Technical Innovation of Land Treatment Systems for Municipal Wastewater in Northeast China

On the basis of ecological principles including holistic optimization, cycling and regeneration, and regional differentiation, land treatment systems (LTSs) for municipal wastewater were continuously explored and updated in the western Shenyang area and the Huolinhe area, China. Intensified pretreatment, addition of a man-made soil filtration layer, and use of an ecologically diversified secondary plant cover were proved to be technically feasible. Hydraulic loading was determined according to the assimilation capacity of soil ecosystems, thus ensuring safe operation of wastewater treatment. This modernized and alternative approach to wastewater treatment had been widely applied in middle-sized and small cities and towns of Northeast China, and these innovative systems in some areas had indicated favorable ecological, social, and economic benefits.

Experimental analysis of a nitrogen removal process simulation of wastewater land treatment under three different wheat planting densities

Nitrogen contaminant transport, transformation and uptake simulation experiments were conducted in green house under three different planting density of winter wheat. They were Group A, planting density of 0.0208 plants/cm 2, Group B, 0.1042 plants /cm 2, and Group C, 0.1415 plants/cm 2. The capacity and ratio of nitrogen removal were different on three kinds of conditions of wastewater land treatment. From analysis of wastewater treatment capacity, wastewater concentration and irrigation intensity for Group C were suitable and nitrogen quantity added was 2 times of that for Group B, 2.6 times for Group A while nitrogen residue was only 7.06%. Hence, wastewater irrigation and treatment design with purpose of waste water treatment should select the design with maximum capacity, optimal removal ratio and least residue in soil, which was closely related to crop planting density, crop growth status and also background nitrogen quantity in soil.

Digital Twins for Wastewater Treatment:A Technical Review

The digital twins concept enhances modeling and simulation through the integration of real-time data and feedback.This review elucidates the foundational elements of digital twins,covering their concept,entities,domains,and key technologies.More specifically,we investigate the transformative potential of digital twins for the wastewater treatment engineering sector.Our discussion highlights the application of digital twins to wastewater treatment plants(WWTPs)and sewage networks,hardware(i.e.,facilities and pipes,sensors for water quality and activated sludge,hydrodynamics,and power consumption),and software(i.e.,knowledge-based and data-driven models,mechanistic models,hybrid twins,control methods,and the Internet of Things).Furthermore,two cases are provided,followed by an assessment of current challenges in and perspectives on the application of digital twins in WWTPs.This review serves as an essential primer for wastewater engineers navigating the digital paradigm shift.

Ecological engineering land treatment systems──A new development in China

This paper elucidated the necessity and possibility of developing the technology of land treatment on the basis of the analysis of shortage and pollution status of water resources in China.The historical development of this technology in the world was briefly reviewed and the distinction between land treatment and conventional wastewater irrigation was discussed in details. The fundamental characteristics and functions as well as the integrity and compatibility of this ecological engineering were also summarized. It was finally concluded that this technology for wastewater treatment has broad prospects of application in China.

Examination of the Level of Heavy Metals in Wastewater of Bandar Abbas Wastewater Treatment Plant

One of the main environmental pollutants is heavy metals. Due to extensive usage in industry, these metals enter biological cycle rapidly and contaminated water and soil resources rapidly. In this work, lead, copper, zinc and chromium of Bandar Abbas wastewater are examined. For this research, nine stations were set for measurement in urban level in Bandar Abbas and sampling of aforesaid metals was performed in fall and winter 2006 in these stations. After extraction and preparation operations using APDC-MIBK, samples were measured using flame atomic absorption system. According to results, concentrate of studied metals was lower than allowable standard value set by Iran environmental protection organization for agricultural purposes and sewage to ground level waters. In addition, efficiency of Bandar Abbas wastewater treatment plant to remove these metals is 40% - 70% from which highest removal is for zinc as much as 71.1% and lowest level is for copper as much as 40.5%. However, copper level was higher than allowable level for agricultural purposes in spring and summer (0.21 mg/L and 0.23 mg/L, respectively) and lower in fall and winter (0.103 mg/L and 0.098 mg/L, respectively). Furthermore, changes in concentration of metals in these stations in various seasons were measured and analyzed using one-way variance analysis and simultaneous effects of time and place on measured variables were analyzed using two-way variance analysis.

