Factors Influencing Wwm Performance_final

Journal of Environmental Management 90 (2009) 455e465 www.elsevier.com/locate/jenvman

Factors influencing wastewater management performance: Case study of housing estates in suburban Bangkok, Thailand Sarunya Sujaritpong*, Vilas Nitivattananon1 Urban Environmental Management Field of Study, School of Environment, Resources and Development, Asian Institute of Technology, P.O. Box 4, Klong Luang, Pathumthani 12120, Thailand Received 18 October 2006; received in revised form 3 November 2007; accepted 30 November 2007 Available online 30 January 2008

Abstract As population densities have risen and settlements become increasingly crowded, wastewater effluent volumes have, not unexpectedly, also risen. The adverse impacts of effluent from housing estates (HEs) in suburban areas of Thailand, served by local wastewater management (WWM) systems, are of particular concern. Because of this problem, which reflects the poor performance of WWM systems, it has become increasingly important that the pivotal factors that hinder WWM improvements be identified and effective solutions be proposed and implemented. The goal of the research described in this paper was to determine the critical factors influencing WWM performance at HEs in suburban Bangkok, using multiple regression analysis. Three significant factors encompassing financial, social, institutional and general aspects were identified for each type of WWM system (community centralized and onsite). For the community centralized system, the key factors were house price, type of organization managing the HE, and the attitudes of the organization. For onsite systems, the three factors were total number of house units, direct experience with water pollution and percentage of occupied houses. These findings reflect the importance of having a WWM that employs an integrated approach rather than focusing on specific aspects in isolation from other factors. WWM performance could be improved if significant factors indicating high priority concerns were to be identified and properly applied. Addressing the priority concerns could, consequently, contribute to the development of appropriate environmental management measures, plans, and policies related to HE WWM. Ó 2007 Elsevier Ltd. All rights reserved. Keywords: Environmental management; Multiple regression analysis; Performance indicator; Suburban area; Wastewater management

1. Introduction Rapid expansion of small urban centers and a high rate of growth in suburban developments are common phenomena in large cities of developing countries. Although most basic facilities have been moderately developed to accommodate residents, the expansion of conventional sewer systems to serve suburban areas has occurred at a very slow pace, or not at all, due to the high cost of wastewater services (Bakir, 2001). Through 2001, the capacity of municipal wastewater treatment facilities could only meet the needs of approximately 30% of * Corresponding author. Tel.: þ66 (0)2 5246368; fax: þ66 (0)2 5246380. E-mail addresses: [email protected] (S. Sujaritpong), vilasn@ait. ac.th (V. Nitivattananon). 1 Tel: þ66 (0)2 5245601, 5245777; fax: þ66 (0)2 5246380. 0301-4797/$ - see front matter Ó 2007 Elsevier Ltd. All rights reserved. doi:10.1016/j.jenvman.2007.11.006

the entire Bangkok Metropolitan Area (Kazmi and Furumai, 2005). Given the significant shortfalls of the major wastewater treatment system, individual onsite and small-scale, community centralized wastewater management (WWM) systems have become preferable alternatives (Parkinson and Kevin, 2003). Other than their appropriateness in terms of economy of scale, these systems also provide extra benefits which support sustainable WWM, such as reducing water input, reducing risks to humans and the environment and increasing reuse opportunities (Bakir, 2001). Successful application of localized WWMs will require several management aspects to be addressed. The World Health Organization (2000) compiled a guide to a broad classification of key concerns, including user opinions and satisfaction, community/household management issues, level of service, financial performance, materials, personnel,

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equipment and work order control. Ineffective WWM may result from a deficiency in one particular aspect or a combination of issues. At this point, the performance assessment can be used to provide baseline management status, and implemented to identify areas in need of improvement (Mbuligwe, 2004). The serious problems with existing WWM in suburban areas have been recognized in recent years. In Southeast Asia, for example, where onsite systems have been widely used, a large number of poorly functioning systems are located in areas with highly impermeable soils or high groundwater levels. Treatment plants may also be crippled by a lack of periodic desludging, or all three of these problems can occur at a single facility (Ludwig et al., 2005). Domestic wastewater volumes can be massive in the suburban areas of the Bangkok Metropolitan Region (BMR),2 where housing estates (HEs) are the main type of urban dwellings (GHB, 2005). Protection of the environment and public health from this discharge requires effective localized WWM. A review of official records of complaints from surrounding communities, as well as previous studies (Auesuwanna, 2000; Sattayapan, 2001), indicated that significant environmental impact has, or will, occur, suggesting that existing WWM is ineffective. It is clear from the existing problems that there is a need to identify the factors that influence WWM performance. Understanding these significant factors will be crucial in determining effective solutions to improve WWM. While the technical and financial aspects of WWM have often been seen as priority concerns (Wilderer and Schreff, 2000; Gray and Booker, 2003; Sarikaya et al., 2003), other concerns, such as social or institutional aspects, have not been considered as serious and have often been disregarded. However, given that integration of these latter aspects with technical and financial factors is necessary for successful management, this paper will cover all of these issues. The Nonthaburi province of BMR is an HE hotspot with over half of all projects being situated in suburban areas. The present study was conducted in Nonthaburi province as a case study. This paper begins with an explanation of the study concept and methodology, followed by a broad view of HE conditions and general characteristics of WWM in the study area. The core section of this paper presents study findings, from identification of the influential factors through multiple regression analysis. This section also explains and discusses the results gathered from performance assessment and the analysis of institutional issues, specifically in a Thailand context. The development of environmental management measures (EMMs), in accordance with the findings, is completed as a means of providing a systematic guide for addressing the problem of increasing amounts of domestic water pollution in suburban areas.

