Microsoft Word - 02Revised.doc
CHEMICAL ENGINEERING TRANSACTIONS
VOL. 55, 2016
A publication of
The Italian Association
of Chemical Engineering
Online at www.aidic.it/cet
Guest Editors: Tichun Wang, Hongyang Zhang, Lei Tian
Copyright © 2016, AIDIC Servizi S.r.l.,
ISBN 978-88-95608-46-4; ISSN 2283-9216
Study on Treatment of Campus Domestic Wastewater for
Landscape Water Treatment by Hydrolytic Acidification -
Biological Contact Oxidation Process
Xiaobo Liu*a, Na Dongb, Qiong Chena, Yi Luoa, Jian Guoa, Shangzhu Tanga
aHebei University Of Architecture, Zhangjiakou 075000, China
bZhangjiakou Kaibofeng Real Estate Development Co., Ltd, Zhangjiakou 075000, China
liuxiaobo1818@163.com
In this paper, the issue of supplementing water source for landscape water is discussed. The quality of
domestic sewage after treatment by hydrolytic acidification-biological contact oxidation method is analysed
from the three aspects of effluent ammonia concentration, BOD concentration and turbidity in a certain period
of time. It is proved that it is feasible the campus sewage as a water feature to supplement water. This will
provide the reasonable suggestion for the domestic sewage as the supplementary water source for landscape
water.
1. Introduction
Building a resource - saving society is the trend of development of the times, the development of universities
must also follow this principle, focus on saving - oriented construction, and conservation - oriented landscape
construction is one of the important part (Li, 2016; Sun, 2015). Water features include rivers, lakes, fountains
and other forms in the university, but no matter what form of water features there is a common problem - to
add water, here we take the river landscape as an example to discuss the facility of using campus sewage as
the replenish water source of landscape water (Toor and LuskReclaimed, 2015). Due to poor mobility and a
series of reasons, river landscape water only through constant replenishment, changing the water to maintain
its water quality (Cabrera, 2013). At present, the vast majority of areas are using pipe network tap water as a
supplementary source of landscape water, but this is a great waste of clean water resources (Toor and Lusk,
2014). Therefore, it is considered that the domestic sewage in the campus can be treated as the
supplementary water source of the landscape water body by using the hydrolytic acidification-biological
contact oxidation method, thus saving the water resources and reducing the running cost of the university
(Cheng, 2010; Pan Qi et al, 2010).
2. Characteristics of campus sewage water quality
With the expansion of the scale of the university and the gradual improvement of functions, set of learning,
living, living, leisure and other functions in one the general, and personnel in colleges and universities are
more intensive, daily water consumption is larger, resulting in relatively stable water quality and water quality,
including food and sewage, bathing water, toilet waste water. It is in good biodegradability and pollutants are
mainly organic matter, easy to handle and the processing cost is relatively low, so it is a very good landscape
water supplement source (Wu et al, 2016; Yang, 2012). Campus sewage generally has the following
characteristics:
(1) Water, water quality and stability of pollutants, mainly organic matter.
(2) Biodegradable, and up to two emission standards.
(3) Large amount of sewage discharge, to meet the characteristics of landscape water consumption, easy to
achieve water balance.
(4) Sewage treatment can be carried out in the school, the implementation of convenient and quick, as
landscape water reuse water, has a high guarantee rate.
DOI: 10.3303/CET1655027
Please cite this article as: Liu X.B., Dong N., Chen Q., Luo Y., Guo J., Tang S.Z., 2016, Study on treatment of campus domestic wastewater
for landscape water treatment by hydrolytic acidification - biological contact oxidation process, Chemical Engineering Transactions, 55, 157-
162 DOI:10.3303/CET1655027
157
3. Characteristics of landscape water and related standards for reuse
Landscape water requirements on the sensory index are high, such as colour, odour and so on. The change
of colour and odour of landscape water is mainly due to the eutrophication of water body and microbes and
algae breeding. After the eutrophication, the first will have a stench smell, the wind spread everywhere,
seriously affecting people's normal life; Secondly, in eutrophic water, with cyanobacteria, green algae as the
dominant species of large algae floating in the landscape water body surface, the formation of a layer of
"green scum", so that the water becomes more turbid, sensory water greatly reduced; at the same time, due to
the large number of algae multiply, water transparency greatly reduced, dissolved oxygen in water
consumption into an anoxic environment, a large number of other aerobic organisms in water death,
accelerated the deterioration of water quality process (Giulio and Onorio, 2015; Giulio et al., 2016; Suvanjan et
al., 2016; Xia et al., 2016; Gurpal Toor et al, 2011; Rahmanm et al, 2014).