Wastewater Management in Third World Cities: Case Study of Cotonou, Benin

Poor wastewater management coupled with lack of sanitation facilities has aggravated the sanitation challenges in developing countries.?This study was aimed at providing information on the current state of sanitation in Cotonou City through surveys. The most common sanitation facilities in the city were septic tanks, latrines and soakaway pits. Mechanical desulging was mainly used (94%) for desludging latrines and septic tanks with a frequency of less than once a year for 73% of the houses;manual desludging was most common for soakaway pits. 84% of sullage generated is disposed without treatment. The only existing stabilization pond plant, managed by a private company SIBEAU, is overloaded;the effluent is poor (up to 2250mg/l BOD5) and does not meet any quality standards. 96% of survey respondents recognise that the sanitation situation in the city is not good;it has to be improved by providing an appropriate and sustainable sanitation management system.

Rapid infiltration wastewater treatment for small communities in Beijing

This rapid infiltration (RI) system is proposed as the first one in China. The RI system treated 500 m3/d of municipal and industrial wastewater. About 0.36 ha of field was used. It has been evaluated that the RI system has an excellent ability to treat the wastewater. The infiltration rate was 50.3 m/a.

The Public Water Supply Protection Value of Forests: A Watershed-Scale Ecosystem Services Analysis Based upon Total Organic Carbon

We developed a cost-based methodology to assess the value of forested watersheds to improve water quality in public water supplies. The developed methodology is applicable to other source watersheds to determine ecosystem services for water quality. We assess the value of forest land for source water mitigation of total organic carbon (TOC) through the use of linked watershed and reservoir simulation models and cost-based valuation economics. Watershed modeling results indicated that expected urbanization will increase TOC loads to Converse Reservoir (Mobile, AL). Reservoir model results indicated that future median TOC concentrations increased by 1.1 mg·L-1 between 1992 and 2020 at the source water intake. Depending upon dynamic reservoir TOC concentrations, additional drinking water treatment with powdered activated carbon (PAC) often is necessary between May and October to comply with Safe Drinking Water Act regulations. The cost for additional treatment was calculated using minimum and maximum volume treated with simulated TOC concentrations at the source water intake. Daily simulated TOC concentrations for the base scenario using 1992 land cover (3% urban) were compared with simulated TOC concentrations following forest to urban land conversion predicted in the watershed by 2020 (22% urban). The daily cost for additional drinking water treatment with PAC was calculated if simulated TOC concentrations exceeded 2.7 mg·L-1. The mean increase in daily treatment costs between base and future scenarios ranged from $91 to $95 per km2 per day for forest land water purification ecosystem services.

A Cradle-to-Cradle Novel Approach for Wastewater Management in Sustainable Urban Communities

Water, a valuable resource to human lives, is being abused and driven to scarcity. This scarcity is leading some countries and areas to face difficulty in accessing drinking water. As the UN recently stated “by 2050 water shortages and harder access will be reached by around 2/3rd of the world total population” [1], thus, there is a high need to treat and reuse wastewater for domestic purposes, which will lead to less reliance on fresh water as an initial water source. Greywater—defined as the water produced in domestic houses including sinks and bathroom showers, and excluding any blackwater mix which is collected from toilets—is a type of wastewater. Greywater accounts for up to 75% of the daily water produced [2] while it has fewer contaminants when compared to blackwater. This makes greywater a focal point for treatment, and reusing to conserve fresh water and approach net zero water concept. Even though the definition of greywater is the same globally, its criteria can differ from one country to another, from one building to another, or even from the same person’s usage along the day. Accordingly, several treatment methods evolved over years aiming at treating the produced greywater for reuse mainly in irrigation and toilet flushing. The objective of this paper is to demonstrate a novel net zero wastewater approach applying cradle-to-cradle concept for urban communities;while also proposing a sustainable greywater treatment technique that is environmentally friendly, cost-effective and socially acceptable.