2

Bangkok Metropolitan Region (BMR) consists of Bangkok and six surrounding provinces, namely Nonthaburi, Pathumthani, Nakornpathom, Samutprakarn, and Samutsakorn.

2. Approach and methodology 2.1. Approach This paper primarily addresses community WWM in suburban areas. Numerous factors affect WWM performance (Fig. 1), and consequently an assessment of WWM performance must also examine several variables. Characteristics, potentiality and capacity of involved stakeholders, which are referred to as ‘institutional aspects’, affect not only these influencing factors but also the degrees of success for measures aimed at enhancing WWM. A given set of indicators was used to assess WWM performance. A set of hypothesized factors was categorized into general, social, financial and institutional groups. Only some of them have been found to be key elements that significantly affect community WWM, and these are the ones that should be given premier consideration when applying any measures to modify the existing system. Identification of key influential factors is very important since effort must be applied to those areas that will result in the greatest WWM improvement, for maximum effective use of available resources. Only through that process can environmental degradation, due to unsustainable WWM, be prevented or mitigated. 2.2. Methodology In Nonthaburi province, HEs established from 1992 to 2003 were located primarily in two suburban districts (Bangbuatong and Bangyai), where a high rate of real estate development has occurred. The estates in this study were classified into two main groups by type of wastewater system: onsite and community centralized. The sample size was determined and HEs were selected on the basis of the feasibility according to multiple regression analysis, an analytical technique that can be applied to find out influencing factors when the reliability of model is a major concern (Tabachnick and Fidell, 1983). Particular HEs were also selected based on how representative they were of the wider HE population. In the case of the onsite system, 30 samples were randomly selected from the total population of 142. All 33 HEs in the community centralized system were included. Using information obtained from a review of the relevant literature, WWM performance was assessed through a set of select indicators in key management areas (WHO, 2000; Balkema et al., 2002; Al-Sa’ed and Mubarak, 2006). For onsite systems, four performance indicators were selected, while 10 indicators were used to assess community centralized systems (Sujaritpong, 2006). The performance results (both continuous and discrete data) were transformed to a standard scale, with a score between 0 and 1 being assigned for each factor. A higher score represents better performance. The manner in which scores were assigned varied, depending upon the type of system and indicator (Tables 1 and 2). For some indicators, score assignment was strictly binary (essentially, ‘yes’ or ‘no’), while others were graded on three, four or five-level scales. The major source of data was a questionnaire

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Characteristics/potentiality/capacity of stakeholders

General factors

Appropriate measures

Social factors

Economic factors

Institutional factors

Influencing factors

Community WMM in suburban area

WWM performance

Performance assessment • User opinions and satisfaction • Community/household management • Level of service • Financial performance • Materials and equipment • Personnel • Work order control

Fig. 1. Overall study approach.

completed by representatives of the HE organization. Field observations and various records were also used. A number of hypothetical factors were identified according to social, financial and institutional aspects. Factors were designated as ‘general’ when they could not be grouped into any of the three specific categories. Key informant consultation was the primary technique, with a goal to screen only high, potentially influential factors. Key informants, including developers, government officers, academics and wastewater facility suppliers and service providers, were asked to select only one factor from each of the four groups as, in their own mind, the most influential factor. Those that were not ranked as a top influential factor by any respondents were eliminated at this stage. Consequently, a questionnaire survey was designed to be inclusive of all of the selected factors that were likely to be important to at least some individuals, resulting in relevant data that could be used for multiple regression analysis. Multiple regression analysis was utilized to determine which factors exert the greatest influence on WWM performance, as well as their cross-relationships, by assigning survey data as independent variables and performance assessment results as dependent variables. In this case, overall performance results, created by summing the assessment results of every management aspect, were used as dependent variables. Since each aspect may affect overall performance at different levels, ‘‘weighing’’ trials were employed to examine the relative importance (thus, ‘‘weight’’) of individual aspects and overall performance. The trials were based on three alternatives, the first being a simple assumption of giving equal importance to the assessment results through each performance indicator. The second one was based on giving equal

value to the management aspects that produced high values of the adjusted coefficient of determination (adjusted R2) and model utility (F-test). This method can produce a valid and reliable model. Weighing for the third alternative was conducted by considering the logic of WWM concepts and practices. 3. Description of HEs and WWM in the study area 3.1. HE conditions By the definition included in the 2000 Land Subdivision Act (LSA),3 which classified HEs by the number of house units and total area, all HE samples with onsite systems were grouped as small and medium sized, while most with community centralized systems were grouped as large. The minimum number of units for samples with an onsite system was 40, while the maximum was 500, with occupancy at 43e100%. For HE samples with a community centralized system, the number of units ranged from 182 to 4436. The occupancy rate was between 50 and 98%. Public utilities management is the main responsibility of the developers when a housing project is still under construction. When a project nears completion, an HE association is organized to take over the responsibility of public utilities management. In this study, five forms of HE organizations were identified: developer, informal HE association, developer accompanied by an informal HE association, HE legal personnel, and cooperatives. However, no organization was found in 3 Small size ¼ 99 plots or <0.03 km2; medium size ¼ 100e499 plots or 0.03e0.16 km2; large size > 500 plots or >0.16 km2.