For the landscape water to add water quality in accordance with relevant provisions of China should meet the
following requirements:
Table 1: Water quality standard for reuse of reclaimed water for landscape water use
Specification and
standard names
Main Water Quality Index
(mg / L) Scope of application
Issuing department
BOD
Ammonia
Nitrogen (N)
Turbidity
Standard for water
quality of reclaimed
water used for
landscape water
bodies CJ / T 95-2000
1 10 5 - 1, the body of non-systemic
contact with the entertainment
landscape water body; 2, the body
of non-direct contact with the
ornamental landscape water
Urban construction
industry standards,
the Ministry of
Construction
2 20 5 -
4. Feasibility analysis of hydrolysing acidification-biological contact oxidation in treating
campus wastewater for landscape water reuse
According to the characteristics of the sewage water quality of the campus, it is proposed to use the system of
hydrolytic acidification - biological contact oxidation to process it. The system has a series of features such as
simple process flow, stable operation, strong anti-shock load capability and easy management (Shan and
Che, 2011; Sun et al, 2015).
The influent concentration of influent BOD was 111 ~ 290mg / L, the influent ammonia concentration was
27.1-53mg / L, and the influent turbidity was 19.2-119mg / L.
4.1 Analysis of BOD removal efficiency
When T = 26 ~ 32 °C, HRT = 6h, the DO value in the 2 ~ 3mg / L (the best working conditions), the influent
BOD concentration and removal rate changes shown in Figure 1.
Figure 1: Influent and effluent BOD concentration and removal rate change
From the hydrolysis and acidification - biological contact oxidation process run for 30 days of the BOD
concentration of water monitoring results can be obtained from the figure3-1, the effluent concentration was 18
~ 26mg / L, the average concentration was 22.5mg / L, and the effluent concentration was relatively stable
158
under the optimal operating conditions. The removal rate of BOD was 84.02% ~ 86.50%, the average removal
rate was 85.41%, the treatment effect was good. The removal rate of BOD in the initial 5 ~ 15 days of the
system operation is lower than that of 20 ~ 30 days, Consider the result of this result is: the initial operation of
the system is in an unstable state, the temperature does not reach the specified experimental temperature,
microbial growth time and lack of activity, but the removal of BOD mainly depends on the reproduction and
metabolism of microorganisms under aerobic condition. Therefore, the quantity and activity of microorganisms
directly affect the removal efficiency of BOD. With the increase of operation days, the temperature of the
system gradually stabilized, and the activity of microorganisms increased with the increase of temperature, so
the removal rate of BOD increased. During the 5 ~ 30 days of operation, the effluent BOD concentration
fluctuates 20mg / L in the BOD concentration standard stipulated in the Water Quality Standard for Landscape
Environment, further considering the deep treatment of the system effluent and further reducing the
concentration of BOD in the water to make it completely compliant.
4.2 Analysis of ammonia nitrogen removal
When T = 26 ~ 32 °C, HRT = 6h, and the DO value is 2 ~ 3mg / L, the concentration and removal rate of NH3-
N in the effluent are shown in Fig. 2.
Figure 2: Influent and effluent NH3-N concentration and removal rate change
The results of the monitoring of NH3-N concentration in the effluent from the hydration-acidification-biological
contact oxidation process for 30 days are shown in Figure 2, the effluent concentration was 4.9 ~ 7.7mg / L,
the average concentration was 6.07mg / L, and the effluent concentration was stable, under the optimal
operating conditions. The removal rate of ammonia nitrogen was about 82.5% and the highest was 86.35%. At
the beginning of the operation, the removal rate of ammonia nitrogen was at a low level, and the removal rate
increased gradually with the increase of operation days. The reason of this phenomenon is that the removal of
ammonia nitrogen mainly depends on the nitrification of nitrifying bacteria, and the nitrification reaction takes a
long time. In the early stage of the system operation, the growth time of nitrifying bacteria was not enough,
and the nitrification reaction was not enough, which led to the low removal rate of ammonia nitrogen. During
the 5 ~ 30 days of operation, the average concentration of NH3-N effluent was slightly higher than the
standard value of NH3-N in the standard of "water quality standard for landscape environment" 5mg / L,
further considering the deep treatment of system effluent and further reducing the concentration of NH3- to
make it fully up to the standard.