Approaches to municipal wastewater irrigation and environmental protection

To reuse the water and nutrient resources from ecological point of view the goals, criteria and constraint conditions of the scientifically municipal wastewater irrigation are discussed as well as the practice in major municipal wastewater irrigation areas in China is introduced, of which particularly the effects of municipal water irrigation mixing with oil refinery wastewater on the agricultural ecosystem are studied and described. It has been revealed that benzo(a)pyrene in various parts of paddy crop is attributed to air pollution, water-soil pollution and biosynthesis of plant. Of exogenous contributions of benzo(a)pyrene in paddy shoot system under natural condition, the dominant factor is the air pollution, whereas the water-soil factor is considered to be secondary. Therefore, it is mostly urgent to control the air pollution source of benzo(a)pyrene, to which the edible parts of various green plants are exposed directly.

Solving Water Problems of a Metropolis

The metropolis of Istanbul has faced water supply challenges throughout history;however the situation escalated in the past decade with rapid population growth. Water demand of an ever-growing city could only be solved by transporting water from surrounding water basins as far as 190 km away from the city border. Moreover, imbalanced distribution of water resources and imbalanced water demand on the European and Asian side of the city was resolved by transporting water from Asian side to the European side, by laying water transmission pipes under the Bosphorus Strait and by constructing a tunnel passing 130 m under the Strait. Another difficulty that required challenging solutions was the protection of water reservoirs of the city, hence illegal settlements arose in the reservoir watershed zones due to fast urban growth and migration from rural areas. Discharge of wastewater from illegal settlements caused not only algae growth in water treatment plant (WTP) of one of the largest reservoirs of Istanbul, but also eventual death of algae was a major setback due to anaerobic conditions created in the reservoir. The problem was solved by tertiary treatment of the wastewater and by diverting the effluent through a tunnel away from the reservoir. The aim of this paper is to provide an insight into setbacks faced in a metropolis of 14 million and technical solutions provided against the pollution of reservoirs.

A^(2)O-MBBR+反硝化深床滤池工艺用于污水处理厂提标扩能

宜宾市杨湾污水处理厂处理规模由6×10^(4)m^(3)/d扩容至12×10^(4)m^(3)/d,出水水质提升至《四川省岷江、沱江流域水污染物排放标准》(DB 51/2311-2016)。针对用地受限和排洪暗渠从厂区中间穿过的实际情况,从工艺选择、总图和构筑物布置角度优化设计。污水处理采用“A^(2)O-MBBR-反硝化深床滤池”工艺;二期生化池和二沉池布置在排洪暗渠上方;加大生化池有效水深和滤池滤层厚度;二次提升泵井、反硝化深床滤池及配套设施集约化组合布置。实际运行效果显示,出水COD、BOD_(5)、NH_(3)^(-)N、TP、TN、SS平均值分别为8.37、2.87、0.08、0.15、5.29、2.56 mg/L,稳定达到排放标准。

城市污水处理技术的进展与未来挑战:以持续减排为目标

本文系统回顾了城市污水的主要污染物,总结了现有的污水处理技术,并重点探讨了以持续减排为目标的新型污水处理技术,如微生物技术、膜分离技术和纳米技术等。最后,本文还分析了未来污水处理技术发展中要面临的挑战,以及未来的研究方向,为城市污水处理技术的发展提供参考。

膜生物反应器(MBR)技术在城市污水处理中的优化探讨

本文主要以某实际项目为例,对膜生物反应器技术在现代城市污水处理中的优化进行分析。包括本次所研究的某城市污水处理项目概况,以及城市污水处理中的膜生物反应器技术优化分析。经分析可知,在对膜生物反应器技术进行优化时,研究者与技术人员首先需要结合实际情况来确定基本的优化思路,然后再以此为依据,科学制定优化方案。通过这样的方式,才可以获得良好的优化效果,满足现代城市污水处理的实际需求。

AAO+二沉池叠加结合现有处理单元的污水厂工艺改造方案

攀枝花某污水厂原设计规模为1.9×10^(4)m^(3)/d,出水水质为一级B排放标准。随着该市对水环境保护要求的不断提高,对再生水用量的日益增加,原有的尾水排放标准已不能满足相关需求,因此,需要对该污水厂进行提标升级改造。而该厂区面临地理位置空间受限、预留用地不足、场地异形等难题。设计团队因地制宜,平面科学布局,立体深挖潜能,采用了AAO+二沉池空间叠加组合工艺的布置形式,同时充分挖掘既有建构筑物的潜能,出水水质由一级B排放标准提标升级为一级A排放标准。该工程土地利用效率高,有良好的社会效益和环境效益,为山区城市用地紧张的污水处理厂提标升级改造提供了新的思路。