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Table 1 Performance assessment indicators and criteria for housing estates with community centralized WWM systems Indicators

Assessment criteria

User opinions and satisfaction

Complaints from neighboring communities

0.00 ¼ Occurred <1 0.25 ¼ Occurred <1 0.50 ¼ Occurred >1 0.75 ¼ Occurred >1 1.0 ¼ No complaint

Community management

Operational practices

0.0 ¼ No operation 0.5 ¼ Inconsistent 1.0 ¼ Complete operation

Maintenance practices

0.0 ¼ No desludging 0.5 ¼ Incorrect desludging 1.0 ¼ Correct desludging

Effluent qualitya

0.0 ¼ Abnormal 0.5 ¼ Suspect 1.0 ¼ Normal

Effluent reuse

0 ¼ No reuse 1 ¼ Reuse

Financial status

Ratios of revenue and expenditure

0.00 ¼ No collection tariff 0.33 ¼ Revenue covers <50% of expenditure 0.66 ¼ Revenue covers >50% of expenditure 1.00 ¼ Revenue covers 100% of expenditure

Materials and equipment

Quality and function of machinery

0.0 ¼ Complete dysfunction 0.5 ¼ Some mechanical device dysfunction 1.0 ¼ Complete machine function

Personnel

Technician/staff availability and training

0.00 ¼ No technician/staff 0.33 ¼ No technician but some staff 0.66 ¼ With technician but untrained 1.00 ¼ Trained staff/technician and/or consultant

Work order control

Availability of WWM documentation

0.00 ¼ No document 0.25 ¼ 1 Type of document without plant manual 0.50 ¼ 1 Type of document with plant manual 0.75 ¼ 2 Types of documents 1.00 ¼ >3 Types of documents with plant manual

Monitoring program

0.00 ¼ No monitoring 0.33 ¼ Routine plant checks without effluent checks 0.66 ¼ No routine plant checks but with effluent checks 1.00 ¼ Routine plant checks and effluent checks

Level of service

a

year year year year

without any correction with correction without any correction with correction

Assessed by an inspection of the physical appearance of the effluent and/or consideration of available laboratory results.

some estates because of the failure of the association after ownership was transferred at project completion.

3.2. Characteristics of WWM Public WWM services within Nonthaburi province are able to service only part of the largest municipality. At present, there are three municipalities served by public sewer systems, but without wastewater treatment facilities (PCD, 2001). Thus wastewater collected by the sewer system, or imported from outside municipal areas, may undergo some form of pretreatment by onsite WWM systems, but is then discharged directly into public canals and eventually drained into rivers.

The provision for HE WWM and effluent standards is specified by the LSA and National Environmental Quality Act (NEQA) of 1992. According to the LSA, the wastewater from a land subdivision project has to be treated either by onsite or community centralized treatment systems, or both, and its effluent has to meet the standards enforced by NEQA. Also according to NEQA, an environmental impact assessment (EIA) is required for large land subdivision projects. However, the effectiveness of mitigation and preventive measures, relevant to the impact from wastewater, has been very poor. Only 50% of estates in the province adhered to the measures specified in the approved EIA report, and none of them have undergone the required effluent quality inspection (ONEP, 1999).

S. Sujaritpong, V. Nitivattananon / Journal of Environmental Management 90 (2009) 455e465 Table 2 Performance assessment indicators and criteria for housing estates with onsite WWM system Indicators

Assessment criteria

User opinions and satisfaction

User satisfaction

Strongly disagree to strongly agree (4 degree scale)

Household management

Maintenance practices

0 ¼ Incorrect practice 1 ¼ Correct practice

Personnel

Operation & maintenance (O & M) training

0 ¼ Never received training 1 ¼ Have received training

Overall user knowledge of O & M

Average scale from every knowledge aspect (continuous scale)

 Knowledge of type of WWTS

0 ¼ Don’t know 1 ¼ Know

 Knowledge of system maintenance

0 ¼ Don’t know 1 ¼ Know

 Knowledge of operational practices

0.00 ¼ Don’t know 0.25 ¼ 1 Answer correct 0.50 ¼ 2 Answers correct 0.75 ¼ 3 Answers correct 1.00 ¼ Complete

 Knowledge of impacts originating from incorrect maintenance

0.00 ¼ Don’t know 0.33 ¼ 1 Answer correct 0.66 ¼ 2 Answers correct 1.00 ¼ Complete