4.3 Analysis of turbidity removal efficiency
When T = 26 ~ 32 °C, HRT = 6h, the DO value in the 2 ~ 3mg / L (the best working condition), the turbidity in
the water concentration and removal rate changes shown in Figure 3
159
Figure 3: Influent and effluent turbidity concentration and removal rate change
The results of the turbidity monitoring of the influent and effluent from the process of hydrolysis and
acidification-biological contact oxidation for 30 days are shown in Figure 3. Under the optimal operating
conditions, the turbidity removal efficiency of the system is very obvious, the turbidity of the effluent is very
stable, which is kept below 2.5NTU, the average concentration is 2.37NTU.The average removal rate of
turbidity is 94.80%, the highest can reach 95.72%.On the 20th day of operation, the removal rate of turbidity
was at the lowest point. The reason of this situation was that the influent suspended matter content was high,
and the packing inside the pool was blocked, so the area of biofilm was greatly reduced. This problem can
then be solved by backwashing the packing. Taking into account the "landscape environmental water quality
standards" for the turbidity is not particularly specified, after this process after treatment of the water turbidity
is also at a relatively low level, it can be considered that the effluent back to the landscape water is feasible.
4.4 Comparison of effluent water quality and regulatory requirements
When T = 26 ~ 32 °C, HRT = 6h, the DO value in the 2 ~ 3mg / L (the best conditions), the water quality
situation shown in Figure 4.
Figure 4: Hydrolysis Acidification - Biological Contact Oxidation Process effluent quality change
Table 2: Comparison of water quality and specification of Hydrolytic Acidification - Biological Contact Oxidation
Process
Experimental results (mg/L) Specification (mg/L)
BOD 22.50 20
NH3-N 6.07 5
Turbidity (NTU) 3.62 -
From the hydrolysis and acidification - biological contact oxidation process run for 30 days on the water quality
monitoring results from the figure available, the average concentration of BOD in effluent was 22.50mg / L; the
average concentration of effluent NH3-N was 6.07mg / L; the effluent turbidity averaged 3.62 NTU. Compared
with the standard data, such as the above table, the resemble degree is high. Taking into account the
experimental conditions are limited and experimental error and other reasons, the results compared to the
existence of a professional sewage treatment station a certain gap, subsequent consideration of effluent
160
advanced treatment, therefore, it can be considered that it is feasible to reuse the campus domestic
wastewater treated by the hydrolytic acidification-biological contact oxidation method in the campus landscape
channel.
5. Conclusion
(1) When the temperature of the system was controlled at 26 ~ 32 °C, the hydraulic retention time was
controlled at 6h, and the dissolved oxygen concentration was controlled at 2 ~ 3mg / L, can guarantee the
integrated effluent quality is ideal, which is most closely to ‘landscape water reuse water quality standards’
(2) The maximal activity of the microorganism can be guaranteed when the temperature of the system is
controlled at about 30 °C; too much deviation from this range will affect the normal microbial survival and
reproduction or even death and thus affect the treatment effect. In some cold areas can be considered to
increase the insulation layer or temperature maintenance device to maintain the temperature of the reaction
tank.
(3) Hydraulic retention time (HRT) remained at about 6h, cannot exceed too much. Because if residence time
is too long, it will make the sludge age increased, thus reduce the treatment effect. And too long residence
time from the economic point of view is not cost-effective.
(4) Application of hydrolysis acidification - biological contact oxidation system for the treatment of campus
sewage effluent quality is stable enough and generally meets the state for the reclaimed water for ornamental
river landscape water quality requirements, Therefore, it can be considered that it is feasible to use the
domestic sewage as supplementary water source for the campus landscape.
6. Suggestion
Based on independent hydrolysis and acidification - biological contact oxidation system, there is still a small
gap between the effluent quality of wastewater treatment and the "landscape water reuse water quality
standards”, so consider the advanced treatment of the water. The current advanced treatment technology is
coagulation sedimentation method and activated carbon adsorption, both of them application in a wide range.
Through these methods can effectively reduce the water chrome, turbidity, but also can remove phosphorus,
nitrogen and other elements which easily lead to eutrophication of commutation water. So, that the water
meets the landscape water requirements (Li and Liu, 2011; Liu, 2014).
In this paper, we do not carry out detailed experiments on the advanced treatment, cited the current domestic
and foreign mature technology theory, so there are many deficiencies. Only provide some reference
suggestions for colleges to use domestic sewage as landscape water to replenish water resources.
Acknowledgement
Financial support for this work is provided by Hebei University of Architecture Research Fund Project
(KYQN201405).
