infiltration and purification tanks in China and abroad were discussed.

Disposal of Rural Domestic Sewage in Ecological Wetland System

Pollution brought by rural domestic sewage has become increasingly serious, so it is imperative to fi gure out economical and efficient solutions. On the basis of comparison between rural domestic sewage treatment means in China and abroad, actual conditions of countryside, current situation and features of domestic sewage, this paper adopted the compound ecological wetland system consisting of anaerobic and aerobic units, ecological floating bed and artifi cial wetland, so as to remove nitrogen and phosphorus efficiently, achieve the goal of low operation and construction cost and less land use.

Fertility of domestic sewage and eutrophication in estuarine harbor

The concentration and partition ratio of various speciations of nutrients in domestic sewage were determined. The transformation and transportation among the speciations, as well as their biological effects during sewage-seawater mixing were simulated in laboratory. The results are compared with field observation and the following findings are: i) The suitable range of ratio DIN/DIP in seawater for growth of phytoplankton in subtropical estuary and harbor is quite wide. It could grow well even in the range of 15-55 in atom ratio, and is independ of the variation in levels of N and P. ii) The transformation rate among the speciations of phosphorus is within the range of 0. 5 to 1. 1 μmol/d . iii) Phytoplankton uptakes P prior to N during its growth. The growth rate for Skeletonema costatum (the major species) and field algae are 0. 34-0. 58/d and 0. 30-0. 31/d, respectively. iv) The red tide species Prorocentrum micans could become the dominant species to a density 107 cells/L after Skeletonema costatum blooms and phosphorus is almost exhausted. In a word, eutrophication may bring out red tide in estuarine harbor, but the acceleration of degredation, transportation and precipitation of nutrients by turbid water is beneficial to the alleviation of eutrophication and red tide.

Study on Pre-treatment of the Domestic Sewage by Water-dropping Aeration Zeolite Bed Technology

[ Objective] The research aimed to study pre-treatment effect of the domestic sewage by water-dropping aeration zeolite bed technology. [ Method] By water-dropping aeration manner, we conducted sewage reoxygenation. Zeolite was used to replace traditional contact oxidization fill- er. We inspected oxygenation effect of the water-dropping aeration manner and removal efficiency of the pollutant in sewage after biological contact oxidation. [ Result] Under the experimental condition with water-dropping heights of 0.30, 0.45 and 0.60 m, average added values of the dissolved oxygen for raw water were respectively 2.4, 3.6 and 4.2 rag/l_ after water-dropping aeration. Under the situation with average HRT of 2 h, when COD, TN and TP of the influent were respectively 309.0 -464.0, 33.3 -95.0 and 4.0 -7.5 mg/L, their corresponding average removal rates were 47.25%, 46.39% and 40.75%. [ Conclusion] The research conducted useful attempt for high-efficiency and low-cost treatment of the domestic sewaqe in rural area.

Advances in the Medicinal Value of Constructed Wetland Plants for Treating Rural Domestic Sewage

Firstly,the advantages and disadvantages of constructed wetlands for treating rural domestic sewage are introduced.Secondly,the types of constructed wetland plants are introduced.Thirdly,the suitability of using medicinal wetland plants to treat rural domestic sewage is analyzed.Fourthly,the principles of selecting wetland plants with medicinal value are studied.Finally,commonly used constructed wetland plants and their medicinal value are introduced.

Study on the Current Situation and Countermeasures of Rural Domestic Sewage Treatment in Beijing City

In recent years,the construction of rural sewage treatment in Beijing City has developed rapidly,but there are still many problems in some rural domestic sewage treatment. In this paper,the current situation of rural domestic sewage in Beijing City is combed,and its characteristics are summarized. Meanwhile,the current situation of rural domestic sewage treatment in Zhejiang Province,Hunan Province and Shandong Province is summarized by consulting relevant data. By comparing with current situation of rural domestic sewage treatment in Beijing City,it is found that there are some problems in the treatment of rural domestic sewage in Beijing City,such as unsuitable treatment mode,unreasonable discharge requirements and inadequate treatment technology. Therefore,some countermeasures and suggestions are proposed,such as strengthening the investigation,research and planning,and differential formulation of the sewage treatment discharge standards,and establishing modular treatment technology system. It is hoped that this paper will be helpful to the treatment of rural domestic sewage in Beijing City.