An onsite system is the typical basic sanitation method for every household in Thailand, as regulated by the Building Control Act of 1979. Not only do small and medium sized HEs have to use this system, but large estates are also required to implement it as a pretreatment system upstream of any further treatment by community centralized wastewater treatment plants. The technology used for onsite systems in almost all HE samples was a septic, anaerobic filter treatment (SAT) tank (package treatment tank). Operation of the SAT tank is automatic and very simple. It only requires users to follow a few precautions, including no flushing of non-biodegradable materials and no pouring of agents that could harm microorganisms into the tank. Periodic pumping of the septic system is a necessary maintenance practice. The community centralized system is usually implemented on large estates because the quality of discharge from onsite systems does not meet the standard. The main treatment equipment identified in this study was fixed film aeration, available as a commercial package plant. Since the community centralized system is an HE utility, it is the responsibility of the community organization. The main operational and maintenance activities are aerator control and desludging. While public utilities are managed by the developer, technicians such as electricians, mechanics and civil foremen were assigned to monitor and conduct routine maintenance on the system. In the case of an HE association, the staff member assigned to monitor the system may be an HE association committee member or

459

a security guard. Staff training and effluent monitoring programs were set up in some estates, mostly managed by the developer. There are two forms of fee collection, either uniform or varied rate, according to land size. Although most HE samples in the study were able to generate sufficient income to pay for general public utilities, only half of them allocated it for WWM costs. 4. Results and discussion 4.1. WWM performance Mean values, representing the central tendencies derived from a performance assessment of all HE samples in each management aspect, were used to represent performance level. They were categorized into three levels: poor (score 0.00e 0.33), medium (0.34e0.66), and high (0.67e1.00). For the community centralized systems, most values fell within the poor or medium range, except for complaints from neighboring communities, which exceeded 0.66 and thus was in the high range (Fig. 2). Management aspects classified as poor were maintenance practice, the monitoring system, availability of WWM documentation, management of revenue and expenditure, and effluent reuse. Issues rated as medium were operational practice, quality and function of machinery, technician/staff availability and training, and effluent quality. These findings seem to suggest that most organizations pay more attention to urgent and critical aspects, such as complaints from surrounding communities or operational practices (including machinery), rather than complicated aspects, that may be perceived as trivial, such as the availability of WWM documentation. A 0.99 J

B 0.66

0.33

I

C

0

H

D

G

E F

A Neighboring communities complaints B Operation practice C Maintenance practice D Effluent quality E Effluent reuse

F Ratios of revenue and expenditure G Quality and function of machinery H Technician/staff availability and training I Availability of WWM documentation J Monitoring program

Fig. 2. Mean values of performance results for housing estates with community centralized systems.

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A 0.99

0.66

0.33

D

0

B

C A User satisfaction B O&M activities

problems. In addition, residents do not necessarily perceive pollution as a real problem, since normal effluent flows take it downgradient, away from its point of origin. As a result, residents are largely satisfied with the WWM system. With regard to overall user knowledge of O & M, the performance result was rated as medium. As far as knowledge of the details in each of the four different performance aspects, it was discovered that although most of the respondents knew their own wastewater treatment system well (mean score ¼ 0.63), their knowledge of O & M in an onsite system was poor (mean score for knowledge of system maintenance ¼ 0.03; operational practice ¼ 0.30). This suggests that residents typically gained knowledge from their own daily experience, rather than through training, which is mostly incomplete and would explain the lack of knowledge of systems’ operations. 4.2. Factors influencing HE WWM performance

C O&M training D Overall user knowledge of WWTS type.

Fig. 3. Mean values of performance results for housing estates with onsite systems.

Data from 30 HE samples from onsite systems show that the performance results for operation and maintenance (‘O & M’) practices and training were classified as poor (Fig. 3). Resident satisfaction results fell into the medium level. These results suggest that although poor operational practices and training tend to have negative consequences for residents, they may not result in serious water pollution

Table 3 provides the details of the 12 factors within the four groups that were selected for multiple regression analysis. In accordance with the characteristics of each wastewater management system, 10 potential factors for the community centralized system, and seven for the onsite system, were considered valid. In order to identify factors that may influence performance, the general forms of two multiple regression models for the community centralized and the onsite systems are presented below as Eqs. (1) and (2), where E( pc) is WWM performance for estates with a community centralized system and E( po) is for those with onsite systems. Variable terms used in both equations are defined in Table 3.

Table 3 Potential factors and application in multiple regression analysis Factor group General

Potential factors and symbols Percentage of occupied houses (R-OCCUPY) Total house units (UNIT)b Occupying period (P-OCCUPY)b

Application in multiple regression model b

House trading (TRADING)a

Percentage of occupied houses Number of total house units Number of years that the majority of residents have occupied HE Dummy variable (1 ¼ HE is still traded and 0 ¼ otherwise)

Financial

House price (PRICE)b

Dummy variable PRICE1 (1 ¼ THB 0.8e1.5 m and 0 ¼ otherwise) PRICE2 (1 ¼ THB 1.5e3 m and 0 ¼ otherwise) PRICE3 (1 ¼ more than THB 3 m and 0 ¼ otherwise)

Social

Level of direct experience in water pollution (EXP)b

Five levels: never (0), very low and no effect (0.25), low (0.50), medium (0.75) and high (1.00). Dummy variable (1 ¼ WWM was a concern as a first environmental issues; 0 ¼ otherwise) Composite rating in terms of continuous score within range of 0e1

Concern about water pollution of resident/HE organization (R/O-CONCERN)b Attitudes of HE organization/residents to various aspects of WWM (PARTICIPATE)a Participation level of resident/HE committee regarding various HE activities (R/O-ATTITUDE)b Institutional

a b

Type of organization managing HE (ORG)a

Community centralized system. Community centralized and onsite systems.