References
Cabrera R., Wagner K., Wherley B., 2013, An evaluation of urban landscape water use in Texas. Texas Water
Journal, 28(5), 427-430.
Cheng X.B., 2010, Centralized living area of recycled water quality problems and countermeasures. Urban
Roads Bridges and Flood Control, 26(9), 188-191, DOI: 10.3969/j.issn.1009-7716.2010.09.045.
Giulio L., Maria F.E.L., Luiz A.O.R., Mateus D.N.G., Elizaldo D.D.S., Liércio A.I., 2015, Constructal design
applied to the study of the geometry and submergence of an oscillating water column, International Journal
of Heat and Technology, 33(2), 31-38. DOI: 10.18280/ijht.330205.
Giulio L., Onorio S., 2015, Analysis of Water Droplet Evaporation through a Theoretical-Numerical Model,
International Journal of Heat and Technology, 34(S2), S189-S198. DOI: 10.18280/ijht.34S201.
Gurpal T., George Hochmuth S.J., Christopher J., Martinez Mark W., Parsons L.R., 2011, Accounting for the
Nutrients in Reclaimed Water for Landscape Irrigation.Agricultural & Biological Engineering, 42(12), 91-92.
Li H.S., 2016, Feasibility and prospect of urban water reuse. Low Carbon World, 53(30), 250-252.
Li L.L., Liu H.M., 2011, Application prospect of reclaimed water reuse in China. North Horticulture, 16(22),
177-179, DOI: 10.7656/j.issn.1001-0009.2011.22.058.
Liu S.F., 2014, Study on Exploitation and Utilization of Urban Water Resources in China. Charming China,
75(10), 243-243.
Pan Q., Wang F., Liu J., Yang H.Z., 2010, Shanghai area large public buildings water project cost-benefit
analysis. China Environmental Science, 30(04), 458-463.
161
Rahman M., Hagare D., Maheshwari B., 2014, Recycled water use for irrigation in urban landscape:
Understanding accumulation of salt over time. International Conference on Peri-urban Landscapes: Water,
45(2), 48-56.
Shan Q., Che M., 2011, Discussion on Biological Contact Oxidation Process. China New Technology New
Product, 24(3), 5-5, DOI: 10.13612/j.cnki.cntp.2011.03.027.
Sun Q.L., 2015, New campus landscape design of water-saving strategy analysis Fujian Forestry Science and
Technology, 32(2), 179-182, DOI: 10.13428/j.cnki.fjlk.2015.02.039.
Sun Y.J., Yu D.J., Ju P.L., Liu J.Z., Li N., 2015, Treatment of organic waste water "hydrolysis acidification
biological contact oxidation". Theoretical study of urban construction, 5(32), 355-365, DOI:
10.3969/j.issn.2095-2104.2015.32.369.
Suvanjan B., Himadri C., Alexander S., Md K.U., 2016, Convective Heat Transfer Enhancement and Entropy
Generation of Laminar Flow of Water through a Wavy Channel, International Journal of Heat and
Technology, 34(4), 727-733. DOI: 10.18280/ijht.340425.
Toor G.S., LuskReclaimed M., 2014, Reclaimed Water Use in the Landscape: What's in Reclaimed Water and
Where Does It Go?. Soil & Water Science, 17(2), 35-42.
Toor G.S., LuskReclaimed M., 2015, Water Use in the Landscape: Frequently Asked Questions about
Reclaimed Water. Soil & Water Science, 7(3), 30-35.
Wu X.K., Wang B.Y., Wang X.S., 2016, Study on the practice and benefit of water reuse in student apartments
in colleges and universities. Sichuan Building Materials, 42(9), 207-210, DOI: 10.3969/j.issn.1672-
4011.2016.09.096.
Xia B.W., Zhao B.Q., Lu Y.Y., Liu C.W., Song C.P., 2016, Drainage Radius after High Pressure Water Jet
Slotting Based on Methane Flow Field, International Journal of Heat and Technology, 34(3), 507-512. DOI:
10.18280/ijht.340323.
Yu Y.N., Zhu J., 2015, Study on the Problems and Measures of Reclaimed Water Reused for Landscape
Water in Yuanmingyuan. China Engineering Consultation, 172(1), 36-40, DOI: 10.3969/j.issn.1009-
5829.2015.01.014.
Zhao L.X., Xu Z.L., Hu X.L., Wu X.H., 2014, Studies on water quality change and water bloom prevention and
control measures of reclaimed water back to urban landscape water bodies. Beijing Water, 35(02), 11-14,
DOI: 10.3969/j.issn.1673-4637.2014.02.004.
162