进一步改善城市网-厂-水体污水系统升级改造和运行效率的四点看法

2022年,《深入打好城市黑臭水体治理攻坚战实施方案》发布,要求努力解决河流雨后黑臭和雨季河流断面水质下降问题,力争到2025年,进水BOD浓度高于100毫克/升的城市生活污水处理厂规模占比达90%以上,城市生活污水集中收集率达到70%以上。水行业正面临着防止雨后河流返黑和改善雨季河流水质等新任务。因此,结合近年来成绩、实践和欧美的经验教训,提出和讨论了与进一步改善网-厂-水体城市污水系统升级改造及运行效率相关的四个问题:分流制管网有没有外(雨)水入侵和溢流、污水处理厂的进水浓度应多高、为什么部分污水处理厂需局部扩容、为什么污水管道中流速低于自净流速,并在此基础上,对相关工作提出了建议。

双模式MSBR工艺在城镇污水厂雨季工况中的中试试验

我国城镇污水处理厂在雨季往往面临短时间激增的水力冲击负荷,因污水厂二级处理系统通常按旱季流量设计,无法应对超量的雨季合流污水,导致厂前溢流或厂内超越,严重污染了受纳水体。研究采用含多点进水功能的双模式改良型序批间歇反应器(MSBR)在浙江某污水处理厂模拟雨季超量合流污水的生化处理,通过中试试验证明了该工艺可在合流污水达到2~4倍旱季设计流量的条件下,确保COD_(Cr)、氨氮、总氮(TN)等主要出水指标稳定达到并优于《城镇污水处理厂污染物排放标准》(GB 18918—2002)中一级A标准,其中出水氨氮平均质量浓度小于1.0 mg/L,TN平均质量浓度小于10 mg/L。其处理效果显著优于物理-化学强化一级处理工艺,为大幅提升污水处理厂的雨季峰值流量处理能力,有效削减雨季受纳水体的冲击性污染,消除城镇黑臭水体提供了新的解决方案。

基于复杂用地条件的地下式污水处理厂精细化设计

广州市黄埔区某水质净化厂二期工程需要在不规则的用地形状、复杂的场地周边环境、较低的建设用地指标及地上高水平建设开发的预期下,实现规模为5万m^(3)/d地下式污水处理厂的设计工作。工艺设计上通过采用“厌氧-缺氧-好氧+膜生物反应器(AAO+MBR)”工艺提升节地效率;结构设计上通过处理单元构筑物的共壁、错层实现“地尽其用”;平面设计上通过优化池体上部建(构)筑物布局、设施设备设置、交通物流规划、管线综合排布来提高操作空间的使用率。本工程项目用地负荷率比同类项目提高了36%,工程直接费用的建设单位成本低于广州市同等规模同类型项目8.5%的情况下,实现了工程设计目标,为同类项目的设计提供了良好示范。

污水回用技术在城市节水与环境保护中的应用

随着社会的发展,工业、农业生产以及生活用水量不断增加,可用淡水资源日渐紧缺。在此背景下,社会愈发关注城市污水的处理与回用工作。应用污水回用技术,对于城市节水与环境保护具有重要意义。基于此,分析污水处理以及污水回用技术,阐述其在城市节水与环保中的应用,以期为相关工作提供参考。

城市废水环境污染的监测与处理方法探究

传统废水环境污染的监测手段滞后、时效性差,难以获得具有参考价值的数据及结果,进而影响城市废水治理成效,给城市生态环境带来严重危害。基于此,文章拟通过对城市废水中所含污染物浓度含量的监测治理方法进行深入研究,并将其控制在国家排放标准所允许的合理范围内。同时,通过分析城市水环境监测治理技术最终选用生物监测的处理方法,以复合生态浮床技术在城市废水污染治理中的实际运用,得出初步效果显著的结论,以期为相关废水处理行业提供借鉴。