Five levels: strong negative (0), negative (0.25), neutral (0.50), positive (0.75) and strong positive (1.00) Dummy variable ORG1 (1 ¼ HE association; 0 ¼ otherwise) ORG2 (1 ¼ developer; 0 ¼ otherwise)

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Eðpc Þ ¼ b0 þ b1 ðPRICE1Þ þ b2 ðPRICE2Þ þ b3 ðPRICE3Þ þ b4 ðR-OCCUPYÞ þ b5 ðEXPÞ þ b6 ðO-CONCERNÞ þ b7 ðPARTICIPATEÞ þ b8 ðORG1Þ þ b9 ðORG2Þ þ b10 ðO-ATTITUDEÞ þ b11 ðP-OCCUPYÞ þ b12 ðUNITÞ þ b13 ðTRADINGÞ

ð1Þ

Eðpo Þ ¼ b0 þ b1 ðPRICE1Þ þ b2 ðPRICE2Þ þ b3 ðPRICE3Þ þ b4 ðR-OCCUPYÞ þ b5 ðEXPÞ þ b6 ðR-CONCERNÞ þ b7 ðR-ATTITUDEÞ þ b8 ðP-OCCUPYÞ þ b9 ðUNITÞ

a high adjusted R2 (representing a high correlation between dependent and independent variables) and significant response as determined using an F-test (measuring the reliability of the model), and also excluding the least possible number of factors, was selected for further use. At this step, the overall performance level was the average score of all management aspects (called Alternative 1). In Step 2, the overall performance results from three weighing alternatives were entered for selection of the model. They were compared to investigate the weighing variation impact on significant factor identification before drawing conclusions as to which factors should be considered the most significant.

ð2Þ

According to the methodology for weighing trials, there were three alternatives for both systems (Table 4). For the third alternative to the community centralized system, the assigned weight was based on giving priority to effluent quality and complaints from neighboring communities. However, complaints were regarded as being of lower importance (30%) than effluent quality (50%) because, in some instances, although HE discharge was poorly treated, there was no community nearby, and thus no residents to complain. For the third alternative to the onsite system, if low environmental degradation was the goal, resident satisfaction was placed as the lowest priority because the majority of HE residents were satisfied with their WWM despite poor effluent quality. Thus, double weighing was applied to high priority management aspects. In order to identify the significant factors that influence WWM performance, a two-step approach in multiple regression analysis was conducted. In Step 1, completed regression and parsimonious models were examined and compared to identify the most representative model. The model with

4.2.1. Community centralized system Table 5 presents the Model CA-1, consisting of nine factors (not including level of direct experience in water pollution), as the most suitable model due to its strong correlation of overall WWM performance with several factors. The parsimonious model presented higher significance levels in most factors than the completed model. Further, overall performance results of the three weighted alternatives to the selected model suggest that models generated using results from Alternatives 1 and 2 did not differ much, while Model CA-3 generated from Alternative 3 provided slightly distinct results, with a higher adjusted R2 value and a lower number of significant factors. Changing the weight of each management aspect based on the few assumptions in this study did not have any demonstrable effect on model characteristics, even in extreme cases like

Table 5 Regression analysis results for housing estates with a community centralized system Variables

Table 4 Weighing trial for WWM performance Management aspect Community centralized system Operational activities Maintenance activities Monitoring program Quality and function of machinery Availability of WWM documentation Technician/staff availability and training Effluent reuse Ratio of revenue and expenditure Effluent quality Complaints from neighboring communities Onsite system O & M practices O & M training User satisfaction Overall user knowledge of O & M

461

Model CAa-1b

t-Value

Standard coefficient Alternative Alternative Alternative 1 (%) 2 (%) 3 (%) 10 10 10 10

20 0 20 20

2.5 2.5 2.5 2.5

10

20

2.5

10

0

2.5

10 10 10 10

0 0 20 0

2.5 2.5 50 30

25 25 25 25

0 33.3 33.3 33.3

28.5 28.5 14.5 28.5

PRICE1 PRICE2 PRICE3 R-OCCUPY EXP O-CONCERN PARTICIPATE ORG1 ORG2 O-ATTITUDE P-OCCUPY UNIT TRADING Adjusted R2 F-test

t-Value

Standard coefficient

0.151 0.031 0.389*** 0.155

1.150 0.256 3.019 1.458

e

e

0.129 0.180 0.588** 0.069 0.535*** 0.241 0.242 0.207

1.134 0.976 2.430 0.411 3.734 1.843 1.655 1.168

0.724 8.003***

Model CA-3c

0.171 0.016 0.360*** 0.066 e 0.070 0.101 0.250 0.193 0.585** 0.072 0.032 0.132

1.377 0.142 2.956 0.655 e 0.646 0.577 1.094 1.223 4.318 0.585 0.232 0.788

0.753 9.151***

**Significant at a ¼ 0.05. ***Significant at a ¼ 0.01. a Model C means model of community centralized WWM. b Model CA-1 is generated by using the overall performance result from Alternative 1 (in Table 4). c Model CA-3 is generated by using the overall performance result from Alternative 3 (in Table 4).

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Alternative 3 where a rather high weight was given to one aspect. Given this response, it can be presumed that there is a relatively close association between individual management aspects and the set of factors evaluated in this study, so that emphasizing any one aspect over another is not critical to the whole outcome. However, assigning a very high weight to a particular management aspect that appears to have little correlation with a set of factors can affect the overall relationship between WWM performance and those factors. Model CA-1 is preferred for drawing conclusions from the significant influential factors because (1) it places importance on every aspect of management performance, (2) it shows a strong relationship (adj. R2 ¼ 0.72) between a set of selected factors and WWM performance, and (3) several significant ( p  0.05), valid factors are included. When an alpha level of at least 0.05 is used as the significance benchmark, three significant factors are indicated in the regression analysis, including two qualitative factors (house price and type of organization managing HE) and one quantitative factor (attitudes of the HE organization to various aspects of WWM). House price is a significant factor, although the relationship with WWM performance is somewhat inconsistent. Higherpriced housing is correlated with better WWM performance. More expensive estates can collect more revenue for public utilities funds. If the fund is large enough such that part of the money can be budgeted for O & M expenses, results will be better. With respect to the type of organization managing the public facilities, a negative correlation was found between HE association and WWM performance. Given their potential in terms of quality and quantity of technicians and financial status, it is not surprising that developers can manage wastewater systems better than HE associations. An HE managed by an association, depending only on the experience of responsible staff without additional training, likely leads to poor management performance. Another important social factor that is a persistent concern, relative to environmental management, is the attitude that people have toward environmental problems. The results of the regression analysis, which showed a positive correlation between this factor and WWM performance, confirm that the attitudes of the organization toward various aspects of wastewater treatment can indeed enhance overall performance. 4.2.2. Onsite system The regression analysis results for samples from the onsite system in this study are presented in Table 6. Compared with a completed model, the parsimonious model (Model OA-1) consisting of four factors (without PRICE, R-CONCERN and P-OCCUPY variables), was the better model since the adjusted R2 improved by roughly 43%. In addition, the accuracy in determining WWM performance from information based on a given set of factors also showed statistically significant improvement (a ¼ 0.05). The trial exercise of the selected model with three weighing alternatives distinguished the results of Alternative 2 from results of the other alternatives. In Model OA-2, O & M practice aspects that did not correlate well

Table 6 Regression analysis results for housing estates with onsite systems Variables

Model OaA-1b

t-Value

Standard coefficient PRICE1 PRICE2 PRICE3 R-CONCERN P-OCCUPY R-OCCUPY EXP R-ATTITUDE UNIT Adjusted R2 F-test

Model OA-2c

t-Value

Standard coefficient

e e e e e

e e e e e

e e e e e

e e e e e

0.436** 0.225 0.253 0.411**

2.502 1.385 0.166 2.366

0.486*** 0.370** 0.191 0.375**

2.957 2.417 1.144 2.290

0.262 3.577***

0.344 4.809***

**Significant at a ¼ 0.05. ***Significant at a ¼ 0.01. a Model O means model of onsite WWM. b Model OA-1 is generated by using the overall performance result from Alternative 1 (in Table 4). c Model OA-2 is generated by using the overall performance result from Alternative 2 (in Table 4).

with WWM performance were omitted, resulting in (1) an increase in the adjusted R2 to 0.344, (2) a change in significant level from 0.05 to 0.01 for ‘percentage of occupied houses’, and (3) addition of another significant factor, namely ‘level of direct experience in water pollution’, at p < 0.05. The adjusted R2 values obtained from the models for the onsite system were not high compared with the community centralized system. A set of potential factors is correlated moderately with WWM performance based on information obtained in this study. Although removing a poorly performing indicator could somewhat improve the apparent correlation, the correlation remained relatively weak due to the limited number of indicators. Thus, the level of correlation can probably be improved by identifying and adding more indicators in order to obtain a more accurate assessment of performance. It is possible that this study did not take into account certain factors that may play a substantive role in determining onsite performance. Some of those potential factors include homeowner education level, members per household, accessibility to septage pumping services and toilet use. Embracing these factors could improve the correlation analyses. Since Model OA-2 provided the highest possible level of correlation between onsite system performance and a number of significant factors, additional discussion of this model is warranted. In this model there are three significant quantitative factors: the percentage of occupied houses, the level of direct experience in water pollution and the number of total house units. Percentage of occupied houses correlated positively with WWM performance. Conversely, the other two factors were inversely related to performance. A higher percentage of occupied houses means more revenue that can be spent on public facility management, including WWM systems. Moreover, development companies that operate upon an ethical and responsible foundation, providing good quality units, a properly functioning sanitation system, well-maintained

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grounds and agreeable after-sales service, will be more likely to see a higher rate of occupancy in their estates. Hence, provisions that encourage and ensure good sanitation and wastewater practices should facilitate progress toward adequate and effective WWM by improving the desirability and occupancy, and ultimately the revenue, of HEs. Interestingly, performance appears to worsen as the degree of direct experience in water pollution rises. While this would seem to counterintuitive, an explanation exists. In general, performance from onsite WWM is usually at its worst when the system has been in use for a long period of time, especially when sludge pumping has been ignored. For estates constructed some time ago, certain effluent parameters may exceed the recommended quality standards, and residents may perceive the lower quality through detection of unpleasant odors and poor water color. Nonetheless, the reason residents ignore sound WWM is that it is of little immediate concern to them. This is in sharp contrast to new HEs with onsite WWTS still functioning efficiently. At these locations, residents are never exposed to polluted water. There is an inverse relationship between number of house units and WWM performance. This relationship is understandable since not only would the number of houses tend to rise as the HE ages, but increased wastewater discharge into an aging treatment system would, no doubt, lead to capacity exceedance and poor overall performance. It is possible that the number of house units does not influence WWM performance in newly established housing estates because the system still functions very well and is able to handle all of the wastewater entering it. 4.3. Institutional issues Institutional constraints were identified through interviews and discussions with key stakeholders. Following are summaries, taken from the interviews, of the pertinent institutional problems and issues relating to HE WWM. 4.3.1. Inadequate monitoring and enforcement Self-monitoring has already been in place for certain organizations, especially large HEs requiring EIA. But due to the lack of direct legal consequences and clear responsibility among authorities, HE organizations often neglect implementation of the required monitoring programs.

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4.3.3. Inadequate capabilities of responsible agencies It was discovered that a lack of technical knowledge associated with WWM is common in most related agencies. Because of the introduction in recent years of a decentralization policy, aimed at empowering and transferring authority from the central to the local level, local government authorities (LGAs) are forced to take on several tasks and responsibilities, for which they may have had inadequate training and/or lack critical knowledge. In this transitional period, training and capacity building are critically needed. 4.3.4. Lack of interest in WWM from LGAs and HE residents Because many aspects of the environmental impacts associated with poor WWM and degraded water quality in suburban areas are not explicitly apparent, LGAs and HE residents often pay little attention. Meanwhile those environmental issues with readily observable consequences, such as solid waste management, water supply provisions and flood prevention, receive more attention from LGAs and HE residents. If residents do not show interest in WWM and do not vocalize their concerns to local authorities, inadequate budgeting is likely. 4.3.5. Inadequate budgets for HE management In the case of HE associations, a limited budget is often spent on activities that are more ‘‘visible’’ and perceived as having substantial impacts on the quality of life, such as safety, security and cleanness. Likewise, in some instances there are sufficient funds to manage public utilities, but none are allocated to WWM, because the effects of ignoring treatment problems are often more apparent for people outside of the HE than for internal HE residents. 4.3.6. Lack of organization to take responsibility for HE public facilities management The main constraints in setting up an HE association stem from three main causes. The first is that residents lack a sense of belonging to the community, a common characteristic of people living in an urban environment. The second is the complicated process of establishing an association, especially for large estates, since it involves a lot of people. Finally, because working for an HE association is a voluntary job with no financial incentive, overall participation among residents is low. 4.4. Measures for enhancing HE WWM

4.3.2. Fragmentation among authorities This occurs within a given level of government as well as between the hierarchical ‘‘chain of command.’’ At the same level, inadequate cooperation among different units occurred, which causes confusion and near paralysis since many parties have to take responsibility for different aspects, even though the ultimate goal is the same. For example, one unit may be responsible for providing construction permits, while another unit has to follow-up on the potential impacts after the permit has been granted. Fragmentation between different levels of government is particularly evident in the inadequate assistance among central and local governments.

In this section, three main kinds of EMM are considered e regulatory, economic and moral persuasive measures (Field and Field, 2002), as a response to the findings previously described within three different dimensions (poor management aspects, key influencing factors and institutional issues). There are several potential measures, which can address at least two dimensions for each type of EMM, such as effluent standards, tax incentives and an awareness campaign. More information about such potential measures, including measure objectives, possible actions, defined target group and the expected results, is provided in Table 7.

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Table 7 Potential actions for responding to different dimensions e influencing factors, performance aspects and institutional issues Potential actions

Response to

Community Onsite centralized system system

Effluent standard (regulatory measure)

Total house units Percentage of occupied houses Reuse 2 Inadequate monitoring 3 and enforcement program

Tax incentive (economic measure)

House price Reuse O & M practices

1 1

1 2

Awareness campaign Attitudes of HE 1 (moral suasive measure) organization Type of organization 1 managing HE Direct experience in water pollution Reuse 2 O & M practices Lack of interest in WWM of LGA and HE resident

2

1

2 3

1: Key influencing factor; 2: poor performance aspect; 3: institutional issue.

4.4.1. Effluent standards Although effluent standards are implemented to control water pollution generated from real estate sources, they may be ineffective. In order to overcome shortcomings in the current standards, the necessary measures are: (1) set both qualitative and quantitative land subdivision effluent standards, (2) enhance the monitoring program for HEs requiring EIA, through enforcement of penalties, and (3) develop a monitoring program and performance assessment for HEs with onsite WWM. Specifying qualitative and quantitative effluent standards can, in the long term, produce strong incentives for developers or suppliers to search for technical and managerial alternatives to reduce the discharge volume and, where feasible, recycle the water. Standards should vary according to HE size, in order to prevent the release of large load volumes from large estates. A link between land subdivision/construction permit programs and monitoring impact mitigation measures may enhance the efficiency of the monitoring program for HEs requiring EIA. In that way, developers who have not followed mitigation measures or submitted EIA monitoring reports for prior projects would have permission for future projects suspended. In the case of situations where ownership is transferred to an HE association, other forms of enforcement can be considered, such as closing the effluent drainage gate installed at the discharge point, or limiting water supply. A monitoring program for the onsite system should also be implemented to ensure that domestic wastewater is handled properly. Since a common monitoring program geared toward effluent quality is not well suited to individual households, inspection of onsite treatment devices and desludging practice controls are proposed as alternative or additional measures.

4.4.2. Tax incentives Tax incentives can improve WWM performance by (1) reducing O & M costs, particularly for lower-priced HEs, by persuading developers to implement effective, inexpensive O & M technology, (2) inducing the developer to initiate and construct an effluent reuse system, and (3) encouraging private contractors to invest in desludging services. With the encouragement of a tax incentive, developers are more likely to make strategic choices that will result in longterm O & M benefits for residents. For the tax incentive to be efficient, a tax reduction has to be attractively designed to, at a minimum, compensate developers for an initial higher monetary commitment that will result in an alternative O & M system with lower long-term costs. Incentives can be imposed through business, property or value-added taxes, which developers have to pay to the authorities. A tax incentive with a similar concept can also be applied to improve the performance of effluent reuse management. The incentive has to be designed properly in order to motivate developers to install a simple reuse system. But a tax incentive measure alone may not be sufficient, as there is limited regulation of water reuse in developing countries. Water reuse, however, can be encouraged and strengthened by a combination of measures. For example, effluent discharge fees can be levied based on quantity, which may have the duel impact of reducing discharge volume and encouraging reuse programs. 4.4.3. Awareness campaign An awareness campaign should be conducted in order to communicate with, and mobilize, residents. For an HE with the community centralized WWM, an awareness campaign would promote the benefits of (1) improved WWM as a whole and, specifically, effluent reuse, and (2) establish an HE association not only for successful WWM but also for the general improvement of many aspects of everyday life for the residents. The target groups of this measure are both the developer and HE organization. There are many ways of encouraging people through awareness campaigns, for example, initiating a demonstration project using actual situations and experiences. This can stimulate a wider interest in the benefits of good WWM, rewarding good practices and stimulating peoples’ sense of duty. Another system that may be effective is notifying the public about the presence of pollution sources through, say, a color-coded rating system, similar to an innovative program used in Indonesia to control water pollution from the industrial sector (Asikin, 1999). For the onsite system, a campaign should communicate, to all system users, the adverse impacts of improper O & M practices on local water sources and community health. The campaign could be executed directly through distributing brochures and leaflets with simple O & M practice guidelines. LGAs should take the initiative in launching an awareness campaign like this. Another approach that LGAs could be involved in, would be to go through developers, who could advise homeowners on how to properly look after their system, and also make direct contact with new

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homeowners before, or soon after, they have occupied a dwelling.

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agencies not only in the WWM sector but also, with adjustments for localized conditions and perspectives, to overall environmental management.

5. Conclusions and recommendations In this study, multiple regression analysis was used to identify key factors that influence housing estate WWM performance. The factors that were assessed encompass general, social, financial and institutional aspects. The study results suggest that, in the context of suburban communities in Thailand, performance improvement can be expected if the factors (house price, type of organization managing the HE, attitudes of the organization for community centralized systems and total house units, direct experience in water pollution and water treatment and percentage of occupied houses for onsite systems) are considered with earnest. The correlation between a set of factors and overall WWM performance results, as measured by the coefficient of determination (R2), was found to be rather high for HEs with community centralized WWM, but only medium for HEs with an onsite system. The difference in correlation values may be artifactual as a result of the disparity in the number and range of management aspects affecting indicators between the two systems. Half of the performance aspects assessed in this study were classified as poor. There are several institutional factors that act as barriers to improvement in community WWM, including inadequate monitoring and enforcement, fragmentation and poor communication among authorities, inadequate capacity of responsible agencies, lack of interest in WWM from LGAs and HE residents, lack of organization for monitoring and maintenance of public facilities and insufficient funds for WWM in HE management. In order to address the findings of this study, three potential EMMs e effluent standards, tax incentives and awareness campaigns e were selected as having a high potential for improving performance. In spite of the fact that most developing countries tend to use decentralized WWM systems in suburban areas, there is a lack of initiative in terms of management at the community/household level. Therefore, more research is required to cope with not only technical but also social and institutional concerns, in order to achieve sustainable environmental sanitation solutions. The significant factors that were identified in this study, and the methodology used to identify them, may be of use in similar situations, particularly suburban areas, where domestic water pollution problems dictate the need for assessment and development of more effective policies and management strategies. Although conducted in the context of HE WWM in Thailand, the present study could have broader applications, providing insights to both practical and research challenges. The systematic approach used in this study, involving performance assessment, identification of significant, influential factors and application of management measures, is expected to be valid and beneficial for concerned

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